Friday, April 13, 2007

MESO: Mesoscale Discussion 0486

ACUS11 KWNS 140355
SWOMCD
SPC MCD 140355
TNZ000-MSZ000-ARZ000-LAZ000-140530-

MESOSCALE DISCUSSION 0486
NWS STORM PREDICTION CENTER NORMAN OK
1055 PM CDT FRI APR 13 2007

AREAS AFFECTED...CNTRL AND ERN AR/FAR WRN MS/NRN LA

CONCERNING...SEVERE THUNDERSTORM WATCH 137...

VALID 140355Z - 140530Z

THE MAIN SEVERE THREAT FOR WW 137 APPEARS TO BE ACROSS CNTRL/ERN AR
WITH A DIMINISHING THREAT ACROSS WCNTRL AR.

LATEST RADAR LOOPS SHOW STRONGEST STORMS IN WW 137 NOW OVER
CNTRL/ERN AR...WITH ANOTHER LINE OF STORMS MOVING THROUGH SE OK. THE
OK STORMS HAVE WEAKENED SINCE THEY HAVE MOVED EAST FROM CNTRL
PORTIONS OF OK...WHERE A FEW REPORTS OF SEVERE HAIL WERE RECEIVED
EARLIER THIS EVENING. SEVERE THREAT APPEARS TO BE DIMINISHING ACROSS
WCNTRL AR...WHERE THE ENVIRONMENT HAS BEEN WORKED OVER FROM PREVIOUS
STORMS.

SFC WARM FRONT IS ANALYZED JUST SOUTH OF LBR EWD TO SHV TO MLU WITH
THE 850MB WARM FRONT BETWEEN LIT/SGF PER 00Z UPPER AIR DATA. AXIS OF
STRONG LOW LEVEL WARM/MOISTURE ADVECTION CONTINUES ACROSS CNTRL
AR/NRN LA WHERE LATEST VAD WIND DATA FROM LITTLE ROCK AND SHREVEPORT
INDICATE 50-60 KT OF FLOW ABOVE 1-2 KM...AND EFFECTIVE DEEP LAYER
SHEAR VALUES IN EXCESS OF 60 KT.

FORCING FOR ASCENT WILL LIKEWISE CONTINUE THROUGH THE EARLY MORNING
HOURS ACROSS AR/LA...AS CLOSED UPPER LOW APPROACHES. LOW LEVEL JET
WILL SHIFT EWD TOWARD THE MS RIVER BETWEEN 06-09Z...WITH A GRADUAL
WEAKENING TREND FOR STORMS THROUGH MIDNIGHT.

.TAYLOR.. 04/14/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MEG...JAN...LZK...SHV...

33219245 33589327 35409235 35569166 35199041 35109021
33039025 33009136

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MESO: Mesoscale Discussion 0485

ACUS11 KWNS 140254
SWOMCD
SPC MCD 140254
TXZ000-140500-

MESOSCALE DISCUSSION 0485
NWS STORM PREDICTION CENTER NORMAN OK
0954 PM CDT FRI APR 13 2007

AREAS AFFECTED...TX HILL COUNTRY...LOWER RIO GRANDE VALLEY INTO
MIDDLE/LOWER TX COAST

CONCERNING...TORNADO WATCH 138...

VALID 140254Z - 140500Z

POTENTIAL FOR MAINLY LARGE HAIL AND LOCALLY DAMAGING WINDS IS
EXPECTED TO CONTINUE THROUGH 04Z. THEREAFTER...STORMS MAY TEND TO
WEAKEN AS THEY APPROACH ERN EDGE OF WW 138.

AS OF 0240Z...SAN ANTONIO RADAR IMAGERY INDICATED A CLUSTER OF
STRONG TO SEVERE TSTMS OVER HAYS...CALDWELL...COMAL...GUADALUPE AND
BEXAR COUNTIES...WITH THE SRN MOST STORM EXHIBITING SUPERCELL
CHARACTERISTICS AS IT MOVES THROUGH THE SAN ANTONIO METRO AREA.
INFLOW AIR MASS REMAINS QUITE MOIST WITH DEWPOINTS IN THE LOWER
70S...EFFECTIVELY CONTRIBUTING TO MLCAPES OF 1000-1500 J/KG.

00Z SOUNDINGS FROM BRO AND CRP INDICATED THAT BOUNDARY LAYER OVER
THE MID AND LOWER TX COAST WAS RELATIVELY SHALLOW WITH A
CONSIDERABLE CAP OBSERVED IN THE 900-700 MB LAYER. CURRENT THINKING
IS THAT ONGOING STORMS MAY TEND TO WEAKEN BY 04Z AS THEY CONTINUE
ESEWD INTO THE PROGRESSIVELY MORE CAPPED AIR MASS. HOWEVER PRIOR TO
THIS TIME...STORM-RELATIVE INFLOW OF AROUND 50 KT COUPLED WITH
NON-HYDROSTATIC PRESSURE GRADIENT FORCE ATTENDANT TO SUPERCELL
UPDRAFT SHOULD HELP SUSTAIN THE SRN STORM FOR A PERIOD OF TIME AS IT
ENCOUNTERS A MORE HOSTILE THERMODYNAMIC ENVIRONMENT.

.MEAD.. 04/14/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...HGX...FWD...CRP...EWX...SJT...

31199833 30889720 30199649 29819647 29259652 28519763
28489997 28080007 28140038 29290098 30929929

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WATCHES: Tornado Watch - Number 135

WWUS20 KWNS 140240
SEL5
SPC WW 140240
TXZ000-140500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH - NUMBER 135
NWS STORM PREDICTION CENTER NORMAN OK
940 PM CDT FRI APR 13 2007

THE NWS STORM PREDICTION CENTER HAS CANCELLED
TORNADO WATCH NUMBER 135 ISSUED AT 325 PM CDT FOR PORTIONS OF

TEXAS

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MESO: Mesoscale Discussion 0484

ACUS11 KWNS 140142
SWOMCD
SPC MCD 140142
LAZ000-ARZ000-TXZ000-OKZ000-140345-

MESOSCALE DISCUSSION 0484
NWS STORM PREDICTION CENTER NORMAN OK
0842 PM CDT FRI APR 13 2007

AREAS AFFECTED...ERN TX INTO WRN AND CNTRL LA

CONCERNING...TORNADO WATCH 135...136...

VALID 140142Z - 140345Z

THROUGH 03-04Z...THE GREATEST TORNADO THREATS APPEAR TO BE: 1) WITH
PORTION OF BROKEN CONVECTIVE LINE INTERACTING WITH WARM FRONT FROM
HOPKINS...RAINS AND VAN ZANDT COUNTIES TX EWD TO NEAR GGG. AND...2)
OVER CNTRL LA /NEAR AND NE OF POE/ AS STORMS FURTHER INTENSIFY ALONG
WARM FRONT. ELSEWHERE...THE SEVERE WEATHER THREAT FOR TORNADO WATCH
135...136...CONTINUES.

01Z MESOANALYSIS INDICATED SURFACE LOWS N OF CRS AND NNE OF HDO WITH
COLD FRONT EXTENDING SWWD FROM THIS NRN LOW THROUGH THE HILL COUNTY
TO SE OF DRT. MEANWHILE...NRN MOST WARM OR QUASI-STATIONARY
BOUNDARY EXTENDED EWD FROM THE LOW N OF CRS TO NEAR SHV INTO CNTRL
MS N OF JAN. A SECONDARY WARM FRONT /DELINEATING THE RICHEST
BOUNDARY LAYER AIR MASS/ STRETCHED MORE SEWD FROM THIS NRN LOW TO N
OF LFK TO N OF POE INTO S-CNTRL LA.

CONVECTIVE LINE FORCED ALONG COLD FRONT CONTINUES TO FEATURE HP
SUPERCELL TYPE COMPLEX ON NRN END OVER HUNT...HOPKINS AND RAINS
COUNTIES TX INVOF SURFACE LOW AND WARM/COLD FRONTAL TRIPLE POINT.
BASED ON CURRENT MOTION...THIS STORM SHOULD BEGIN TO WEAKEN WITH
TIME OR BECOME PROGRESSIVELY MORE ELEVATED AS IT ENCOUNTERS MORE
STABLE...SURFACE-BASED AIR MASS IN PLACE OVER FAR NERN TX. OTHER
STORMS IN PROGRESS ALONG CONVECTIVE LINE WILL HAVE THE POTENTIAL TO
DEVELOP STRONG LOW-LEVEL ROTATION AS THEY PROGRESS EWD AND ENCOUNTER
ENHANCED NEAR GROUND SHEAR INVOF RETREATING WARM FRONTS.

FARTHER TO THE SE...MORE DISCRETE CONVECTIVE INITIATION HAS OCCURRED
OVER THE PAST 1 TO 2 HOURS INVOF SRN MOST WARM FRONT OVER W-CNTRL LA
WITHIN ENVIRONMENT QUITE FAVORABLE FOR SUPERCELL AND TORNADOES /REF.
00Z SHV AND LCH SOUNDINGS/. ANY OF THESE STORMS THAT CAN BECOME
SUSTAINED OVER E-CNTRL/SE TX INTO SWRN INTO CNTRL LA WILL HAVE A
HIGH POTENTIAL TO PRODUCE TORNADOES...A FEW OF WHICH COULD BE
SIGNIFICANT.

.MEAD.. 04/14/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...JAN...LZK...LCH...SHV...TSA...HGX...FWD...OUN...EWX...SJT...

29809643 31429930 34189749 34029464 33359202 32209164
31129188 30219260 29999373

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WATCHES: Severe Thunderstorm Watch - Number 134

WWUS20 KWNS 140103
SEL4
SPC WW 140103
OKZ000-140100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH - NUMBER 134
NWS STORM PREDICTION CENTER NORMAN OK
803 PM CDT FRI APR 13 2007

THE NWS STORM PREDICTION CENTER HAS CANCELLED
SEVERE THUNDERSTORM WATCH NUMBER 134 ISSUED AT 200 PM CDT FOR PORTIONS OF

OKLAHOMA

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 140100
SWODY1
SPC AC 140058

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0758 PM CDT FRI APR 13 2007

VALID 140100Z - 141200Z

..THERE IS A HIGH RISK OF SVR TSTMS FROM A PORTION OF NERN TX INTO
NWRN AND W CNTRL LA...

..THERE IS A MDT RISK OF SVR TSTMS FROM PARTS OF CNTRL AND ERN TX
INTO LA...

..THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF THE ERN HALF OF
TX...SERN OK THROUGH THE LOWER MS VALLEY...

..S CNTRL THROUGH NERN TX...SERN OK AND THE LOWER MS VALLEY...

A COLD FRONT EXTENDS FROM N CNTRL TX SWWD THROUGH CNTRL TX AND
FARTHER SW TO NEAR DEL RIO. A WARM FRONT EXTENDS EWD THROUGH NERN
TX...NRN LA AND CNTRL MS. BOUNDARY LAYER DEWPOINTS IN THE UPPER 60S
HAVE ADVECTED AS FAR N AS CNTRL AND E CNTRL TX INTO CNTRL LA BENEATH
STEEP 700-500 MB LAPSE RATES. THIS HAS RESULTED IN MLCAPE FROM 2500
J/KG OVER S CNTRL TX TO NEAR 1000 J/KG OVER ERN TX THROUGH CNTRL AND
SRN LA DESPITE WIDESPREAD LOW CLOUDS IN THAT AREA. N OF WARM FRONT
THROUGH ERN OK AND AR...INSTABILITY REMAINS ELEVATED WITH MUCAPE
FROM 1000 TO 2500 J/KG.

LOW LEVEL JET WILL STRENGTHEN OVER ERN TX AND THE LOWER MS VALLEY
THIS EVENING DOWNSTREAM FROM ERN ADVANCING UPPER TROUGH. THIS WILL
MAINTAIN INFLUX OF UPPER 60S DEWPOINTS THROUGH ERN TX AND THE LOWER
MS VALLEY AND PROMOTE A SLOW NWD RETREAT OF THE WARM FRONT. STORMS
CONTINUE DEVELOPING ALONG EWD ADVANCING COLD FRONT FROM NERN TX SWWD
TO JUST NE OF DEL RIO. STORMS WITHIN THE LINE CONTAIN MIXED MODES
WITH BOTH SUPERCELL STRUCTURES AND LINE SEGMENTS. SUPERCELL THAT
PRODUCED A TORNADO EARLIER IN THE DALLAS/FORT WORTH AREA REMAINS
INTENSE AND IS MOVING INTO NERN TX. DAMAGING WIND...VERY LARGE HAIL
AND A FEW TORNADOES WILL REMAIN POSSIBLE WITH STORMS WITHIN THE LINE
AS IT ADVANCES EWD THROUGH TX THIS EVENING.

FARTHER EAST...OTHER STORMS ARE DEVELOPING ALONG WARM CONVEYOR BELT
WITHIN ZONE OF WARM ADVECTION AND ISENTROPIC ASCENT ASSOCIATED WITH
THE LOW LEVEL JET FROM SERN TX THROUGH WRN LA AND FARTHER NWD INTO
AR. STORMS IN AR ARE ELEVATED N OF THE WARM FRONT. HOWEVER...THE 00Z
SHREVEPORT RAOB SHOWS 8C/KM MID LEVEL LAPSE RATES...SUBSTANTIAL
MUCAPE AND CLOUD LAYER SHEAR SUFFICIENT FOR ROTATING UPDRAFTS. LARGE
HAIL WILL BE THE MAIN THREAT WITH THIS ACTIVITY. FARTHER S ALONG THE
WARM CONVEYOR BELT...STORMS ARE EXPECTED TO GRADUALLY INTENSIFY AS
THE BOUNDARY LAYER MOISTENS AND DESTABILIZES NWD. FORECAST SOUNDINGS
SHOW LARGE LOW LEVEL HODOGRAPHS AND STORM RELATIVE HELICITY IN
VICINITY OF THE LOW LEVEL JET WITH EFFECTIVE INFLOW LAYER BASES NEAR
THE SURFACE WHERE DEWPOINTS ARE IN THE UPPER 60S. POTENTIAL WILL
EXIST FOR A FEW SUPERCELLS CAPABLE OF PRODUCING STRONG TORNADOES
WITH THIS ACTIVITY THIS EVENING AND INTO THE OVERNIGHT. HAVE SHIFTED
THE HIGH RISK A LITTLE FARTHER EAST INTO LA TO ACCOUNT FOR THIS
POSSIBILITY.

.DIAL.. 04/14/2007

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WATCHES: Tornado Watch - Number 133

WWUS20 KWNS 140003
SEL3
SPC WW 140003
TXZ000-140000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH - NUMBER 133
NWS STORM PREDICTION CENTER NORMAN OK
703 PM CDT FRI APR 13 2007

THE NWS STORM PREDICTION CENTER HAS CANCELLED
TORNADO WATCH NUMBER 133 ISSUED AT 1230 PM CDT FOR PORTIONS OF

TEXAS

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WATCHES: Tornado Watch Number 138

WWUS20 KWNS 132325
SEL8
SPC WW 132325
TXZ000-140700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 138
NWS STORM PREDICTION CENTER NORMAN OK
625 PM CDT FRI APR 13 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

SOUTH CENTRAL TEXAS

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 625 PM
UNTIL 200 AM CDT.

TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 95 STATUTE
MILES EAST AND WEST OF A LINE FROM 45 MILES NORTH OF AUSTIN TEXAS
TO 50 MILES SOUTH SOUTHEAST OF HONDO TEXAS. FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU8).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 133...WW 134...WW
135...WW 136...WW 137...

DISCUSSION...THUNDERSTORMS DEVELOPING ALONG/AHEAD OF COLD FRONT.
WITH MLCAPES TO 3000 J/KG AND DEEP LAYER SHEAR OF 50-60KT SUPERCELLS
ARE EXPECTED AS STORMS DEVELOP E. WHILE PRIMARY THREAT WILL BE VERY
LARGE HAIL/DAMAGING WINDS WITH MARGINAL LOW LEVEL SHEAR...THE
INSTABILITY SUPPORTS A TORNADO THREAT...PARTICULARLY EWD TOWARD THE
I-35 CORRIDOR DURING THE EVENING.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 26035.


..HALES

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WATCHES: Severe Thunderstorm Watch Number 137

WWUS20 KWNS 132300
SEL7
SPC WW 132300
ARZ000-MSZ000-140700-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 137
NWS STORM PREDICTION CENTER NORMAN OK
600 PM CDT FRI APR 13 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CENTRAL AND SOUTHERN ARKANSAS
NORTHWESTERN MISSISSIPPI

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 600 PM
UNTIL 200 AM CDT.

HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES NORTH OF DE
QUEEN ARKANSAS TO 65 MILES NORTHEAST OF GREENVILLE MISSISSIPPI.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU7).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 133...WW 134...WW
135...WW 136...

DISCUSSION...ELEVATED TSTMS INTENSIFYING OVER NRN LA ARE EXPECTED TO
EXPAND IN COVERAGE THIS EVENING AS 50-55 KT LLJ DEVELOPS NEWD INTO
THE LOWER MS VALLEY. MUCAPES OF 1000-1500 J/KG COUPLED WITH STRONG
SHEAR THROUGH THE CLOUD BEARING LAYER INDICATE THE POTENTIAL FOR
ELEVATED SUPERCELLS CAPABLE OF LARGE HAIL AND PERHAPS LOCALLY
DAMAGING WINDS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 24035.


..MEAD/HALES

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MESO: Mesoscale Discussion 0483

ACUS11 KWNS 132258
SWOMCD
SPC MCD 132258
TXZ000-140000-

MESOSCALE DISCUSSION 0483
NWS STORM PREDICTION CENTER NORMAN OK
0558 PM CDT FRI APR 13 2007

AREAS AFFECTED...S CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 132258Z - 140000Z

SCATTERED STORMS ARE LIKELY TO PERSIST ALONG FRONTAL BOUNDARY AS IT
SHIFTS SEWD WITH MAINLY A LARGE HAIL AND DAMAGING WIND THREAT.
ISOLATED TORNADOES MAY OCCUR OVER ERN PORTIONS OF THE AREA WHERE LOW
LEVEL MOISTURE IS RICHER...BUT ONLY IF STORM MODE IS NON-LINEAR.

STRONG INSTABILITY EXIST AHEAD OF THE COLD FRONT WHERE SIGNIFICANT
SURFACE HEATING HAS TAKEN PLACE. ALTHOUGH DEWPOINTS HAVE MIXED OUT
INTO THE 50S WITHIN PRE FRONTAL TROUGH...STRONG COOLING ALOFT AND
STEEP LAPSE RATES SHOULD ALLOW FOR MINIMAL CIN FOR SEVERAL HOURS.
THUS...STORMS SHOULD PERSIST ALONG FRONT AS IT CONTINUES SE.

DEEP LAYER SHEAR VECTORS ARE CURRENTLY PARALLEL TO THE FRONT. THIS
WILL FOSTER MORE OF A LINEAR STORM MODE WITH DAMAGING WIND GUSTS AND
LARGE HAIL THE PRIMARY THREATS. ISOLATED TORNADOES CANNOT BE RULED
OUT FARTHER E TOWARD SAT WHERE DEWPOINTS ARE IN THE UPPER
60S...SHOULD STORMS REMAIN SEMI-CELLULAR BY THE TIME THEY GET INTO
THAT REGION.

.JEWELL.. 04/13/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FWD...EWX...SJT...

29690143 30410049 31419921 30799708 29449878 28240019
28740045 29130070

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WATCHES: Tornado Watch Number 136

WWUS20 KWNS 132245
SEL6
SPC WW 132245
ARZ000-LAZ000-TXZ000-140700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 136
NWS STORM PREDICTION CENTER NORMAN OK
545 PM CDT FRI APR 13 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

PART OF SOUTHWEST ARKANSAS
LARGE PART OF NORTHERN AND WESTERN LOUISIANA
LARGE PART OF EASTERN TEXAS

EFFECTIVE THIS FRIDAY AFTERNOON AND SATURDAY MORNING FROM 545 PM
UNTIL 200 AM CDT.

..THIS IS A PARTICULARLY DANGEROUS SITUATION...

DESTRUCTIVE TORNADOES...LARGE HAIL TO 2.5 INCHES IN DIAMETER...
THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE
POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 130 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES EAST NORTHEAST OF
TEXARKANA ARKANSAS TO 40 MILES SOUTHEAST OF HUNTSVILLE TEXAS.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU6).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 133...WW 134...WW 135...

DISCUSSION...INTENSE SQUALL LINE HAS DEVELOPED NCENTRAL TX AND WILL
CONTINUE E INTO WATCH AREA. AHEAD OF SQUALL LINE CONDITIONS ARE NOW
FAVORABLE FOR DEVELOPMENT OF SUPERCELLS ACROSS THE WATCH AREA WITH
VERY STRONG SHEAR AND INCREASINGLY MOIST AND UNSTABLE AIR MASS. THE
PARAMETERS IN PLACE SUGGEST POTENTIAL FOR STRONG TO VIOLENT
TORNADOES DEVELOPING DURING THE EVENING.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 24040.


..HALES

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MESO: Mesoscale Discussion 0482

ACUS11 KWNS 132208
SWOMCD
SPC MCD 132208
LAZ000-TXZ000-132345-

MESOSCALE DISCUSSION 0482
NWS STORM PREDICTION CENTER NORMAN OK
0508 PM CDT FRI APR 13 2007

AREAS AFFECTED...ERN TX INTO WRN LA

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 132208Z - 132345Z

SUPERCELL AND ATTENDANT TORNADO THREAT IS FORECAST TO INCREASE
ACROSS DISCUSSION AREA THROUGH 14/00Z AND A TORNADO WATCH WILL
LIKELY BE REQUIRED.

REGIONAL RADAR AND VISIBLE SATELLITE IMAGERY INDICATE THAT
CONSIDERABLE FORCING FOR ASCENT IS OCCURRING ALONG PRIMARY LLJ AXIS
AS EVIDENCED BY WEAK RETURNS OVER SERN TX TRANSITIONING TO ELEVATED
TSTMS OVER NERN TX INTO NWRN LA AS ISENTROPIC ASCENT FORCES PARCELS
TO THEIR LFC NEAR/N OF SURFACE WARM FRONT. 18Z LCH/20Z SHV OBSERVED
SOUNDINGS INDICATED A CAP IN PLACE AROUND 850 MB...HOWEVER THIS
PERSISTENT FORCING ALONG LLJ AXIS COUPLED WITH A
MOISTENING/DEEPENING BOUNDARY LAYER ARE LIKELY RESULTING IN EROSION
OF THIS FEATURE. INDEED...LATEST SHORT TERM MODEL GUIDANCE SUGGEST
THAT SURFACE-BASED TSTMS WILL BECOME INCREASINGLY LIKELY ACROSS
DISCUSSION AREA BETWEEN 13/23Z-14/03Z.

THE COMBINATION OF MLCAPES OF 1000-1500 J/KG COUPLED WITH 40-50 KT
OF EFFECTIVE BULK SHEAR AND 0-1 KM SRH OF 300-350 M2/S2 INDICATES
THE HIGH POTENTIAL FOR SUPERCELLS CAPABLE OF TORNADOES...LARGE HAIL
AND DAMAGING WINDS.

.MEAD.. 04/13/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LCH...SHV...HGX...FWD...

29219516 30249569 31499549 32219516 32599467 32639405
32609346 32029298 31119287 30439326 29869364

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WATCHES: Tornado Watch Number 135

WWUS20 KWNS 132025
SEL5
SPC WW 132025
TXZ000-140500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 135
NWS STORM PREDICTION CENTER NORMAN OK
325 PM CDT FRI APR 13 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

NORTH CENTRAL TEXAS

EFFECTIVE THIS FRIDAY AFTERNOON FROM 325 PM UNTIL MIDNIGHT CDT.

..THIS IS A PARTICULARLY DANGEROUS SITUATION...

DESTRUCTIVE TORNADOES...LARGE HAIL TO 3 INCHES IN DIAMETER...
THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE
POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE
MILES EAST AND WEST OF A LINE FROM 15 MILES NORTH OF SHERMAN
TEXAS TO 45 MILES WEST SOUTHWEST OF TEMPLE TEXAS. FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU5).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 133...WW 134...

DISCUSSION...SUPERCELL THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON ALONG SURFACE DRYLINE OVER WESTERN NORTH TX. THESE STORMS
WILL TRACK EAST-NORTHEASTWARD ACROSS THE DFW METRO AREA THIS
EVENING...WHILE OTHER MORE ISOLATED FORM ACROSS THE REGION. VERY
STRONG LOW LEVEL VERTICAL SHEAR PROFILES AND FAVORABLE LOW LEVEL
MOISTURE PARAMETERS SUGGEST THE THREAT OF STRONG TORNADOES ACROSS
THE WATCH AREA.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 24035.


..HART

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 132003
SWODY1
SPC AC 132001

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0301 PM CDT FRI APR 13 2007

VALID 132000Z - 141200Z

..THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF NORTH CENTRAL
AND NORTHEAST TEXAS THROUGH THIS EVENING...

..THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK ACROSS
NRN/ERN TX...PARTS OF FAR SRN OK TO SWRN AR AND NRN/WRN LA...

..THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK
ACROSS THE SRN PLAINS TO THE LOWER MS VALLEY...

..THREAT FOR ACTIVE SEVERE WEATHER WITH POTENTIAL FOR A FEW
SIGNIFICANT TORNADOES...VERY LARGE AND DESTRUCTIVE HAIL...AND
DAMAGING WINDS BECOMING MORE PROBABLE ACROSS NORTH CENTRAL TO
NORTHEAST TX INTO THIS EVENING...

STRONG MID LEVEL SHORT WAVE TROUGH LOCATED OVER ERN HALF OF NM IS
PROGGED TO MOVE ENEWD THIS FORECAST PERIOD ACROSS THE SRN PLAINS AND
SHOULD REACH THE OZARKS/LOWER MO VALLEY BY 12Z SATURDAY...WITH LONG
WAVE TROUGH EDGING EWD INTO THE SRN PLAINS. ASCENT AHEAD OF THESE
FEATURES AND ATOP MODIFYING AIR MASS WILL SUPPORT AN ACTIVE SEVERE
WEATHER EVENT ACROSS PARTS OF N TX TO NRN LA THROUGH TONIGHT...WITH
A RISK OF A FEW STRONG TO SIGNIFICANT TORNADOES... VERY LARGE HAIL
AND DAMAGING WINDS. THUS...A HIGH RISK HAS BEEN ADDED TO THE
CONVECTIVE OUTLOOK ACROSS PARTS OF NORTH CENTRAL TO NE TX.

AFTERNOON WATER VAPOR IMAGERY INDICATED A LEAD SHORT WAVE TROUGH
CENTERED OVER THE TX/OK PANHANDLES. ATTENDANT DEEP LAYER ASCENT
WITH THIS FEATURE IS AIDING STRONG/SEVERE TSTM DEVELOPMENT VICINITY
OF SURFACE LOW SWD ALONG WIND SHIFT/DRY LINE IN NW TX. ALTHOUGH
THIS LEAD WAVE IS PROGGED TO MOVE NEWD INTO KS...A SECOND ZONE OF
ASCENT NOW MOVING INTO TX AHEAD OF PRIMARY NM SHORT WAVE TROUGH WILL
SPREAD EWD ACROSS TX/OK TOWARD THE LOWER MS VALLEY MAINTAINING TSTM
DEVELOPMENT THROUGH THE FORECAST PERIOD ALONG/E OF DRY LINE. EARLY
AFTERNOON SURFACE ANALYSIS SHOWED A LOW/TRIPLE POINT OVER NW TX
/VICINITY STONEWALL COUNTY/ WITH A WARM FRONT EXTENDING SEWD TO
SOUTH OF FTW/DAL METRO AREA TO NORTH OF HOU. DRYLINE EXTENDED SSWWD
FROM SURFACE LOW TO THE TX BIG BEND REGION. SURFACE LOW SHOULD
TRACK ENEWD ALONG THIS WARM FRONT AND BE LOCATED ALONG/JUST EAST OF
THE ARKLATEX REGION BY 12Z SUNDAY.

BROAD 50 KT SLY LLJ LOCATED OVER THE ERN HALF OF TX INTO LA WILL
MAINTAIN INFLUX OF RICH GULF MOISTURE ACROSS THE WARM SECTOR...AS
WARM FRONT CONTINUES TO SHIFT N TOWARD THE RED RIVER VALLEY AND
EVENTUALLY INTO NRN LA/SRN AR AND SWRN MS LATER THIS EVENING. STEEP
LAPSE RATES ATOP THIS MOISTURE RETURN COMBINED WITH ADDITIONAL
SURFACE HEATING ALONG/E OF DRY LINE WILL SUPPORT MODERATE
INSTABILITY DEVELOPING/EXPANDING EWD INTO CENTRAL/NRN PARTS OF TX.

DEEP LAYER SHEAR WILL REMAIN SUPPORTIVE FOR ORGANIZED STORMS THIS
AFTERNOON INTO THE EVENING WITH POTENTIAL FOR LONG-LIVED TORNADIC
SUPERCELLS VICINITY OF SURFACE LOW AND WARM FRONT...WHERE 0-3 KM SRH
VALUES IN EXCESS OF 400 M2/S2 WILL FAVOR LOW LEVEL ROTATIONS WITHIN
MOISTENING AIR MASS. SEVERE THREAT IS EXPECTED TO SPREAD EWD
OVERNIGHT INTO THE LOWER MS VALLEY WITH POTENTIAL FOR MORE LINEAR
STRUCTURE AS SHEAR VECTORS BECOME ORIENTED MORE PARALLEL TO
PROGRESSIVE COLD FRONT.

NORTH OF THE WARM FRONT...SCATTERED STRONG TO SEVERE THUNDERSTORMS
ARE EXPECTED TO INCREASE THROUGH THE AFTERNOON/EVENING FROM SRN OK
EWD TO PARTS OF AR/NRN MS...AHEAD OF APPROACHING UPPER TROUGH.
ELEVATED SUPERCELLS ARE POSSIBLE OVER THIS REGION...ABOVE STABLE
BOUNDARY LAYER...WITH LARGE HAIL BEING THE MAIN THREAT.

.PETERS.. 04/13/2007

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MESO: Mesoscale Discussion 0481

ACUS11 KWNS 131952
SWOMCD
SPC MCD 131951
TXZ000-OKZ000-132045-

MESOSCALE DISCUSSION 0481
NWS STORM PREDICTION CENTER NORMAN OK
0251 PM CDT FRI APR 13 2007

AREAS AFFECTED...NORTHERN/CNTRL TX...EXTREME SRN OK NEAR THE RED
RIVER

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 131951Z - 132045Z

RAPID BOUNDARY LAYER RECOVERY IS UNDERWAY ACROSS NCNTRL TX THIS
AFTERNOON AS WARM FRONT LIFTS THROUGH THE METROPLEX...NWWD INTO NWRN
TX JUST SW OF SPS WHERE LONG-LIVED POTENTIALLY TORNADIC SUPERCELL IS
TRACKING SOUTH OF SEY. STRONG HEATING IS ALSO OCCURRING WEST OF
I-35 AND THIS WILL UNDOUBTEDLY ASSIST NEW UPDRAFT DEVELOPMENT OVER
THE NEXT FEW HOURS AS CAP ERODES. STRONG LOW LEVEL SHEAR IS NOTED
ACROSS MOST OF THE WARM SECTOR...ESPECIALLY FOCUSED ALONG NW-SE
ORIENTED WARM FRONT. LATEST THINKING IS ADDITIONAL THUNDERSTORMS
WILL EVOLVE OVER THE NEXT FEW HOURS WITHIN STRONGEST ZONE OF
HEATING...TO THE NW-SW OF THE METROPLEX...THEN SPREAD NEWD INTO ZONE
OF FAVORABLE LOW LEVEL SHEAR WHERE TORNADO DEVELOPMENT APPEARS
LIKELY.

PDS TORNADO WATCH WILL BE ISSUED BY 21Z FOR MUCH OF NCNTRL/CNTRL TX.
ADDITIONALLY...THIS REGION WILL BE UPGRADED TO A HIGH RISK.

.DARROW.. 04/13/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...SHV...HGX...FWD...OUN...EWX...

34049772 33779528 31809492 30829618 30969805 32239784

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WATCHES: Severe Thunderstorm Watch Number 134

WWUS20 KWNS 131859
SEL4
SPC WW 131859
OKZ000-140100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 134
NWS STORM PREDICTION CENTER NORMAN OK
200 PM CDT FRI APR 13 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CENTRAL AND SOUTHERN OKLAHOMA

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 200 PM UNTIL 800
PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES SOUTH OF
CLINTON OKLAHOMA TO 10 MILES SOUTHEAST OF POTEAU OKLAHOMA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU4).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 133...

DISCUSSION...SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED
TO INCREASE THROUGH THE AFTERNOON ACROSS SOUTHERN OK...AHEAD OF
APPROACHING UPPER TROUGH. ELEVATED SUPERCELLS ARE POSSIBLE OVER
THIS REGION...ABOVE STABLE BOUNDARY LAYER. LARGE HAIL APPEARS TO BE
THE MAIN THREAT.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 24030.


..HART

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MESO: Mesoscale Discussion 0480

ACUS11 KWNS 131737
SWOMCD
SPC MCD 131737
ARZ000-LAZ000-TXZ000-OKZ000-131930-

MESOSCALE DISCUSSION 0480
NWS STORM PREDICTION CENTER NORMAN OK
1237 PM CDT FRI APR 13 2007

AREAS AFFECTED...CNTRL AND SRN OK INTO SWRN AR...AND EXTREME NWRN TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 131737Z - 131930Z

THUNDERSTORMS SHOULD INCREASE IN COVERAGE AND INTENSITY THIS
AFTERNOON WITH A THREAT OF SEVERE HAIL. A WW COULD BE REQUIRED AFTER
18Z.

SURFACE ANALYSIS SHOWS WARM FRONT WELL SOUTH INTO TX WITH STABLE
SURFACE AIR TO THE N INTO OK AND AR. 850 MB FRONT EXTENDED ACROSS
SRN OK TO NEAR TXK AT 17Z AND WILL CONTINUE SLOWLY NWD AND STALL
NEAR I-40 BY MID AFTERNOON. SCATTERED THUNDERSTORMS WILL PERSIST
AREA-WIDE AS WARM/MOIST ADVECTION OCCURS ALOFT. SEVERE THREAT WILL
INCREASE WITH TIME AS EFFECTIVE PARCEL LEVELS DROP FROM NEAR 750 MB
TO AROUND 850 MB. THIS WILL INCREASE STORM RELATIVE HELICITY WHICH
CAN BE INGESTED BY THE UPDRAFTS...AND WILL ALLOW STORMS TO GRADUALLY
CHANGE IN CHARACTER AND BECOME SUPERCELLS.

.JEWELL.. 04/13/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LZK...SHV...TSA...FWD...OUN...LUB...

35869660 35889573 35599457 34709314 34079220 33439225
32959339 33469419 34279640 34059756 33919859 33739994
33890038 34530005 35079931 35749818 35859698

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DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 131730
SWODY2
SPC AC 131728

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT FRI APR 13 2007

VALID 141200Z - 151200Z

..THERE IS A MDT RISK OF SVR TSTMS ACROSS SERN LA...SERN
MS...CENTRAL AND SRN AL...PARTS OF WRN AND SWRN GA...AND THE FL
PANHANDLE...

..THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER MS VALLEY EWD TO
SRN ATLANTIC STATES...

..SYNOPSIS...
AMPLIFIED UPPER PATTEN ACROSS THE CONTINENTAL U.S. WILL REMAIN
PROGRESSIVE ON SATURDAY AS A PACIFIC TROUGH MOVES INLAND OVER THE
WRN STATES. DOWNSTREAM TROUGH...INITIALLY EXTENDING FROM THE GREAT
LAKES SWWD TO THE SRN HIGH PLAINS...WILL BECOME MORE NEUTRALLY
ORIENTED AS IT TRACKS EWD THROUGH THE OH VALLEY AND GULF COAST
STATES. THIS LATTER TROUGH WILL BE THE MAIN UPPER FEATURE
SUPPORTING A SEVERE WEATHER THREAT FROM THE LOWER MS VALLEY EWD TO
THE SRN ATLANTIC COAST DURING DAY 2.

IN THE LOW LEVELS...SURFACE LOW SHOULD BE OVER THE ARKLATEX REGION
AT 12Z SATURDAY WITH COLD FRONT TRAILING SWWD INTO DEEP S TX. THESE
SURFACE FEATURES WILL SPREAD EWD ATTENDANT WITH PROGRESSIVE UPPER
TROUGH. SURFACE LOW IS EXPECTED TO DEEPEN SATURDAY AS IT TRACKS E
TOWARD AL BY 15/00Z...WITH STRONGEST DEEPENING OCCURRING THROUGH
SECOND HALF OF PERIOD...AS STRONG HEIGHT FALLS /120-180 METERS/
DEVELOP EWD ACROSS GULF COAST STATES. SURFACE LOW SHOULD REACH THE
ERN CAROLINAS BY 12Z SUNDAY.

..LOWER MS VALLEY EWD TO SRN ATLANTIC STATES...
STRONG UPPER TROUGH...NOW LOCATED OVER NM...IS FORECAST TO
DE-AMPLIFY SATURDAY AS IT MOVES NEWD INTO MID LEVEL CONFLUENT FLOW
REGIME OVER THE MIDWEST/SRN GREAT LAKES REGION. MEANWHILE...AN
UPSTREAM SHORT WAVE TROUGH...NOW LOCATED OVER LOWER CO RIVER
VALLEY...IS EXPECTED TO STRENGTHEN DURING DAY 2 WITHIN BASE OF ERN
LONGWAVE TROUGH AS IT PHASES WITH A NRN STREAM TROUGH. THIS PHASING
IS EXPECTED TO STRENGTHEN WIND FIELDS FROM THE LOWER MS VALLEY EWD
THROUGH THE GULF COAST STATES.

LOW LEVEL SLY WINDS IN ADVANCE OF COLD FRONT ARE EXPECTED TO PROVIDE
INFLUX OF GULF MOISTURE FROM THE LOWER MS VALLEY EWD TO NERN GULF
COAST STATES. ALTHOUGH LAPSE RATES ARE EXPECTED TO BE SOMEWHAT
WEAK...SURFACE DEWPOINTS IN THE MID-UPPER 60S WITH VALUES AROUND 70
ALONG THE GULF COAST COMBINED WITH SURFACE HEATING SHOULD RESULT IN
MUCAPE VALUES 1000-1500 J/KG. STRONGEST INSTABILITY SHOULD DEVELOP
ALONG THE COAST AND INLAND OVER THE SRN HALF OF THE GULF STATES.

AT 12Z SATURDAY...STRONG TO SEVERE STORMS ARE EXPECTED TO BE ONGOING
ALONG THE COLD FRONT...WITH DEEP LAYER SHEAR VECTORS PARALLEL TO
FRONT SUGGESTING A DAMAGING WIND AND HAIL THREAT WITH THIS EARLY
ACTIVITY. DIFFLUENT FLOW DOWNSTREAM ATOP DESTABILIZING WARM SECTOR
SUGGESTS THE POTENTIAL FOR ISOLATED TSTMS TO DEVELOP IN ADVANCE OF
STORMS ALONG THE COLD FRONT. SHEAR VECTORS OVER THE WARM SECTOR
SHOULD BE MORE CONDUCIVE FOR DISCRETE SUPERCELLS WITH THREAT FOR
TORNADOES...DAMAGING WINDS AND HAIL.

STRONGER HEIGHT FALLS AND STRENGTHENING WIND FIELDS EXPECTED FROM
LATE AFTERNOON INTO SATURDAY NIGHT SHOULD COMPENSATE FOR THE WEAKER
LAPSE RATES/INSTABILITY AND SUPPORT AN INCREASE IN SEVERE STORMS...
SOME STRONG TO SIGNIFICANT...FROM THE MS DELTA REGION INTO AL AND
EWD. ALL SEVERE TYPES SHOULD BE EXPECTED THROUGH LATE IN THE PERIOD
AS ACTIVITY SPREADS E TOWARD NRN FL TO THE CAROLINAS BY 12Z SUNDAY.

.PETERS.. 04/13/2007

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WATCHES: Tornado Watch Number 133

WWUS20 KWNS 131728
SEL3
SPC WW 131728
TXZ000-140000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 133
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT FRI APR 13 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

NORTHWEST TEXAS

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 1230 PM UNTIL
700 PM CDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE
MILES EAST AND WEST OF A LINE FROM 70 MILES WEST SOUTHWEST OF
BROWNWOOD TEXAS TO 20 MILES WEST NORTHWEST OF WICHITA FALLS
TEXAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

DISCUSSION...SCATTERED THUNDERSTORMS WILL DEVELOP EARLY THIS
AFTERNOON ALONG DRYLINE WEST OF ABI-SJT. THESE STORMS WILL MOVE
EASTWARD INTO AN INCREASINGLY MOIST AND UNSTABLE AIR MASS. BACKED
LOW LEVEL WINDS AND OBSERVED VERTICAL SHEAR PROFILES APPEAR VERY
FAVORABLE FOR SUPERCELLS CAPABLE OF TORNADOES...AS WELL AS VERY
LARGE HAIL AND DAMAGING WINDS. STRONG TORNADOES ARE POSSIBLE.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 25035.


..HART

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MESO: Mesoscale Discussion 0479

ACUS11 KWNS 131712
SWOMCD
SPC MCD 131712
TXZ000-131815-

MESOSCALE DISCUSSION 0479
NWS STORM PREDICTION CENTER NORMAN OK
1212 PM CDT FRI APR 13 2007

AREAS AFFECTED...NWRN/NCNTRL TX

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 131712Z - 131815Z

WELL DEFINED UPPER LOW IS EJECTING EWD ACROSS NM WITH LEADING EDGE
OF STRONGER FORCING NOW SPREADING INTO THE TX SOUTH PLAINS. STRONG
BOUNDARY LAYER HEATING/MIXING HAS DEVELOPED ACROSS WEST TX WITH WELL
DEFINED DRY LINE BEGINNING TO SURGE EAST ACROSS THE PERMIAN BASIN.
DOWNSTREAM...WARM FRONT CONTINUES TO LIFT NORTH WITH 60S SFC DEW
POINTS INTO STONEWALL AND HASKELL COUNTIES. LATEST VIS IMAGERY
SUGGESTS CU FIELD IS EXPANDING/DEEPENING ACROSS THE WARM
SECTOR...ALONG/EAST OF DRY LINE TO THE W-N OF ABI. IT APPEARS
THUNDERSTORMS WILL DEVELOP WITHIN MOIST SECTOR FROM THIS
AGITATED...INCREASINGLY BUOYANT AIRMASS BY 20Z. SUPERCELLS SHOULD
EVOLVE WITHIN THIS STRONGLY SHEARED ENVIRONMENT THEN QUICKLY MOVE
NEWD INTO THAT REGION BOUNDED BY ABI-SPS-FTW ZONE. TORNADOES APPEAR
LIKELY WITH STRONGEST SUPERCELLS...WHILE LARGE HAIL SHOULD ALSO BE
COMMON.

.DARROW.. 04/13/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FWD...OUN...SJT...LUB...

33350055 34109919 33589808 32309774 32429928 32470050

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DAY1SVR: Public Severe Weather Outlook (Automatic)

023
WOUS40 KWNS 131632
PWOSPC
ARZ000-LAZ000-TXZ000-140030-

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1131 AM CDT FRI APR 13 2007

...SEVERE THUNDERSTORMS EXPECTED OVER PARTS OF THE SOUTHERN PLAINS
LATER TODAY AND TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF A FEW STRONG TORNADOES OVER PARTS OF THE SOUTHERN
PLAINS LATER TODAY AND TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

EXTREME SOUTHWEST ARKANSAS
NORTHERN LOUISIANA
CENTRAL AND NORTHEAST TEXAS

SURROUNDING THIS AREA...THERE IS A SLIGHT RISK OF SEVERE
THUNDERSTORMS AS FAR EAST AS WESTERN MISSISSIPPI.

A STRONG UPPER SYSTEM IS MOVING ACROSS SOUTHERN NEW MEXICO THIS
MORNING. AS THIS SYSTEM TRACKS EASTWARD INTO TEXAS...STRONG
SOUTHERLY LOW LEVEL WINDS WILL TRANSPORT RICH GULF MOISTURE INTO
THREAT AREA. A MODERATELY UNSTABLE AIR MASS IS EXPECTED TO
RESULT...SETTING THE STAGE FOR AN ACTIVE SEVERE WEATHER EVENT THIS
AFTERNOON AND TONIGHT.

THUNDERSTORMS ARE LIKELY TO DEVELOP THIS AFTERNOON ALONG A DRYLINE
FROM WEST OF THE DALLAS/FORT WORTH AREA SOUTHWARD TO WEST OF WACO.
THESE STORMS WILL HAVE THE POTENTIAL TO BECOME SUPERCELLS...TRACKING
EAST-NORTHEASTWARD DURING THE EVENING. STRONG TORNADOES ARE
POSSIBLE WITH THE STRONGEST STORMS...ALONG WITH VERY LARGE AND
DAMAGING HAIL. SEVERE WEATHER WILL LIKELY PERSIST MUCH OF THE NIGHT
AS STORMS INCREASE IN NUMBER AND SPREAD ACROSS PARTS OF LA...AND
EVENTUALLY INTO WESTERN MS.

THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE WEATHER
SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA WEATHER
RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER TODAY.

..HART.. 04/13/2007

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 131623
SWODY1
SPC AC 131621

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1121 AM CDT FRI APR 13 2007

VALID 131630Z - 141200Z

..THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER
PARTS OF EAST TX...NORTHERN LA...AND SOUTHWEST AR...

..THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SOUTHERN
PLAINS AND LOWER MS VALLEY...

POWERFUL UPPER TROUGH NOW SHOWN BY WATER VAPOR IMAGERY OVER SOUTHERN
NM WILL TRACK EASTWARD ACROSS TX TONIGHT. AHEAD OF THE
SYSTEM...STRONG SOUTHERLY LOW LEVEL WINDS ARE TRANSPORTING RICH GULF
MOISTURE NORTHWARD ACROSS PARTS OF TX/LA. PRESENT INDICATIONS ARE
FOR AN ACTIVE SEVERE WEATHER EVENT ACROSS PARTS OF NORTHERN TX INTO
NORTHERN LA THIS AFTERNOON THROUGH TONIGHT...WITH A RISK OF A FEW
STRONG TORNADOES...VERY LARGE HAIL...AND DAMAGING WINDS.

CURRENT SURFACE ANALYSIS SHOWS MAIN LOW NORTH OF MAF...WITH WARM
FRONT EXTENDING EAST-SOUTHEASTWARD TO NEAR ACT. THIS BOUNDARY WILL
LIFT NORTHWARD THROUGH THE DAY WITH MID/UPPER 60S DEWPOINTS
SPREADING INTO MUCH OF NORTH-CENTRAL AND EAST TX. MORNING OBSERVED
AND FORECAST SOUNDINGS OVER THIS REGION SHOW STEEP MID LEVEL LAPSE
RATES...FAVORABLE FOR THE DEVELOPMENT OF MODERATE INSTABILITY BY
LATE THIS AFTERNOON. SOUNDINGS ALSO SHOW RATHER WARM TEMPERATURES
AT 700MB...SUGGESTING THAT CAPPING INVERSION WILL INHIBIT WARM
SECTOR CONVECTION UNTIL LATER THIS AFTERNOON.

STRONG WARM ADVECTION AND STRENGTHENING LOW LEVEL JET WILL HELP TO
MAINTAIN A RISK OF SCATTERED STORMS ALONG AND NORTH OF WARM FRONT
FROM NORTHWEST TX...ACROSS SOUTHERN OK...INTO SOUTHERN AR. THERE IS
A NARROW ZONE ALONG THE WARM FRONT OVER NORTHWEST TX WHERE STORMS
COULD BECOME SURFACE-BASED WITH A RISK OF ISOLATED TORNADOES.
OTHERWISE...LARGE HAIL WILL BE THE MAIN THREAT.

LATER THIS AFTERNOON...SUFFICIENT HEATING ALONG THE DRYLINE COMBINED
WITH APPROACHING UPPER TROUGH WILL LIKELY RESULT IN SCATTERED
THUNDERSTORMS WEST/SOUTHWEST OF THE DFW AREA. OTHER ISOLATED CELLS
MAY DEVELOP WITHIN THE WARM SECTOR WHERE LOW LEVEL WARM ADVECTION
WILL BE OCCURRING. VERTICAL SHEAR PROFILES THROUGHOUT THIS REGION
WILL BE FAVORABLE FOR SUPERCELLS. LOW LEVEL SHEAR AND MOISTURE
PROFILES WILL ALSO BE QUITE FAVORABLE FOR TORNADOES /PERHAPS STRONG/
AS STORMS SPREAD EASTWARD ACROSS NORTHEAST TX AND INTO LA DURING THE
EVENING/NIGHT. DAMAGING WINDS AND HAIL WILL ALSO BE POSSIBLE ACROSS
THE MDT RISK AREA.

OVERNIGHT...STORMS MAY BECOME MORE LINEARLY FORCED AS UPPER TROUGH
SPREADS EASTWARD. THIS WILL INCREASE THE RISK OF DAMAGING WINDS AS
FAR EAST AS EASTERN LA AND WESTERN MS.

.HART/JEWELL.. 04/13/2007

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 131235
SWODY1
SPC AC 131233

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0733 AM CDT FRI APR 13 2007

VALID 131300Z - 141200Z

..THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON INTO EARLY
TONIGHT FROM CENTRAL/NE TX INTO NW LA AND EXTREME SW AR...

..THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK...FROM
CENTRAL TX AND SRN OK EWD TO THE LOWER MS VALLEY...

..SYNOPSIS...
A STRONG MID LEVEL TROUGH OVER SE AZ HAS NOW TURNED TO THE E AND
WILL CONTINUE EWD OVER SRN NM THE FIRST PART OF THE DAY...AND THEN
NEWD OVER NW TX AND OK BY TONIGHT. AN ASSOCIATED SURFACE LOW INVOF
THE TX/NM BORDER WILL DEVELOP EWD ACROSS NW INTO N CENTRAL TX BY
THIS EVENING...AND THEN CONTINUE TO THE ENE OVER SRN AR TONIGHT. A
MOIST WARM SECTOR /BOUNDARY LAYER DEWPOINTS OF 65-70 F/ NOW ACROSS S
TX WILL SPREAD NWD INTO N CENTRAL AND NE TX BY MID-LATE AFTERNOON AS
A RESULT OF ADVECTION ON A 40 KT SLY LLJ IN ADVANCE OF THE SURFACE
LOW AND MID LEVEL WAVE...AND VERTICAL MIXING WITH DAYTIME HEATING.
THE INCREASING LOW-LEVEL MOISTURE WILL CONTRIBUTE TO SUBSTANTIAL
DESTABILIZATION ACROSS CENTRAL AND E TX...WHILE VERTICAL SHEAR WILL
BECOME QUITE FAVORABLE FOR SUPERCELLS IN THE WARM SECTOR.

..CENTRAL/NE TX TODAY EWD ACROSS SRN AR AND NRN LA TONIGHT...
ONE CONCERN TODAY WILL BE THE EXTENT OF ELEVATED CONVECTION ACROSS
N/NE TX...WHERE RAINFALL AND EVAPORATIVE COOLING WITHIN THE
INITIALLY DRIER BOUNDARY LAYER COULD TEND TO LIMIT THE NWD EXTENT OF
THE UNSTABLE WARM SECTOR. HOWEVER...CONSENSUS OF SHORT RANGE MODELS
SUGGESTS THAT THE MAJORITY OF CONVECTION FROM THIS MORNING INTO MID
AFTERNOON SHOULD BE NEAR AND N OF THE RED RIVER WHERE ASCENT WILL BE
FOCUSED N OF THE DEEP BAROCLINIC ZONE. THEREFORE...MODERATE
INSTABILITY WILL LIKELY DEVELOP IN THE WARM SECTOR ROUGHLY ALONG AND
S OF A LINE FROM THE DFW METROPLEX TO THE TXK-SHV AREA BY THIS
EVENING.

VERTICAL SHEAR PROFILES ARE FORECAST TO BECOME QUITE FAVORABLE FOR
TORNADIC SUPERCELLS IN ADVANCE OF THE SURFACE LOW AND EWD ALONG AND
EVEN S OF THE WARM FRONT INTO E/NE TX. A FEW DISCRETE SUPERCELLS
WILL LIKELY DEVELOP ALONG THE DRYLINE AND PERHAPS IN THE OPEN WARM
SECTOR BY MID AFTERNOON AND MOVE ENEWD INTO THE REGION OF STRONGER
LOW-LEVEL SHEAR. BOUNDARY LAYER DEWPOINTS IN THE MID-UPPER 60S AND
LARGE HODOGRAPHS WITH EFFECTIVE SRH OF 400-500 M2/S2 APPEAR
SUPPORTIVE OF SUPERCELLS WITH STRONG TORNADOES LATE THIS AFTERNOON
INTO THIS EVENING ACROSS NE TX.

BY TONIGHT...CONVECTION SHOULD TEND TOWARD A MORE LINEAR STRUCTURE
AS THE DEEP LAYER SHEAR AND BOUNDARY ORIENTATIONS BECOME MORE
PARALLEL /SW TO NE/. THE NET RESULT WILL BE A TRANSITION TO MORE OF
A DAMAGING WIND THREAT ACROSS LA...THOUGH VERTICAL SHEAR WILL STILL
FAVOR A FEW EMBEDDED MESOCYCLONES/LEWPS WITHIN THE BAND OF
STORMS...AND AN ASSOCIATED THREAT FOR A FEW TORNADOES OVERNIGHT.

..NW TX AND SRN OK TODAY...
A LARGE CLUSTER OF ELEVATED THUNDERSTORMS IS DEVELOPING FROM NW TX
INTO CENTRAL OK IN ASSOCIATION WITH INCREASINGLY MOIST WAA AND A
LEAD SHORTWAVE TROUGH EJECTING NEWD IN ADVANCE OF THE MAIN WAVE OVER
AZ/NM. MUCAPE OF 750-1250 J/KG BASED IN THE 800-700 MB LAYER AND
STEEP MID LEVEL LAPSE RATES WILL SUPPORT A FEW STORMS WITH LARGE
HAIL THROUGH THE DAY SPREADING EWD OVER SRN OK AND ADJACENT RED
RIVER COUNTIES IN N TX.

.THOMPSON/CROSBIE.. 04/13/2007

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MESO: Mesoscale Discussion 0478

ACUS11 KWNS 131212
SWOMCD
SPC MCD 131211
KSZ000-COZ000-131815-

MESOSCALE DISCUSSION 0478
NWS STORM PREDICTION CENTER NORMAN OK
0711 AM CDT FRI APR 13 2007

AREAS AFFECTED...WRN KS AND SERN CO

CONCERNING...HEAVY SNOW

VALID 131211Z - 131815Z

HEAVY SNOW WITH HRLY RATES UP TO 1 INCH WILL DEVELOP ACROSS THE AREA
THROUGH THE LATE MORNING HOURS. GUSTY NELY WINDS FROM 20-25 MPH WILL
AID IN BLOWING SNOW.

LATEST RADAR IMAGE INDICATED EXPANSION OF PRECIPITATION OVER SERN
CO/SWRN KS WHILE IR IMAGERY SHOWS MODEST CLOUD TOP COOLING. BOTH ARE
REPRESENTATIVE OF INCREASING FRONTOGENETIC FORCING OVER THE AREA AS
THE MID LEVEL DEFORMATION ZONE DEVELOPS AHEAD OF THE UPPER LOW
CENTERED OVER SWRN NM. SFC ANALYSIS INDICATES THAT THE SFC FREEZING
LINE EXTENDS FROM NEAR GLD SWWD TO NEAR SPRINGFIELD COLORADO. AS
PRECIPITATION RATES CONTINUE TO INCREASE IN THE NEXT FEW HRS...A SWD
MOVEMENT OF THE SFC FREEZING LINE IS EXPECTED THROUGH WRN KS. THUS
HEAVY SNOWFALL IS ANTICIPATED TO OCCUR AS FAR SOUTH AS A LINE FROM
LIBERAL TO GARDEN CITY BY 18Z. STEEP MID LEVEL LAPSE RATES ALONG
WITH THE AFOREMENTIONED FORCING WILL SUPPORT SOME CONVECTIVE
SNOWBURSTS WITH 1 IN/HR SNOWFALL RATES. AS THE SFC LOW OVER ECENTRAL
NM DEVELOPS EWD INTO THE REGION OF GREATEST PRESSURE FALLS /OVER THE
SERN TX PANHANDLE AT 12Z/ AND STRONG WAA CONTINUES OVER THE TX
PANHANDLE...RESULTANT STRONG LOW LEVEL FRONTOGENESIS WILL SUPPORT
INCREASING N-S ORIENTED PRESSURE GRADIENT ACROSS THE AREA. SUSTAINED
WINDS SHOULD REACH 20-25 MPH BY 16-18Z WHICH WILL LEAD TO SOME
BLOWING SNOW.

.CROSBIE.. 04/13/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...DDC...GLD...PUB...BOU...

38940243 38160381 37170342 37160174 37320104 38260055
39260092

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WATCHES: Severe Thunderstorm Watch - Number 132

WWUS20 KWNS 131203
SEL2
SPC WW 131203
NMZ000-OKZ000-TXZ000-131200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH - NUMBER 132
NWS STORM PREDICTION CENTER NORMAN OK
703 AM CDT FRI APR 13 2007

THE NWS STORM PREDICTION CENTER HAS CANCELLED
SEVERE THUNDERSTORM WATCH NUMBER 132 ISSUED AT 1150 PM CDT FOR PORTIONS OF

NEW MEXICO
OKLAHOMA
TEXAS

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MESO: Mesoscale Discussion 0477

ACUS11 KWNS 131034
SWOMCD
SPC MCD 131034
OKZ000-TXZ000-131200-

MESOSCALE DISCUSSION 0477
NWS STORM PREDICTION CENTER NORMAN OK
0534 AM CDT FRI APR 13 2007

AREAS AFFECTED...PARTS OF WRN/NW TX...TX/OK PNHDLS...WRN AND CNTRL
OK

CONCERNING...SEVERE THUNDERSTORM WATCH 132...

VALID 131034Z - 131200Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 132
CONTINUES. SOME UNCERTAINTY EXISTS AS TO WHETHER A NEW WW WILL BE
NEEDED AT 12Z...BUT TRENDS ARE BEING MONITORED FOR THIS POSSIBILITY.

LATEST RUC GUIDANCE INDICATES THAT 90-100 KT CORE OF A CYCLONIC 500
MB JET STREAK IS NOW PROGRESSING ACROSS NORTHERN SONORA/CHIHUAHUA.
THIS IS SUPPORTED BY WATER VAPOR IMAGERY...AND MOST MODEL GUIDANCE
INDICATES THAT THIS FEATURE WILL BEGIN NOSING INTO SOUTHWEST TEXAS
BY THE 12-15Z TIME FRAME. AS THIS OCCURS...DIVERGENT UPPER FLOW
FIELD IN ITS LEFT EXIT REGION WILL OVERSPREAD THE TEXAS/OKLAHOMA
PANHANDLE REGION AND THE TEXAS SOUTH PLAINS. THIS IS EXPECTED TO
MAINTAIN VIGOROUS CONVECTIVE DEVELOPMENT ACROSS PARTS OF THE TEXAS
PANHANDLE INTO WESTERN OKLAHOMA...WHERE CAPE FOR PARCELS BASED IN
ELEVATED MOIST LAYER RETURNING ABOVE DEVELOPING SURFACE FRONT IS
INCREASING INTO THE 500-1000 J/KG RANGE. AN EXPANDING CONVECTIVE
CLUSTER APPEARS POSSIBLE THROUGH THE MORNING HOURS...WITH PERSISTENT
HEAVY RAINFALL BECOMING AN INCREASING THREAT...IN ADDITION TO A
CONTINUING RISK FOR MOSTLY MARGINALLY SEVERE HAIL.

UNCERTAINTY EXISTS CONCERNING PROSPECTS FOR CONVECTIVE DEVELOPMENT
TO THE SOUTH OF SURFACE FRONTAL ZONE...ROUGHLY SOUTHEAST OF A LAWTON
OK/LUBBOCK TX LINE. IT APPEARS THAT VEERING LOW-LEVEL FLOW MAY
CONTRIBUTE TO A ZONE OF ENHANCED LOW-LEVEL WARM ADVECTION SOUTH OF
CHILDRESS INTO THE ABILENE AREA...WHERE ADDITIONAL CONVECTIVE
DEVELOPMENT IS POSSIBLE DURING THE 12-15Z TIME FRAME. IF THIS
OCCURS...HODOGRAPHS WILL BE MORE THAN SUPPORTIVE OF SUPERCELLS.
BUT...THROUGH AT LEAST MID MORNING...STORMS PROBABLY WILL BE ROOTED
ABOVE A COOLER/DRIER BOUNDARY LAYER...WITH LARGE HAIL THE PRIMARY
SEVERE THREAT.

.KERR.. 04/13/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FWD...OUN...SJT...LUB...AMA...

36090176 36780091 36950001 36689855 36019793 34879821
34409849 33969850 32919806 32269846 32109960 32860015
33490115 34200186 35330189

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DAY1SVR: Public Severe Weather Outlook (Automatic)

976
WOUS40 KWNS 131001
PWOSPC
ARZ000-LAZ000-TXZ000-131800-

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0501 AM CDT FRI APR 13 2007

...SEVERE THUNDERSTORMS EXPECTED OVER PARTS OF THE SOUTHERN PLAINS
LATER TODAY AND TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF A FEW STRONG TORNADOES OVER PARTS OF THE SOUTHERN
PLAINS LATER TODAY AND TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

EXTREME SOUTHWEST ARKANSAS
NORTHWEST LOUISIANA
CENTRAL AND NORTHEAST TEXAS

SURROUNDING THE MODERATE RISK AREA...THERE IS A SLIGHT RISK OF
SEVERE THUNDERSTORMS FROM SOUTH CENTRAL TEXAS NORTHWARD INTO
OKLAHOMA TODAY AND EASTWARD TO THE LOWER MISSISSIPPI VALLEY BY LATE
TONIGHT.

A STRONG UPPER LEVEL STORM SYSTEM OVER SOUTHERN ARIZONA THIS MORNING
WILL MOVE EASTWARD INTO WEST TEXAS THIS AFTERNOON...AND CONTINUE
NORTHEASTWARD OVER OKLAHOMA TONIGHT. THIS UPPER LEVEL SYSTEM WILL
BE ACCOMPANIED BY A SURFACE LOW PRESSURE CENTER THAT IS EXPECTED TO
DEVELOP EASTWARD INTO NORTH TEXAS BY LATE TODAY...AND INTO SOUTHERN
ARKANSAS OVERNIGHT. A DRYLINE WILL MOVE EASTWARD FROM WESTERN INTO
CENTRAL TEXAS BY THIS AFTERNOON...WHILE A WARM FRONT WILL LIFT
NORTHWARD INTO EAST AND NORTHEAST TEXAS...AS WELL AS NORTHERN
LOUISIANA. THESE SURFACE BOUNDARIES WILL HELP FOCUS THE SEVERE
THUNDERSTORM THREAT TODAY INTO TONIGHT.

EAST OF THE DRYLINE AND SOUTH OF THE WARM FRONT...A VERY MOIST AIR
MASS WILL OVERSPREAD MUCH OF CENTRAL AND EASTERN TEXAS. THIS
MOISTURE...ALONG WITH DAYTIME HEATING...WILL CONTRIBUTE TO AN
UNSTABLE ENVIRONMENT SUPPORTIVE OF SEVERE THUNDERSTORMS. IN
ADDITION...THE CHANGE IN WINDS FROM THE LOWER TO THE MIDDLE
ATMOSPHERE WILL BE FAVORABLE FOR SUPERCELL THUNDERSTORMS THAT COULD
PRODUCE A FEW STRONG TORNADOES...ALONG WITH LARGE HAIL AND DAMAGING
WINDS THIS AFTERNOON AND EVENING. THE AFTERNOON AND EVENING STORMS
SHOULD GROW INTO A LARGER SQUALL LINE BY TONIGHT WHILE MOVING ACROSS
SOUTHERN ARKANSAS AND LOUISIANA WITH A CONTINUED THREAT FOR DAMAGING
WINDS AND A FEW TORNADOES.

THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE WEATHER
SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA WEATHER
RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER TODAY.

..THOMPSON.. 04/13/2007

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DAY48SVR: Nws Storm Prediction Center Norman Ok

ACUS48 KWNS 130841
SWOD48
SPC AC 130841

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0341 AM CDT FRI APR 13 2007

VALID 161200Z - 211200Z

..DISCUSSION...
UPPER LOW FORECAST OVER THE FOUR CORNERS AREA AT THE START OF THE
PERIOD WILL MOVE PROGRESSIVELY EWD ACROSS THE S CENTRAL/SERN CONUS
THROUGH DAY 6 /WED. APR. 18/ WHILE WEAKENING SLOWLY. THOUGH AN
ASSOCIATED SURFACE LOW WILL MOVE INTO THE SRN PLAINS FOR DAY 4 /MON.
APR. 16/...PREVIOUS COLD AIR SURGE INTO THE GULF SHOULD HINDER
FAVORABLE MOISTURE RETURN INTO THE PLAINS FOR A SIGNIFICANT SEVERE
EVENT. WITH THE SYSTEM THEN WEAKENING THROUGH MID-WEEK...SEVERE
PROBABILITIES SHOULD REMAIN LIMITED.

THE NEXT SYSTEM OF INTEREST SHOULD BEGIN AFFECTING THE PLAINS IN THE
DAYS 7-8 TIME FRAME /I.E. THU. APR. 19 TO FRI. APR. 20/.
HOWEVER...MODELS DIFFER GREATLY IN THE INTENSITY OF THIS SYSTEM --
AND THUS THE POTENTIAL FOR ADEQUATE MOISTURE RETURN INTO THE CENTRAL
CONUS. THEREFORE...IT APPEARS THAT OVERALL THE POTENTIAL FOR A
SIGNIFICANT SEVERE WEATHER EVENT THROUGH DAY 8 REMAINS LOW ATTM.

.GOSS.. 04/13/2007

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MESO: Mesoscale Discussion 0476

ACUS11 KWNS 130736
SWOMCD
SPC MCD 130736
OKZ000-TXZ000-130900-

MESOSCALE DISCUSSION 0476
NWS STORM PREDICTION CENTER NORMAN OK
0236 AM CDT FRI APR 13 2007

AREAS AFFECTED...PARTS OF W TX...TX/OK PNHDLS...WRN OK

CONCERNING...SEVERE THUNDERSTORM WATCH 132...

VALID 130736Z - 130900Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 132
CONTINUES.

WHILE AN INITIAL IMPULSE EMANATING FROM THE SOUTHWESTERN U.S. TROUGH
IS NOW WEAKENING WITHIN BROADER SCALE RIDGING OVER THE CENTRAL
PLAINS...THE PRIMARY SHORT WAVE IMPULSE IS JUST NOW BEGINNING TO
TURN EASTWARD THROUGH CENTRAL/SOUTHERN ARIZONA.
CONSEQUENTLY...LOW/MID-LEVEL WARM ADVECTION REMAINS THE PRIMARY
FORCING FOR CONVECTIVE DEVELOPMENT ACROSS THE SOUTHERN HIGH PLAINS.
AND...PARCELS IN MOIST RETURN FLOW ACROSS WEST TEXAS ARE NOT
REACHING LEVELS OF FREE CONVECTION UNTIL BEING LIFTED ABOVE A
MID-LEVEL BAROCLINIC ZONE...AROUND 700 MB...ACROSS NORTHWEST TEXAS
AND THE TEXAS PANHANDLE. THIS IS OCCURRING ABOVE A COLD SURGE TO
THE LEE OF THE ROCKIES...WHICH IS ALREADY ADVANCING THROUGH THE
TEXAS PANHANDLE...BUT CAPE FOR THE ELEVATED MOIST LAYER IS
INCREASING TO 500-1000 J/KG. IN A FAVORABLY SHEARED
ENVIRONMENT...THIS WILL MAINTAIN THE RISK FOR LARGE HAIL IN STRONGER
CELLS...WHICH ARE EXPECTED TO PERSIST MAINLY ACROSS THE
TEXAS/OKLAHOMA PANHANDLE REGION INTO EXTREME WESTERN OKLAHOMA
THROUGH 09-10Z. HAIL POTENTIAL WILL TEND TO DIMINISH WITH
CONVECTION DEVELOPING NORTHEASTWARD WITHIN MEAN SOUTHWESTERLY FLOW
REGIME...AS CAPE FOR INCREASINGLY ELEVATED MOIST LAYER WEAKENS AWAY
FROM THE SOUTHERN HIGH PLAINS.

.KERR.. 04/13/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...OUN...LUB...AMA...

36350247 36660129 36209963 35279898 34609897 33690012
33720142 34280227 35100263 35790267

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DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 130723
SWODY3
SPC AC 130721

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0221 AM CDT FRI APR 13 2007

VALID 151200Z - 161200Z

..NO SVR TSTM AREAS FORECAST...

..SYNOPSIS...
HIGHLY-AMPLIFIED/PROGRESSIVE UPPER FLOW PATTERN FORECAST TO CONTINUE
OVER THE CONUS FOR DAY 3...WITH TWO CLOSED LOWS EXPECTED OVER THE
CONUS BY THE END OF THE PERIOD -- ONE INVOF THE FOUR CORNERS AND THE
OTHER OVER THE MID-ATLANTIC REGION.

THOUGH SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST OVER THE
ROCKIES AS WRN TROUGH/LOW SHIFTS ACROSS THIS REGION...SEVERE
POTENTIAL SHOULD REMAIN CONFINED TO THE ERN SYSTEM AS IT MOVES
OFFSHORE DURING THE FIRST HALF OF THE PERIOD.

..CAROLINAS...
STORMS MAY BE ONGOING OVER COASTAL SC/ERN NC AND THE OUTER BANKS AT
THE START OF THE PERIOD...WITH BOTH THE GFS AND THE NAM PROGGING THE
FRONT TO CLEAR THE CAROLINA COAST BETWEEN 15/15Z AND 15/18Z. WITH
THE MAIN SEVERE THREAT POSSIBLY OFFSHORE WITHIN A PRE-FRONTAL BAND
OF STORMS PRIOR TO 12Z...WILL NOT INTRODUCE A SLIGHT RISK FOR THE
COASTAL CAROLINAS THIS FORECAST.

MODELS HINT THAT A SECONDARY AREA OF LOW-TOPPED/POST-FRONTAL STORMS
MAY DEVELOP DURING THE AFTERNOON OVER PORTIONS OF THE CAROLINAS...AS
DAYTIME HEATING WITHIN CLEAR SLOT OCCURS BENEATH -20C AIR AT H5
SPREADING ATOP THIS REGION. DEGREE OF INSTABILITY COULD SUPPORT A
FEW VIGOROUS UPDRAFTS CAPABLE OF PRODUCING MARGINAL HAIL. ANY
SEVERE THREAT LINGERING OVER THE CAROLINAS SHOULD END BY EARLY
EVENING.

..S FL...
COLD FRONT -- LYING NE-SW ACROSS NRN FL AT THE START OF THE PERIOD
PER LATEST NAM/GFS GUIDANCE -- SHOULD SWEEP RAPIDLY SEWD ACROSS THE
FL PENINSULA THROUGH THE DAY...CLEARING S FL/THE KEYS DURING THE
AFTERNOON. SWLY LOW-LEVEL FLOW ROUGHLY PARALLEL TO THE FRONT WOULD
YIELD LITTLE LOW-LEVEL CONVERGENCE...WHILE H5 TEMPERATURES GREATER
THAN -8C SUGGEST VERY WEAK LAPSE RATES/LITTLE POTENTIAL FOR
APPRECIABLE DESTABILIZATION. THEREFORE...WILL INTRODUCE ONLY 5%
SEVERE PROBABILITIES FOR THE FL PENINSULA THIS PERIOD.

.GOSS.. 04/13/2007

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 130559
SWODY1
SPC AC 130557

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT FRI APR 13 2007

VALID 131200Z - 141200Z

..THERE IS A MDT RISK OF SVR TSTMS FROM PARTS OF CNTRL THROUGH NERN
TX INTO THE LOWER MS VALLEY...

..THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN PLAINS INTO THE
LOWER MS VALLEY...

..SYNOPSIS...

SHORTWAVE TROUGH CURRENTLY OVER THE SWRN U.S. WILL ADVANCE EAST INTO
THE SRN PLAINS FRIDAY AFTERNOON. ATTENDANT LEE SURFACE LOW AND COLD
FRONT WILL SHIFT EAST THROUGH TX WHILE WARM FRONT LIFTS NWD TO NEAR
THE RED RIVER AREA BY EARLY FRIDAY EVENING.


..CNTRL AND ERN TX THROUGH LOWER MS VALLEY...

LATEST OBSERVATIONS AND THE 00Z RAOB DATA SHOW RICH BOUNDARY LAYER
MOISTURE OVER S TX WITH DEWPOINTS AROUND 70. STRONG SLY LOW LEVEL
JET WILL PERSIST IN ADVANCE OF THE APPROACHING SHORTWAVE TROUGH AND
CONTRIBUTE TO THETA-E ADVECTION THROUGH CNTRL AND ERN TX FRIDAY IN
WAKE OF RETREATING WARM FRONT. SOME LOW CLOUDS MAY ACCOMPANY THE
INITIAL MOISTURE SURGE. HOWEVER...UPPER 60S DEWPOINTS RETURNING NWD
BENEATH STEEP MID LEVEL LAPSE RATES SHOULD CONTRIBUTE TO MODERATE
INSTABILITY WITH MLCAPE FROM 1500 TO 2000 J/KG. STORMS WILL LIKELY
BE ONGOING EARLY FRIDAY...MOSTLY WITHIN ZONE OF WARM ADVECTION AND
ISENTROPIC LIFT N OF WARM FRONT FROM PARTS OF N TX INTO OK AND KS.
THIS ACTIVITY SHOULD BE ELEVATED WITH A THREAT FOR MAINLY HAIL.

STORMS SHOULD GRADUALLY DEVELOP SWD INTO THE PRE-FRONTAL WARM SECTOR
ALONG WARM CONVEYOR BELT AS THE ATMOSPHERE DESTABILIZES AND AS UPPER
DIVERGENCE AND FORCING FOR ASCENT INCREASES WITH THE APPROACH OF THE
UPPER TROUGH. A STRONG 50+ KT LOW LEVEL JET WILL PERSIST OVER CNTRL
AND ERN TX WITHIN EXIT REGION OF CYCLONICALLY CURVED UPPER JET. THIS
WILL RESULT IN FAVORABLE LOW LEVEL HODOGRAPHS AND DEEP LAYER SHEAR
FOR ORGANIZED STORM STRUCTURES INCLUDING SUPERCELLS AND BOW ECHOES
CAPABLE OF PRODUCING A FEW TORNADOES...VERY LARGE HAIL AND DAMAGING
WIND. GIVEN THE EXPECTED COMBINATION OF LOW-MID LEVEL SHEAR AND CAPE
ISOLATED STRONG TORNADOES WILL BE POSSIBLE...ESPECIALLY WITH ANY
DISCRETE SUPERCELL MODES. ACTIVITY WILL SHIFT EAST INTO THE LOWER MS
VALLEY FRIDAY EVENING WITH A CONTINUED SEVERE THREAT.

..NWRN TX INTO SWRN OK...

MUCH OF THE STORMS IN OK ARE EXPECTED TO REMAIN ELEVATED N OF WARM
FRONT WITH A THREAT FOR MAINLY HAIL. HOWEVER...MODELS SUGGEST MID
LEVEL DRY SLOT COULD ADVANCE NEWD INTO NWRN TX AND PARTS OF SWRN OK
DURING THE AFTERNOON...AND THIS WILL INCREASE THE CHANCES FOR LOW
CLOUDS TO MIX OUT. IF LOW CLOUDS CAN MIX OUT...SURFACE HEATING AND
COLD MID LEVEL PROFILES SHOULD RESULT IN AT LEAST MARGINAL SURFACE
BASED INSTABILITY IN A RELATIVELY NARROW CORRIDOR. ADDITIONAL STORMS
MAY DEVELOP WITHIN ZONE OF DPVA NEAR TRIPLE POINT OR SWD ALONG COLD
FRONT AND ADVANCE EAST. A CONDITIONAL THREAT WILL EXIST FOR DAMAGING
WIND...LARGE HAIL AND POSSIBLY AN ISOLATED TORNADO OR TWO.

.DIAL/CROSBY.. 04/13/2007

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DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 130559
SWODY2
SPC AC 130558

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT FRI APR 13 2007

VALID 141200Z - 151200Z

..THERE IS A MDT RISK OF SVR TSTMS ACROSS SERN LA...SERN MS...SRN
AL...SWRN GA...AND THE FL PANHANDLE...

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS SURROUNDING AREAS OF THE
SOUTHEASTERN U.S....

..SYNOPSIS...
HIGHLY-AMPLIFIED/PROGRESSIVE UPPER PATTERN IS FORECAST ACROSS THE
CONUS THIS PERIOD. WHILE A STRONG UPPER TROUGH IS FORECAST TO MOVE
ONSHORE/INLAND ACROSS THE WRN CONUS THROUGH THE PERIOD...THE MAIN
FEATURE WITH RESPECT TO THE SEVERE CONVECTIVE FORECAST WILL BE A
SECOND LARGE TROUGH FURTHER E. THIS TROUGH -- INITIALLY EXTENDING
FROM ONTARIO SWWD INTO W TX -- WILL SHIFT EWD WITH TIME...WHILE
TAKING ON A MORE NEUTRAL TILT. BY THE END OF THE PERIOD...THE
TROUGH AXIS SHOULD EXTEND FROM ROUGHLY JAMES BAY SWD INTO THE ERN
GULF OF MEXICO.

AT THE SURFACE...A WEAK LOW IS INITIALLY FORECAST OVER THE MS DELTA
REGION...WITH A COLD FRONT EXTENDING SWWD INTO SERN TX. THE LOW IS
FORECAST TO DEEPEN SLOWLY WITH TIME...WHILE IT AND THE ASSOCIATED
COLD FRONT MOVE EWD ACROSS THE SOUTHEAST THROUGH THE FIRST HALF OF
THE PERIOD. DURING THE SECOND HALF OF THE PERIOD...THIS LOW IS
FORECAST TO DEEPEN MORE RAPIDLY...WHILE MOVING NEWD ACROSS THE
ATLANTIC COAST STATES TO VA BY THE END OF THE PERIOD.

..THE SOUTHEAST...
STRONG TO SEVERE THUNDERSTORMS ARE FORECAST TO BE ONGOING
ALONG/AHEAD OF COLD FRONT AT THE START OF THE PERIOD...FROM WRN MS
SWWD TO SWRN LA. MEANWHILE...BROAD REGION OF SLY SURFACE WIND IS
FORECAST TO BE ADVECTING RICH BOUNDARY-LAYER MOISTURE NWD OFF THE
GULF INTO THE GULF COAST STATES. THOUGH WEAK LAPSE RATES SHOULD
LIMIT THE OVERALL POTENTIAL FOR WARM SECTOR DESTABILIZATION...MID
60S TO LOW 70S DEWPOINTS SPREADING ACROSS THE SRN HALVES OF THE GULF
COAST STATES BY MIDDAY COMBINED WITH DAYTIME HEATING SHOULD RESULT
IN 500 TO 1000 J/KG MEAN-LAYER CAPE BY MIDDAY/EARLY AFTERNOON.

STORMS SHOULD INTENSIFY WITHIN THE LINEAR COMPLEX ALONG/AHEAD OF
COLD FRONT THROUGH MIDDAY...WHILE A FEW ISOLATED STORMS MAY DEVELOP
AHEAD OF THE MAIN CONVECTIVE LINE NEAR SUBTLE LOW-LEVEL BOUNDARIES
POSSIBLY ASSOCIATED WITH WEAK LEAD MID-LEVEL FEATURE.

THOUGH MAIN UPPER TROUGH AND ASSOCIATED COOLING ALOFT SHOULD REMAIN
WELL TO THE W OF THE SURFACE FRONT...STRONG SWLY LOW-LEVEL WIND
FIELD BENEATH DIFFLUENT 60 TO 70 KT SWLY MID-LEVEL FLOW ACROSS THE
WARM SECTOR WILL RESULT IN SHEAR FAVORABLE FOR ORGANIZED/SUPERCELL
STORMS. WHILE IT APPEARS THAT FLOW FROM ROUGHLY 850 MB AND ABOVE
WILL BE ROUGHLY UNIDIRECTIONAL...SLY SURFACE WINDS VEERING TO SWLY
AT 850 MB SHOULD YIELD SUFFICIENT SHEAR FOR LOW-LEVEL UPDRAFT
ROTATION. THIS COMBINED WITH MOIST BOUNDARY LAYER -- PARTICULARLY
WITH SWD EXTENT TOWARD THE GULF COAST -- AS WELL AS THE OVERALL
INTENSITY OF THIS SYSTEM SUGGEST THAT SEVERAL TORNADOES WILL BE
POSSIBLE. IN ADDITION...STRENGTH OF DEEP-LAYER WIND FIELD AND
ANTICIPATED LINEAR ORGANIZATION OF CONVECTION ALONG THE COLD FRONT
ALSO APPEARS SUPPORTIVE OF WIDESPREAD DAMAGING WINDS.
A SECONDARY AREA OF STORMS MAY DEVELOP NEAR THE WARM FRONT --
ANTICIPATED OVER GA/SC DURING THE AFTERNOON...WHERE AN ASSOCIATED
POTENTIAL FOR SEVERE STORMS/TORNADOES WOULD EXIST. OVERNIGHT...THE
COLD FRONT SHOULD SHIFT EWD ACROSS GA/THE CAROLINAS/NRN FL...ALONG
WITH AN INCREASE IN STORM COVERAGE AND A CONTINUATION OF THE SEVERE
THREAT THROUGH THE END OF THE PERIOD.

.GOSS.. 04/13/2007

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WATCHES: Severe Thunderstorm Watch Number 132

WWUS20 KWNS 130447
SEL2
SPC WW 130447
NMZ000-OKZ000-TXZ000-131200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 132
NWS STORM PREDICTION CENTER NORMAN OK
1150 PM CDT THU APR 12 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

SMALL PART OF SOUTHEASTERN NEW MEXICO
SMALL PART OF SOUTHWEST OKLAHOMA
NORTHWEST TEXAS INCLUDING SOUTHERN PANHANDLE

EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 1150 PM
UNTIL 700 AM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 115
STATUTE MILES EAST AND WEST OF A LINE FROM 70 MILES NORTHWEST OF
CHILDRESS TEXAS TO 55 MILES WEST SOUTHWEST OF SAN ANGELO TEXAS.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU2).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...THIS SEVERE THUNDERSTORM WATCH REPLACES
SEVERE THUNDERSTORM WATCH NUMBER 131. WATCH NUMBER 131 WILL NOT
BE IN EFFECT AFTER 1150 PM CDT.

DISCUSSION...MOISTURE AND INSTABILITY CONTINUES TO INCREASE ACROSS
WATCH AREA ON 50KT LOW LEVEL JET. WITH APPROACH OF STRONG UPPER
SYSTEM OVER AZ...EXPECT SEVERE THUNDERSTORMS TO CONTINUE ACROSS SRN
PANHANDLE AND DEVELOP SOUTHWARD IN RESPONSE TO LARGE SCALE ASCENT
WITH APPROACHING TROUGH. SUPERCELLS ARE LIKELY GIVEN VERY STRONG
SHEAR AND STEEP LAPSE RATES SUPPORTING LARGE HAIL AND DAMAGING
WINDS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 24035.


..HALES

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MESO: Mesoscale Discussion 0475

ACUS11 KWNS 130431
SWOMCD
SPC MCD 130431
TXZ000-130630-

MESOSCALE DISCUSSION 0475
NWS STORM PREDICTION CENTER NORMAN OK
1131 PM CDT THU APR 12 2007

AREAS AFFECTED...WRN TX INTO THE TX PNHDL

CONCERNING...SEVERE THUNDERSTORM WATCH 131...

VALID 130431Z - 130630Z

THE SEVERE WEATHER THREAT IS EXPECTED TO PERSIST BEYOND 05Z AND A
NEW WW WILL LIKELY BE REQUIRED.

LATEST SURFACE OBSERVATIONS AND RUC OBJECTIVE FIELDS INDICATE THAT
LOW-LEVEL MOISTURE AND ATTENDANT INSTABILITY AXES CONTINUE TO
DEVELOP NWWD THROUGH THE CONCHO VALLEY AND W-CNTRL TX INTO THE
PERMIAN BASIN AND TX S PLAINS ALONG THE WRN EDGE OF 45-55 KT SSELY
LLJ. TSTM AREAL COVERAGE HAS TENDED TO DIMINISH OVER THE PAST
HOUR...PRESUMABLY AS STRONGER LARGE-SCALE FORCING FOR ASCENT
ASSOCIATED WITH LEAD SHORT WAVE TROUGH LIFTS NEWD THROUGH NWRN OK
AND SWRN KS...AND AWAY FROM DEVELOPING INSTABILITY AXIS FARTHER TO
THE SW.

THIS TREND MAY CONTINUE FOR THE NEXT COUPLE OF HOURS...HOWEVER BY
07-09Z...MODEL GUIDANCE SUGGESTS THAT LARGE-SCALE FORCING FOR UPWARD
VERTICAL MOTION WILL REINTENSIFY IN RESPONSE TO APPROACH OF MAIN
UPPER SYSTEM INTO WRN NM. AS THIS OCCURS...EXPECT RENEWED TSTM
DEVELOPMENT NEAR AND N OF QUASI-STATIONARY BOUNDARY CURRENTLY
EXTENDING FROM SURFACE LOW OVER SERN NM NEWD THROUGH THE TX S PLAINS
AND THEN MORE EWD THROUGH NWRN TX. ADDITIONAL STORMS MAY ALSO FORM
SWD ALONG AND E OF DRYLINE WHICH HAS RETREATED TO JUST W OF THE
PERMIAN BASIN.

THE PRESENCE OF QUITE STEEP MID-LEVEL LAPSE RATES /8-8.5 C PER KM/
IN CONJUNCTION WITH THE INCREASING BOUNDARY LAYER MOISTURE WILL
SUPPORT A CONTINUED INCREASE IN CONVECTIVE INSTABILITY WITH MUCAPES
APPROACHING 1500-1800 J/KG. WHEN COUPLED WITH THE STRONGLY SHEARED
ENVIRONMENT...POTENTIAL WILL EXIST FOR SUPERCELLS CAPABLE OF MAINLY
LARGE HAIL AND DAMAGING WINDS.

.MEAD.. 04/13/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...SJT...LUB...AMA...MAF...

32920290 33540303 34780296 35380281 35970196 36000099
35460033 34400008 33470019 32630038 31890101 32120262

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