Severe Thunderstorm Warning 68, NWS San Angelo, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
315 PM CDT WED APR 19 2000

THE 19Z SURFACE ANALYSIS PLACES THE DRYLINE JUST EAST OF A FDR TO ABI TO
SANDERSON LINE WITH THE PACIFIC FRONT LAGGING BEHIND ACROSS THE TEXAS
PANHANDLE. MEANWHILE A NARROW LINE OF THUNDERSTORMS HAS ALREADY DEVELOPED
IN OUR SERN ZONES. THIS CONVECTION COULD HAVE FORMED ALONG A LEFTOVER
OUTFLOW BOUNDARY FROM ISOLATED THUNDERSTORMS TUESDAY EVENING. THE AIRMASS
IS VERY UNSTABLE ALONG AND EAST OF THE DRYLINE WITH SATELLITE DERIVED
CAPES APPROACHING 4000 J/KG ACROSS OUR SERN ZONES. ANY STORMS THAT DEVELOP
HAVE THE POTENTIAL TO BECOME QUICKLY SEVERE. IN ADDITION... THE ETA/AVN
SHOW A WEAK SHORTWAVE MOVING THROUGH THE FORECAST AREA AROUND 00Z ALONG
WITH A DECENT BAND OF 700 MB UVV/S. AS A RESULT... PLAN TO GO WITH  CHANCE
POPS ALONG AND EAST OF A COLEMAN TO SONORA LINE THIS EVENING.

THE PACIFIC FRONT WILL CATCH UP WITH THE DRYLINE LATER TONIGHT AND SWING
THROUGH OUR FORECAST AREA BEFORE 12Z. THE AIRMASS BEHIND THE FRONT WILL BE
A LITTLE COOLER WITH HIGHS ON THURSDAY ABOUT 10 TO 15 DEGREES COOLER THAN
TODAY. CLEAR SKIES... DRY AIR AND DIMINISHING WINDS SHOULD SUPPORT COOL
TEMPS THURSDAY NIGHT WITH LOWS DROPPING INTO THE 40S MOST AREAS.

IN THE EXTENDED... A SHORTWAVE RIDGE IS PROGGED TO MOVE OVER THE REGION
LATE FRIDAY AND SATURDAY. THIS COMBINED WITH RETURN FLOW DEVELOPING ON THE
BACK SIDE OF THE DEPARTING SURFACE HIGH WILL RESULT IN A WARMING TREND.
THE MRF AND ECMWF SWING A DRYLINE/WEAK PACIFIC FRONT THROUGH THE REGION ON
SUNDAY... SO PLAN TO KEEP A SLIGHT CHANCE OF THUNDERSTORMS IN THE
FORECAST.

PRELIMS...

ABI 055/079/050/083 0000
SJT 056/081/047/086 -000
JCT 059/082/045/084 3000

.SJT...NONE.

TEW
N

TXZ049-054-064>066-071>073-076>078-098-099-113-114-127-128-139-
140-154-155-168>170-192305-

WEST CENTRAL TEXAS THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE SAN ANGELO TX
220 PM CDT WED APR 19 2000

...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
ACROSS THE EASTERN PORTIONS OF WEST CENTRAL TEXAS THIS AFTERNOON AND
TONIGHT...

ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE MAINLY EAST OF A
LINE FROM THROCKMORTON TO EDEN TO SONORA THIS AFTERNOON AND TONIGHT.
A WARM AND UNSTABLE AIRMASS REMAINS IN PLACE ACROSS WEST CENTRAL
TEXAS TODAY.  HOWEVER A STRONG CAP...EVIDENT BY WARM TEMPERATURES IN
THE MID LEVELS OF THE ATMOSPHERE...REMAINS IN PLACE.  SEVERAL
FEATURES THIS AFTERNOON COULD TRIGGER THUNDERSTORM DEVELOPMENT LATER
TODAY. A DRY LINE WILL CROSS THE AREA THIS AFTERNOON AND A COLD
FRONT WILL CROSS THE REGION THIS EVENING. THE DRY LINE...COMBINED
WITH DAYTIME HEATING...COULD GENERATE THE NECESSARY LIFT TO BREAK
THE CAP AND PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE
HEARTLAND AND THE NORTHWEST HILL COUNTRY.  ALSO...SHOWERS AND
THUNDERSTORMS ARE POSSIBLE ALONG THE COLD FRONT LATER THIS EVENING.

WITH AN UNSTABLE AIRMASS AND STRONG DYNAMICS ALOFT...ANY
THUNDERSTORMS THAT DO DEVELOP COULD QUICKLY REACH SEVERE LEVELS.
LARGE HAIL AND DAMAGING WINDS ARE THE MAIN THREAT...WITH ISOLATED
TORNADOES POSSIBLE.

SPOTTER ACTIVATION MAY BE REQUIRED..

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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