Georgia-Florida SKYWARN: 04/12/07

Thursday, April 12, 2007

MESO: Mesoscale Discussion 0474

ACUS11 KWNS 130235
SWOMCD
SPC MCD 130235
TXZ000-OKZ000-NMZ000-130430-

MESOSCALE DISCUSSION 0474
NWS STORM PREDICTION CENTER NORMAN OK
0935 PM CDT THU APR 12 2007

AREAS AFFECTED...TX S PLAINS AND PNHDL

CONCERNING...SEVERE THUNDERSTORM WATCH 131...

VALID 130235Z - 130430Z

POTENTIAL FOR SEVERE STORMS CAPABLE OF LARGE HAIL AND LOCALLY
DAMAGING WIND IS EXPECTED TO CONTINUE ACROSS WW AREA FOR THE NEXT
SEVERAL HOURS. CONTINUE WW.

LATEST MESOANALYSIS INDICATES PRIMARY SURFACE LOW OVER SERN NM /NE
OF ROW/ WITH AN OUTFLOW-REINFORCED BAROCLINIC ZONE STRENGTHENING
ACROSS THE TX S PLAINS AND LOW ROLLING PLAINS. THIS BOUNDARY THEN
EXTENDED ESEWD ACROSS NRN TX. A SECONDARY LOW-LEVEL
BOUNDARY...DELINEATING THE NRN EDGE OF RICHER BOUNDARY LAYER
MOISTURE...WAS ANALYZED FROM W-CNTRL TX SEWD TO THE UPPER TX COAST.

AS MENTIONED ABOVE...CONSIDERABLE OUTFLOW HAS BEEN GENERATED BY
DIURNAL TSTMS OVER THE PNHDL AND S PLAINS WITH ONGOING ACTIVITY
LIKELY BECOMING SLIGHTLY ELEVATED ABOVE A SHALLOW...NEAR SURFACE
INVERSION. LATEST NAM/WRF AND RUC GUIDANCE SUGGEST THAT PRIMARY
INSTABILITY AXIS WILL REMAIN IN PLACE ACROSS WRN TX OVERNIGHT AS
INCREASING LOW-LEVEL MOISTURE CONTINUES TO RETURN NWWD BENEATH STEEP
MID-LEVEL LAPSE RATES.

ISENTROPIC ASCENT ABOVE SOLIDIFYING S PLAINS BAROCLINIC ZONE WILL
LIKELY PROVIDE THE FOCUS FOR RENEWED TSTM DEVELOPMENT OVERNIGHT
WITHIN THERMODYNAMIC ENVIRONMENT CHARACTERIZED BY MUCAPES OF
500-1000 J/KG. STRONG CLOUD BEARING SHEAR WILL REMAIN SUPPORTIVE OF
ELEVATED SUPERCELLS WITH LARGE HAIL BEING THE PRIMARY SEVERE WEATHER
THREAT. HOWEVER...LOCALLY DAMAGING DOWNBURSTS WILL ALSO BE POSSIBLE
OWING TO THE RELATIVELY SHALLOW SURFACE INVERSION AND MODERATELY
STRONG POTENTIAL NEGATIVE BUOYANCY /DCAPES AROUND 1000 J PER KG/.

.MEAD.. 04/13/2007

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

ATTN...WFO...OUN...SJT...LUB...AMA...MAF...ABQ...

36610308 36590040 34860026 34819993 32759984 32920330
34160426 35370427 35970332

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 130044
SWODY1
SPC AC 130042

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0742 PM CDT THU APR 12 2007

VALID 130100Z - 131200Z

..THERE IS A SLGT RISK OF SVR TSTMS OVER THE SRN HIGH PLAINS AND
PORTIONS OF THE SRN PLAINS...

..SRN HIGH PLAINS THROUGH PORTIONS OF THE SRN PLAINS...

MODEST BOUNDARY LAYER MOISTURE HAS RETURNED NWD THROUGH THE SRN HIGH
PLAINS OF WRN TX. EARLY THIS EVENING...DEWPOINTS RANGE FROM THE 40S
OVER SRN PORTIONS OF WRN TX TO THE 30S IN THE TX PANHANDLE. STEEP
MID LEVEL LAPSE RATES OVERLAPPING THE MOIST AXIS AND BOUNDARY LAYER
HEATING HAVE RESULTED IN AN AXIS OF 500 TO 1000 J/KG MUCAPE ACROSS
WRN TX. HIGH BASED STORMS ARE IN PROGRESS EARLY THIS EVENING FROM
NERN NM THROUGH THE TX PANHANDLE PROMOTED BY BOUNDARY LAYER MIXING
AND DEEP LAYER ASCENT ASSOCIATED WITH LEAD SHORTWAVE TROUGH MOVING
EWD THROUGH NM. DEEP LAYER VERTICAL SHEAR PROFILES WILL REMAIN
FAVORABLE FOR SUPERCELLS THIS EVENING. HOWEVER...HIGH BASED NATURE
OF THE STORMS SUGGESTS LARGE HAIL AND ISOLATED DAMAGING WIND GUSTS
WILL REMAIN THE PRIMARY THREATS.

OVERNIGHT THETA-E ADVECTION ASSOCIATED WITH STRENGTHENING LOW LEVEL
JET WILL CONTRIBUTE TO FURTHER DESTABILIZATION. THIS ALONG WITH
INCREASING ISENTROPIC ASCENT SHOULD RESULT IN THE DEVELOPMENT OF
ADDITIONAL STORMS. HOWEVER...ACTIVITY WILL LIKELY BECOME ELEVATED AS
THE BOUNDARY LAYER DECOUPLES. STORMS MAY EVENTUALLY EVOLVE INTO AN
MCS AND SPREAD EWD THROUGH PARTS OF THE SRN PLAINS AND KS. THE
THREAT FOR MOSTLY LARGE HAIL MAY PERSIST...ESPECIALLY ALONG THE WRN
AND SRN FLANKS OF THE MCS WHERE FEED OF HIGHER THETA-E AIR WILL
EXIST.

.DIAL.. 04/13/2007

MESO: Mesoscale Discussion 0473

ACUS11 KWNS 130037
SWOMCD
SPC MCD 130037
OKZ000-TXZ000-130230-

MESOSCALE DISCUSSION 0473
NWS STORM PREDICTION CENTER NORMAN OK
0737 PM CDT THU APR 12 2007

AREAS AFFECTED...FAR ERN TX PNHDL INTO NWRN TX AND WRN OK

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 130037Z - 130230Z

SEVERE THREAT /MAINLY IN THE FORM OF ELEVATED TSTMS CAPABLE OF LARGE
HAIL/ IS EXPECTED TO DEVELOP E OF WW 131 AFTER 02-03Z AND AN
ADDITIONAL WW MAY BECOME NECESSARY PRIOR TO THAT TIME.

AS OF 0020Z...REGIONAL RADAR IMAGERY INDICATED A CLUSTER OF STRONG
TO POTENTIALLY SEVERE STORMS /SOME OF WHICH HAVE EXHIBITED SUPERCELL
CHARACTERISTICS/ OVER ARMSTRONG...CASTRO...SWISHER...BRISCOE AND
FLOYD COUNTIES WITH A GENERAL MOTION OF 225/30-35 KT. RUC OBJECTIVE
FIELDS AND VISIBLE SATELLITE IMAGERY SUGGEST THAT THESE STORMS HAVE
LIKELY MOVED E OF PRIMARY SURFACE-BASED INSTABILITY AXIS IN PLACE
OVER THE HIGHER TERRAIN...AND INTO A PROGRESSIVELY MORE STABLE
BOUNDARY LAYER OVER THE LOW ROLLING PLAINS BASED ON BILLOW CLOUD
FORMATIONS IMMEDIATELY E OF ONGOING ACTIVITY.

THEREFORE...AS THESE STORMS CONTINUE TO MOVE EWD...THEY MAY TEND TO
WEAKEN AS THEY ENCOUNTER MORE STABLE BOUNDARY LAYER. BY AROUND
03Z...LATEST SHORT TERM MODEL GUIDANCE SUGGESTS THAT RAPID
INTENSIFICATION OF NOCTURNAL LLJ WILL OCCUR FROM W-CNTRL TX INTO THE
ERN TX PNHDL AND WRN OK. STEEPENING MID-LEVEL LAPSE RATES COUPLED
WITH INCREASING MOISTURE JUST ABOVE COLLAPSING BOUNDARY LAYER WILL
CONTRIBUTE TO AIR MASS DESTABILIZATION FOR ELEVATED PARCELS WITH
MUCAPES INCREASING TO 500-1000 J/KG.

ANY LINGERING DIURNAL STORMS MAY TEND TO REINTENSIFY AT THIS TIME
WHILE BECOMING SLIGHTLY ELEVATED WITH ADDITIONAL STORM DEVELOPMENT
LIKELY ACROSS DISCUSSION AREA WITHIN ZONE OF STRENGTHENING WAA.
GIVEN THE MODEST INSTABILITY AND STRONG SHEAR THROUGH THE CLOUD
BEARING LAYER...POTENTIAL WILL EXIST FOR ELEVATED SUPERCELLS.

.MEAD.. 04/13/2007

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

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

34499994 34839997 34870034 35240038 35550028 35730005
35729959 35329874 34369835 33769852 33559902 33639984

WATCHES: Severe Thunderstorm Watch Number 131

WWUS20 KWNS 122210
SEL1
SPC WW 122210
NMZ000-TXZ000-130500-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 131
NWS STORM PREDICTION CENTER NORMAN OK
510 PM CDT THU APR 12 2007

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

SMALL PART OF EASTERN NEW MEXICO
MUCH OF TEXAS PAN HANDLE

EFFECTIVE THIS THURSDAY AFTERNOON FROM 510 PM UNTIL MIDNIGHT CDT.

HAIL TO 2.5 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 80
STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH
NORTHEAST OF DALHART TEXAS TO 50 MILES SOUTH SOUTHEAST OF LUBBOCK
TEXAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

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.

DISCUSSION...MOISTURE WILL CONTINUE TO INCREASE NWD ACROSS WATCH
AREA THRU THE EVENING ON STRONG SELY JET. WITH VERY FAVORABLE DEEP
SHEAR AND STEEP LAPSE RATES IN PLACE...THUNDERSTORMS SHOULD DEVELOP
FROM W TO E ACROSS THE WATCH AREA. PRIMARY THREAT WILL BE LARGE
HAIL...PARTICULARLY WITH ANY SUPERCELL THAT DEVELOPS. DAMAGING
DOWNBURSTS ALSO POSSIBLE GIVEN THE STEEP LAPSE RATES AND STRONG
SHEAR PROFILES.

AVIATION...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 450. MEAN STORM
MOTION VECTOR 24030.

..HALES

MESO: Mesoscale Discussion 0472

ACUS11 KWNS 122149
SWOMCD
SPC MCD 122149
TXZ000-NMZ000-122315-

MESOSCALE DISCUSSION 0472
NWS STORM PREDICTION CENTER NORMAN OK
0449 PM CDT THU APR 12 2007

AREAS AFFECTED...ERN NM INTO W TX

CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY

VALID 122149Z - 122315Z

TSTMS ARE EXPECTED TO DEVELOP ACROSS DISCUSSION AREA BETWEEN 22-23Z
AND A SEVERE TSTM WATCH WILL LIKELY BE NEEDED.

LATEST VISIBLE SATELLITE IMAGERY SHOWS DEEPENING CUMULUS OVER THE TX
S PLAINS JUST W OF A LBB TO PVW LINE AND OVER PORTIONS OF S-CNTRL
NM...SUGGESTING THAT FORCING FOR ASCENT ASSOCIATED WITH SHORT WAVE
TROUGH OVER S-CNTRL NM IS BEGINNING TO ACT ON STEEP LAPSE RATE
ENVIRONMENT. WHILE LOW-LEVEL MOISTURE REMAINS SOMEWHAT LIMITED E OF
LEE TROUGH/DRYLINE CURRENTLY SITUATED IN N-S FASHION OVER ERN
NM...THE PRESENCE OF THESE STEEP LAPSE RATES IS RESULTING IN A
WEAKLY UNSTABLE ENVIRONMENT FOR SURFACE-BASED PARCELS WITH SBCAPES
OF AROUND 500 J/KG PER 20Z REESE AFB AND RUC PROXIMITY SOUNDINGS.

VERTICAL SHEAR IS QUITE SUPPORTIVE OF UPDRAFT ROTATION WITH 0-3 KM
SRH OF AROUND 250 M2/S2 AND EFFECTIVE BULK SHEARS OF 50 KT. AS
SUCH...EXPECT THAT A FEW STORMS WILL EVOLVE INTO SUPERCELLS DESPITE
THE MARGINAL INSTABILITY WITH THE PRIMARY THREATS BEING LARGE HAIL
AND LOCALLY DAMAGING WINDS. TSTMS DEVELOPING OVER ERN NM/WRN TX
SHOULD GRADUALLY MOVE EWD/NEWD INTO THE LOW ROLLING PLAINS/ERN TX
PNHDL LATER THIS EVENING AS SHORT WAVE TROUGH LIFTS OUT OF THE SRN
ROCKIES.

.MEAD.. 04/12/2007

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

ATTN...WFO...OUN...SJT...LUB...AMA...MAF...ABQ...

33530344 35040337 35390304 35680247 35760139 35260040
34390000 33240007 32790063 32610207 33000326

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 121942
SWODY1
SPC AC 121940

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0240 PM CDT THU APR 12 2007

VALID 122000Z - 131200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF WEST TX...SW
OK...NE NM...FAR SE CO AND FAR SW KS...

..WRN PART OF THE SRN PLAINS...
WATER VAPOR IMAGERY CURRENTLY SHOWS AN UPPER-LEVEL TROUGH DIGGING
SEWD OVER SRN CA. THIS FEATURE WILL BEGIN TO MOVE ESEWD INTO AZ BY
EARLY THIS EVENING WITH A LARGE AREA OF DIFFLUENCE UPSTREAM FROM THE
TROUGH OVER ERN NM AND WEST TX. IN RESPONSE TO THE APPROACHING
UPPER-LEVEL TROUGH...A LOW-LEVEL JET WILL STRENGTHEN ACROSS THE SRN
PLAINS THIS EVENING. THIS WILL ADVECT LOW-LEVEL MOISTURE NWD ACROSS
WEST TX WITH INSTABILITY INCREASING ALONG THE MOIST AXIS. ISOLATED
TO SCATTERED THUNDERSTORM ACTIVITY SHOULD DEVELOP ALONG THE LEADING
EDGE OF ASCENT AS A SHORTWAVE TROUGH EJECTS EWD ACROSS WEST TX THIS
EVENING AHEAD OF THE MAIN UPPER-LEVEL TROUGH.

FORECAST SOUNDINGS IN THE LUBBOCK AREA AND ALONG THE MOIST AXIS
EARLY THIS EVENING SHOW VERTICAL SHEAR EXCEEDING 60 KT SUGGESTING
SUPERCELLS WILL BE POSSIBLE UPON INITIATION. THE SUPERCELL THREAT
MAY INCREASE BY LATE EVENING AS AN AREA OF MODERATE INSTABILITY
DEVELOPS. MODEL FORECASTS SHOW VERY STEEP LAPSE RATES EXCEEDING 9.0
C/KM ALONG THE WRN EDGE OF THE SLIGHT RISK SUGGESTING LARGE HAIL
WILL BE LIKELY WITH THE STRONGER THUNDERSTORMS. THE GREATEST WIND
DAMAGE THREAT SHOULD BE CONFINED TO FAR NE NM AND WEST TX WHERE
LOW-LEVEL LAPSE RATES WILL BE THE STEEPEST. STRONG THUNDERSTORMS
WILL LIKELY SPREAD EWD FROM THE CAPROCK INTO THE LOW-ROLLING PLAINS
AND SW OK OVERNIGHT AS A BAND OF LARGE-SCALE ASCENT ASSOCIATED WITH
THE LEAD SHORTWAVE TROUGH EJECTS NEWD ACROSS THE REGION.

..NEW ENGLAND/MID-ATLANTIC...
WATER VAPOR IMAGERY CURRENTLY SHOWS A LARGE UPPER-LOW OVER THE GREAT
LAKES WITH SEVERAL SUBTLE SHORTWAVE TROUGHS ROUNDING THE BASE OF THE
TROUGH ACROSS THE NERN STATES. THE FIRST SHORTWAVE TROUGH IS MOVING
ACROSS NEW ENGLAND WHERE CONVECTION IS ONGOING. ALTHOUGH INSTABILITY
IS WEAK...FORECAST SOUNDINGS SHOW 0-1 KM SHEAR VALUES EXCEEDING 50
KT THIS AFTERNOON ACROSS SRN NEW ENGLAND. THIS SHOULD BE ENOUGH FOR
ISOLATED MARGINALLY SEVERE WIND GUSTS WITH THE STRONGER CONVECTION
OVER THE NEXT FEW HOURS.

FURTHER SOUTHWEST ACROSS THE MID-ATLANTIC STATES...A POCKET OF
INSTABILITY CURRENTLY EXISTS SHOWN ON OBJECTIVE ANALYSIS. FORECAST
SOUNDINGS IN THIS AREA THIS AFTERNOON SHOW LOW-LEVEL LAPSE RATES
EXCEEDING 8.0 C/KM WITH UNIDIRECTIONAL LOW-LEVEL WINDS INCREASING
FROM AROUND 10 KT AT THE SFC TO 35 KT AT 850 MB. THIS MAY BE ENOUGH
FOR A MARGINAL WIND DAMAGE THREAT AS THUNDERSTORMS MOVE EWD OUT OF
THE HIGHER TERRAIN ONTO THE COASTAL PLAINS LATE THIS AFTERNOON.

.BROYLES.. 04/12/2007

WATCHES: Test...tornado Watch - Number 9999...test

WWUS20 KWNS 121903
SEL9
SPC WW 121903
WIZ000-LMZ000-LSZ000-121900-

URGENT - IMMEDIATE BROADCAST REQUESTED
TEST...TORNADO WATCH - NUMBER 9999...TEST
NWS STORM PREDICTION CENTER NORMAN OK
203 PM CDT THU APR 12 2007

THE NWS STORM PREDICTION CENTER HAS CANCELLED...TEST...
TORNADO WATCH NUMBER 9999 ISSUED AT 100 PM CDT FOR PORTIONS OF

WISCONSIN
LAKE MICHIGAN
LAKE SUPERIOR

WATCHES: Test...tornado Watch Number 9999...test

WWUS20 KWNS 121757
SEL9
SPC WW 121757
WIZ000-LMZ000-LSZ000-121900-

URGENT - IMMEDIATE BROADCAST REQUESTED
TEST...TORNADO WATCH NUMBER 9999...TEST
NWS STORM PREDICTION CENTER NORMAN OK
100 PM CDT THU APR 12 2007

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

WISCONSIN
LAKE MICHIGAN
LAKE SUPERIOR

EFFECTIVE THIS THURSDAY AFTERNOON FROM 100 PM UNTIL 200 PM CDT.

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

THE TEST TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 95 STATUTE
MILES EAST AND WEST OF A LINE FROM 80 MILES NORTHWEST OF
RHINELANDER WISCONSIN TO 20 MILES WEST SOUTHWEST OF JANESVILLE
WISCONSIN. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).

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...THIS IS A TEST FOR COORDINATION.

AVIATION...TORNADOES AND 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
500. MEAN STORM MOTION VECTOR 24035.

..DARROW

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 121724
SWODY2
SPC AC 121723

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1223 PM CDT THU APR 12 2007

VALID 131200Z - 141200Z

..THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF NE AND ECNTRL
TX...FAR SE OK...SRN AR AND NRN LA...

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...ARKLATX REGION AND LOWER MS VALLEY...

..ARKLATX/LOWER MS VALLEY...
LATEST WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED
UPPER-LEVEL TROUGH OVER THE SWRN STATES WITH AN UPPER-LOW LOCATED
OVER CNTRL CA AND WRN NV. THIS FEATURE WILL CONTINUE TO DIG SEWD
INTO AZ TONIGHT AND MOVE QUICKLY EWD INTO WEST TX FRIDAY. A
LOW-LEVEL JET AHEAD OF THE APPROACHING TROUGH WILL BRING WARM MOIST
AIR INTO EAST TX AND MODERATE INSTABILITY SHOULD DEVELOP ACROSS MOST
OF EAST TX BY FRIDAY AFTERNOON. THE GREATEST INSTABILITY SHOULD
EXIST SOUTH OF A WARM FRONT WHICH SHOULD BE LOCATED FROM NEAR
DALLAS/FORT WORTH EXTENDING EWD ACROSS FAR SRN AR. THUNDERSTORMS
SHOULD BE ONGOING IN NORTHWEST AND NCNTRL TX DURING THE MORNING
ASSOCIATED WITH THE LOW-LEVEL JET. THIS ACTIVITY SHOULD SPREAD EWD
AND EXPAND IN COVERAGE ACROSS NE TX AND SRN OK FRIDAY AFTERNOON. THE
GREATEST THUNDERSTORM COVERAGE SHOULD EXIST ALONG THE WARM FRONT
EXTENDING NWD FOR 100 MILES OR SO. THUNDERSTORMS SHOULD CONTINUE TO
EXPAND THROUGH THE EVENING HOURS WITH A LARGE MCS MOVING EWD ACROSS
AR/LA INTO WRN MS DURING THE OVERNIGHT PERIOD. THUNDERSTORM
DEVELOPMENT MAY ALSO OCCUR SWD ACROSS FAR EAST TX AS THE CAPPING
INVERSION WEAKENS OVERNIGHT.

THE GREATEST SEVERE THREAT SHOULD EXIST WITH THUNDERSTORMS THAT
DEVELOP IN A FAIRLY NARROW ZONE NEAR THE WARM FRONT FRIDAY AFTERNOON
AND EVENING. FORECAST SOUNDINGS ALONG AND JUST SOUTH OF THE WARM
FRONT LATE FRIDAY AFTERNOON SHOW IMPRESSIVE WIND SHEAR PROFILES WITH
0-6 KM SHEAR VALUES OF 60 KT SUGGESTING SUPERCELLS WILL BE LIKELY
UPON THUNDERSTORM INITIATION FRIDAY AFTERNOON. IN ADDITION...0-1 KM
SHEAR VALUES OF 25 TO 30 KT AND SUBSTANTIAL DIRECTIONAL TURNING
BELOW 850 MB SHOULD BE FAVORABLE FOR TORNADOES ESPECIALLY WITH
SUPERCELLS THAT DEVELOP NEAR THE WARM FRONTAL BOUNDARY. THE TORNADO
THREAT MAY BECOME ENHANCED WITH RIGHT MOVING SUPERCELLS THAT TRACK
EWD ALONG THE WARM FRONT. THE SYNOPTIC SETUP APPEARS SOMEWHAT
SIMILAR TO THE MARCH 28, 2000 FORT WORTH TX TORNADO EVENT ONLY THIS
SYSTEM AND THE WIND FIELDS FRIDAY WILL BE STRONGER. ALSO...THE MID
TO UPPER-LEVEL JET IS MORE CYCLONICALLY CURVED AND THE GREATEST
TORNADO THREAT AREA MAY BE SHIFTED SEWD COMPARED TO MARCH 28, 2000.
A FEW SIGNIFICANT TORNADOES ARE POSSIBLE ACROSS NE TX AND NW LA WITH
LONGER-LIVED SUPERCELLS ALSO POSSIBLE. LARGE HAIL AND WIND DAMAGE
WILL ALSO LIKELY ACCOMPANY SUPERCELLS THAT DEVELOP FRIDAY AFTERNOON
AND EVENING. ISOLATED VERY LARGE HAIL COULD OCCUR WITH SUPERCELLS
ALONG THE WRN EDGE OF THE INSTABILITY AXIS IN NCNTRL TX DUE TO
STEEPER MID-LEVEL LAPSE RATES THERE. HOW FAR SOUTH THE SEVERE THREAT
WILL EXIST STILL REMAINS HIGHLY UNCERTAIN AND THE STRENGTH OF THE
CAPPING INVERSION WILL LIKELY DETERMINE SEVERE WEATHER REPORT
COVERAGE ACROSS ECNTRL TX. AS A LARGE MCS DEVELOPS FRIDAY
EVENING...THE SEVERE THREAT SHOULD CONTINUE SPREADING EWD ACROSS SRN
AR AND LA WITH THE THREAT DIMINISHING LATE FRIDAY NIGHT ACROSS CNTRL
MS.

..ERN TX PANHANDLE/SW OK...
AN UPPER-LOW EVIDENT ON WATER VAPOR IMAGERY WILL MOVE SEWD INTO AZ
TONIGHT AND EWD TO THE VICINITY OF THE TX PANHANDLE FRIDAY
AFTERNOON. THUNDERSTORM DEVELOPMENT NEAR AND SOUTHEAST OF THE
UPPER-LOW SHOULD OCCUR AS SFC TEMPS WARM LATE FRIDAY MORNING INTO
THE AFTERNOON. FORECAST SOUNDINGS NEAR THE UPPER-LOW FRIDAY
AFTERNOON SHOW VERTICAL SHEAR PROFILES SUFFICIENT FOR SUPERCELLS.
IN ADDITION...LAPSE RATES WILL BE VERY STEEP AND SEVERE
THUNDERSTORMS WITH LARGE HAIL APPEAR LIKELY. THE SEVERE THREAT
SHOULD SPREAD EWD FROM THE TX PANHANDLE INTO SW OK AND NCNTRL TX BY
LATE AFTERNOON AND EARLY EVENING. A FEW DAMAGING WIND GUSTS AND AN
ISOLATED TORNADO THREAT MAY ALSO OCCUR WITH THE STRONGER SUPERCELL
THUNDERSTORMS.

.BROYLES.. 04/12/2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 121630
SWODY1
SPC AC 121628

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1128 AM CDT THU APR 12 2007

VALID 121630Z - 131200Z

..THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SOUTHERN HIGH
PLAINS...

..SOUTHERN HIGH PLAINS...
MORNING WATER VAPOR IMAGERY SHOWS LARGE UPPER TROUGH DEVELOPING OVER
THE WESTERN STATES TODAY...WITH LEAD SHORTWAVE TROUGH NOW EVIDENT
ACROSS CENTRAL AZ. THIS FEATURE IS FORECAST TO MOVE ACROSS NM TODAY
AND INTO WEST TX/OK OVERNIGHT. STRONG DAYTIME HEATING IS OCCURRING
OVER MUCH OF THE SOUTHERN HIGH PLAINS WITH STRENGTHENING SOUTHERLY
LOW LEVEL WINDS ACROSS THE REGION. BY LATE THIS AFTERNOON...A
DEVELOPING DRYLINE SHOULD EXTEND FROM THE NM/TX BORDER WEST OF
MAF...INTO NORTHEAST NM. DEWPOINTS EAST OF THE DRYLINE WILL ONLY BE
IN THE 40S. HOWEVER...TEMPERATURES WELL INTO THE 60S WILL RESULT IN
STEEP DEEP LAYER LAPSE RATES AND MUCAPE VALUES APPROACHING 1000
J/KG.

SCATTERED HIGH-BASED CONVECTION IS EXPECTED TO DEVELOP WEST OF THE
DRYLINE AND BUILD EASTWARD INTO THE UNSTABLE AIR DURING THE LATE
AFTERNOON. THIS WILL LIKELY RESULT IN ISOLATED THUNDERSTORMS BY 00Z
OVER NORTHEAST NM AND WEST TX. THESE STORMS WILL LIKELY BECOME
SUPERCELLS WITH A RISK OF LARGE HAIL AND DAMAGING WINDS. AXIS OF
SURFACE-BASED INSTABILITY WILL BE RATHER NARROW...WITH ACTIVITY
BECOMING ELEVATED AS IT DEVELOPS NORTHEASTWARD INTO PARTS OF
SOUTHWEST KS AND WESTERN OK. POTENTIAL FOR ELEVATED HAIL STORMS
WILL LIKELY PERSIST THROUGHOUT THE NIGHT IN THOSE AREAS.

..EASTERN AZ...
PRIMARY UPPER TROUGH IS NOW DIGGING SOUTHWARD ACROSS CA/NV. LARGE
SCALE FORCING IN ADVANCE OF THIS FEATURE WILL BEGIN AFFECTING PARTS
OF AZ BY THIS EVENING. FORECAST SOUNDINGS IN THIS AREA SHOW ONLY
MARGINAL INSTABILITY...BUT VERY STEEP LAPSE RATES AND A DEEP...MIXED
BOUNDARY LAYER. ISOLATED THUNDERSTORMS MAY DEVELOP IN THIS
REGIME...WITH STRONGEST CELLS CAPABLE OF GUSTY/DAMAGING WINDS.

.HART/GRAMS.. 04/12/2007

WATCHES: Tornado Watch - Number 130

WWUS20 KWNS 121517
SEL0
SPC WW 121517
NCZ000-SCZ000-VAZ000-CWZ000-121500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH - NUMBER 130
NWS STORM PREDICTION CENTER NORMAN OK
1117 AM EDT THU APR 12 2007

THE NWS STORM PREDICTION CENTER HAS CANCELLED
TORNADO WATCH NUMBER 130 ISSUED AT 325 AM EDT FOR PORTIONS OF

NORTH CAROLINA
SOUTH CAROLINA
VIRGINIA
COASTAL WATERS

SWODY 3

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0231 AM CDT THU APR 12 2007

VALID 141200Z - 151200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE DEEP S INTO
THE SERN STATES...

..DEEP SOUTH INTO THE SERN STATES...
STRONG UPR LOW THAT WILL MOVE INTO THE SRN PLAINS AREA ON FRI WILL
DEAMPLIFY FOR A TIME SATURDAY AS IT PHASES WITH THE NRN STREAM. NRN
STREAM ENERGY DIGGING SWD ALONG THE LONGWAVE TROUGH AXIS LATER
SATURDAY WILL ENHANCE THE UPR LEVEL JET ACROSS THE CNTRL/ERN GULF
COASTAL AREA.

WIDESPREAD TSTMS...SOME SVR...WILL LIKELY BE ONGOING ACROSS THE
MID-SOUTH AND WRN GULF COAST REGION EARLY SATURDAY. THE WARM SECTOR
AHEAD OF THE STORMS WILL CONTINUE TO MODIFY THROUGH THE DAY
SATURDAY...WITH 60S DEW POINTS ADVECTING NWD INTO ERN LA...SRN PARTS
OF AL/MS AND THE WRN FL PNHDL. THIS SHOULD RESULT IN SUFFICIENT
DESTABILIZATION FOR TSTM INTENSIFICATION...EITHER FROM MORNING
ACTIVITY...OR FROM NEW DEVELOPMENT ALONG BOUNDARIES ACROSS THE DEEP
SOUTH.

SUFFICIENT SHEAR WILL EXIST FOR SUPERCELLS...THOUGH THE SOMEWHAT
UNIDIRECTIONAL CHARACTER TO THE EXPECTED PROFILE WOULD SUGGEST
LINES/BOWS WITH POSSIBLE HIGH WINDS...HAIL AND ISOLD TORNADOES. AS
THE TROUGH INTENSIFIES AGAIN DURING THE EVE...THERE MIGHT BE A
SLIGHTLY HIGHER POTENTIAL FOR MORE DISCRETE CELLS FARTHER DOWNSTREAM
ACROSS SRN AL...SRN GA AND NRN FL. ACTIVITY IS EXPECTED TO
MOVE/DEVELOP ENEWD TOWARD THE ERN CAROLINAS BY 12Z SUNDAY AS THE LLJ
AXIS SHIFTS QUICKLY ENEWD TO NEAR THE SERN COAST.

.RACY.. 04/12/2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 121232
SWODY1
SPC AC 121229

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0729 AM CDT THU APR 12 2007

VALID 121300Z - 131200Z

..THERE IS A SLGT RISK OF SVR TSTMS OVER WRN PARTS OF THE SRN
PLNS...

..SYNOPSIS...
DIFFLUENT...NEGATIVE TILT TROUGH NOW ENTERING THE WRN GRT BASIN
SHOULD FURTHER AMPLIFY AS IT CONTINUES SE INTO THE LWR CO VLY THIS
EVENING...AND THEN TURNS E TO REACH WRN NM AS A CLOSED LOW EARLY
FRIDAY. AHEAD OF THIS SYSTEM...SATELLITE AND VWP DATA SHOW A WEAKER
LEAD FEATURE NOW APPROACHING THE CA/AZ BORDER THAT SHOULD REACH FAR
ERN NM THIS EVENING. IN THE EAST...VIGOROUS DOWNSTREAM SYSTEM NOW
CENTERED OVER LWR MI EXPECTED TO ELONGATE E TOWARD UPSTATE NY/NRN
ENGLAND.

AT LWR LEVELS...PRESSURES HAVE JUST BEGUN TO FALL OVER ERN NM/FAR W
TX. THESE FALLS SHOULD INCREASE THROUGH TONIGHT AS LEE CYCLONE
DEVELOPS NEAR CVS...AND WARM FRONT GRADUALLY EVOLVES ESE TOWARD
HOU/GLS.

..FAR ERN NM INTO W TX...OK...AND SRN KS
SFC OBSERVATIONS AND SATELLITE DATA SHOW LEADING EDGE OF RICH GULF
MOISTURE /DEWPOINTS NEAR 70 F/ JUST BEGINNING TO EDGE NW INTO DEEP S
TX. MUCH DRIER AIR IS PRESENT N AND W OF THERE...WITH DEWPOINTS IN
THE 40S AND 30S OVER MUCH OF THE REMAINDER OF TX. STRENGTHENING LLJ
WILL ALLOW AT LEAST A NARROW RIBBON OF ENHANCED MOISTURE TO SPREAD
RAPIDLY NNW INTO W CNTRL TX AND THE SRN TX PANHANDLE BY
EVENING...WHERE DEWPOINTS SHOULD INCREASE TO AROUND 50. A MORE
SUBSTANTIAL MOISTURE INCREASE LIKELY WILL OCCUR TONIGHT...WITH
READINGS AROUND 60 POSSIBLE NWD TO VICINITY OF DEVELOPING WARM FRONT
NEAR CDS BY 12Z FRIDAY.

COMBINATION OF STRONG SFC HEATING...INCREASING MOISTURE...
CONVERGENCE INVOF STRENGTHENING LEE CYCLONE/TROUGH...AND
FAVORABLY-TIMED LARGE SCALE ASCENT PROVIDED BY LEAD UPR IMPULSE
EXPECTED TO SUPPORT DEVELOPMENT OF HIGH-BASED TSTMS BY LATE THIS
AFTERNOON IN NE NM AND THE WRN TX PANHANDLE. ADDITIONAL SOMEWHAT
MORE SUBSTANTIAL ACTIVITY LIKELY WILL APPEAR A BIT LATER FARTHER S
OR SE ACROSS W CNTRL TX...WHERE MLCAPE SHOULD FROM 500 TO 1000 J/KG.

50-60 KT WSWLY 500 MB FLOW ATOP 40+ KT SLY LLJ WILL MAINTAIN DEEP
SHEAR FAVORABLE FOR SUPERCELLS GIVEN STEEP LOW TO MID LEVEL LAPSE
RATES. WHILE LARGE HAIL AND POSSIBLY DAMAGING WIND SHOULD BE THE
INITIAL SEVERE THREATS...POTENTIAL WILL INCREASE FOR A BRIEF TORNADO
OR TWO THROUGH MID EVENING AS LLJ STRENGTHENS AND MOISTENS.

LATER TONIGHT...ARRIVAL OF RICHER MOISTURE AND INCREASING WARM
ADVECTION LIKELY WILL RESULT IN INCREASED STORM COVERAGE ALONG AND
EVEN WELL N OF DEVELOPING WARM FRONT. STRENGTH AND BREADTH OF LLJ
..AND APPROACH OF MAIN UPR SYSTEM...SUGGEST THAT THIS ACTIVITY WILL
EVOLVE INTO ONE OR MORE OVERNIGHT MCSS. THESE SYSTEMS SHOULD
MOVE/DEVELOP E/NE ACROSS NW TX...MUCH OF OK AND SRN KS...POSING A
THREAT FOR LARGE HAIL AND...IN TX...ALSO PERHAPS DAMAGING WIND.

..MD/DE/PA/NJ...
DRY SLOT ASSOCIATED WITH DEEP GRT LKS UPR LOW WILL SWEEP ENE ACROSS
THE MID ATLANTIC REGION TODAY...WHERE IT WILL OVERSPREAD NARROW AXIS
OF LOW LEVEL MOISTURE OVER THE UPR CHESAPEAKE BAY/LOWER
SUSQUEHANNA/DELAWARE VLYS AROUND MAX HEATING. RELATIVELY STEEP LOW
TO MID LEVEL LAPSE RATES AND MODERATE TO STRONG WSWLY FLOW APPEAR
FAVORABLE FOR DEVELOPMENT OF ONE OR TWO SHORT LINES OF SUSTAINED
STORMS THAT COULD YIELD MARGINALLY SEVERE HAIL.

..SE FL...
TSTMS NOW OVER SW FL AND OFF THE SW FL CST APPEAR TO HAVE FORMED IN
RESPONSE TO INCREASED WARM ADVECTION ATOP SHALLOW COLD DOME LEFT
FROM YESTERDAY'S ACTIVITY. THE STORMS SHOULD MOVE/DEVELOP GENERALLY
E ACROSS THE REMAINDER OF S FL THROUGH MIDDAY. MODEST SWLY LOW TO
MID LEVEL FLOW WILL MINIMIZE UPDRAFT LONGEVITY/ ORGANIZATION. BUT
PRESENCE OF 60 KT JET LEVEL WINDS... UNIDIRECTIONAL NATURE OF DEEP
FLOW...AND ONSET OF DAYTIME HEATING IN FAIRLY UNSTABLE ENVIRONMENT
/SBCAPE TO 2000 J PER KG/ SUGGEST POTENTIAL FOR A FEW SPOTS OF
LOCALLY DAMAGING WIND AND HAIL /REF MCD #470/.

.CORFIDI/CROSBIE.. 04/12/2007

MESO: Mesoscale Discussion 0471

ACUS11 KWNS 121225
SWOMCD
SPC MCD 121225
NCZ000-VAZ000-121400-

MESOSCALE DISCUSSION 0471
NWS STORM PREDICTION CENTER NORMAN OK
0725 AM CDT THU APR 12 2007

AREAS AFFECTED...PORTIONS ERN NC...SERN VA.

CONCERNING...TORNADO WATCH 130...

VALID 121225Z - 121400Z

SVR THREAT CONTINUES OVER WW BUT IS DIMINISHING...AND WW MAY BE
CANCELED BEFORE SCHEDULED 15Z EXPIRATION IF PRESENT CONVECTIVE
TRENDS CONTINUE.

STRONGEST ACTIVITY HAS MOVED OVER ATLANTIC WATERS E OF MHX AREA AND
S OF HSE...AS SMALL BUT WELL DEFINED BOW ECHO. THIS ACTIVITY
SHOULD REMAIN OVER WATER WITH APEX OF BOW PASSING OVER -- OR VERY
CLOSE TO -- BUOY 41025 BEFORE 13Z. STRONGEST BOUNDARY LAYER FORCING
ALSO HAS MOVED OFFSHORE FARTHER N -- OFF ERN NC AND VA.
WEAK/PREFRONTAL CONFLUENCE LINE HAS MOVED EWD TO NEAR
ECG...NKT...OAJ...AND SHOULD CONTINUE CROSSING REMAINDER COASTAL
PLAIN AND SOUNDS THROUGH 15Z. VEERING LOW LEVEL WIND PROFILES W OF
THAT LINE SHOULD CONTINUE...AS STRONGEST ISALLOBARIC FORCING EJECTS
NEWD ACROSS MID-ATLANTIC REGION. THIS PROCESS WILL FURTHER REDUCE
BOTH CONVERGENCE AND LOW LEVEL VERTICAL SHEAR. POCKET OF PRONOUNCED
MIDLEVEL WARMING -- EVIDENT IN 12Z GSO RAOB -- ALSO MAY FURTHER
RESTRICT POTENTIAL FOR ADDITIONAL DEVELOPMENT W OF CONFLUENCE LINE.

.EDWARDS.. 04/12/2007

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

ATTN...WFO...AKQ...MHX...

34557726 35127710 36447625 36757591 36167573 35637544
35247553 35027606 34587653 34687671 34657702

MESO: Mesoscale Discussion 0470

ACUS11 KWNS 121106
SWOMCD
SPC MCD 121106
FLZ000-121330-

MESOSCALE DISCUSSION 0470
NWS STORM PREDICTION CENTER NORMAN OK
0606 AM CDT THU APR 12 2007

AREAS AFFECTED...PORTIONS S FL AND KEYS.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 121106Z - 121330Z

SCATTERED-NUMEROUS TSTMS SHOULD MOVE EWD ACROSS SRN PORTIONS FL
PENINSULA...AND PERHAPS PORTIONS LOWER-MIDDLE KEYS...DURING NEXT FEW
HOURS. ISOLATED HAIL/GUSTS NEAR SVR LEVELS ARE POSSIBLE...HOWEVER
THREAT APPEARS TOO MRGL TO WARRANT WW.

RICHLY MOIST MARINE AIR MASS -- CHARACTERIZED BY 70S F SFC DEW
POINTS -- ARE EXPECTED TO SPREAD INLAND OVER MORE OF SRN PENINSULA
BEFORE ARRIVAL OF MAIN AREA OF CONVECTION. THIS...ALONG WITH SOME
HEATING FROM MORNING INSOLATION...SHOULD OFFSET WEAK LOW-MIDLEVEL
LAPSE RATES ENOUGH TO YIELD MUCAPES 1000-1500 J/KG AND WEAKENING
SBCINH. WEAK LOW LEVEL WINDS -- EVIDENT IN AVAILABLE VWP DATA AND
IN RUC FCST SOUNDINGS -- WILL KEEP LOW LEVEL SHEAR WEAK AND
HODOGRAPHS SMALL. STRONG UPPER LEVEL WINDS...HOWEVER....WILL AID IN
VENTING OF UPDRAFT COLUMNS ALOFT AND MAY CONTRIBUTE TO SUSTAINED AND
SOMEWHAT ORGANIZED MULTICELLULAR/LINEAR SEGMENTED STRUCTURES.

.EDWARDS.. 04/12/2007

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

ATTN...WFO...MFL...KEY...TBW...

26098179 26878155 27038120 26638001 24908071 24528180
24638295 24628215 24758161 24878105 25038091 25098108
25268117 25438118 25728133 25918162 25778168

MESO: Mesoscale Discussion 0469

ACUS11 KWNS 121042
SWOMCD
SPC MCD 121042 COR
NCZ000-VAZ000-121115-

MESOSCALE DISCUSSION 0469
NWS STORM PREDICTION CENTER NORMAN OK
0542 AM CDT THU APR 12 2007

AREAS AFFECTED...PORTIONS ERN NC...SERN VA.

CONCERNING...TORNADO WATCH 130...

VALID 121042Z - 121115Z

CORRECTED FOR WW TYPE

SVR POTENTIAL CONTINUES IN REMAINING PORTIONS WW...ESPECIALLY E OF
WIND SHIFT/CONFLUENCE LINE DELINEATED BELOW.

STRONGEST ACTIVITY AS OF 10Z -- OVER ONSLOW/PENDER COUNTIES NC --
WILL MOVE OFFSHORE ATLANTIC COAST BETWEEN ILM-NKT BY 11Z...EXCEPT
FOR COASTAL AREAS AROUND MHX AND CAPE LOOKOUT WHERE NRN PORTION OF
COMPLEX WILL PASS THROUGH 12Z. FARTHER N...ALTHOUGH BUOYANCY/SHEAR
ENVIRONMENT REMAINS FAVORABLE...MESSY/DISORGANIZED CONVECTIVE MODE
HAS HINDERED SVR THREAT FOR ACTIVITY MOVING EWD ACROSS
E-CENTRAL/NERN NC TOWARD PAMLICO/ALBEMARLE SOUNDS. SFC WINDS ARE
VEERING E OF I-95 NOW IN RESPONSE TO NEWD EJECTION OF STRONGEST
ISALLOBARIC FORCING ACROSS DELMARVA REGION. AT
10Z...ASSOCIATED/PREFRONTAL WIND SHIFT LINE WAS ANALYZED FROM SUSSEX
COUNTY VA SWWD THROUGH GSB THEN SSWWD TO COASTAL NC/SC
BORDER...MOVING EWD APPROXIMATELY 15-20 KT. W OF THAT WIND SHIFT
LINE...LOW LEVEL SHEAR AND CONVERGENCE EACH DIMINISH
MARKEDLY...LOWERING PROBABILITY FOR ADDITIONAL CONVECTIVE
INITIATION. E OF THAT LINE...ADDITIONAL CONVECTION STILL MAY
DEVELOP WITH SUPERCELLS AND SMALL BOWS POSSIBLE...THEREFORE WW
SHOULD BE MAINTAINED INVOF SOUNDS AND ADJACENT ERN COASTAL
PLAIN...UNTIL PASSAGE OF CONFLUENCE LINE.

.EDWARDS.. 04/12/2007

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

ATTN...WFO...AKQ...MHX...RAH...ILM...

33867851 35507774 36787703 37117653 37117589 36957599
36247579 35637544 35227553 35037603 34597651 34687669
34647704 34337764 33847796 33917829

MESO: Mesoscale Discussion 0469

ACUS11 KWNS 121018
SWOMCD
SPC MCD 121018
NCZ000-VAZ000-121115-

MESOSCALE DISCUSSION 0469
NWS STORM PREDICTION CENTER NORMAN OK
0518 AM CDT THU APR 12 2007

AREAS AFFECTED...PORTIONS ERN NC...SERN VA.

CONCERNING...SEVERE THUNDERSTORM WATCH 130...

VALID 121018Z - 121115Z

SVR POTENTIAL CONTINUES IN REMAINING PORTIONS WW...ESPECIALLY E OF
WIND SHIFT/CONFLUENCE LINE DELINEATED BELOW.

.EDWARDS.. 04/12/2007

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

ATTN...WFO...AKQ...MHX...RAH...ILM...

33867851 35507774 36787703 37117653 37117589 36957599
36247579 35637544 35227553 35037603 34597651 34687669
34647704 34337764 33847796 33917829

DAY48SVR: Nws Storm Prediction Center Norman Ok

ACUS48 KWNS 120849
SWOD48
SPC AC 120849

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0349 AM CDT THU APR 12 2007

VALID 151200Z - 201200Z

..DISCUSSION...
UPR FLOW REGIME WILL REMAIN QUITE ENERGETIC WITH A NUMBER OF
SHORTWAVE TROUGHS TRAVERSING NORTH AMERICA DURING THE NEXT WEEK OR
SO. THE UPPER TROUGH EXPECTED TO BE IMPETUS FOR SEVERE WEATHER
DURING THE END OF THE WEEK ACROSS THE SRN PLAINS TO THE SERN STATES
WILL CLOSE OFF INTO A LOW AGAIN BY SUNDAY NEAR THE MID-ATLANTIC.
THIS FEATURE WILL THEN MOVE NWD INTO NEW ENGLAND THROUGH EARLY NEXT
WEEK. DEEP NWLY FLOW ALOFT IN WAKE OF THIS SYSTEM WILL SEND A
CONTINENTAL POLAR AIR MASS SWD INTO THE GULF OF MEXICO.

NEXT IN A SERIES OF UPPER TROUGHS WILL QUICKLY MOVE SEWD INTO THE
SRN PLAINS BY MON-TUE NEXT WEEK. BUT...SHORT WAVELENGTHS BETWEEN
TROUGHS WILL PROBABLY NOT ALLOW AMPLE TIME FOR QUALITY MOISTURE TO
WORK NWWD. NONETHELESS...STEEP LAPSE RATES AND FAST FLOW ALOFT MAY
YIELD ISOLD-SCT TSTMS...SOME OF WHICH COULD BE SVR...OVER PARTS OF
THE SRN PLAINS EARLY NEXT WEEK. BUT...THIS SCENARIO DOES NOT FALL
INTO THE FRAMEWORK OF A MEDIUM RANGE SVR OUTLOOK.

.RACY.. 04/12/2007

WATCHES: Severe Thunderstorm Watch - Number 128

WWUS20 KWNS 120837
SEL8
SPC WW 120837
GAZ000-SCZ000-121000-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH - NUMBER 128
NWS STORM PREDICTION CENTER NORMAN OK
437 AM EDT THU APR 12 2007

THE NWS STORM PREDICTION CENTER HAS CANCELLED
SEVERE THUNDERSTORM WATCH NUMBER 128 ISSUED AT 1100 PM EDT FOR PORTIONS OF

GEORGIA
SOUTH CAROLINA

MESO: Mesoscale Discussion 0468

ACUS11 KWNS 120801
SWOMCD
SPC MCD 120801
SCZ000-GAZ000-120930-

MESOSCALE DISCUSSION 0468
NWS STORM PREDICTION CENTER NORMAN OK
0301 AM CDT THU APR 12 2007

AREAS AFFECTED...PORTIONS SERN GA...CENTRAL/SRN SC.

CONCERNING...SEVERE THUNDERSTORM WATCH 128...

VALID 120801Z - 120930Z

11 128 SVR POTENTIAL CONTINUES BUT IS DIMINISHING...AND REMAINING
PORTIONS WW MAY BE CANCELED BEFORE SCHEDULED 10Z EXPIRATION. WFO
FFC IS CLEARING THEIR COUNTIES PER COORDINATION.

OVERALL WEAKENING TREND EVIDENT IN REFLECTIVITY PATTERNS SHOULD
CONTINUE AS STRONGEST ISALLOBARIC FORCING SHIFTS NE OF
AREA...BOUNDARY LAYER FLOW VEERS...AND CONSEQUENTIALLY...BOTH LOW
LEVEL CONVERGENCE AND SHEAR GRADUALLY WILL WEAKEN. LOW LEVEL AIR
MASS ACROSS REGION REMAINS AT LEAST MRGLLY FAVORABLE WITH SFC DEW
POINTS MID 60S F CONTRIBUTING TO MUCAPES AROUND 500-700 J/KG...AND
0-3 KM SRH 150-200 J/KG FOR ANY EWD MOVING/DISCRETE CELLS.
THEREFORE REMAINING PORTIONS WW SHOULD BE MAINTAINED UNTIL PRIMARY
BAND OF CONVECTION HAS PASSED. HOWEVER...WW MAY NOT BE NECESSARY
FARTHER E OVER SRN COASTAL PLAIN OF SC IF PRESENT TRENDS CONTINUE.

.EDWARDS.. 04/12/2007

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

ATTN...WFO...CHS...CAE...JAX...FFC...

31668111 31808198 31978245 31768286 33068150 33668071
33478005 33037933 32348047

DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 120732
SWODY3
SPC AC 120731

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0231 AM CDT THU APR 12 2007

VALID 141200Z - 151200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE DEEP S INTO
THE SERN STATES...

..DEEP SOUTH INTO THE SERN STATES...
STRONG UPR LOW THAT WILL MOVE INTO THE SRN PLAINS AREA ON FRI WILL
DEAMPLIFY FOR A TIME SATURDAY AS IT PHASES WITH THE NRN STREAM. NRN
STREAM ENERGY DIGGING SWD ALONG THE LONGWAVE TROUGH AXIS LATER
SATURDAY WILL ENHANCE THE UPR LEVEL JET ACROSS THE CNTRL/ERN GULF
COASTAL AREA.

WIDESPREAD TSTMS...SOME SVR...WILL LIKELY BE ONGOING ACROSS THE
MID-SOUTH AND WRN GULF COAST REGION EARLY SATURDAY. THE WARM SECTOR
AHEAD OF THE STORMS WILL CONTINUE TO MODIFY THROUGH THE DAY
SATURDAY...WITH 60S DEW POINTS ADVECTING NWD INTO ERN LA...SRN PARTS
OF AL/MS AND THE WRN FL PNHDL. THIS SHOULD RESULT IN SUFFICIENT
DESTABILIZATION FOR TSTM INTENSIFICATION...EITHER FROM MORNING
ACTIVITY...OR FROM NEW DEVELOPMENT ALONG BOUNDARIES ACROSS THE DEEP
SOUTH.

SUFFICIENT SHEAR WILL EXIST FOR SUPERCELLS...THOUGH THE SOMEWHAT
UNIDIRECTIONAL CHARACTER TO THE EXPECTED PROFILE WOULD SUGGEST
LINES/BOWS WITH POSSIBLE HIGH WINDS...HAIL AND ISOLD TORNADOES. AS
THE TROUGH INTENSIFIES AGAIN DURING THE EVE...THERE MIGHT BE A
SLIGHTLY HIGHER POTENTIAL FOR MORE DISCRETE CELLS FARTHER DOWNSTREAM
ACROSS SRN AL...SRN GA AND NRN FL. ACTIVITY IS EXPECTED TO
MOVE/DEVELOP ENEWD TOWARD THE ERN CAROLINAS BY 12Z SUNDAY AS THE LLJ
AXIS SHIFTS QUICKLY ENEWD TO NEAR THE SERN COAST.

.RACY.. 04/12/2007

WATCHES: Tornado Watch Number 130

WWUS20 KWNS 120727
SEL0
SPC WW 120727
NCZ000-SCZ000-VAZ000-CWZ000-121500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 130
NWS STORM PREDICTION CENTER NORMAN OK
325 AM EDT THU APR 12 2007

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

EASTERN NORTH CAROLINA
NORTHEAST SOUTH CAROLINA
SOUTHEASTERN VIRGINIA
COASTAL WATERS

EFFECTIVE THIS THURSDAY MORNING FROM 325 AM UNTIL 1100 AM EDT.

TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 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 55 MILES SOUTHEAST OF FLORENCE
SOUTH CAROLINA TO 20 MILES NORTH NORTHEAST OF NORFOLK VIRGINIA.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).

OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES SEVERE
THUNDERSTORM WATCH NUMBER 129. WATCH NUMBER 129 WILL NOT BE IN
EFFECT AFTER 325 AM EDT. CONTINUE...WW 128...

DISCUSSION...SUSTAINED TSTMS/MARGINAL SUPERCELLS CONTINUE TO FORM IN
BROKEN BAND EXTENDING SW/NE ACROSS ERN PORTIONS OF THE SC/NC
PIEDMONT. THIS BAND SHOULD CONTINUE E ACROSS THE CSTL PLN LATER
THIS MORNING...WHERE STORMS WILL ENCOUNTER A SLOWLY WARMING AND
MOISTENING BOUNDARY LAYER. WITH SFC LOW CENTER FORMING IN E CNTRL
VA...BACKED LOW LEVEL WINDS IN WW AREA WILL REMAIN SUPPORTIVE OF LOW
LEVEL STORM ROTATION...WHILE 60+ KT WSWLY FLOW ROUNDING BASE OF DEEP
IL UPR LOW PROVIDES SUFFICIENT DEEP SHEAR FOR SUSTAINED UPDRAFTS/
SUPERCELLS. MAIN SEVERE THREAT WILL BE ISOLATED TORNADOES FROM
SUSTAINED SEMI-DISCRETE STORMS AND/OR SPIN UP TORNADOES INVOF LEWPS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400.
MEAN STORM MOTION VECTOR 25045.

..CORFIDI

MESO: Mesoscale Discussion 0467

ACUS11 KWNS 120639
SWOMCD
SPC MCD 120639
NCZ000-VAZ000-SCZ000-120745-

MESOSCALE DISCUSSION 0467
NWS STORM PREDICTION CENTER NORMAN OK
0139 AM CDT THU APR 12 2007

AREAS AFFECTED...PORTIONS NERN SC...CENTRAL/ERN NC...S-CENTRAL/SERN
VA.

CONCERNING...SEVERE THUNDERSTORM WATCH 129...

VALID 120639Z - 120745Z

WW 129 SVR THREAT CONTINUES. ERN PORTION WW -- FROM E-CENTRAL NC TO
SERN VA THEN ADDITIONAL TERRITORY EWD TO COAST -- MAY REQUIRE
TORNADO WW. ANY SUCH WW WOULD REPLACE OVERLAPPING PORTION OF WW
129...AND WOULD CONSTITUTE NEW WW FARTHER E.

SFC MESOANALYSIS INDICATES LOW DEEPENING OVER E-CENTRAL VA...WITH
STRONGEST ASSOCIATED PRESSURE FALLS EXTENDING SWD TO NEAR ILM.
ISALLOBARIC FORCING SHOULD SHIFT NEWD ACROSS NERN NC AND SERN
VA...MAINTAINING RELATIVELY BACKED LOW LEVEL FLOW AND ENLARGED
HODOGRAPHS...AND ALSO CONTRIBUTING TO INFLUX OF MARINE AIR.
EFFECTIVE LIFTED PARCELS ARE FCST TO BECOME CLOSER TO SFC-BASED
BECAUSE OF BOUNDARY LAYER THETAE ADVECTION SHIFTING RICHER AIR MASS
NEWD ACROSS REGION E OF ONGOING CONVECTION. VWP DATA AND MODEL FCST
SOUNDINGS INDICATE FAVORABLE LOW LEVEL HODOGRAPHS WILL PERSIST FROM
SERN NC NEWD TO SERN VA...WITH VEERING TREND IN NEAR-SFC FLOW
EXPECTED FARTHER S. 0-3 KM SRH INCREASES WITH NWD EXTENT FROM
AROUND 300 J/KG OVER SRN-MOST NC TO ABOVE 500 J/KG SERN VA.
OCCASIONAL SUPERCELLS ALREADY HAVE BEEN EVIDENT WITHIN PRIMARY BAND
OF CONVECTION MOVING EWD ACROSS WW 129 AREA IN NC...AND TORNADO
POTENTIAL THEREWITH SHOULD INCREASE ONTO COASTAL PLAIN AS INFLOW AIR
BECOMES MORE MOIST AND BUOYANT NEAR SFC.

.EDWARDS.. 04/12/2007

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

ATTN...WFO...AKQ...MHX...RAH...ILM...

34827959 35847860 36627758 37027640 36917598 36137569
35647542 35207553 35067599 34587650 34727676 34327766
33847796 33847855 34057934 34697960

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 120600
SWODY2
SPC AC 120559

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT THU APR 12 2007

VALID 131200Z - 141200Z

..THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF NERN TX INTO
SRN AR AND NRN LA...

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE SRN PLAINS
INTO THE LWR MS VLY...

..SRN PLAINS TO THE LWR MS VLY REGION...
PRIMARY FEATURE OF INTEREST WILL BE THE UPR LOW THAT WILL DIG INTO
THE DESERT SW TODAY AND THEN TURN EWD TOWARD THE SRN PLAINS ON FRI.
UPR LEVELS WILL BECOME QUITE DIFFLUENT AHEAD OF THIS SYSTEM WITH THE
SUB-TROPICAL JET PEELING OFF ALONG THE GULF COAST AND A SEPARATE
STREAM ROTATING NEWD AROUND THE LOW. A STRONG SLY LLJ OF 50-60 KTS
ORIENTED FROM CNTRL TX/OK EARLY IN THE DAY WILL TRANSLATE EWD INTO
THE LWR MS VLY OVERNIGHT FRIDAY. ELEVATED TSTMS WILL LIKELY BE
ONGOING ACROSS NRN TX AND OK EARLY FRIDAY WHERE THE SLY LLJ IMPINGES
ON THE NW-SE ORIENTED WARM FRONT. A FEW OF THESE STORMS MAY PRODUCE
HAIL AND PERHAPS GUSTY WINDS INTO THE MORNING HOURS.

ATTENTION WILL THEN TURN TO FRI AFTN INTO THE OVERNIGHT WHEN A
SIGNIFICANT AND ACTIVE SEVERE WEATHER EPISODE WILL LIKELY UNFOLD.
WARM AND MOIST AIR MASS...CHARACTERIZED BY MID-UPPER 60S DEW
POINTS...SHOULD ADVECT QUICKLY NWD FRI AFTN AHEAD OF THE DEVELOPING
DRYLINE IN CNTRL TX AND TO THE S OF THE WARM FRONT LIFTING NWD TO
ALONG THE RED RVR VLY...SRN AR AND NRN LA. THIS AIR MASS SHOULD
BECOME UNSTABLE OWING TO STEEP MID-LEVEL LAPSE RATES AND INCREASING
BOUNDARY LAYER MOISTURE.

TSTMS ARE EXPECTED TO GRADUALLY DEVELOP WITHIN THE SLY LLJ AXIS AND
WELL WITHIN THE DEVELOPING WARM SECTOR AWAY FROM THE DRYLINE DURING
THE AFTN. STORMS WILL MOVE RATHER QUICKLY NWD THROUGH ERN TX AND
ENCOUNTER THE BAROCLINIC ZONE ACROSS NERN TX...SWRN AR AND NWRN LA.
AS THEY DO SO...THEY WILL LIKELY BECOME SUPERCELLULAR GIVEN THE
50-60 KTS OF VERTICAL SHEAR. FORECAST LOW-LEVEL HODOGRAPHS WILL BE
QUITE SUPPORTIVE FOR TORNADIC SUPERCELLS... ESPECIALLY NEAR THE WARM
FRONT AND ALONG THE NRN EDGE OF THE RICHER LOW-LEVEL MOISTURE SURGE
DURING THE LATE AFTN/EARLY EVE. VERY LARGE HAIL AND DAMAGING WINDS
CAN ALSO BE EXPECTED. THIS ACTIVITY WILL SHIFT EWD DURING THE
EVENING INTO CNTRL/NRN LA AND SCNTRL/SERN AR.

TO THE WEST OF THIS ACTIVITY...PRIMARY HEIGHT FALLS WILL EMERGE
ACROSS N TX AND OK DURING THE MID-AFTN HOURS...STRENGTHENING THE
MASS CONVERGENCE FROM SWRN/SCNTRL OK INTO CNTRL TX VCNTY THE SFC
LOW/DRYLINE. AS A RESULT...A SECONDARY AREA OF TSTM INITIATION WILL
LIKELY OCCUR. THE MID-UPPER LEVEL FLOW WILL BE BACKING WITH
TIME...AND ACTIVITY HERE MAY VERY WELL EVOLVE INTO LINEAR SEGMENTS
BY EVENING. VERTICAL SHEAR...HOWEVER...WILL BE MORE THAN SUFFICIENT
FOR SUPERCELLS WITH VERY LARGE HAIL. THE LOW-LEVEL WIND FIELDS
ALONG THE DRYLINE WILL BE COMPARATIVELY WEAKER THAN FARTHER E...BUT
ISOLD TORNADOES CANNOT BE RULED OUT.

OVERNIGHT...THE ACTIVITY THAT DEVELOPS ALONG THE DRYLINE WILL LIKELY
PROPAGATE EWD AND MERGE WITH THE STORMS DOWNSTREAM. BACKING OF THE
LOW-MID LEVEL FLOW SUGGEST THAT A SQUALL LINE WILL PROBABLY EVOLVE
LATER AT NIGHT FROM SRN AR INTO LA AND PERHAPS THE UPR TX COAST WITH
POSSIBLE EMBEDDED LEWPS/SUPERCELLS. LARGE HAIL AND DAMAGING WINDS
WILL BE PRIMARY THREATS. BUT...TORNADOES WILL ALSO BE
POSSIBLE...ESPECIALLY ALONG THE NERN PERIPHERY OF THE RETURNING GULF
AIR MASS ACROSS CNTRL/SRN LA INTO SWRN MS.

.RACY.. 04/12/2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 120552
SWODY1
SPC AC 120550

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1250 AM CDT THU APR 12 2007

VALID 121200Z - 131200Z

..THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SRN HIGH
PLAINS...

..SYNOPSIS...

UPPER TROUGH OVER THE PACIFIC NW WILL AMPLIFY SEWD THROUGH CA AND
INTO THE SWRN STATES BY THURSDAY EVENING ACCOMPANIED BY A COLD
FRONT. PRIMARY SURFACE LOW WILL CONSOLIDATE OVER THE SWRN STATES IN
RESPONSE TO INCREASING UPPER DIVERGENCE AND ASCENT DOWNSTREAM FROM
THE SEWD ADVANCING SHORTWAVE TROUGH. A WARM FRONT WILL LIKELY
DEVELOP AND EXTEND ESEWD FROM THE LOW THROUGH THE TX PANHANDLE INTO
NWRN TX BY THURSDAY EVENING. A LEAD SHORTWAVE TROUGH MOVING THROUGH
SRN CA AND SWRN NV WILL ADVANCE EAST INTO THE SRN HIGH PLAINS DURING
THE AFTERNOON.

..SRN HIGH PLAINS THROUGH PORTIONS OF THE SRN PLAINS...

RICHER LOW LEVEL MOISTURE WITH MID TO UPPER 60S DEWPOINTS REMAINS
OFF THE SRN TX COAST EARLY THIS MORNING. THE BOUNDARY LAYER IS MUCH
DRYER FARTHER INLAND WITH DEWPOINTS PRIMARILY IN THE 40S OVER CNTRL
TX AND 20S TO 30S FARTHER NW INTO WRN TX. A SSELY LOW LEVEL JET WILL
DEVELOP OVER WRN TX THURSDAY AND STRENGTHEN SIGNIFICANTLY BY
THURSDAY EVENING DOWNSTREAM FROM SURFACE LOW. THIS WILL RESULT IN
THE ADVECTION OF PARTIALLY MODIFIED GULF AIR NWWD THROUGH THE SRN
HIGH PLAINS WITH BOUNDARY LAYER DEWPOINTS PRIMARILY IN THE 40S TO
AROUND 50. DRYLINE WILL LIKELY SET UP ACROSS ERN NM OR WRN TX AS
MOISTURE RETURNS NWWD DURING THE AFTERNOON. THE MODEST LOW LEVEL
MOISTURE RETURN BENEATH STEEP MID LEVEL LAPSE RATES WILL CONTRIBUTE
TO DESTABILIZATION DURING THE AFTERNOON WITH MLCAPE FROM 500 TO 1000
J/KG FROM EXTREME ERN NM THROUGH WRN TX.

FORCING FOR ASCENT ASSOCIATED WITH LEAD SHORTWAVE TROUGH WILL
ADVANCE INTO THE HIGH PLAINS DURING THE AFTERNOON. THIS ALONG WITH
STRONG SURFACE HEATING AND MIXING WITHIN THE BOUNDARY LAYER SHOULD
CONTRIBUTE TO HIGH BASED STORMS FROM ERN NM THROUGH WRN TX. DEEP
LAYER SHEAR AND LOW LEVEL HODOGRAPHS WILL BECOME FAVORABLE FOR
SUPERCELLS BY LATE AFTERNOON INTO THE EVENING AS THE LOW LEVEL JET
STRENGTHENS. HOWEVER...HIGH BASED NATURE OF THE STORMS SUGGESTS
PRIMARY THREATS SHOULD BE LARGE HAIL AND ISOLATED DAMAGING WIND.

OVERNIGHT...RICHER MOISTURE WILL LIKELY RETURN NWD AS THE BOUNDARY
LAYER DECOUPLES AND THE LOW LEVEL JET STRENGTHENS. STRONG ISENTROPIC
LIFT N OF THE WARM FRONT SUGGESTS ADDITIONAL STORMS WILL DEVELOP AND
MAY EVOLVE INTO AN MCS OVERNIGHT. ACTIVITY WILL SHIFT EAST THROUGH
PARTS OF NRN TX...OK AND SRN KS. LARGE HAIL WILL REMAIN
POSSIBLE...ESPECIALLY ON THE SRN AND WRN FLANKS OF THE MCS WHERE
FEED OF HIGHER THETA-E AIR WILL EXIST.

.DIAL/CROSBIE.. 04/12/2007

WATCHES: Severe Thunderstorm Watch Number 129

WWUS20 KWNS 120455
SEL9
SPC WW 120455
NCZ000-SCZ000-VAZ000-121200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 129
NWS STORM PREDICTION CENTER NORMAN OK
1255 AM EDT THU APR 12 2007

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

MUCH OF CENTRAL AND EASTERN NORTH CAROLINA
PARTS OF NORTHEASTERN SOUTH CAROLINA
PARTS OF SOUTHERN VIRGINIA

EFFECTIVE THIS THURSDAY MORNING FROM 1255 AM UNTIL 800 AM EDT.

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 65
STATUTE MILES EITHER SIDE OF A LINE FROM 60 MILES NORTHWEST OF
FLORENCE SOUTH CAROLINA TO 40 MILES NORTHEAST OF ROANOKE RAPIDS
NORTH CAROLINA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).

OTHER WATCH INFORMATION...CONTINUE...WW 128...

DISCUSSION...STORMS WILL INCREASE IN NUMBER AND INTENSITY ACROSS
WATCH AS VERY STRONG WIND PROFILES ROTATE THRU AREA ALONG WITH
INCREASING WARM ADVECTION AND MID LEVEL INSTABILITY. PRIMARILY
ELEVATED STORMS WITH LARGE HAIL POTENTIAL...HOWEVER STORMS COULD
BECOME NEAR SURFACE BASED WITH TIME INCREASING THREAT OF WIND DAMAGE
AND SUPERCELLS.

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 400. MEAN STORM
MOTION VECTOR 23045.

..HALES

MESO: Mesoscale Discussion 0466

ACUS11 KWNS 120416
SWOMCD
SPC MCD 120416
NCZ000-SCZ000-120545-

MESOSCALE DISCUSSION 0466
NWS STORM PREDICTION CENTER NORMAN OK
1116 PM CDT WED APR 11 2007

AREAS AFFECTED...CNTRL AND ERN NC

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 120416Z - 120545Z

POTENTIAL FOR A FEW SEVERE STORMS CAPABLE OF MAINLY LARGE HAIL WILL
INCREASE OVERNIGHT. CONVECTIVE TRENDS ARE BEING MONITORED FOR A
POSSIBLE WW.

AS OF 04Z...REGIONAL RADAR IMAGERY INDICATES TSTMS CONTINUING TO
INCREASE IN COVERAGE AND INTENSITY OVER PORTIONS OF CNTRL NC /FROM
JUST SE OF RDU TO 20 S OF SOP/ AND WRN NC /FROM GSO TO 20 W CLT/.
THE FORMER APPEARS TO BE ASSOCIATED WITH STRONG LOW-LEVEL WAA REGIME
E OF PIEDMONT OR WEDGE FRONT EXTENDING FROM NEAR OR JUST W OF CAE TO
W OF RDU TO RIC AS OF 04Z. MEANWHILE...THE LATTER CLUSTER OF STORMS
IS LIKELY ASSOCIATED WITH INCREASED LARGE-SCALE FORCING FOR ASCENT
ATTENDANT TO EXIT REGION OF 80 KT MID-LEVEL JET STREAK PROPAGATING
THROUGH THE TN VALLEY.

STORMS ARE LIKELY ELEVATED IN BOTH REGIMES...THOUGH MORE SO TO THE W
OF WEDGE FRONT OVER WRN NC...WITHIN WEAKLY UNSTABLE AIR MASS WITH
MUCAPES OF 400-600 J/KG. RUC FORECAST SOUNDINGS SUGGEST THAT
MID-LEVEL LAPSE RATES WILL STEEPEN OVERNIGHT WITH APPROACH OF UPPER
TROUGH...SUPPORTING POCKETS OF LOCALLY STRONGER INSTABILITY. THE
PRIMARY SEVERE THREAT WITH THE MOST INTENSE STORMS WILL BE LARGE
HAIL OWING TO THE STEEPENING LAPSE RATES AND COOL THERMODYNAMIC
PROFILES. SOME STORMS DEVELOPING OVER PARTS OF CNTRL AND ERN NC
WILL HAVE THE POTENTIAL TO BECOME NEAR SURFACE-BASED WHERE LOCALLY
DAMAGING WINDS AND PERHAPS A TORNADO WOULD BE POSSIBLE.

.MEAD.. 04/12/2007

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

ATTN...WFO...AKQ...MHX...RAH...ILM...RNK...CAE...GSP...

35508078 36038024 36267957 36417830 36477766 36327718
35797717 35247751 34667804 34397874 34347952 34467995

WATCHES: Severe Thunderstorm Watch - Number 127

WWUS20 KWNS 120403
SEL7
SPC WW 120403
KYZ000-OHZ000-WVZ000-120500-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH - NUMBER 127
NWS STORM PREDICTION CENTER NORMAN OK
1203 AM EDT THU APR 12 2007

THE NWS STORM PREDICTION CENTER HAS CANCELLED
SEVERE THUNDERSTORM WATCH NUMBER 127 ISSUED AT 715 PM EDT FOR PORTIONS OF

KENTUCKY
OHIO
WEST VIRGINIA

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