Severe Thunderstorm Warning 45, NWS San Angelo, TX

WEST CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
249 PM CDT SAT APR 14 2001

TONIGHT...LARGE SCALE UPWARD VERTICAL MOTION WITH SHORTWAVE TROF MOVING
EWRD INTO THE CNTRL PLAINS ALONG WITH DRYLINE AND WARM FRONT IN THE AREA
WILL SPARK TSTMS ACROSS THE RED RIVER VALLEY OF N TX AND WRN OK THIS
EVENING. THICKNESS PROGS SUGGEST THAT OUR ZONES MAY CONTINUE CAPPED THRU
THE AFTERNOON BY WARMING MID LEVEL TEMPERATURES AND LACK OF STRONG SFC
HEATING DUE TO WIDESPREAD LOW CLOUDS. HOWEVER...AS THE SFC TROF/DRYLINE
BULGES EWRD INTO OUR ZONES...WILL INCLUDE A 20 PERCENT CHANCE POP FOR
THE BIG COUNTRY AND POINTS FURTHER SOUTH...AFTER THE EVENING HOURS.
THE SFC TROF IS FORECAST TO MOVE TO AN OZONA-BROWNWOOD LINE BY 12Z BUT
NOT TOO CONFIDENT ON TSTM FORMATION SOUTH OF THE BIG COUNTRY.
SUNDAY...THE SURFACE TROF WILL SLIDE SOUTH OF OUR ZONES IN THE AFTERNOON
WITH NLY WINDS ADVECTING IN DRIER AND MORE STABLE AIR IN THE LOW LEVELS.
WITH THE UPPER WINDS BECOMING MORE WRLY...THE MID/HI CLOUDS SHOULD BE
SHUNTED TO OUR SOUTH AND EXPECT CONSIDERABLY MORE SUNSHINE THAN TODAY.
SUNDAY NIGHT...LOW LEVEL WINDS SHIFT QUICKLY TO THE SOUTHEAST WHICH
SHOULD ALLOW MOISTURE TO MAKE A HASTY RETURN WITH LOW CLOUDS EXPECTED TO
ENVELOPE ALL ZONES. MONDAY...POWERHOUSE UPPER LOW OVER THE WRN GREAT
LAKES WILL SEND A STRONG CANADIAN ORIGIN SURFACE HI SWRD THRU THE PLAINS
STATES. THE ETA IS MUCH FASTER THAN THE AVN ON THE COLD FRONT POSITION
AND SEEMS TOO FAST BASED ON THE UPPER PATTERN...SO WILL DISREGARD THE
ETA/S COLD FRONT MOVING INTO OUR NRN ZONES BY 00Z/TUE AND WILL KEEP
MONDAY DRY. MONDAY NIGHT...EXPECT THE SHALLOW COLD FRONT TO MOVE THRU
MOST OF OUR FOREACAST AREA AND WITH SUBSTANTIAL LOW LEVEL MOISTURE AHEAD
OF FRONT AND CONVERGENCE ALONG THE FRONT...ANTICIPATE AT LEAST CHANCE
(30-50 PERCENT) POPS WHICH WILL LIKELY BE INCREASED AS THE PERIOD DRAWS
CLOSER AND TIMING CONFIDENCE INCREASES. TUESDAY STILL LOOKS TO BE CLOUDY
AND COOL WITH STRONG ERLY LOW LEVEL UPSLOPE AND THE 1030 MB SURFACE HIGH
NOSING INTO WEST TEXAS. UPSLOPE WILL BE THE ONLY FORCING MECHANISM FOR
RAIN AS NO DYNAMICS WILL BE PRESENT UNDER THE ERN SIDE OF THE UPPER
RIDGE. HIGHS FROM PREVIOUS ZONES LOOK GOOD BASED ON EXPECTED CLOUD COVER
AND AVN FORECAST 850 MB TEMPERATURES. ON WEDNESDAY...LEE TROFFING
STRENGTHENS WITH LOW LEVEL WINDS BECOMING SLY/SWLY AND COMBINED WITH
MUCH LESS CLOUD COVER...TEMPERATURES SHOULD REBOUND BACK INTO THE 70S.
THURSDAY THRU SATURDAY...RAIN CHANCES LOOK SLIM WITH DRY SWLY FLOW ALOFT
AND LACK OF NEARBY SHORTWAVE TROF PASSAGES. EXPECT TEMPERATURES TO
RETURN TO NEAR NORMAL.

ABI 063/080/058/078 200-
SJT 065/082/062/082 2000
JCT 067/084/066/084 2-00

.SJT...NONE.

RUBIN

TXZ049-054-064>066-071>073-076>078-098-099-113-114-127-128-139-140-
154-155-168>170-142230-

WEST CENTRAL TEXAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN ANGELO TX
225 PM CDT SAT APR 14 2001

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE BIG
COUNTRY AND NORTHWEST CONCHO VALLEY TONIGHT...

A WEAK STATIONARY FRONT WILL EXTEND ACROSS THE LOW ROLLING PLAINS...
NORTH OF THE BIG COUNTRY THIS EVENING. SCATTERED SHOWERS AND
THUNDERSTORMS WILL OCCUR ALONG AND NEAR THE STATIONARY FRONT...OVER
THE LOW ROLLING PLAINS. A DRYLINE WILL BE IN PLACE WEST OF THE
CONCHO VALLEY AND BIG COUNTRY THIS EVENING...BEFORE IT RETREATS
WESTWARD OVERNIGHT.

WARM TEMPERATURES ALOFT SHOULD PRECLUDE THUNDERSTORM DEVELOPMENT
OVER WEST CENTRAL TEXAS TONIGHT. HOWEVER...SHOULD A THUNDERSTORM
DEVELOP EAST OF THE DRYLINE THIS EVENING...INSTABILITY AND WIND
SHEAR WILL BE SUFFICIENT TO SUPPORT SEVERE THUNDERSTORM DEVELOPMENT.
THE SEVERE WEATHER THREAT WILL BE PRIMARILY CONFINED TO THE EARLY
AND MIDDLE EVENING HOURS...WHEN ATMOSPHERIC INSTABILITY WILL BE
MAXIMIZED.

SPOTTER ACTIVATION MAY BE REQUIRED TONIGHT...MAINLY NORTH OF A LINE
FROM MERTZON TO SAN ANGELO TO CROSS PLAINS..

FOR THE SOUTHWEST TEXAS AND SOUTHEAST NEW MEXICO OUTLOOK SEE
PRODUCT LBBSPSMAF. FOR THE SOUTH PLAINS OUTLOOK SEE PRODUCT
LBBSPSLBB. FOR THE CENTRAL OKLAHOMA OUTLOOK SEE PRODUCT OKCSPSOKC.
FOR THE NORTH TEXAS OUTLOOK SEE PRODUCT FTWSPSFTW. FOR THE SOUTH
CENTRAL TEXAS OUTLOOK SEE PRODUCT SATSPSSAT.

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