WATCHES: Tornado Watch Number 171

WWUS20 KWNS 240340
SEL1
SPC WW 240340
COZ000-KSZ000-NEZ000-241100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 171
NWS STORM PREDICTION CENTER NORMAN OK
1040 PM CDT MON APR 23 2007

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

NORTHEAST COLORADO
NORTHWEST KANSAS
SOUTHWEST NEBRASKA

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 1040 PM
UNTIL 600 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 45 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 45 MILES NORTHWEST OF
BURLINGTON COLORADO TO 25 MILES NORTH NORTHEAST OF HILL CITY
KANSAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

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...THIS TORNADO WATCH REPLACES TORNADO
WATCH NUMBER 168. WATCH NUMBER 168 WILL NOT BE IN EFFECT AFTER
1040 PM CDT. CONTINUE...WW 167...WW 170...

DISCUSSION...SUPERCELLS WILL CONTINUE ACROSS WW FOR MUCH OF THE
NIGHT ALONG AND JUST WEST OF INCREASING SLY LLJ. STORMS SHOULD
REMAIN ROOTED IN AND JUST ABOVE THE BOUNDARY LAYER INVOF SURFACE
WARM FRONT EXPECTED TO REMAIN IN PLACE OVER NWRN KS. LARGE HAIL AND
ISOLATED TORNADOES... ALONG WITH ISOLATED DAMAGING WINDS...WILL
ACCOMPANY THIS ACTIVITY FOR SEVERAL MORE HOURS.

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
500. MEAN STORM MOTION VECTOR 22025.

..EVANS

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MESO: Mesoscale Discussion 0554

ACUS11 KWNS 240323
SWOMCD
SPC MCD 240322
TXZ000-240445-

MESOSCALE DISCUSSION 0554
NWS STORM PREDICTION CENTER NORMAN OK
1022 PM CDT MON APR 23 2007

AREAS AFFECTED...PORTIONS W-CENTRAL/NW TX.

CONCERNING...TORNADO WATCH 167...

VALID 240322Z - 240445Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 167 CONTINUES.

SBCINH INCREASES SUBSTANTIALLY WITH EWD EXTENT ACROSS NWRN/N-CENTRAL
TX...WHICH INDICATES THAT HORIZONTAL SHRINKING TREND EVIDENT IN
REFLECTIVITY IMAGERY SHOULD CONTINUE FOR SUPERCELL N ABI. BEFORE
THIS STORM DISSIPATES COMPLETELY...HOWEVER...IT STILL MAY POSE
THREAT OF LARGE HAIL...STG-SVR GUSTS AND PERHAPS A TORNADO.

MEANWHILE CONVECTION ACROSS GARZA/KENT/DICKENS COUNTIES HAS
CONSOLIDATED INTO POTENTIALLY TORNADIC SUPERCELL WHICH...ACCORDING
TO MODIFIED RUC SOUNDINGS...BARELY HAS SFC-BASED EFFECTIVE INFLOW
LAYER. AS FARTHER SE...MODIFIED RAOBS AND RUC SOUNDINGS SUGGEST
STRENGTHENING SBCINH WITH TIME ACROSS NW TX IN PROJECTED PATH OF
THIS ACTIVITY...INDICATING THREAT SHOULD NOT EXTEND SPATIALLY E OF
PRESENT WW AREA. LOCAL WW EXTENSION IN TIME MAY BE REQUIRED -- FOR
A FEW COUNTIES IN PATH OF THIS ACTIVITY -- BEFORE IT DISSIPATES.
OTHERWISE...CONVECTIVE INITIATION WILL BECOME LESS PROBABLE WITH
TIME...AND WW OUTSIDE THOSE LOCALIZED THREATS MAY BE ALLOWED TO
EXPIRE AS SCHEDULED AT 4Z.

.EDWARDS.. 04/24/2007

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

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

31720087 33150125 33430183 34060183 34240013 33899906
32789890 32059923

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WATCHES: Tornado Watch - Number 166

WWUS20 KWNS 240303
SEL6
SPC WW 240303
KSZ000-OKZ000-TXZ000-240300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH - NUMBER 166
NWS STORM PREDICTION CENTER NORMAN OK
1003 PM CDT MON APR 23 2007

THE NWS STORM PREDICTION CENTER HAS CANCELLED
TORNADO WATCH NUMBER 166 ISSUED AT 345 PM CDT FOR PORTIONS OF

KANSAS
OKLAHOMA
TEXAS

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WATCHES: Severe Thunderstorm Watch Number 170

WWUS20 KWNS 240254
SEL0
SPC WW 240254
KSZ000-NEZ000-241100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 170
NWS STORM PREDICTION CENTER NORMAN OK
955 PM CDT MON APR 23 2007

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

NORTH CENTRAL KANSAS
SOUTHWEST AND SOUTH CENTRAL NEBRASKA

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 955 PM UNTIL
600 AM 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 55
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES WEST
NORTHWEST OF IMPERIAL NEBRASKA TO 45 MILES SOUTH SOUTHEAST OF
HASTINGS NEBRASKA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).

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 165...WW 166...WW
167...WW 168...

DISCUSSION...STRENGTHENING...SLY LLJ WILL MAINTAIN INCREASING ASCENT
NORTH OF SURFACE WARM FRONT EXPECTED TO REMAIN ESTABLISHED ACROSS
NRN KS. IN ADDITION...STEEP MID LEVEL LAPSE RATES AND SUFFICIENT
MOISTURE WILL MAINTAIN AN AXIS OF MODERATE ELEVATED INSTABILITY
ACROSS WW. GIVEN SUFFICIENT DEEP LAYER SHEAR FOR SUPERCELLS...LARGE
HAIL WILL BE PRIMARY THREAT AS ACTIVITY LIKELY REMAINS SLIGHTLY
ELEVATED. ANY STORM NEAR THE WARM FRONT MAY DEVELOP LOW LEVEL
ROTATION TONIGHT.

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 500. MEAN STORM
MOTION VECTOR 19025.

..EVANS

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WATCHES: Tornado Watch - Number 169

WWUS20 KWNS 240235
SEL9
SPC WW 240235
TXZ000-240400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH - NUMBER 169
NWS STORM PREDICTION CENTER NORMAN OK
935 PM CDT MON APR 23 2007

THE NWS STORM PREDICTION CENTER HAS CANCELLED
TORNADO WATCH NUMBER 169 ISSUED AT 750 PM CDT FOR PORTIONS OF

TEXAS

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MESO: Mesoscale Discussion 0553

ACUS11 KWNS 240217
SWOMCD
SPC MCD 240217
TXZ000-240415-

MESOSCALE DISCUSSION 0553
NWS STORM PREDICTION CENTER NORMAN OK
0917 PM CDT MON APR 23 2007

AREAS AFFECTED...SWRN TX

CONCERNING...TORNADO WATCH 169...

VALID 240217Z - 240415Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 169 CONTINUES.

ISOLATED SUPERCELL OVER KINNEY COUNTY MAY PERSIST FOR A WHILE IN
STRONGLY UNSTABLE ENVIRONMENT...BUT CAPPING INVERSION JUST ABOVE 850
MB WILL LIKELY PREVENT ANY ADDITIONAL DEVELOPMENT ACROSS WW 169.
EVEN THIS CELL HAS SHOWN SIGNS OF WEAKENING AS OF 02Z. GIVEN EWD
STORM MOTION...MAIN THREAT WITHIN WATCH WILL BE OVER KINNEY AND
UVALDE COUNTIES...WHILE COUNTIES IN NRN AND SRN PORTIONS OF WATCH
MAY BE CANCELLED EARLY.

.JEWELL.. 04/24/2007

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

ATTN...WFO...EWX...

29280083 29690080 29789970 29599935 29119939 29200037

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MESO: Mesoscale Discussion 0552

ACUS11 KWNS 240154
SWOMCD
SPC MCD 240154
OKZ000-KSZ000-NEZ000-240400-

MESOSCALE DISCUSSION 0552
NWS STORM PREDICTION CENTER NORMAN OK
0854 PM CDT MON APR 23 2007

AREAS AFFECTED...PORTIONS SRN/WRN KS...EXTREME N-CENTRAL
OK...EXTREME SWRN NEB.

CONCERNING...TORNADO WATCH 168...

VALID 240154Z - 240400Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 168 CONTINUES.

SVR THREAT MAY SHIFT NWD OR EXPAND OVER MORE OF NRN KS AND/OR SRN
NEB DURING NEXT SEVERAL HOURS INVOF STRENGTHENING LLJ.
MEANWHILE...ISOLATED/TORNADIC SUPERCELLS EVIDENT AT 145Z OVER
COMANCHE AND WALLACE/SHERMAN COUNTIES...EACH WITH HISTORY OF TORNADO
REPORTS.

SFC MESOANALYSIS INDICATES WARM FRONT HAS REDEVELOPED/SHIFTED NWD
OVER KS...CURRENTLY INVOF GLD/RSL/SLN/CNU LINE. HOWEVER...BACKED
LOW LEVEL WINDS AND RELATIVELY SMALL DEW POINT DEPRESSIONS LINGER
ASSOCIATED WITH EARLIER WARM FRONTAL ANALYSIS OVER SRN KS..AND
SHOULD BE MAINTAINED NOW THAT SFC DIABATIC HEATING NO LONGER IS
OCCURRING. ISALLOBARIC FORCING ACROSS ERN CO/WRN KS...ASSOCIATED
WITH DEEPENING SFC CYCLONE OVER CO...WILL MAINTAIN BACKED WINDS
ACROSS WW REGION. THIS WILL KEEP LOW LEVEL HODOGRAPHS FAVORABLY
LARGE -- AS EVIDENT IN VWP/PROFILER DATA...MODIFIED 00Z DDC RAOB
AND RUC FCST SOUNDINGS. 150-250 J/KG SRH NOW EVIDENT ACROSS MUCH OF
THIS REGION SHOULD INCREASE WITH ONSET OF 50 KT LLJ. SFC MOIST
ADVECTION WILL COUNTERACT WEAK SFC COOLING ENOUGH TO KEEP EFFECTIVE
INFLOW PARCELS ROOTED AT OR VERY NEAR SFC FOR SEVERAL MORE HOURS.
THEREFORE...PRIND TORNADO THREAT WILL CONTINUE FOR ANY DISCRETE
SUPERCELLS...ALONG WITH DAMAGING GUSTS AND LARGE HAIL WITH ANY
SUSTAINED CONVECTION.

.EDWARDS.. 04/24/2007

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

ATTN...WFO...TSA...TOP...ICT...OUN...GID...DDC...GLD...

37020201 39940192 40090062 40039928 39509796 37999673
36979668 36619740 36669819 36999856

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 240113
SWODY1
SPC AC 240110

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0810 PM CDT MON APR 23 2007

VALID 240100Z - 241200Z

..THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF ERN
COLORADO...FAR SWRN NEBRASKA...WRN AND CENTRAL KANSAS...NORTHWEST
OKLAHOMA INCLUDING THE ERN OK PANHANDLE...AND FAR NERN TX
PANHANDLE...

..THERE IS A SLGT RISK OF SVR TSTMS EXTENDS ACROSS THE CENTRAL AND
SRN PLAINS...

..THERE IS A SLGT RISK OF SVR TSTMS SOUTHWEST TX...

..CENTRAL/SRN PLAINS...
ASCENT WITH MID/UPPER LEVEL SHORT WAVE TROUGH...NOW MOVING EWD
ACROSS THE FOUR CORNERS REGION...WILL CONTINUE TO SPREAD OVER THE
SRN/CENTRAL HIGH PLAINS SUPPORTING AN INCREASE IN TSTM COVERAGE FROM
ERN CO INTO WRN AND CENTRAL KS THIS FORECAST PERIOD. MODELS REMAIN
CONSISTENT WITH SUGGESTING THIS SCENARIO. STRENGTHENING SSWLY MID
LEVEL WINDS TO 70-80 KT INTO ERN CO/WRN KS AND SRN HIGH PLAINS ATOP
STRENGTHENING SLY LLJ IN RESPONSE TO HEIGHT FALLS WILL MAINTAIN
STRONG DEEP LAYER AND LOW LEVEL SHEAR FOR SUPERCELLS WITH BOTH
TORNADOES AND VERY LARGE AND DAMAGING HAIL THE PRIMARY THREATS.
ELEVATED ACTIVITY LATER TONIGHT MAY REACH PARTS OF SRN NEB WITH HAIL
BEING THE PRIMARY THREATS THIS FAR NORTH.

FURTHER S ACROSS THE TX PANHANDLE...A WEAK MID LEVEL INVERSION BASED
AROUND 600 MB AS INDICATED BY 00Z AMA SOUNDING APPEARS TO BE
LIMITING STRONGER TSTM DEVELOPMENT EARLY THIS EVENING IN AN AIR MASS
OTHERWISE CHARACTERIZED BY MODERATE INSTABILITY AND STRONG DEEP AND
LOW LEVEL LAYER SHEAR. THE LOSS OF DAYTIME HEATING....DRY LINE
RETREATING WWD INTO THE WRN PARTS OF THE OK/TX PANHANDLES...AND WARM
FRONT MOVING NWD THROUGH KS WOULD SUGGEST A LOW POTENTIAL FOR
ADDITIONAL TSTM DEVELOPMENT ACROSS OK/TX PANHANDLES.

..PARTS OF W...CENTRAL AND SW TX...
STRONG ASCENT WITH SUB-TROPICAL SHORT WAVE TROUGH...NOW LOCATED OVER
THE TRANS-PECOS REGION OF SW TX PER WATER VAPOR IMAGERY...WILL
CONTINUE TO SPREAD NEWD ACROSS WEST/CENTRAL TX AND REACH ARKLATEX
AND AR BY 12Z TUESDAY. AIR MASS SHOULD REMAIN UNSTABLE AND
SUFFICIENTLY SHEARED FOR ADDITIONAL ROTATING UPDRAFTS WITH CONTINUED
POTENTIAL FOR ISOLATED TORNADOES...LARGE HAIL AND DAMAGING WINDS.

..NY SWWD TO UPPER OH VALLEY...
WATER VAPOR IMAGERY INDICATED A PROGRESSIVE AND AMPLIFIED SHORT WAVE
TROUGH LOCATED OVER THE LOWER GREAT LAKES/UPPER OH VALLEY WITH THIS
FEATURE EXPECTED TO MOVE EWD THROUGH THE NERN STATES OVERNIGHT.
ENHANCED LOW TO MID LEVEL DRYING WAS ALSO INDICATED ON WATER VAPOR
IMAGERY IMMEDIATELY UPSTREAM WITH THIS MID LEVEL TROUGH. LOSS OF
DAYTIME HEATING IS EXPECTED TO FURTHER DECREASE CONVECTIVE
INSTABILITY THAT IS ALREADY RATHER WEAK. ADDITIONAL TSTMS SHOULD
DEVELOP ALONG COLD FRONT AS IT PROGRESSES EWD THROUGH NY INTO
CENTRAL AND SWRN PA...NRN WV AND SERN OH THIS EVENING. WEAK
INSTABILITY SHOULD LIMIT ADDITIONAL SEVERE THREAT. HOWEVER...
ISOLATED WIND GUSTS WILL REMAIN POSSIBLE GIVEN THE COMBINATION OF
THE APPROACH OF MID LEVEL DRYING...LARGE PRE-FRONTAL SURFACE
DEWPOINT DEPRESSIONS ENHANCING DOWNWARD MOMENTUM TRANSFER OF 50 KT
SWLY LLJ.

.PETERS.. 04/24/2007

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MESO: Mesoscale Discussion 0551

ACUS11 KWNS 240053
SWOMCD
SPC MCD 240052
COZ000-240245-

MESOSCALE DISCUSSION 0551
NWS STORM PREDICTION CENTER NORMAN OK
0752 PM CDT MON APR 23 2007

AREAS AFFECTED...PORTIONS ERN CO.

CONCERNING...TORNADO WATCH 165...

VALID 240052Z - 240245Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 165 CONTINUES.

LONG-LIVED AND POSSIBLY TORNADIC SUPERCELL OVER MORGAN COUNTY SHOULD
CONTINUE TO MOVE ENEWD ACROSS PORTIONS LOGAN COUNTY WITH CONTINUED
THREAT OF DAMAGING GUSTS AND HAIL...AND PERHAPS TORNADOES. BAND OF
CONVECTION HAS DEVELOPED SWWD FROM THIS ACTIVITY WHICH MAY SEED IT
AND CAUSE TREND TOWARD HEAVY-PRECIP THEN BOWING CHARACTER. TRAILING
CONVECTION EXTENDS ERN ADAMS/ARAPAHOE AND WRN ELBERT
COUNTY...BECOMING BKN TOWARD COS. ISALLOBARIC FORCING ACROSS THIS
REGION SHOULD MAINTAIN BACKED/UPSLOPE SFC WINDS NOW OBSERVED AT
LIC/AKO/ITR. THIS ALSO WILL BE PROVIDING FAVORABLY STG
STORM-RELATIVE INFLOW...AS WELL AS MAINTAINING LARGE LOW LEVEL
HODOGRAPHS NOW EVIDENT IN GLD VWP AND ERN CO RUC SOUNDINGS. 200-250
J/KG OF 0-1 KM SRH WILL CONTINUE ALONG WITH 50-55 KT EFFECTIVE
SHEAR. ADDITIONALLY...EXPECT MOIST ADVECTION TO OFFSET SFC DIABATIC
COOLING ENOUGH FOR EFFECTIVE LIFTED PARCELS TO REMAIN ROOTED AT OR
VERY NEAR SFC...ACROSS E-CENTRAL/NERN CO...FOR AT LEAST ANOTHER 2-3
HOURS. THIS INDICATES DAMAGING WIND AND TORNADO POTENTIAL CONTINUES
AS WELL AS LARGE HAIL.

.EDWARDS.. 04/24/2007

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

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

38810502 39810457 40720352 40900277 40570222 39210205
37630209 38140377 38500459

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WATCHES: Tornado Watch Number 169

WWUS20 KWNS 240049
SEL9
SPC WW 240049
TXZ000-240400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 169
NWS STORM PREDICTION CENTER NORMAN OK
750 PM CDT MON APR 23 2007

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

SOUTHWEST TEXAS

EFFECTIVE THIS MONDAY EVENING FROM 750 PM UNTIL 1100 PM CDT.

TORNADOES...HAIL TO 3 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 45 STATUTE
MILES EAST AND WEST OF A LINE FROM 70 MILES NORTH NORTHEAST OF
DEL RIO TEXAS TO 75 MILES SOUTHEAST OF DEL RIO TEXAS. 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.

OTHER WATCH INFORMATION...CONTINUE...WW 165...WW 166...WW
167...WW 168...

DISCUSSION...SMALL BUT INTENSE AND POTENTIALLY TORNADIC SUPERCELL
JUST WEST OF DRT AT 01Z MAY CONTINUE EWD FOR A COUPLE MORE HOURS.
OTHER DEVELOPMENT MAY OCCUR ACROSS WW THROUGH THE EVENING. AIR MASS
IS VERY UNSTABLE AND STRONGLY SHEARED...SUGGESTING VERY LARGE HAIL
AND ISOLATED TORNADO THREAT WILL ACCOMPANY STRONGER CORES. CAPPING
AND NOCTURNAL COOLING OF THE BOUNDARY LAYER MAY LIMIT EWD
DEVELOPMENT LATER THIS EVENING AND CONFINE MAIN THREAT NEARER THE
RIO GRANDE AND COUNTIES JUST EAST.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 27020.

..EVANS

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MESO: Mesoscale Discussion 0550

ACUS11 KWNS 240039
SWOMCD
SPC MCD 240038
NYZ000-PAZ000-240245-

MESOSCALE DISCUSSION 0550
NWS STORM PREDICTION CENTER NORMAN OK
0738 PM CDT MON APR 23 2007

AREAS AFFECTED...SCENTRAL/ECENTRAL NY...WRN/CENTRAL PA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 240038Z - 240245Z

ISOLATED DMGG WIND GUSTS WILL BE POSSIBLE WITH CONVECTIVE LINE AS IT
PROGRESSES EWD AROUND 35 KTS ACROSS THE AREA THROUGH 02Z. SVR THREAT
IS EXPECTED TO DIMINISH AROUND THAT TIME. THUS GIVEN LIMITED
REMAINING SVR THREAT...A WW IS NOT EXPECTED.

00Z BUF SOUNDING INDICATED VERY STRONG WLY LOW LEVEL FLOW IN THE
WAKE OF CONVECTIVE LINE MOVING EWD ACROSS WCENTRAL/SWRN NY AND NWRN
PA. WARM/DRY CONDITIONS EXIST AHEAD OF THIS CONVECTIVE LINE...WITH A
DEEPLY MIXED BOUNDARY LAYER /NOTED ON THE 00Z ALB SOUNDING/. THUS
DESPITE MINIMAL MUCAPES /LESS THAN 500 J/KG ON THE 00Z PIT SOUNDING/
PRECIP INDUCED COLD DOWNDRAFTS INTO THIS DEEPLY MIXED LAYER ARE
LIKELY AIDING IN MOMENTUM TRANSFER OF STRONGER WINDS ALOFT TO THE
SFC /AS EVIDENCE BY THE RECENT SFC OBS AT SYRACUSE/. AS LOW LEVELS
COOL EAST OF THE CONVECTIVE LINE IN THE NEXT FEW HOURS...EXPECT SVR
WIND THREAT TO BEGIN DIMINISHING AS CONVECTIVE LINE REACHES NCENTRAL
PA AND ECENTRAL NY.

.CROSBIE.. 04/24/2007

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

ATTN...WFO...BTV...ALY...BGM...BUF...CTP...PBZ...

43977458 43217594 41957828 40908048 40268032 40417847
40947679 41657544 42207471 42937362 43917359

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MESO: Mesoscale Discussion 0549

ACUS11 KWNS 240006
SWOMCD
SPC MCD 240005
OKZ000-KSZ000-TXZ000-240200-

MESOSCALE DISCUSSION 0549
NWS STORM PREDICTION CENTER NORMAN OK
0705 PM CDT MON APR 23 2007

AREAS AFFECTED...PORTIONS TX/OK PANHANDLES...WRN OK...W-CENTRAL/SW
TX.

CONCERNING...TORNADO WATCH 166...167...

VALID 240005Z - 240200Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 166...167...CONTINUES.

CLUSTER OF SVR TSTMS -- INCLUDING SVR LEFT- AND RIGHT-MOVING
SUPERCELLS -- SHOULD CONTINUE ACROSS PLAINS BELOW CAPROCK...WITH
RIGHT-MOVING MEMBER HEADING GENERALLY ALONG I-20 TOWARD SWW AREA AND
LEFT MOVERS CROSSING PORTIONS GARZA/KENT/DICKENS/CROSBY COUNTIES.
PREVIOUSLY TORNADIC ACTIVITY OVER NWRN OK IS MOVING NWD INTO WW
168...AS WELL AS LEFT-MOVING TSTM WHICH PRODUCED HAIL ESTIMATED NEAR
1 INCH DIAMETER OVER BEAVER COUNTY OK. ISOLATED/SMALL SUPERCELL
EVIDENT AT 2330Z CARSON COUNTY TX...WITH PRONOUNCED VISUAL SUPERCELL
CHARACTERISTICS BASED ON STORM OBSERVER REPORTS AND AMA AREA
TOWER-CAMS DURING PAST HOUR...MAY TURN MORE RIGHTWARD AND CROSS
PORTIONS NRN GRAY/SRN ROBERTS COUNTIES NEXT 1-2 HOURS.

ADDITIONAL DEVELOPMENT S OF I-40 AND N OF PERMIAN BASIN CLUSTER HAS
FAILED TO BECOME SUSTAINED SO FAR...AND MAY CONTINUE TO BE LIMITED
BY CONTINUED IMPEDIMENT OF REMAINING INSOLATION BY THICK HIGH CLOUD
COVER. STILL...ADDITIONAL TSTM DEVELOPMENT IS POSSIBLE ALONG
DRYLINE...WHICH MAY CONTINUE TO RETREAT FOR A FEW MORE HOURS GIVEN
BACKING OF FLOW AND ISALLOBARIC FORCING EVIDENT TO ITS W. ANY TSTMS
WHICH DO DEVELOP INTO MOIST SECTOR MAY BECOME SUPERCELLULAR GIVEN
FAVORABLE VERTICAL SHEAR PROFILES FCST TO CONTINUE ACROSS MOIST
SECTOR...AS WELL AS MOIST ADVECTION EXPECTED OVER NEXT SEVERAL
HOURS. FCST HODOGRAPHS APPEAR FAVORABLE FOR LEFT-SPLITS AND
ASSOCIATED HAIL RISK AS WELL.

.EDWARDS.. 04/24/2007

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

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

32500189 34100181 36080193 36930196 37009850 36399855
34569889 32089912 31569977 31110191

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WATCHES: Tornado Watch Number 168

WWUS20 KWNS 232335
SEL8
SPC WW 232335
KSZ000-OKZ000-240700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 168
NWS STORM PREDICTION CENTER NORMAN OK
635 PM CDT MON APR 23 2007

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

WESTERN AND CENTRAL KANSAS
FAR NORTH CENTRAL OKLAHOMA

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 635 PM UNTIL
200 AM CDT.

TORNADOES...HAIL TO 3 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 75 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 40 MILES SOUTH SOUTHWEST OF
GOODLAND KANSAS TO 5 MILES SOUTHEAST OF WICHITA KANSAS. 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 165...WW 166...WW 167...

DISCUSSION...SEVERE THUNDERSTORMS ARE EXPECTED TO CONTINUE
INCREASING IN COVERAGE AND INTENSITY THIS EVENING/OVERNIGHT ACROSS
MUCH OF THE WRN HALF OF KS. THIS WILL OCCUR ALONG NOSE/AXIS OF 40+
KT SLY LLJ WITHIN MODERATE INSTABILITY AND STRONG DEEP LAYER SHEAR.
SURFACE WARM FRONT WILL BECOME BETTER DEFINED AND LIFT NWD INTO
CENTRAL/NWRN KS AND FAR SWRN NEB THIS EVENING...INCREASING LOW LEVEL
SHEAR ACROSS WW. GIVEN LIKELIHOOD OF SUPERCELLS AND STEEP LAPSE
RATES...VERY LARGE HAIL SHOULD ACCOMPANY STRONGER STORMS. TORNADO
THREAT WILL ALSO BECOME ENHANCED THIS EVENING AND LIKELY PERSIST
WELL INTO THE NIGHT.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 22025.

..EVANS

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MESO: Mesoscale Discussion 0548

ACUS11 KWNS 232315
SWOMCD
SPC MCD 232315
MOZ000-OKZ000-KSZ000-COZ000-240115-

MESOSCALE DISCUSSION 0548
NWS STORM PREDICTION CENTER NORMAN OK
0615 PM CDT MON APR 23 2007

AREAS AFFECTED...PORTIONS OF WRN/CENTRAL AND SRN KS...NCENTRAL OK
AND SWRN MO

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 232315Z - 240115Z

ISOLATED SVR TSTMS MAY DEVELOP ALONG THE WARM FRONTAL BOUNDARY
EXTENDING FROM FAR WCENTRAL KS ESEWD INTO SCENTRAL/SERN KS AND
EXTREME NRN OK OVER THE NEXT FEW HOURS AS LOW LEVEL JET INTENSIFIES
AND DEEP MOIST CONVERGENCE INCREASES. A WW IS LIKELY FROM AREAS WEST
OF I-35 BY 00Z.

LATEST VISIBLE SAT IMAGERY SHOWS MODERATE CU DEVELOPING OVER EXTREME
NCENTRAL OK AND SCENTRAL KS ALONG A WARM FRONT. ADDITIONAL TSTMS
DEVELOPING OVER WW 166 /SOUTH OF DDC/ WILL CONTINUE TO MOVE NNEWD
ALONG LEADING EDGE OF DEEPER MOISTURE CONVERGENCE ALONG THE NOSE OF
A DEVELOPING LOW LEVEL JET. AIRMASS NORTH OF WW 166 AND ACROSS
WCENTRAL AND SRN KS/FAR NRN OK WAS MODERATELY UNSTABLE WITH MLCAPE
FROM 750-1500 J/KG. GIVEN MODERATE DEEP LAYER SHEAR PROFILES...AND
STRENGTHENING LOW LEVEL SHEAR PROFILES.../0-1 KM VECTOR SHEAR AROUND
25 KTS OBSERVED JUST NORTH OF THE RETREATING WARM FRONTAL BOUNDARY
ON BOTH THE DDC VWP AND HAVILAND PROFILER/ AN ISOLATED TORNADO
THREAT WILL EXIST WITH ANY STORMS THAT DEVELOP. THE ERN EDGE OF ANY
WELL ORGANIZED SVR THREAT APPEARS TO BE NEAR I-35 BASED ON RECENT
OBJECTIVE ANALYSIS AND EXPECTED LOCATION OF LOW LEVEL JET THIS
EVENING. THUS ALTHOUGH AN ISOLATED SVR THREAT MAY DEVELOP ALONG THE
WARM FRONT ACROSS SERN KS AND SWRN MO...BUT A WW IS NOT EXPECTED IN
THIS AREA ATTM.

.CROSBIE.. 04/23/2007

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

ATTN...WFO...SGF...TSA...ICT...OUN...DDC...GLD...PUB...

39710185 38490210 38039941 36779853 36829734 36969538
37009465 36949385 37329392 37519496 37869645

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MESO: Mesoscale Discussion 0547

ACUS11 KWNS 232240
SWOMCD
SPC MCD 232240
TXZ000-240045-

MESOSCALE DISCUSSION 0547
NWS STORM PREDICTION CENTER NORMAN OK
0540 PM CDT MON APR 23 2007

AREAS AFFECTED...PORTIONS SW TX.

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 232240Z - 240045Z

OROGRAPHIC FORCING AND UPSLOPE ADVECTION OF HIGH THETAE AIR HAS
CONTRIBUTED TO DEVELOPMENT OF WIDELY SCATTERED TSTMS OVER SERRANIAS
DEL BURRO REGION OF NRN COAHUILA. THIS ACTIVITY HAS DEVELOPED UNDER
BREAK IN HIGH CLOUDS WHICH IS SHIFTING NEWD ACROSS ADJACENT PORTIONS
OF SW TX...AND WHICH WILL ALLOW ADDITIONAL/FAVORABLE DESTABILIZATION
OF BOUNDARY LAYER. OTHER DEVELOPMENT MAY OCCUR ALONG SRN PORTION OF
DRYLINE...WHICH WAS ANALYZED AT 22Z OVER EXTREME WRN CROCKETT...ERN
PECOS AND TERRELL COUNTIES. MAIN THREAT IS COMBINATION OF DAMAGING
HAIL AND SVR GUSTS.

ACTIVITY OVER THIS REGION ALSO MAY BECOME SEEDED BY THICK HIGH
CLOUDS AND/OR NEARBY STORMS...LEADING TO MESSY MIXED MODES INCLUDING
HEAVY-PRECIP SUPERCELLS...SPLITTING STORM POTENTIAL...AND ALSO
SMALL/BOWING LINE SEGMENTS. STRONG MID/UPPER JET WINDS AHEAD OF
EJECTING MEX SHORTWAVE TROUGH WILL MAINTAIN FAVORABLE DEEP-LAYER
BULK SHEAR...I.E. 60-70 KT EFFECTIVE SHEAR. INITIAL WEAKNESSES IN
LOW LEVEL HODOGRAPHS ARE EVIDENT BECAUSE OF AREAS OF 10 KT FLOW
BETWEEN 1-2 KM AGL...EVIDENT IN DFX VWP AND IN RUC FCST SOUNDINGS.
HODOGRAPHS SHOULD ENLARGE AFTER DARK FOR ANY REMAINING
CONVECTION...HOWEVER...AS LLJ STRENGTHENS. 70 DEG F SFC DEW POINT
AT UVA AWOS SITE IS BOGUS...HOWEVER MID-UPPER 60S F FARTHER E AND S
ARE NOT...AND SHOULD SPREAD NWWD ACROSS THIS REGION THROUGH EVENING
HOURS. THIS WILL CONTRIBUTE TO MLCAPES 2500-3000 J/KG.

.EDWARDS.. 04/23/2007

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

ATTN...WFO...CRP...EWX...SJT...MAF...

28280030 28830055 29490113 29760141 29770163 29830217
30930190 30439921 28299941

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WATCHES: Tornado Watch Number 167

WWUS20 KWNS 232238
SEL7
SPC WW 232238
TXZ000-240400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 167
NWS STORM PREDICTION CENTER NORMAN OK
535 PM CDT MON APR 23 2007

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

WEST CENTRAL INTO NORTHWEST TEXAS

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 535 PM UNTIL
1100 PM CDT.

TORNADOES...HAIL TO 3 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 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 60 MILES EAST NORTHEAST OF
PLAINVIEW TEXAS TO 75 MILES SOUTHEAST OF BIG SPRING TEXAS. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU7).

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 165...WW 166...

DISCUSSION...SRN STREAM SHORTWAVE TROUGH NOW MOVING INTO SWRN TX MAY
CONTINUE ENHANCING THUNDERSTORM DEVELOPMENT ALONG AND EAST OF THE
DRY LINE THIS EVENING. DEEP LAYER SHEAR REMAINS QUITE STRONG AND
WILL SUSTAIN SUPERCELLS...WITH INCREASING POTENTIAL FOR A FEW
TORNADOES IF STORMS CAN BE SUSTAINED ENEWD ACROSS WW THIS EVENING.
VERY LARGE HAIL IS ALSO LIKELY WITH THESE STORMS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 22025.

..EVANS

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MESO: Mesoscale Discussion 0546

ACUS11 KWNS 232220
SWOMCD
SPC MCD 232219
OKZ000-TXZ000-232315-

MESOSCALE DISCUSSION 0546
NWS STORM PREDICTION CENTER NORMAN OK
0519 PM CDT MON APR 23 2007

AREAS AFFECTED...PORTIONS TX SOUTH PLAINS...PERMIAN BASIN AND LOW
ROLLING PLAINS.

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON

VALID 232219Z - 232315Z

ISOLATED TSTM DEVELOPING OVER MIDLAND COUNTY MAY BECOME
SUPERCELLULAR AS IT MOVES NEWD AND EVENTUALLY ENEWD INTO MORE MOIST
BOUNDARY LAYER. OTHER TSTMS ALSO MAY DEVELOP ACROSS PORTIONS
PERMIAN BASIN AND SOUTH PLAINS REGION -- ALONG/AHEAD OF DRYLINE AND
S OF WW 166 IN FAVORABLY SHEARED ENVIRONMENT TO SUPPORT DISCRETE
SUPERCELL STRUCTURES.

SFC MESOANALYSIS SHOWS DRYLINE FROM JUST E LBB SSWWD ACROSS MIDLAND
AND TERRELL COUNTIES. THIS DRYLINE SHOULD MARK WRN BOUND OF SVR
POTENTIAL...BUT MAY RETREAT WWD TOWARD NM BORDER LATER THIS EVENING
AMIDST CONTINUING PRESSURE FALLS AND BACKING OF SFC FLOW. MODIFIED
RUC SOUNDINGS INDICATE AIR MASS OVER CORRIDOR BETWEEN SJT-CDS IS
CHARACTERIZED BY MLCAPES 2000-3000 J/KG...SUPPORTED BY POCKETS OF
STG SFC HEATING...DEW POINTS LOW 60S F...AND 8-9 DEG C/KM MIDLEVEL
LAPSE RATES. JTN PROFILER WINDS SHOW NEARLY STRAIGHT LINE HODOGRAPH
CHARACTER INDICATING POTENTIAL FOR SPLITTING STORMS...WITH LARGE
HAIL POSSIBLE BOTH FROM RIGHT- AND LEFT-MOVING MEMBERS.
RIGHT-MOVING STORMS WILL CARRY SOME TORNADO POTENTIAL AS WELL AS
THEY MOVE INTO PROGRESSIVELY LOWER LCL ENVIRONMENTS WITH TIME AND
WITH EWD EXTENT. 50-60 KT EFFECTIVE BULK SHEAR AND 0-3 KM SRH
200-300 J/KG SHOULD BE AVAILABLE TO CONVECTION ACROSS THIS REGION.

.EDWARDS.. 04/23/2007

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

ATTN...WFO...OUN...SJT...LUB...MAF...

31060211 31840221 34290196 34339917 31259958

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MESO: Mesoscale Discussion 0545

ACUS11 KWNS 232104
SWOMCD
SPC MCD 232103
NYZ000-PAZ000-OHZ000-232330-

MESOSCALE DISCUSSION 0545
NWS STORM PREDICTION CENTER NORMAN OK
0403 PM CDT MON APR 23 2007

AREAS AFFECTED...WRN NY/FAR NWRN PA/FAR NERN OH

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 232103Z - 232330Z

LINE OF STRONG-ISOLATED SVR STORMS OVER SERN ONTARIO WAS MOVING EWD
FROM 35-40 KTS. ISOLATED DMGG WIND GUSTS WILL BE POSSIBLE WITH THIS
LINE AND INDIVIDUAL CELLS SOUTH OF THE LINE AS ACTIVITY MOVES
ACROSS WRN NY/FAR NWRN PA/FAR NERN OH BETWEEN 22-01Z. RELATIVELY
MARGINAL INSTABILITY SHOULD PRECLUDE A MORE WIDESPREAD SVR
EVENT...THUS A WW IS NOT ANTICIPATED.

LATEST VISIBLE SAT/RADAR IMAGERY SHOWS A WELL ORGANIZED CONVECTIVE
LINE MOVING EWD AROUND 35 KTS ACROSS SERN ONTARIO JUST AHEAD OF MID
LEVEL VORT CENTER MOVING EWD ACROSS SRN GEORGIAN BAY. RECENT SFC OBS
WHERE THIS LINE HAS CROSSED HAVE REPORTED WIND GUSTS TO BETWEEN
40-50 KTS. THE ENVIRONMENT DOWNSTREAM OF THIS ACTIVITY WAS WEAKLY
UNSTABLE /MUCAPES FROM 500 TO 1000 J/KG/. DESPITE MARGINAL
INSTABILITY...STEEP LOW LEVEL LAPSE RATES /AWAY FROM THE IMMEDIATE
LAKESHORE/ AND STRONG LOW LEVEL WIND FIELDS /50 KTS AT 0.5 KM FROM
THE BUFFALO RADAR VWP/ INDICATE THAT SOME DMGG WIND GUSTS MAY REACH
THE SFC WITH THIS LINE AS IT PROGRESSES ACROSS THE AREA. SOME
BACKBUILDING OF THE SRN EXTENT OF THIS LINE MAY OCCUR AS INSTABILITY
AXIS IS ORIENTED SW-NE ACROSS THE AREA. CURRENT EXTRAPOLATION OF
STORM MOTIONS WOULD TAKE THIS LINE ACROSS WRN NY BETWEEN 22-01Z.

.CROSBIE.. 04/23/2007

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

ATTN...WFO...BGM...BUF...CTP...PBZ...CLE...

43447741 43387834 42437921 41868052 41428075 41727896
42087767 42507725 43127685 43467696

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WATCHES: Tornado Watch Number 165

WWUS20 KWNS 232011
SEL5
SPC WW 232011
COZ000-240300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 165
NWS STORM PREDICTION CENTER NORMAN OK
210 PM MDT MON APR 23 2007

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

EASTERN COLORADO

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 210 PM UNTIL 900
PM MDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 60 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 60 MILES NORTH NORTHWEST OF
AKRON COLORADO TO 40 MILES WEST SOUTHWEST OF SPRINGFIELD
COLORADO. 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.

DISCUSSION...TSTMS EXPECTED TO DEVELOP OVER THE NEXT HOUR OR SO IN
INCREASINGLY MOIST/UPSLOPE FLOW INVOF DENVER CYCLONE OVER E CNTRL
CO. OTHER STORMS MAY FORM OVER THE FOOTHILLS AND MOVE/DEVELOP EWD.
BACKED LOW LEVEL WINDS AND EXPECTED DISCRETE TO SEMI-DISCRETE NATURE
OF STORMS SUGGEST POTENTIAL FOR TORNADOES IN ADDITION TO HAIL. SOME
OF THE STORMS MAY STRENGTHEN AND CONSOLIDATE INTO A CLUSTER OR TWO
THIS EVENING AS SHEAR/LARGE SCALE ASCENT INCREASE AHEAD OF
EWD-MOVING GRT BASIN UPR LOW.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 50 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
400. MEAN STORM MOTION VECTOR 21030.

..CORFIDI

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 232002
SWODY1
SPC AC 232000

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0300 PM CDT MON APR 23 2007

VALID 232000Z - 241200Z

..THERE IS A MDT RISK OF SVR TSTMS LATE THIS AFTN AND TONIGHT
ACROSS PARTS OF THE ERN TX PNHDL...NW OK...WRN KS...ERN CO AND PARTS
OF SW NEB....

..THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK
AREA...ACROSS MUCH OF THE CNTRL/SRN HIGH PLAINS....

..CENTRAL/SOUTHERN PLAINS...
SOUTHERN BRANCH TROUGH REMAINS OVER THE INTERMOUNTAIN WEST...WITH A
NEW CLOSED LOW NOW DEVELOPING ACROSS PARTS OF THE SOUTHERN GREAT
BASIN. THIS IS OCCURRING IN RESPONSE TO STRONGER MID/UPPER JET
CORE...WHICH IS JUST NOW NOSING ACROSS SOUTHERN CALIFORNIA/ARIZONA.
MODELS SUGGEST THAT THIS FEATURE WILL EVENTUALLY DEVELOP AROUND THE
SOUTHERN/EASTERN PERIPHERY OF THE MID-LEVEL CIRCULATION...INTO THE
SOUTHERN/CENTRAL HIGH PLAINS...BUT THIS WILL NOT OCCUR UNTIL LATER
TONIGHT INTO EARLY TUESDAY.

HOWEVER...BROADER SCALE DIFLUENT/DIVERGENT UPPER FLOW REGIME
DOWNSTREAM OF SOUTHERN BRANCH TROUGH ALREADY EXTENDS ACROSS THE
CENTRAL/SOUTHERN HIGH PLAINS...WHERE A MOIST RETURN FLOW OFF THE
GULF OF MEXICO IS UNDERWAY. SOUTH/SOUTHWESTERLY MID-LEVEL
FLOW...ABOVE SLOWLY STRENGTHENING SOUTHERLY LOW-LEVEL FLOW...IS ALSO
ALREADY OF SUFFICIENT STRENGTH TO SUPPORT FAVORABLE DEEP LAYER SHEAR
FOR SUPERCELL DEVELOPMENT...AND THIS WILL IMPROVE THROUGH THE LATE
AFTERNOON AND EVENING HOURS. IN CONJUNCTION WITH ONGOING
DESTABILIZATION...POTENTIAL FOR SEVERE THUNDERSTORMS IS INCREASING
ACROSS MUCH OF THE CENTRAL/SOUTHERN HIGH PLAINS.

INHIBITION ASSOCIATED WITH A WARM LOWER/MID TROPOSPHERE IS
CONSIDERABLE ACROSS THE SOUTHERN PLAINS. BUT...A WEAK SUBTROPICAL
IMPULSE NOW PROGRESSING ACROSS WESTERN TEXAS MAY SUPPRESS THIS A
BIT. AND...IN CONJUNCTION WITH CONFLUENT LOW-LEVEL FLOW AND
LOW-LEVEL WARM ADVECTION...CAP MAY WEAKEN ENOUGH FOR AT LEAST
SCATTERED STORMS BY LATE AFTERNOON. FORCING SEEMS LIKELY TO FOCUS
DEVELOPMENT FROM PARTS OF WESTERN OKLAHOMA AND THE EASTERN TEXAS
PANHANDLE INTO SOUTHWEST KANSAS...WHERE RETURN OF 60F+ DEW POINTS
AND STEEPENING LAPSE RATES WILL CONTRIBUTE TO MIXED LAYER CAPE AS
HIGH AS 2000 J/KG. A FEW SUPERCELLS ARE LIKELY...WITH POTENTIAL FOR
VERY LARGE HAIL/ISOLATED DAMAGING WIND GUSTS. TORNADOES ARE ALSO
POSSIBLE...PARTICULARLY AS LOW-LEVEL SHEAR PROFILES BECOME ENHANCED
BENEATH STRENGTHENING LOW-LEVEL JET BY THE 24/00-02Z TIME FRAME.

FAVORABLE OROGRAPHY MAY AID ADDITIONAL CONVECTIVE DEVELOPMENT LATE
THIS AFTERNOON TO THE LEE OF THE COLORADO FRONT RANGE...WHERE
SIGNIFICANT DESTABILIZATION HAS YET TO OCCUR. HOWEVER...THE
BOUNDARY LAYER IS MOISTENING ON SOUTHEASTERLY UPSLOPE FLOW...AND A
FEW SUPERCELLS SEEM LIKELY WITH POTENTIAL FOR LARGE HAIL/DAMAGING
WIND GUSTS...PERHAPS BRIEF TORNADOES.

LATER THIS EVENING...INCREASING INHIBITION WITH THE LOSS OF DAYTIME
HEATING MAY SUPPRESS SOUTHERN HIGH PLAINS ACTIVITY...BUT STORMS SEEM
LIKELY TO INCREASE IN COVERAGE AND MAINTAIN OR INCREASE IN INTENSITY
ACROSS PARTS OF EASTERN COLORADO INTO WESTERN KANSAS. THIS WILL
OCCUR AS MID/UPPER FORCING FOR UPWARD VERTICAL MOTION STRENGTHENS
WITH THE APPROACH OF THE UPPER JET...AND MOIST RETURN FLOW
CONTINUES. TRENDS ARE EXPECTED FOR MUCH OF THE CONVECTION TO BECOME
BASED ABOVE A WARM FRONTAL INVERSION LAYER...WITH LARGE HAIL
BECOMING THE PRIMARY SEVERE THREAT BEFORE ACTIVITY CONTINUES TO
SPREAD NORTHWARD INTO NEBRASKA OVERNIGHT.

..OHIO VALLEY...
IN THE WAKE OF SHORT WAVE TROUGH NOW ACCELERATING INTO THE LOWER
GREAT LAKES/ST. LAWRENCE VALLEY...A TRAILING LOW/MID-LEVEL
CONFLUENCE ZONE MAY STILL BECOME THE FOCUS FOR THUNDERSTORM
ACTIVITY. LAPSE RATES ACROSS THIS REGION ARE WEAK...BUT A HEATED
MOIST BOUNDARY WITH SIZABLE TEMPERATURE/DEW POINTS SPREADS AND 40+
KT MEAN ENVIRONMENTAL FLOW WILL PROVIDE POTENTIAL FOR GUSTY WINDS
NEAR ANY STORMS THAT DO DEVELOP...THROUGH MID EVENING.

.KERR.. 04/23/2007

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MESO: Mesoscale Discussion 0544

ACUS11 KWNS 231936
SWOMCD
SPC MCD 231936
COZ000-232130-

MESOSCALE DISCUSSION 0544
NWS STORM PREDICTION CENTER NORMAN OK
0236 PM CDT MON APR 23 2007

AREAS AFFECTED...ERN CO

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

VALID 231936Z - 232130Z

ISOLATED SVR TSTMS SHOULD BEGIN TO DEVELOP ALONG THE FRONT RANGE OF
ERN CO IN THE NEXT 2-3 HRS. GIVEN STRENGTH OF LOW LEVEL SHEAR...
ISOLATED TORNADOS WILL BE POSSIBLE ALONG WITH LARGE HAIL/DMGG WINDS.
A TORNADO WATCH IS LIKELY SOON.

LATEST VISIBLE SATELLITE IMAGERY SHOWS ISOLATED TSTMS BEGINNING TO
DEVELOP INVOF OF LEE LOW LOCATED JUST SE OF THE DENVER METRO AREA.
THE 18Z DEN SOUNDING SHOWED A MODERATE TO STRONGLY SHEARED
ENVIRONMENT IN THE LOW-MID LEVELS WITH LITTLE CINH REMAINING AND
AROUND 750 J/KG OF MUCAPE. AS LOW LEVEL MOISTURE CONTINUES TO
INCREASE ALONG AN INSTABILITY AXIS EXTENDING FROM NEAR DEN SWWD
TOWARDS LAA...CONVECTION SHOULD CONTINUE TO INTENSIFY ALONG THE LEE
LOW. ADDITIONAL DEVELOPMENT AND INTENSIFICATION OF CONVECTION SHOULD
OCCUR ALONG THE SRN FRONT RANGE BETWEEN DEN AND COS AS A SECONDARY
AREA OF LOW PRESSURE DEEPENS INTENSIFYING THE LOW LEVEL JET WHICH
WILL AID IN GREATER MOISTURE ADVECTION /DWPTS IN THE LOWER TO MID
50S/ INTO THE AREA TOWARDS AND AFTER 00Z. STRENGTHENING LOW LEVEL
SHEAR AROUND THAT TIME WILL FAVOR ISOLATED TORNADOS GIVEN THE AMT OF
POTENTIAL INSTABILITY.

.CROSBIE.. 04/23/2007

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

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

38760465 39760482 40290478 40740412 40660346 40160268
39080211 38600205 38220214 37860247 37670278 37760347
38320410

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MESO: Mesoscale Discussion 0543

ACUS11 KWNS 231902
SWOMCD
SPC MCD 231902 COR
OKZ000-TXZ000-KSZ000-232045-

MESOSCALE DISCUSSION 0543
NWS STORM PREDICTION CENTER NORMAN OK
0202 PM CDT MON APR 23 2007

AREAS AFFECTED...SWRN KS SWD INTO THE ERN HALF OF THE TX
PANHANDLE/WRN OK

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

VALID 231902Z - 232045Z

CORRECTED FOR MISSING GRAPHIC

SCATTERED TO ISOLATED SEVERE STORMS ARE FORECAST TO DEVELOP ACROSS
THE SRN HIGH PLAINS ALONG/AHEAD OF THE DRYLINE LATER THIS AFTERNOON.
TORNADO WATCH WILL LIKELY BE REQUIRED.

AMA 18Z RAOB SHOWS FAIRLY STRONG LOW-LEVEL CAP...BUT DAYTIME HEATING
IS ONGOING ALONG NRN/WRN FRINGES OF THICKER CLOUD SHIELD OF WRN N
TX/WRN OK. AS HEATING CONTINUES THROUGH THE AFTERNOON AND
PERSISTENT/WEAK LOW-LEVEL CONVERGENCE CONTINUES ALONG THE
DRYLINE...CAP SHOULD CONTINUE TO SLOWLY WEAKEN. THIS SHOULD
EVENTUALLY RESULT IN ISOLATED STORM DEVELOPMENT -- WITH INITIAL
DEVELOPMENT ANTICIPATED OVER THE TX PANHANDLE WHERE SHALLOW CU FIELD
IS NOW DEVELOPING. FAIRLY STEEP LAPSE RATES ARE CONTRIBUTING TO
MODERATE INSTABILITY ABOVE THE CAP LAYER...WHICH COMBINED WITH AMPLE
SHEAR FOR UPDRAFT ROTATION SUGGESTS THAT STORMS SHOULD BECOME
SUPERCELLULAR SHORTLY AFTER DEVELOPMENT.

IN ADDITION TO THE THREAT FOR LARGE HAIL...LOCALLY-DAMAGING WINDS
WILL ALSO BE POSSIBLE. DEGREE OF BOUNDARY-LAYER MOISTURE AND
INCREASING LOW-LEVEL SHEAR BY EARLY EVENING WILL ALSO SUPPORT A
THREAT FOR TORNADOES.

.GOSS.. 04/23/2007

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

ATTN...WFO...OUN...DDC...GLD...LUB...AMA...

36760155 38270200 37709990 36139924 33689998 33290148
34120160 35490156

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MESO: Mesoscale Discussion 0543

ACUS11 KWNS 231852
SWOMCD
SPC MCD 231852
MNZ000-232045-

MESOSCALE DISCUSSION 0543
NWS STORM PREDICTION CENTER NORMAN OK
0152 PM CDT MON APR 23 2007

AREAS AFFECTED...SWRN KS SWD INTO THE ERN HALF OF THE TX
PANHANDLE/WRN OK

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

VALID 231852Z - 232045Z

SCATTERED TO ISOLATED SEVERE STORMS ARE FORECAST TO DEVELOP ACROSS
THE SRN HIGH PLAINS ALONG/AHEAD OF THE DRYLINE LATER THIS AFTERNOON.
TORNADO WATCH WILL LIKELY BE REQUIRED.

AMA 18Z RAOB SHOWS FAIRLY STRONG LOW-LEVEL CAP...BUT DAYTIME HEATING
IS ONGOING ALONG NRN/WRN FRINGES OF THICKER CLOUD SHIELD OF WRN N
TX/WRN OK. AS HEATING CONTINUES THROUGH THE AFTERNOON AND
PERSISTENT/WEAK LOW-LEVEL CONVERGENCE CONTINUES ALONG THE
DRYLINE...CAP SHOULD CONTINUE TO SLOWLY WEAKEN. THIS SHOULD
EVENTUALLY RESULT IN ISOLATED STORM DEVELOPMENT -- WITH INITIAL
DEVELOPMENT ANTICIPATED OVER THE TX PANHANDLE WHERE SHALLOW CU FIELD
IS NOW DEVELOPING. FAIRLY STEEP LAPSE RATES ARE CONTRIBUTING TO
MODERATE INSTABILITY ABOVE THE CAP LAYER...WHICH COMBINED WITH AMPLE
SHEAR FOR UPDRAFT ROTATION SUGGESTS THAT STORMS SHOULD BECOME
SUPERCELLULAR SHORTLY AFTER DEVELOPMENT.

IN ADDITION TO THE THREAT FOR LARGE HAIL...LOCALLY-DAMAGING WINDS
WILL ALSO BE POSSIBLE. DEGREE OF BOUNDARY-LAYER MOISTURE AND
INCREASING LOW-LEVEL SHEAR BY EARLY EVENING WILL ALSO SUPPORT A
THREAT FOR TORNADOES.

.GOSS.. 04/23/2007

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

ATTN...WFO...DLH...MPX...FGF...

47429474 47479448 47549401 47589328 47829250 47709186
47349199 46819284 46089313 45829378 46179435

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DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 231735
SWODY2
SPC AC 231733

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1233 PM CDT MON APR 23 2007

VALID 241200Z - 251200Z

..THERE IS A MDT RISK OF SVR TSTMS TUE/TUE NIGHT ACROSS MUCH OF THE
CNTRL/SRN PLAINS...INCLUDING MUCH OF KS/ERN OK...CNTRL/NRN TX AND
PARTS OF WRN MO/WRN AR...WHERE POTENTIAL EXISTS FOR A WIDESPREAD
OUTBREAK OF SEVERE THUNDERSTORMS...INCLUDING A FEW TORNADOES....

..THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK
AREA...ACROSS MUCH OF THE CNTRL/S CNTRL STATES....

..SYNOPSIS...
LARGE UPPER TROUGH EMBEDDED WITHIN THE SOUTHERN BRANCH OF SPLIT
POLAR WESTERLIES APPEARS LIKELY TO PROGRESS EASTWARD INTO THE PLAINS
TUESDAY...MUCH AS HAS BEEN SUGGESTED BY MODEL FORECASTS THE PAST
SEVERAL DAYS. THIS IS EXPECTED TO OCCUR AS ANOTHER SIGNIFICANT
SHORT WAVE TROUGH...EMANATING FROM STRONG ZONAL PACIFIC
JET...PROGRESSES INTO BRITISH COLUMBIA/PACIFIC NORTHWEST COASTAL
AREAS. SMALLER SCALE DETAILS OF THIS EVOLUTION ARE STILL A BIT
UNCERTAIN. BUT...IT CURRENTLY SEEMS MOST PROBABLE THAT AN INITIAL
MID-LEVEL JET STREAK/IMPULSE ASSOCIATED WITH THE SOUTHERN BRANCH
SYSTEM WILL ALREADY BE IN THE PROCESS OF LIFTING OUT OF THE SOUTHERN
ROCKIES INTO THE CENTRAL HIGH PLAINS BY 12Z TUESDAY. THIS FEATURE
IS EXPECTED TO CONTINUE PIVOTING ACROSS THE CENTRAL PLAINS DURING
THE DAY TUESDAY...AROUND THE EASTERN/NORTHEASTERN PERIPHERY OF A
BROADER SCALE MID-LEVEL CIRCULATION. THEN...ON THE SOUTHERN
PERIPHERY OF THE CIRCULATION...ANOTHER SIGNIFICANT IMPULSE IS
PROGGED TO DIG SOUTHEAST OF THE SOUTHERN ROCKIES THROUGH CENTRAL
TEXAS...LATER TUESDAY INTO 12Z WEDNESDAY.

IN RESPONSE TO THE EVOLVING UPPER FLOW PATTERN...A FAIRLY DEEP
/NEAR OR JUST BELOW 1000 MB/ SURFACE CYCLONE SHOULD FORM TO THE LEE
OF THE CENTRAL ROCKIES. THIS WILL CONTRIBUTE TO STRENGTHENING DEEP
LAYER SHEAR ACROSS A BROAD AREA OF THE CENTRAL U.S...WHERE A
SIGNIFICANT MOISTURE RETURN FROM THE WESTERN GULF OF MEXICO IS
ALREADY WELL UNDERWAY. WARM SECTOR SURFACE DEW POINTS IN THE
MID/UPPER 60S SHOULD BE COMMON...PERHAPS NEAR 70F ACROSS PARTS OF
SOUTHERN/EASTERN TEXAS. SOME CONCERN EXISTS ABOUT THE POSSIBILITY
OF CONSIDERABLE CLOUD COVER...AND ITS INFLUENCE ON INSOLATION...BUT
MIXED LAYER CAPE OF 1000-2000 J/KG SEEMS PROBABLE BY TUESDAY
AFTERNOON. THIS IS EXPECTED TO BE MORE THAN SUFFICIENT...GIVEN
FAVORABLE LARGE SCALE FORCING...TO SUPPORT WIDESPREAD CONVECTIVE
DEVELOPMENT...INCLUDING AN OUTBREAK OF SEVERE THUNDERSTORMS WITH THE
POTENTIAL FOR TORNADOES...VERY LARGE HAIL...AND DAMAGING WINDS.

..CENTRAL PLAINS INTO THE OZARKS...
FORCING IN THE EXIT REGION OF A 70+ KT 500 MB JET STREAK LIKELY WILL
OVERSPREAD THE CENTRAL HIGH PLAINS BY/SHORTLY AFTER 12Z
TUESDAY...BEFORE SHIFTING EASTWARD ACROSS KANSAS DURING THE DAYTIME
HOURS. ELEVATED CONVECTIVE DEVELOPMENT IS EXPECTED TO BE ONGOING AT
THE OUTSET OF THE FORECAST PERIOD TO THE NORTH OF WARM FRONT ACROSS
NORTHERN KANSAS...AND INITIATION OF BOUNDARY LAYER BASED STORMS MAY
NOT TAKE MUCH HEATING NEAR SURFACE LOW/WARM FRONT/DRY LINE
INTERSECTION. THIS MAY OCCUR BY MIDDAY ACROSS WEST CENTRAL
KANSAS...BEFORE ACTIVITY SPREADS EASTWARD ALONG DEVELOPING FRONTAL
OCCLUSION...ROUGHLY NEAR THE INTERSTATE 70 CORRIDOR...INTO WEST
CENTRAL MISSOURI BY TUESDAY EVENING. RISK OF TORNADOES WITH
SUPERCELLS APPEARS HIGHEST WITH THIS ACTIVITY...AS WELL AS WELL AS
WITH DISCRETE SUPERCELLS LIKELY TO DEVELOP SOUTHWARD ALONG DRY LINE
THROUGH SOUTHERN KANSAS INTO NORTH CENTRAL/EASTERN OKLAHOMA ...AND
POSSIBLY SOUTHWEST MISSOURI...BY THE 25/00-03Z TIME FRAME. ISOLATED
STRONG TORNADOES ARE POSSIBLE...ALONG WITH POTENTIAL FOR VERY LARGE
HAIL AND ISOLATED DAMAGING DOWNBURSTS.

..SOUTHERN PLAINS...
CONSIDERABLE CONVECTIVE INHIBITION AND LATE ARRIVAL OF STRONGER
MID/UPPER FORCING MAY DELAY ONSET OF PRIMARY CONVECTION. BUT...
ISOLATED TO WIDELY SCATTERED STORMS APPEAR POSSIBLE ALONG DRY
LINE/PACIFIC FRONT ACROSS PARTS OF CENTRAL/NORTHERN TEXAS BY LATE
AFTERNOON. IF THIS OCCURS...POTENTIAL FOR VERY LARGE HAIL/DAMAGING
WINDS WILL EXIST...IN ADDITION TO ISOLATED TORNADOES. MODELS ARE
SUGGESTIVE THAT LARGE-SCALE FORCING WILL BE SUPPORTIVE OF A BROKEN
SQUALL LINE DURING THE EVENING HOURS... WHICH MAY PERSIST WELL INTO
THE NIGHT...SPREADING THROUGH NORTHEAST TEXAS/SOUTHEAST OKLAHOMA
INTO THE PARTS OF THE LOWER MIDDLE MISSISSIPPI VALLEY. LARGE
HAIL/DAMAGING WIND GUSTS COULD BECOME QUITE NUMEROUS...ALONG WITH A
CONTINUING RISK FOR ISOLATED TORNADOES.

.KERR.. 04/23/2007

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 231631
SWODY1
SPC AC 231629

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT MON APR 23 2007

VALID 231630Z - 241200Z

..THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF E CO...WRN KS AND
THE OK/TX PANHANDLES...

..THERE IS A SLGT RISK OF SVR TSTMS OVER REMAINING PARTS OF THE
CNTRL AND SRN PLNS...

..SYNOPSIS...
SRN GRT BASIN UPR LOW SHOULD CONTINUE SLOWLY E TOWARD THE FOUR
CORNERS REGION TODAY...REACHING N CNTRL NM EARLY TUESDAY AS HEIGHTS
SLIGHTLY REBOUND OVER THE SRN/CNTRL PLNS. SUBTROPICAL IMPULSE NOW
CROSSING THE GULF OF CA SHOULD ACCELERATE NEWD IN TIGHTENING
GRADIENT ON SIDE OF GRT BASIN LOW. IN THE EAST...SYSTEM THAT
CROSSED THE PLAINS OVER THE WEEKEND WILL CONTINUE TO BECOME ABSORBED
IN FAST NRN STREAM FLOW OVER THE LWR GRT LKS.

AT THE SFC...LEE LOW LIKELY TO DEEPEN OVER NE NM TODAY BEFORE
TURNING NE INTO SE CO EARLY TUESDAY. COLD FRONT AND PREFRONTAL
TROUGH ASSOCIATED WITH GRT LKS SYSTEM WILL SETTLE SLOWLY S INTO THE
OH VLY.

..CO FRONT RANGE AND ADJACENT HI PLNS...
PATTERN STILL APPEARS FAVORABLE FOR THE DEVELOPMENT OF DENVER
CYCLONE N OF THE PALMER DIVIDE TODAY. COMBINATION OF SFC HEATING
WITH STEEP LOW TO MID LEVEL LAPSE RATES AND ADVECTION OF MID 40S SFC
DEWPOINTS W TO THE FRONT RANGE WILL BOOST MLCAPE TO AROUND 1000
J/KG. COUPLED WITH UPSLOPE FLOW AND VEERING WIND PROFILES...SETUP
WILL SUPPORT SUSTAINED STORMS/SUPERCELLS BY MID TO LATE AFTERNOON
OVER N CNTRL/NE CO. ALONG WITH LARGE HAIL... ENHANCED LOW LEVEL
DIRECTIONAL SHEAR N OF THE DENVER CYCLONE MAY PROMOTE DEVELOPMENT OF
A FEW TORNADOES.

IN CONTRAST TO MOST ERN CO SVR WX SITUATIONS...CONDITIONS EXPECTED
TO BECOME FAVORABLE FOR MORE WIDESPREAD SVR ACTIVITY OVER THE CO
PLNS LATER THIS EVENING. INFLUX OF RICHER BOUNDARY LAYER MOISTURE
FROM KS /DEWPOINTS IN THE 50S/...COUPLED WITH STRENGTHENING
SHEAR/LARGE SCALE ASCENT IN EXIT REGION OF JET STREAK WITH GRT BASIN
TROUGH...EXPECTED TO SUPPORT INTENSIFICATION OF EXISTING STORMS
AND/OR DEVELOPMENT OF NEW ACTIVITY IN E CNTRL/NE CO. THESE STORMS
MAY EXTEND A THREAT FOR LARGE HAIL...HIGH WIND AND A COUPLE
TORNADOES INTO EARLY TUESDAY.

..CNTRL/SRN PLNS...
A CONDITIONAL THREAT FOR SUPERCELLS WILL EXIST THIS AFTERNOON AND
EARLY TONIGHT IN INCREASINGLY UNSTABLE ENVIRONMENT ALONG DRY LINE
FROM THE TX PANHANDLE NNW INTO SW KS AND PERHAPS FAR ERN CO. STORMS
MAY ALSO FORM BY SUNSET IN ZONE OF STRENGTHENING ASCENT ALONG
DEVELOPING WARM FRONT IN SW/S CNTRL KS. AMPLE SHEAR/CAPE
WILL BE PRESENT FOR SUPERCELLS...ESPECIALLY IN THE PANHANDLES REGION
WHERE ASCENT MAY BE ENHANCED BY APPROACH OF BAJA DISTURBANCE.
MOISTURE WILL BE QUITE RICH AND DEEP MIXING SHOULD BE LIMITED OVER
MUCH OF THE AREA BY HIGH CLOUDS. THUS...POTENTIAL WILL EXIST FOR
TORNADOES IN ADDITION TO LARGE HAIL.

..OH VLY/LWR GRT LKS...
DEEP...LARGELY UNIDIRECTIONAL WLY WIND FIELD /WITH 40-50 KT 0-6 KM
SHEAR/ ON SRN FRINGE OF EJECTING UPR TROUGH WILL BE FAVORABLE FOR
SVR STORMS IN WARM SECTOR OVER THE OH VLY/LWR GRT LKS TODAY. BUT
PLUME OF WARM MID LEVEL AIR AND MODEST LOW LEVEL MOISTURE
AVAILABILITY WILL STRONGLY LIMIT SFC-BASED INSTABILITY. CAPPING AND
LIMITED CONVERGENCE SHOULD PROHIBIT STORM DEVELOPMENT THROUGH MOST
OF THE DAY. CONVERGENCE WILL..HOWEVER...DEEPEN OVER THE REGION BY
EARLY EVENING AS COLD FRONT OVERTAKES PREFRONTAL TROUGH. THIS MAY
SUPPORT DEVELOPMENT OF A BAND OF STORMS FROM WRN NY/PA WSW INTO SRN
IND/IL. RELATIVELY STEEP LOW LEVEL LAPSE RATES AND MODERATE WIND
FIELD MAY YIELD STRONG WIND GUSTS/MARGINAL HAIL IN A FEW STORMS.

.CORFIDI/CROSBIE.. 04/23/2007

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 231227
SWODY1
SPC AC 231224

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0724 AM CDT MON APR 23 2007

VALID 231300Z - 241200Z

..THERE IS A MDT RISK OF SVR TSTMS PARTS OF WESTERN KANSAS...ERN
COLORADO AND PARTS OF NWRN OK AND TX PANHANDLE...

..THERE IS A SLGT RISK OF SVR TSTMS PARTS OF CENTRAL AND SRN
PLAINS...

..SYNOPSIS...
CONDITIONS WILL BECOME FAVORABLE FOR SEVERE THUNDERSTORMS BEGINNING
THIS AFTERNOON FROM THE COLORADO FRONT RANGE EWD ACROSS MUCH OF
CENTRAL AND NRN PORTION OF SRN PLAINS AS A MAJOR TROUGH NOW
INTERMOUNTAIN REGION APPROACHES.

SURFACE LOW MOVING EWD ACROSS GREAT LAKES WITH TRAILING FRONTAL ZONE
SWWD ACROSS LWR MO VALLEY. FRONT THEN EXTENDS WWD ACROSS NRN OK TO
DEVELOPING SURFACE LOW SERN CO. FRONT TO RETURN NWD AS A WARM FRONT
ACROSS KS AS CO LOW DEEPENS. GULF MOISTURE WITH DEWPOINTS INTO THE
LOW/MID 60S SPREADING NWD ON SLY LLJ THRU SRN INTO CENTRAL PLAINS
TODAY ...WHILE DRY LINE SETS UP THIS AFTERNOON FROM TX/OK PANHANDLE
SWD TO TX BIG BEND.

BAND OF STRONG MID/UPR WINDS WILL SWING OUT INTO CENTRAL AND SRN
HIGH PLAINS THIS AFTERNOON AND TONIGHT AS TROUGH MAKES STEADY EWD
PROGRESS ACROSS ROCKIES. SFC-6KM SHEAR WILL INCREASE OVER A LARGE
PORTION OF HIGH PLAINS TO 50-60KT WHICH COUPLED WITH BACKED BOUNDARY
LAYER WINDS PROVIDES KINEMATIC ENVIRONMENT VERY FAVORABLE FOR
SUPERCELL DEVELOPMENT.

..CO FRONT RANGE AND ADJACENT HIGH PLAINS...
MODELS ALL SUPPORT DEVELOPMENT OF DEN CYCLONE N OF PALMER DIVIDE
THIS AFTERNOON. WITH STEEP LAPSE RATES AND STRONG VEERING SHEAR
PROFILES...THE ADVECTION OF MID 40S DEWPOINTS WWD TO NEAR FRONT
RANGE WILL SUPPORT MLCAPES TO 1000 J/KG AND DEVELOPMENT OF SEVERE
THUNDERSTORMS BY MID AFTERNOON. ALONG WITH LARGE HAIL...TORNADOES
WILL BE POSSIBLE WITH THE ENHANCED SHEAR CREATED BY DEN CYCLONE.

..ERN CO PLAINS/WRN KS SWD THRU TX PANHANDLE AND WRN OK...
SEVERE THUNDERSTORMS WILL DEVELOP BY MID/LATE AFTERNOON ALONG THE
DEVELOPING DRY LINE TO SE OF CO SURFACE LOW. THE CURRENT CANOPY OF
SUBTROPICAL MID/UPR CLOUDINESS SHOULD SHIFT AWAY TO THE E BY THIS
AFTERNOON PERMITTING STRONG SURFACE HEATING ALONG DRY LINE. WITH
MLCAPES CLIMBING TO 1000-1500 J/KG SEVERE THUNDERSTORMS SHOULD
DEVELOP ALONG AND JUST E OF DRY LINE BY LATE AFTERNOON. VEERING
SHEAR PROFILES BOTH ALONG DRY LINE AND RETREATING WARM FRONT SUPPORT
SUPERCELLS. IN ADDITION TO VERY LARGE HAIL A FEW TORNADOES ARE
EXPECTED. STRONG TORNADOES WILL BE POSSIBLE BY EVENING AS BOTH
KINEMATIC AND THERMODYNAMIC SUPPORT CONTINUES TO INCREASE.

OVERNIGHT NAM FORECAST SOUNDINGS INDICATE THAT IMPRESSIVE ELEVATED
INSTABILITY DEVELOPS ACROSS MUCH OF WRN HALF OF KS AS THE MOIST GULF
AIRMASS IS LIFTED BY THE WARM FRONT. MUCAPES IN EXCESS OF 2000 J/KG
ALONG WITH STRONG/VEERING SHEAR PROFILES WILL MAINTAIN SUPERCELL
DEVELOPMENT ALONG WITH A VERY LARGE HAIL THREAT THRU THE NIGHT
POSSIBLY AS FAR N AS SRN NEB.

..OH VALLEY...
GREAT LAKES SURFACE LOW MOVES RAPIDLY EWD AND DEEPENS ACROSS SERN
ONTARIO TODAY. AHEAD OF THE TRAILING COLD FRONT 40-50 KT SHEAR
WOULD SUPPORT SEVERE THUNDERSTORMS PROVIDED ADEQUATE INSTABILITY WAS
AVAILABLE. HOWEVER WITH DEWPOINTS NOT EXPECTED TO RISE HIGHER THAN
LOW/MID 50S...MEAGER INSTABILITY WITH MLCAPES LESS THAN 500 J/KG
EXPECTED. THUNDERSTORMS SHOULD DEVELOP ALONG/AHEAD OF COLD FRONT BY
MID AFTERNOON. PRIMARY THREAT WILL BE GUSTY WINDS...GENERALLY BELOW
SVR LEVELS.

.HALES/JEWELL.. 04/23/2007

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DAY48SVR: Nws Storm Prediction Center Norman Ok

ACUS48 KWNS 230826
SWOD48
SPC AC 230826

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0326 AM CDT MON APR 23 2007

VALID 261200Z - 011200Z

..DISCUSSION...

LATEST MODEL GUIDANCE IS CONSISTENT IN DEPICTING A GRADUAL SHIFT IN
THE LONG WAVE PATTERN TO THAT OF TROUGHING OVER THE ERN U.S. AND
RIDGING OVER THE ROCKIES. HOWEVER EARLY IN THIS TRANSITION...SOME
THREAT OF SEVERE WEATHER WILL EXIST OVER THE ERN GULF COAST STATES
TO THE SERN ATLANTIC STATES ON DAYS 4 AND 5 /THU-FRI/...APRIL 26TH
AND 27TH. THIS WILL BE IN ASSOCIATION WITH WEAKENING SHORTWAVE
TROUGH AND ATTENDANT FRONTAL SYSTEM MOVING EWD THROUGH THE REGION.
THIS THREAT SHOULD REMAIN RELATIVELY LOCALIZED AS INSTABILITY AND
VERTICAL SHEAR ARE FORECAST TO BE MARGINALLY SUPPORTIVE OF ORGANIZED
STORMS.

THEREAFTER...ANY PROSPECTS OF ORGANIZED SEVERE WEATHER APPEAR QUITE
SMALL.

.MEAD.. 04/23/2007

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DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 230702
SWODY3
SPC AC 230700

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0200 AM CDT MON APR 23 2007

VALID 251200Z - 261200Z

..THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE MIDDLE INTO
LOWER MS VALLEY AND LOWER OH VALLEY...

..SYNOPSIS...

LATEST MODEL GUIDANCE REMAINS CONSISTENT IN SUGGESTING THE UPPER LOW
OVER KS/OK WEDNESDAY MORNING WILL GRADUALLY WEAKEN AND EVOLVE INTO
AN OPEN WAVE AS IT TRANSLATES EWD INTO THE MID MS/LOWER OH VALLEYS
THURSDAY MORNING. THOUGH MID AND HIGH-LEVEL WIND FIELDS WILL
CONCURRENTLY WEAKEN THROUGH THE PERIOD...A BELT OF MODERATELY STRONG
FLOW WILL PERSIST FROM THE LOWER MS INTO OH VALLEYS.

IN THE LOW-LEVELS...PRIMARY SURFACE LOW WILL DEVELOP SEWD FROM SERN
KS INTO NERN AR OR WRN TN BY 26/12Z. A SECONDARY LOW WILL DEVELOP
MORE EWD ALONG LOW-LEVEL BAROCLINIC ZONE SITUATED ALONG THE OH RIVER
TO THE MID ATLANTIC COAST BY WEDNESDAY EVENING. MEANWHILE...COLD
FRONT ATTENDANT TO WRN-MOST LOW WILL PUSH SEWD THROUGH THE LOWER MS
VALLEY.

..MIDDLE INTO LOWER MS VALLEY AND LOWER OH VALLEY...

WIDESPREAD TSTM ACTIVITY IS EXPECTED TO BE ONGOING ACROSS THE REGION
WEDNESDAY MORNING...RESULTING IN CONSIDERABLE UNCERTAINTY IN SEVERE
WEATHER POTENTIAL THROUGH THE FORECAST PERIOD.

A MOIST LOW-LEVEL AIR MASS WILL BE IN PLACE WITHIN WARM SECTOR WITH
DEWPOINTS IN THE LOW/MID 60S. WITH THE EXCEPTION OF CLOSE VICINITY
TO UPPER LOW...MID-LEVEL LAPSE RATES WILL NOT BE PARTICULARLY STEEP
AND THIS WILL LIMIT THE DEGREE OF INSTABILITY DEVELOPING BY
AFTERNOON.

IT APPEARS THE MOST LIKELY AREAS FOR SEVERE STORM DEVELOPMENT
WEDNESDAY WILL BE: 1) AHEAD OF SURFACE LOW AND ALONG WARM OR
QUASI-STATIONARY BOUNDARY OVER SRN MO AND AR EWD INTO THE LOWER OH
VALLEY WHERE LOW-LEVEL CONVERGENCE WILL BE MAXIMIZED AND VERTICAL
SHEAR IS SUFFICIENTLY STRONG FOR ORGANIZED SEVERE STORMS. AND...2)
ALONG LEADING EDGE OF EXPECTED...PRE-FRONTAL MCS WHICH WILL LIKELY
PERSIST THROUGH THE PERIOD OVER THE LOWER MS VALLEY. GIVEN THE POOR
LAPSE RATE...A FEW TORNADOES AND LOCALLY DAMAGING WINDS APPEAR TO BE
THE PRIMARY SEVERE WEATHER THREATS.

..MIDDLE OH VALLEY EWD TO THE MID ATLANTIC COAST...

LOW-LEVEL MOISTURE IS FORECAST TO INCREASE THROUGH THE PERIOD ALONG
AND TO THE S OF LOW-LEVEL BOUNDARY STRETCHED W-E THROUGH THE REGION.
LAPSE RATES WILL REMAIN RELATIVELY POOR HERE AS WELL...THOUGH THE
INCREASE IN BOUNDARY LAYER MOISTURE WILL SUPPORT POCKETS OF WEAK
INSTABILITY. GIVEN THE RELATIVELY STRONG VERTICAL SHEAR
FORECAST...POTENTIAL WILL EXIST FOR A FEW ORGANIZED STORMS WEDNESDAY
AFTERNOON INTO EVENING INVOF THIS BOUNDARY...ESPECIALLY NEAR AND
AHEAD OF SECONDARY SURFACE LOW DEVELOPING EWD.

.MEAD.. 04/23/2007

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DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 230559
SWODY1
SPC AC 230557

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT MON APR 23 2007

VALID 231200Z - 241200Z

..THERE IS A MDT RISK OF SVR TSTMS LATER THIS AFTERNOON AND TONIGHT
ACROSS E CENTRAL CO...W CENTRAL AND SWRN KS...THE OK/TX PANHANDLE
AND A SMALL PART OF NWRN OK....

..THERE IS A SLGT RISK OF SVR TSTMS SURROUNDS THE MDT RISK ACROSS
PARTS OF THE CENTRAL AND SRN HIGH PLAINS....

..SIGNIFICANT SEVERE WEATHER EVENT IS EXPECTED ACROSS PARTS OF THE
CENTRAL AND SOUTHERN HIGH PLAINS LATE THIS AFTERNOON AND TONIGHT...

..SYNOPSIS...

MID/UPPER LEVEL LOW DEEPENING OVER W CENTRAL/SRN NV THIS MORNING IS
FORECAST TO MOVE EWD OVER THE FOUR CORNERS AREA AND INTO CENTRAL/SRN
COLORADO BY THE END OF THE PERIOD. MODELS ARE DIFFERENT IN HANDLING
OF SURFACE FEATURES WITH THE NAM BEING THE MOST AGGRESSIVE IN
BRINGING A DRYLINE/SURFACE TROUGH EWD INTO THE NERN TX PANHANDLE/WRN
OK BY 24/00Z. HOWEVER...THE UKMET AND GFS MODELS ARE ALL SLOWER
PLACING THIS FEATURE FROM A LOW BETWEEN PUB AND DEN THEN SEWD/SWD
THROUGH THE CENTRAL PARTS OF THE OK/TX PANHANDLE WHICH IS THE
PREFERRED LOCATION AT THIS TIME.

..E CENTRAL CO AND WRN KS INTO PARTS OF THE OK/TX PANHANDLE/NWRN
OK...

LOW LEVEL JET IS EXPECTED TO INCREASE THIS AFTERNOON AS BROAD
CYCLONIC CIRCULATION ASSOCIATED WITH MID/UPPER LEVEL TROUGH MOVING
EWD ACROSS THE SOUTHERN INTERMOUNTAIN REGION. THIS JET WILL
INCREASE FROM 30-35 KT THIS AFTERNOON EXTENDING FROM NWRN PARTS OF
TX NWD/NWWD INTO NWRN KS. A WARM FRONTAL BOUNDARY IS EXPECTED TO
MOVE NWD FROM NRN OK THIS MORNING INTO E CENTRAL CO EXTENDING SEWD
INTO SERN KS BY TONIGHT. LOW LEVEL THERMAL AND MOISTURE ADVECTION
IS EXPECTED IN THE VICINITY OF THE LOW LEVEL JET/FRONTAL BOUNDARY BY
THIS EVENING AS EXIT REGION OF 50-70 KT SWLY MID LEVEL JET EXTENDS
OVER THE BOUNDARY ENHANCING VERTICAL SHEAR PROFILES ACROSS PARTS OF
ERN CO INTO SWRN KS AND THE OK AND NRN TX PANHANDLES.

AIR MASS WILL BECOME MODERATELY UNSTABLE DURING THE DAY AS FORECAST
SURFACE TEMPERATURES ARE EXPECTED TO BE INTO THE LOW/MID 70S ALONG
THE CO/KS BORDER GIVING MLCAPE VALUES BETWEEN 2000 AND 2300 J/KG.
THIS COMBINED WITH DEEP LAYER SHEAR VALUES BETWEEN 50-60 KT CREATES
VERY FAVORABLE ENVIRONMENT TO SUPPORT STRONG UPDRAFTS/DISCRETE
SUPERCELLS IN THE VICINITY/JUST OFF THE DRYLINE BY LATE AFTERNOON.
GIVEN THAT LOW/MID LEVEL LAPSE RATES ARE BETWEEN 7.0 AND 8.0C/KM BY
LATE AFTERNOON...LARGE HAIL MAY BE THE INITIAL THREAT WHEN THE
STORMS DEVELOP. BY 24/00Z...FORECAST SOUNDINGS SHOW EXIT REGION OF
MID/UPPER LEVEL JET COUPLING WITH SSELY LOW LEVEL FLOW TO ENHANCE
THE LOW/MID LEVEL SHEAR PROFILE INCREASING 0-3KM HELICITY TO AROUND
325 M2/S2 AND 0-1 KM HELICITY TO NEAR 150 M2/S2 SUFFICIENT
MESOCYCLONE/TORNADO DEVELOPMENT NEAR THE CO/KS BORDER INTO SWRN KS.

THERE ARE INDICATIONS THAT A FEW DAMAGING TORNADOES COULD OCCUR WITH
THESE STORMS GIVEN THE SUFFICIENT 0-1KM SHEAR AND LCL/LFC HEIGHTS
BETWEEN 1000 AND 1500 M.

..LOWER OHIO VALLEY NEWD INTO PARTS OF THE LOWER GREAT LAKES...

COLD FRONTAL BOUNDARY WILL MOVE SLOWLY SEWD TODAY AND TONIGHT
EXTENDING FROM CENTRAL LAKE ERIE SWWD THROUGH CENTRAL INDIANA AND
SRN MO. SCATTERED THUNDERSTORMS ARE EXPECTED ALONG THE FRONTAL
BOUNDARY THIS AFTERNOON AND EARLY TONIGHT AS AIR MASS JUST AHEAD OF
THE BOUNDARY WILL BECOME UNSTABLE WITH MLCAPE BETWEEN 500 AND 1000
J/KG. SOME OF THIS ACTIVITY COULD PRODUCE SOME STRONG GUSTY WINDS
GIVEN DRY AIR AT MID LEVELS AND THE PRESENCE OF 30-40 KT OF DEEP
LAYER SHEAR. GIVEN THE LIMITED INSTABILITY IS REASON FOR LIMITING
SEVERE POTENTIAL WITH THIS ACTIVITY.

.MCCARTHY/JEWELL.. 04/23/2007

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DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 230536
SWODY2
SPC AC 230535

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1235 AM CDT MON APR 23 2007

VALID 241200Z - 251200Z

..THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF CNTRL/ERN KS/OK
AND NERN TX...

..THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL PLAINS EWD INTO
PARTS OF THE MIDWEST AND SWD INTO SRN TX...

..SYNOPSIS...

LATEST NAM/WRF AND GFS GUIDANCE REMAIN CONSISTENT IN EWD PROGRESSION
OF MID AND UPPER-LEVEL LOW FROM NM/CO INTO OK/KS BY 25/12Z. IN THE
LOW-LEVELS...ATTENDANT SURFACE LOW IS FORECAST TO DEEPEN THROUGH THE
DAY AS IT CONCURRENTLY DEVELOPS EWD FROM SWRN INTO S-CNTRL KS BY
EARLY EVENING...AND THEN INTO FAR SERN KS BY WEDNESDAY MORNING.
ATTENDANT WARM FRONT INITIALLY FROM SURFACE LOW THROUGH CNTRL KS TO
SRN IL WILL STEADILY LIFT NWD...STRETCHING FROM FAR NRN KS THROUGH
NRN MO INTO CNTRL IL BY LATE AFTERNOON/EARLY EVENING.
MEANWHILE...DRYLINE WILL RAPIDLY ADVECT/MIX EWD FROM THE ERN OK/TX
PNHDLS TO VICINITY OF THE I-35 CORRIDOR BY MID AFTERNOON.

..OUTBREAK OF SEVERE STORMS CAPABLE OF TORNADOES /A FEW
SIGNIFICANT/...LARGE HAIL AND DAMAGING WINDS APPEARS LIKELY TUESDAY
AND TUESDAY NIGHT...

..CNTRL/SRN PLAINS...

23/00Z SOUNDINGS FROM BRO/CRP INDICATE A CONSIDERABLE INCREASE TO
BOUNDARY LAYER DEPTH AND MOISTURE CONTENT OVER THE PAST 24 HOURS
WITH MEAN MIXING RATIOS OF 14-15 G/KG. STRENGTHENING SLY LOW-LEVEL
FLOW WILL ALLOW THIS AIR MASS TO BE ADVECTED NWD THROUGH CNTRL/ERN
PORTIONS OF TX/OK/KS WITH A SECONDARY LOW-LEVEL MOISTURE AXIS ALSO
DEVELOPING MORE NNEWD THROUGH THE LOWER/MID MS VALLEY. STEEPENING
MID-LEVEL LAPSE RATES COUPLED WITH DAYTIME HEATING AND THIS MOISTURE
WILL CONTRIBUTE TO A MODERATELY UNSTABLE WARM SECTOR WITH AFTERNOON
MLCAPES OF 1500-2500 J/KG.

CLUSTERS OF POTENTIALLY SEVERE...ELEVATED TSTMS ARE EXPECTED TO BE
ONGOING TUESDAY MORNING WITHIN STRONG LOW-LEVEL WAA REGIME NEAR AND
N OF WARM FRONT ACROSS NRN KS INTO SRN NEB. SURFACE-BASED
CONVECTION MAY TEND TO DEVELOP FAIRLY EARLY IN THE DAY OVER PARTS OF
WRN INTO CNTRL KS AS LARGE-SCALE FORCING FOR ASCENT ACTS ON ONLY A
WEAKLY CAPPED AIR MASS. DESPITE BEING EARLY IN THE DIURNAL HEATING
CYCLE...FORECAST SOUNDINGS INDICATE THAT BOTH THERMODYNAMIC AND
KINEMATIC ENVIRONMENT WILL BE QUITE SUPPORTIVE OF SUPERCELLS CAPABLE
OF TORNADOES AND LARGE HAIL. TSTMS ARE EXPECTED TO INCREASE IN
AREAL COVERAGE TUESDAY OVER CNTRL/ERN KS AS DRYLINE SURGES EWD/NEWD
WITH A CONTINUING THREAT OF TORNADIC SUPERCELLS ALONG DRYLINE...WARM
FRONT AND WITHIN FREE WARM SECTOR.

BY MID TO LATE AFTERNOON...ADDITIONAL STORMS ARE EXPECTED TO
PROGRESSIVELY DEVELOP SWD ALONG DRYLINE NEAR THE I-35 CORRIDOR
/CNTRL OK INTO N-CNTRL TX/ INTO A MODERATELY UNSTABLE BUT STRONGER
CAPPED ENVIRONMENT. HERE TOO...PROXIMITY OF 100-120 KT 250 MB/60-70
KT 500 MB JET STREAKS WILL RESULT IN STRONG VERTICAL SHEAR WITH THE
LIKELIHOOD OF SUPERCELLS CAPABLE OF TORNADOES...LARGE HAIL AND
DAMAGING WINDS.

THE SEVERE STORMS OVER KS/OK ARE EXPECTED TO MOVE RAPIDLY EWD INTO
WRN/CNTRL MO AND WRN AR TUESDAY NIGHT WITH A CONTINUING THREAT OF
TORNADOES...LARGE HAIL AND DAMAGING WINDS. OTHER STORMS /SUPERCELLS
WITH HAIL AND A FEW TORNADOES/ WILL BE POSSIBLE SWWD ALONG DRYLINE
THROUGH CNTRL INTO SWRN TX TUESDAY AFTERNOON INTO EVENING...WITH
THIS THREAT APPROACHING SERN/ERN TX LATE TUESDAY NIGHT.

..LOWER MO/MID MS VALLEYS INTO THE OH VALLEY...

ENVIRONMENT ALONG AND S OF RETREATING WARM FRONT IS EXPECTED TO
BECOME INCREASINGLY FAVORABLE FOR SUPERCELLS CAPABLE OF TORNADOES
AND HAIL TUESDAY AFTERNOON AND NIGHT AS LOW/MID 60S DEWPOINTS
CONTRIBUTE TO MLCAPES OF 700-1500 J/KG. BROAD LOW-LEVEL WAA REGIME
SHOULD SUPPORT A GRADUAL EXPANSION IN TSTMS TUESDAY OVER NRN/CNTRL
MO INTO CNTRL/SRN IL. GIVEN THE RELATIVELY STRONG LOW-LEVEL SHEAR
AND ANTICIPATED STORM MOTIONS LARGELY PARALLEL TO WARM FRONT...THE
POTENTIAL WILL EXIST FOR A COUPLE LONGER-LIVED STORMS CAPABLE OF A
STRONG TORNADO OR TWO.

.MEAD.. 04/23/2007

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