Damaging Winds in Texas, September 20, 2001

WEST CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
217 PM CDT THU SEP 20 2001

MONITORING POSSIBILITY OF CONVECTIVE DEVELOPMENT FROM MERGER OF A
COUPLE OF OUTFLOW BOUNDARIES THIS AFTERNOON. ONE BOUNDARY MOVING INTO
BIG COUNTRY FROM THE WEST...WHILE THE OTHER APPROACHES FROM THE
NORTHEAST. MERGER COULD OCCUR OVER BIG COUNTRY. GIVEN THE
INSTABILITY...MOISTURE AVAILABILITY AND CONVERGENCE...SHOULD SEE
SCATTERED THUNDERSTORM DEVELOPMENT WITH THE MERGER. ALTHOUGH VISIBLE
IMAGERY HAD BEEN GARBLED...NOTICED A CURL IN THE CLOUD FEATURES
DURING LATE MORNING OVER FAR NORTHEAST NM ASSOCIATED WITH WEAK
EMBEDDED SHORTWAVE. EXPECT THUNDERSTORMS TO DEVELOP WITH THIS FEATURE
AS IT MOVES INTO OK/TX PANHANDLES...WITH POSSIBLE MCS FORMATION.
EXPECT THIS FEATURE TO MOVE SSE TONIGHT TO NEAR OUR FAR NORTHEAST
CWFA BY FRI MORNING. WILL CARRY HIGH CHANCE TO LIKELY POP FOR BIG
COUNTRY TONIGHT. WILL PROBABLY KEEP POPS OUT OF FORECAST TONIGHT FOR
REST OF CWFA.

TRACK OF MCS WILL PLAY AN IMPORTANT ROLE IN FRIDAY FORECAST ACROSS
OUR CWFA. AT THIS TIME APPEARS THE FEATURE WILL TRACK SLOWLY
SOUTHEAST FRIDAY. WILL CARRY A MORNING POP BIG COUNTRY AND INCLUDE A
POP CENTRAL AND SOUTH. SHOWERS AND STORMS FROM DECAYING MCS COULD
MOVE DOWN INTO CONCHO VALLEY/HEARTLAND...AND ASSOCIATED OUTFLOW
BOUNDARY SHOULD PRESS SOUTH DURING THE DAY. WITH MORE CLOUDCOVER AND
LOWER 850 MILLIBAR TEMPERATURES/THICKNESS EXPECT HIGHS TO BE SEVERAL
DEGREES COOLER ON FRI. PLAN TO CONTINUE POP IN SOUTHEAST COUNTIES
INTO FRI NIGHT.

EXPECT LITTLE CHANGE IN MOISTURE AVAILABILITY INTO THE WEEKEND. WILL
KEEP SATURDAY FORECAST DRY WITH LACK OF A DEFINITIVE SURFACE OR UPPER
FEATURE. ON SUNDAY A STRONG SHORTWAVE IS PROGGED TO DIVE SSE INTO
MIDWEST/GREAT LAKES IN AMPLIFYING UPPER FLOW. ASSOCIATED STRONG COLD
FRONT TO MOVE QUICKLY SOUTH ACROSS OUR CWFA SUNDAY AFTERNOON. WILL
CARRY POSSIBILITY FOR SHOWERS/THUNDERSTORMS WITH THIS FRONT.

IN THE EXTENDED...UPPER RIDGE TO EXTEND NORTH INTO ROCKIES WITH NORTH
FLOW ALOFT INTO TX. EXPECT NOTICABLY COOLER AND DRIER CONDITIONS FOR
FIRST PART OF NEXT WEEK AS STRONG SURFACE HIGH PRESSURE RIDGE BUILDS
SOUTH FROM SOUTHERN CANADA INTO TX.

ABI 068/087/067/088 6400
SJT 071/087/067/088 1310
JCT 071/087/067/087 0320

.SJT...NONE.

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TXZ054-064>066-071>073-076>078-098-099-113-114-127-128-139-140-154-
155-168>170-202245-

WEST CENTRAL TEXAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN ANGELO TX
202 PM CDT THU SEP 20 2001

...A FEW SEVERE STORMS ARE POSSIBLE ACROSS THE BIG COUNTRY THIS
AFTERNOON AND TONIGHT...

WITH A VERY UNSTABLE AIRMASS AND A COUPLE OF SURFACE BOUNDARIES
MOVING INTO THE REGION...SCATTERED THUNDERSTORMS ARE EXPECTED OVER
THE BIG COUNTRY THIS AFTERNOON AND EARLY EVENING. AN UPPER LEVEL
DISTURBANCE IS EXPECTED TO TRIGGER THUNDERSTORM DEVELOPMENT OVER THE
TEXAS PANHANDLE LATE THIS AFTERNOON AND EVENING. THIS MAY ORGANIZE
INTO A THUNDERSTORM COMPLEX AND THEN TRACK SOUTH AND SOUTHEAST INTO
THE BIG COUNTRY LATE TONIGHT.

A FEW SEVERE STORMS WILL BE POSSIBLE. THE MAIN SEVERE WEATHER
THREATS WILL BE LARGE HAIL AND DAMAGING WINDS. WITH ABUNDANT
MOISTURE IN PLACE...HEAVY RAIN IS POSSIBLE...ESPECIALLY LATE
TONIGHT. ACROSS PARTS OF THE BIG COUNTRY...RAINFALL AMOUNTS OF 1 TO
3 INCHES WILL BE POSSIBLE BY FRIDAY MORNING.

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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