Tornado Warning 20, NWS San Angelo, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
200 PM CDT MON MAY 25 1998

SURFACE LOW IS CURRENTLY NEAR SJT WITH A QUASISTATIONARY FRONT
EXTENDING NORTH-NORTHEAST INTO SOUTHWEST OKLAHOMA...AND COLD FRONT
DIPPING INTO THE TRANS PECOS REGION BEFORE CURVING BACK INTO
SOUTHERN NEW MEXICO. UPPER LOW IS STILL TRACKING NORTHEASTWARD ACROSS
SOUTHEAST NEW MEXICO. ATMOSPHERE REMAINS VERY UNSTABLE WITH ADAP AND
SATELLITE LIFTED INDEXES AROUND -8...BUT CAP HAS SO FAR PREVENTED
ANY CONVECTION. THICKER CIRRUS AND AREAS OF HAZE HAS KEPT
TEMPERATURES BELOW 90 DEGREES AT THIS POINT IN THE AFTERNOON.

MODELS ARE IN DISAGREEMENT WITH THE LOCATION OF THE UPPER LOW BY 00Z
AND 12Z WITH NGM APPEARING TO BE TOO FAST AND TOO WEAK. WATER VAPOR
SATELLITE CURRENTLY SHOWS NO EVIDENCE OF ADDITIONAL SHORTWAVES
BEHIND THIS UPPER LOW...WHICH MAY HINDER RAIN CHANCES BEYOND THE
FIRST PERIOD. IF CONVECTION CAN GET GOING IN THE VICINITY OF THE
FRONT THIS EVENING...PERHAPS OUR DRY STREAK WOULD END. IF EXPECTED
COOLING OF MID LEVEL TEMPERATURES TAKES PLACE SOME STORMS MAY
FORM IN OUR CENTRAL AND SOUTHERN COUNTIES...BUT LIGHT SURFACE WINDS
WILL PROVIDE ONLY LIMITED MOISTURE CONVERGENCE. THIS WILL BE A VERY
CLOSE CALL FOR RAIN FROM SJT SOUTHWARD WITH NORTHEAST COUNTIES
STANDING A BETTER CHANCE WITH COOLER 700 MB TEMPERATURES AND CLOSER
PROXIMITY TO THE TRACK OF THE UPPER LOW. THIS SYSTEM MAY FIRE A
COMPLEX OF STORMS BY LATE EVENING IN THE NORTHEAST COUNTIES AS WELL
WITH AREAS NORTH AND EAST OF OUR REGION

IF WIDESPREAD CONVECTION DEVELOPS TONIGHT...OUTFLOW WILL PUSH THE
COLD FRONT EVEN FARTHER SOUTH AND DECREASE THE RAIN CHANCES FOR
TUESDAY. OTHERWISE...IF THE FRONT IS STILL AROUND SOME LATE DAY
STORMS WILL BE POSSIBLE. HAZY CONDITIONS WILL REMAIN IN OUR
SOUTHEAST COUNTIES UNLESS CONVECTIVE OUTFLOW CLEARS THE NORTHWEST
HILL COUNTRY.

ABI 071/091 43
SJT 073/092 32
JCT 070/091 32

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TXZ049-053-054-064>066-071>073-076>078-098-099-113-114-127-128-
139-140-154-155-168>170-261315-

WEST CENTRAL TEXAS THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE SAN ANGELO TX
228 PM CDT MON MAY 25 1998

...THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS OVER WEST
CENTRAL TEXAS LATE THIS AFTERNOON AND TONIGHT...

A COLD FRONT NEAR A SAN ANGELO TO ABILENE LINE WILL REMAIN NEARLY
STATIONARY THROUGH THIS EVENING...WHILE AN UPPER LEVEL DISTURBANCE
OVER SOUTHEAST NEW MEXICO MOVES INTO NORTHWEST TEXAS TONIGHT. THE
ATMOSPHERE OVER WEST CENTRAL TEXAS HAS BECOME VERY UNSTABLE BUT WARM
AIR ALOFT HAS ACTED AS A CAP AND PREVENTED THUNDERSTORM DEVELOPMENT
SO FAR THIS AFTERNOON.

ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY DEVELOP LATE
THIS AFTERNOON AND EARLY THIS EVENING NEAR THE COLD FRONT WITH AN
EASTWARD CELL MOVEMENT EXPECTED DURING THE REMAINDER OF THE EVENING.
DUE TO SUFFICIENT INSTABILITY...THUNDERSTORMS THAT DEVELOP COULD
QUICKLY BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS BEING THE
MAIN THREATS. AREAS NORTH AND EAST OF A HASKELL TO WINTERS TO
BROWNWOOD LINE HAVE A GREATER CHANCE OF THUNDERSTORMS DUE TO
SLIGHTLY COOLER TEMPERATURES ALOFT.

THE APPROACHING UPPER LEVEL DISTURBANCE MAY PRODUCE AN AREA OF
THUNDERSTORMS LATER THIS EVENING IN NORTHWEST TEXAS...WHICH
COULD MOVE OVER THE EASTERN BIG COUNTRY LATER TONIGHT. A FEW OF
THESE LATE NIGHT STORMS MAY ALSO REACH SEVERE LEVELS.

SPOTTER ACTIVATION MAY BE REQUIRED.

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 NORTH TEXAS OUTLOOK SEE PRODUCT FTWSPSFTW. FOR THE CENTRAL
OKLAHOMA OUTLOOK SEE PRODUCT OKCSPSOKC.

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TXZ114-128-252225-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN ANGELO TX
456 PM CDT MON MAY 25 1998

THE SEVERE THUNDERSTORM WARNING IN EFFECT FOR SHACKELFORD AND
NORTHERN CALLAHAN COUNTIES HAS BEEN CANCELLED. ALTHOUGH SHOWERS AND
A FEW THUNDERSTORMS CONTINUE TO MOVE ACROSS CALLAHAN AND SHACKELFORD
COUNTIES AS OF 455 PM...THESE STORMS HAVE FALLEN BELOW SEVERE
LEVELS. HOWEVER...A TORNADO WATCH WILL REMAIN IN EFFECT UNTIL 10 PM
WITH ADDITIONAL SEVERE THUNDERSTORMS AND TORNADOES POSSIBE OVER
THESE SAME AREAS LATER THIS EVENING.

15

TXZ114-128-252225-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN ANGELO TX
456 PM CDT MON MAY 25 1998

THE SEVERE THUNDERSTORM WARNING IN EFFECT FOR SHACKELFORD AND
NORTHERN CALLAHAN COUNTIES HAS BEEN CANCELLED. ALTHOUGH SHOWERS AND
A FEW THUNDERSTORMS CONTINUE TO MOVE ACROSS CALLAHAN AND SHACKELFORD
COUNTIES AS OF 455 PM...THESE STORMS HAVE FALLEN BELOW SEVERE
LEVELS. HOWEVER...A TORNADO WATCH WILL REMAIN IN EFFECT UNTIL 10 PM
WITH ADDITIONAL SEVERE THUNDERSTORMS AND TORNADOES POSSIBE OVER
THESE SAME AREAS LATER THIS EVENING.

15