Severe Thunderstorm Warning 64, NWS San Angelo, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
250 PM CDT TUE APR 18 2000

AT 19Z...DRYLINE EXTENDED FROM NEAR WRN TIP OF CROCKETT CNTY NNEWD
BETWEEN MAF AND SJT...BETWEEN LBB AND ABI...AND INTO SWRN OK. VERY
WARM MID LEVEL TEMPERATURES WILL PERSIST INTO THE EVENING HOURS
ACROSS THE AREA ACCORDING TO MODEL FORECAST SOUNDINGS AND MID LEVEL
TEMPERATURE FORECASTS. CONVERGENCE ALONG DRYLINE SHOULD REMAIN WEAK
INTO THE EVENING AS WINDS BEHIND THE DRYLINE WILL BE BACKING IN
RESPONSE TO APPROACHING TROF. MID/HI LEVEL CLOUDS APPROACHING FROM
NRN MEXICO/FAR WEST TX WILL LIMIT SFC HEATING AND INSTABILITY. WITH
WEAK CONVERGENCE ALONG DRYLINE AND STRONG MID LEVEL CAP...WE BELIEVE
TSTM CHANCES ARE MINIMAL THIS EVENING...BUT WILL LEAVE IN 20 PERCENT
CHANCE IN FAR NW ZONES. SHOULD SEE A RETURN OF LOW CLOUDS LATE
TONIGHT ALTHOUGH PERHAPS NOT AS WIDESPREAD AS LAST NIGHT AS INDICATED BY
MODELS.

FOR WED...STRONG POS TILT TROF PASSES ACROSS THE TX/OK PNHDLS...WITH
THE MODELS SUGGESTING THE DRYLINE WILL PUSH INTO THE HEARTLAND/NW
HILL COUNTRY IN THE AFTERNOON. FRONTAL BNDRY WILL LIKELY STALL
ACROSS THE BIG COUNTRY. BELIEVE THE MODELS MAY BE DRYING OUT THE LOW
LEVELS TOO FAST...SO WILL RETAIN 10-20 PERCENT POPS AS CONVERGENCE
ALONG THE DRYLINE AND COOLING ALOFT MAY BE ENOUGH TO WEAKEN CAP
SUFFICIENTLY TO ALLOW TSTMS TO DEVELOP. WILL LEAVE IN 20 PERCENT
POPS ACROSS THE NW HILL CNTRY WED EVENING AS LOW LEVEL CONVERGENCE
LOOKS IMPRESSIVE ALONG BNDRY. ELSEWHERE...DRIER MORE STABLE AIR WILL
BE ADVECTING SWD FOR CLEAR SKIES/COOLER TEMPERATURES. FWC/FAN
TEMPERATURES LOOK TOO COOL FOR THU BASED ON 850 MB TEMPERATURES AND
DRY LOW LEVELS. UPPER RIDGING FRI WILL KEEP IT DRY OVER WC TX. THE
MRF IS LIKELY EJECTING THE SWRN US CLOSED LOW TOO FAST ON SAT AND
PREFER SLOWER ECMWF...SO BELIEVE SAT WILL BE DRY AS WELL. KICKER
ENTERING WEST COAST SUN MAY BE ENOUGH TO EJEC>T THE CLOSED LOW INTO
CNTRL PLAINS WITH POSSIBLE DRYLINE DEVELOPMENT OVER WC TX...SO WILL
MENTION SLIGHT CHANCE TSTMS FOR SUN.

ABI 066/092/056/084 -200
SJT 065/093/057/087 -200
JCT 068/088/060/088 0220

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TXZ049-054-064>066-071>073-076>078-098-099-113-114-127-128-139-
140-154-155-168>170-182230-

WEST CENTRAL TEXAS THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE SAN ANGELO TX
228 PM CDT TUE APR 18 2000

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ALONG AND WEST OF
A HASKELL TO STERLING CITY LINE LATE THIS AFTERNOON AND EVENING...

A MOIST AND MODERATELY UNSTABLE AIRMASS WILL PREVAIL OVER WEST
CENTRAL TEXAS THROUGH THIS EVENING. WARM TEMPERATURES IN THE MIDDLE
LEVELS OF THE ATMOSPHERE WILL SERVE TO INHIBIT THUNDERSTORM
DEVELOPMENT OVER MOST OF WEST CENTRAL TEXAS. HOWEVER...A DRYLINE
EXTENDING FROM THE PERMIAN BASIN TO THE LOW ROLLING PLAINS WILL SERVE
AS A POSSIBLE FOCAL POINT FOR THUNDERSTORM DEVELOPMENT THROUGH LATE
EVENING. ANY THUNDERSTORMS THAT FORM NEAR THE DRYLINE WILL LIKELY
AFFECT NORTHWEST PORTIONS OF THE CONCHO VALLEY AND WESTERN BIG
COUNTRY. SUFFICIENT INSTABILITY WILL BE IN PLACE SUPPORT SEVERE
THUNDERSTORM DEVELOPMENT. THE PRIMARY SEVERE WEATHER THREAT WILL BE
LARGE HAIL AND DAMAGING WINDS. THE SEVERE WEATHER THREAT SHOULD END
BY MIDNIGHT...AS THE DRYLINE RETREATS TOWARD NEW MEXICO.

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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