Severe Thunderstorm Warning 74, NWS San Angelo, TX

WEST CENTRAL TEXAS FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE SAN ANGELO TX
147 PM CDT FRI MAY 2 2003

ZONE UPDATE AND UPDATED HAZARDOUS WEATHER OUTLOOKS WERE RECENTLY
SENT TO ACCOUNT FOR EXPANDED SEVERE WEATHER THREAT THIS AFTERNOON.

GOES 17Z SOUNDING ESTIMATES CAPE AT KSJT IN EXCESS OF 4000 J/KG...
WITH LITTLE OR CAP. KSJT VAD WIND PROFILER SHOWS NO DIRECTIONAL
SHEAR AND VERY LITTLE SPEED SHEAR. PRIMARY SEVERE WEATHER THREAT
THIS AFTERNOON WILL LIKELY BE LARGE HAIL AND DAMAGING WINDS. STRAIT
LINE HODOGRAPHS FROM 12Z FWD/DRT SOUNDINGS SUGGEST CELL SPLITS
POSSIBLE. TORNADO THREAT SHOULD BE LOW AND PRIMARILY CONFINED TO
AREAS NEAR SIGNIFICANT OUTFLOW BOUNDARIES OR PERHAPS THE STATIONARY
FRONT ORIENTED ALONG OR JUST SOUTH OF INTERSTATE 20.

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1045 AM DISCUSSION...

LOW CLOUDS GRADUALLY BREAKING UP OVER WC TX AT MIDMORNING. MESOETA
900 MB MOISTURE PROGS SUGGEST LOW CLOUDS WILL BE SLOWEST TO BURN OFF
OVER THE BIG COUNTRY...WHERE LOW LEVEL THERMAL INVERSION IS DEEPER.

DIFFICULT TO PIN DOWN WHERE EXACTLY THUNDERSTORMS WILL FIRE THIS
AFTERNOON. AN OLD COLD FRONT APPEARS TO EXTEND ALONG OR JUST SOUTH
OF INTERSTATE 20. OVER THE REMAINDER OF WC TX...A FEW OUTFLOW
BOUNDARIES LIKELY ARE LEFT OVER FROM YESTERDAYS CONVECTION.
DIFFERENTIAL HEATING MAY PLAY A ROLE IN THUNDERSTORM INITIATION AS
WELL...AS MESO-ETA PROGS LITTLE OR NO CONVECTIVE INHIBITION OVER THE
EASTERN TWO-THIRDS OF WC TX.

FORECAST WAS RECENTLY UPDATED FOR MINOR CHANGES IN FIRST PERIOD SKY
CONDITION WORDING AND TO EXTEND SLIGHT CHANCE POPS INTO THE WESTERN
BIG COUNTRY ZONES. REMAINDER OF THE FORECAST ON TRACK.

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630 AM DISCUSSION...

SATELLITE IMAGERY SHOWS LOW CLOUDS WORKING NORTHWARD INTO CONCHO
VALLEY...AND ADVANCING SOUTH ACROSS THE BIG COUNTRY. WILL SEND A
ZONE UPDATE TO INCLUDE MORNING LOW CLOUD MENTION IN THOSE AREAS.

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245 AM DISCUSSION...

CURRENT...
TRAILING PORTION OF COLD FRONT HAS STALLED IN AN EAST-WEST
CONFIGURATION VICINITY OF INTERSTATE 20. DRYLINE HAS RETREATED
WESTWARD ACROSS CENTRAL AND SOUTHERN PARTS OF WEST CENTRAL TX...
WITH DEWPOINTS AT OR ABOVE 60 DEGREES F. LOW CLOUDS ADVANCING
NORTHWESTWARD ACROSS HILL COUNTRY INTO OUR SOUTHEAST COUNTIES.
WILL MONITOR LOW CLOUD TREND FOR MORNING MENTION IN THE ZONES.

TODAY THE QUASISTATIONARY FRONT TO BE OVER THE BIG COUNTRY WHILE THE
DRYLINE MIXES EASTWARD TOWARD THE HEARTLAND AND NORTHWEST HILL
COUNTRY. ALTHOUGH UPPER SUPPORT IS WEAK...THERMODYNAMICS WILL BE
FAVORABLE FOR THUNDERSTORM DEVELPOPMENT WITH ETA CAPES OF 2000-
3000 J/KG OVER EASTERN HALF OF BIG COUNTRY AND OUR FAR EASTERN
COUNTIES. BEST CHANCE FOR STORM DEVELOPMENT SHOULD BE OVER EASTERN
BIG COUNTRY NEAR THE FRONT...AND IN OUR FAR EASTERN COUNTIES WHERE
DRYLINE BULGE OCCURS. WITH SUFFICIENT MID-LEVEL FLOW AND AMOUNT OF
INSTABILITY PER SPC DAY 1 OUTLOOK...A FEW SEVERE STORMS WILL BE
POSSIBLE. WITH 850 MILLIBAR TEMPERATURES CONTINUING TO CLIMB...
EXPECT HIGHS WEST OF THE DRYLINE AND SOUTH OF THE FRONT TO BE WELL
INTO THE 90S. THUNDERSTORM ACTIVITY TO DIMINISH EARLY TONIGHT WITH
LOSS OF HEATING.

ON SATURDAY HEIGHTS BEGIN TO BUILD ALOFT OVER SOUTHERN PLAINS AS
UPPER TROUGH AFFECTS THE WESTERN US. DRYLINE TO MIX INTO AT LEAST
OUR EASTERN COUNTIES...POSSIBLY FARTHER EAST. STRONGER CAP SHOULD
SUPPRESS THUNDERSTORM DEVELOPMENT. MAY INCLUDE A NOMINAL POP FOR OUR
EASTERN COUNTIES WHERE CONVERGENCE ON THE DRYLINE MAY BE SUFFICIENT
FOR AN ISOLATED STORM OR TWO. HOT TEMPERATURES AGAIN SATURDAY WITH
ETA 850 MILLIBAR TEMPS CLIMBING INTO THE MID TO UPPER 20S. BREEZY
CONDITIONS ANTICIPATED FOR ABOUT NORTHERN HALF OF OUR COUNTIES WITH
TIGHTENING SURFACE PRESSURE GRADIENT AND MIXING EFFECTS. SOUTHWEST
LOW LEVEL JET IS PROGGED SATURDAY NIGHT WHICH WOULD KEEP WINDS AND
TEMPERATURES UP...SO WILL GO ABOVE GUIDANCE FOR LOWS.

ON SUNDAY A STRONG UPPER SHORTWAVE TROUGH TO EMERGE INTO CENTRAL AND
NORTHERN PLAINS WITH WSW FLOW ALOFT INTO TX. DRYLINE INDICATED TO
ADVANCE INTO OUR EASTERN COUNTIES. THETA E RIDGE IS PROGGED OVER OUR
SOUTHEAST COUNTIES WITH DECENT CONVERGENCE ALONG THE DRYLINE. WITH
WEAKER CAP COULD SEE SCATTERED STORMS...SO WILL CARRY A 20 OR 30 POP
IN THOSE AREAS. HIGHS ONCE AGAIN ABOVE 90 ANTICIPATED WEST OF THE
DRYLINE...WITH BREEZY CONDITIONS IN THE BIG COUNTRY.

WITH UPPER TROUGH OVER NORTH-CENTRAL US EARLY NEXT WEEK...SURFACE
COLD FRONT IS PROGGED TO DROP SOUTH INTO WEST CENTRAL TX BY EARLY
TUESDAY MORNING BEFORE STALLING. WHERE THE FRONT STALLS WILL HAVE
IMPACT FOR PLACEMENT FOR BEST CHANCE OF SHOWERS/THUNDERSTORMS.
LITTLE OR NO CHANGES PLANNED FOR THE EXTENDED AT THIS TIME.

ABI 088/064/094/072/094 3100-
SJT 096/066/097/071/096 -0000
JCT 093/065/094/067/093 2-101

.SJT....NONE

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TXZ049-054-064>066-071>073-076>078-098-099-113-114-127-128-139-140-
154-155-168>170-031100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN ANGELO TX
222 PM CDT FRI MAY 2 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WEST CENTRAL TEXAS.

.DAY ONE...TODAY
THE ATMOSPHERE OVER WEST CENTRAL TEXAS WILL BE MODERATELY UNSTABLE
AND SUPPORTIVE OF THUNDERSTORM DEVELOPMENT THIS AFTERNOON.
THUNDERSTORMS SHOULD INITIALLY DEVELOP NEAR A STATIONARY FRONT THAT
EXTENDS ALONG AND TO THE SOUTH OF INTERSTATE 20. THIS AREA
INCLUDES THE SOUTHERN BIG COUNTRY... NORTHERN CONCHO VALLEY...AND
THE HEARTLAND. INSTABILITY WILL BE SUFFICIENT TO SUPPORT SEVERE
THUNDERSTORM DEVELOPMENT OVER ALL BUT THE WESTERN MOST PORTIONS OF
WEST CENTRAL TEXAS THROUGH MID EVENING. LARGE HAIL AND DAMAGING
WINDS WILL BE THE PRIMARY SEVERE WEATHER THREATS.

.DAYS TWO THROUGH SEVEN...
ISOLATED THUNDERSTORMS ARE EXPECTED SATURDAY AFTERNOON ACROSS THE
HEARTLAND AND NORTHWEST HILL COUNTRY. AN UPPER LEVEL DISTURBANCE
WILL APPROACH WEST CENTRAL TEXAS BY THE MIDDLE OF NEXT WEEK...
BRINGING A CHANCE OF THUNDERSTORMS TUESDAY AND WEDNESDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE REQUIRED.

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