Severe Thunderstorm Warning 39, NWS San Angelo, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
201 PM CDT SUN APR 26 1998

VIGOROUS UPPER LEVEL STORM SYSTEM WILL INTERACT WITH AN EASTWARD
MOVING DRYLINE TO PRODUCE STRONG TO SEVERE THUNDERSTORMS THIS
AFTERNOON WITH STRONG STORMS ALREADY UNDERWAY OVER WESTERN PORTIONS.
AT 1 PM...DRYLINE WAS LOCATED ALONG AN OZONA TO SJT TO BGS LINE WITH
A DRY PUNCH ALREADY PUSHING INTO SJT. THE BULGE IN THE DRYLINE WILL
ALSO HELP TO ENHANCE CONVERGENCE AND HELICITIES NEAR THE TRIPLE POINT
WHICH APPEARED TO BE CLOSE TO THE JAYTON PROFILER AT 1 PM.

COLD FRONT CONTINUES TO STRENGTHEN THIS AFTERNOON AS SURFACE LOW
CONTINUES TO DEEPEN WESTWARD AND STALL OUT THE FRONT IN REPSONSE TO
THE APPROACHING UPPER SUPPORT.  THIS MAY HAVE AN ADVERSE EFFECT ON
THE BIG COUNTRY WITH LOCALLY HEAVY RAINFALL POSSIBLE.  AN 850 MB
THETA-E RIDGE EXTENDS WEST ALONG THE FRONT.  LAPSE RATES SUPPORT A
CONTINUED GOOD CHANCE OF RAIN THROUGHOUT THE AFTERNOON AND EVENING
HOURS WITH ACTIVITY CONTINUING ALONG AND BEHIND THE COLD FRONT. WITH
ABQ 12Z PRECIPITABLE WATER VALUE AT 167 PERCENT OF NORMAL...AM
BECOMING CONCERNED ABOUT HEAVY RAINFALL AMOUNTS ACCUMULATING BY 00Z.

COMPARISON OF RECENT MODEL RUNS TO PREVIOUS SHOWED ALL MODELS MOVING
A BIT FAST ON THE 00Z RUN. THUS WILL PICK THE SLOWEST MODEL WHICH
IS THE NGM FOR TIMING OF THE LOW LEVEL CONVERGENCE. MEANWHILE...WILL
PICK A BLEND OF ETA AND AVIATION QPF WITH A SOUTHWARD DISPLACEMENT OF
PRECIPITATION. ABUNDANCE OF RAINFALL AND CURRENT OBSEVATIONS BEHIND
THE COLD FRONT SUGGEST LOW CLOUDS OVER ABI AND SJT WITH FRONT
REMAINING TOO SHALLOW OVER OUR SOUTHERN SIX COUNTIES. THUS NGM
GUIDANCE LOOKS REASONABLE. SLIGHT CHANCE POPS LOOKS REASONABLE FOR
TOMORROW WITH A ISENTROPIC LIFT OFFSETTING MID LEVEL NVA.

ABI 051/069 22
SJT 051/072 12
JCT 050/077 12

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TXZ049-053-054-064>066-071>073-076>078-098-099-113-114-127-128-
139-140-154-155-168>170-271310-

WEST CENTRAL TEXAS THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE SAN ANGELO TX
230 PM CDT SUN APR 26 1998

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN BROWN AND SAN
SABA COUNTIES...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WEST CENTRAL TEXAS EAST OF A SWEETWATER TO BALLINGER TO MASON LINE...

AN UPPER LEVEL DISTURBANCE AND DAYTIME HEATING WILL INTERACT WITH A
DRYLINE LOCATED ALONG A COLORADO CITY TO MILES TO SONORA LINE AT 225
PM TO PRODUCE A THREAT OF SEVERE WEATHER ACROSS MUCH OF WEST CENTRAL
TEXAS. SCATTERED STRONG THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG
THIS DRYLINE OVER PARTS OF THE BIG COUNTRY AND CONCHO VALLEY.

WITH MODERATE LEVELS OF INSTABILITY AND VERTICAL WIND SHEAR...A
FEW OF THESE THUNDERSTORMS WILL LIKELY REACH SEVERE LEVELS WITH
LARGE HAIL AND DAMAGING WINDS BEING THE PRIMARY WEATHER THREAT.
HOWEVER...ISOLATED TORNADOES AND LOCALLY HEAVY RAINFALL WILL ALSO BE
POSSIBLE.

SPOTTERS HAVE ALREADY BEEN ACTIVATED IN WESTERN AND CENTRAL SECTIONS
OF WEST CENTRAL TEXAS WITH ACTIVATION POSSIBLY NEEDED OVER EASTERN
SECTION BY LATE THIS AFTERNOON.

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

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