Flash Flood Warning 7, NWS San Angelo, TX

WEST CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
255 PM CDT MON AUG 13 2001

TONIGHT...EXPANSIVE CU/TCU FIELD HAS DEVELOPED ACROSS THE CNTRL/SRN
ZONES WHILE SLIGHTLY COOLER AIR PREVAILS ACROSS THE BIG COUNTRY
BEHIND OUTFLOW FROM LAST NIGHTS TSTMS ALONG THE RED RIVER REGION.
TWO DISTINCT CONVECTIVE VORTICES SEEN ON VISIBLE IMAGERY ACROSS THE SRN TX
PNHDL AND NEAR WICHITA FALLS. GREATEST CHANCE OF EVENING TSTMS
EXPECTED ACROSS THE CNTRL/SRN ZONES WHERE 850/700 MB THETA-E RIDGES
COINCIDE AND CUMULUS FIELD HAS BECOME MOST MATURE. WILL CONFINE TSTM
CHANCES TO THE EVENING WITH LIMITED UPPER SUPPORT AND LOSS OF
DAYTIME HEATING AND OTHER FORCING THEREAFTER.

TUE...WILL CONTINUE WITH A DRY FORECAST. EXPECT AFTERNOON/EVENING
TSTMS TO REMAIN WEST OF OUR ZONES WHERE LOW/MID LEVEL THETA-E RIDGE
IS MOST PRONOUNCED...AND WHERE LIFTED INDICES/CAPE VALUES ARE MORE
FAVORABLE. AVN MOS GUIDANCE HIGHS LOOK TOO COOL BASED ON EXPECTED
CLOUD COVER AS WELL AS THICKNESS/850 MB TEMPERATURE TRENDS.

WED...A SHORTWAVE TROF WILL MOVE EWRD ACROSS THE CNTRL PLAINS STATES
WITH ITS ASSOCIATED SFC TROF EXTENDING FROM IOWA SWWD INTO NORTH TX
BY 00Z/THU. WITH THE SFC TROF REMAINING NORTH OF OUR ZONES IN THE
AFTERNOON...A STRENGTHENING CAP ACROSS WEST CNTRL TX ACCORDING TO
THICKNESS TRENDS...AND LIMITED MOISTURE...WILL CONTINUE WITH A DRY
FORECAST. AVN MOS HIGHS AGAIN LOOK TOO COOL BASED ON THICKNESS AND
850 MB TEMPERATURE TRENDS.

THU/FRI/SAT...CURRENT FORECAST HAS SLIGHT CHANCE TSTMS ACROSS THE
BIG COUNTRY ON THESE DAYS WITH DRY CONDITIONS ELSEWHERE. THE 12Z AVN
RUN IS FORECASTING A COLD FRONT MOVING AS FAR SOUTH AS THE CNTRL/SRN
ZONES ON THU...WHICH MAY BE TOO FAR SOUTH BASED ON RECENT SURFACE
BOUNDARY TRENDS AND MODEL BIAS. WILL THEREFORE CONFINE RAIN CHANCES
TO THE BIG COUNTRY ON THU. ON FRI/SAT...THE BOUNDARY WILL LIKELY
BECOME MORE DIFFUSE AND RAIN CHANCES WILL LESSEN AS THE UPPER
SUPPORT WANES...BUT WILL CONTINUE WITH BIG COUNTRY SLIGHT CHANCE
POPS AS IN PREVIOUS FORECAST...TO AVOID YO-YO FORECAST.

SUN/MON...FORECAST CONFIDENCE IS HIGH AS AWIPS DPROG/DT FEATURE
SHOWS LITTLE VARIATION IN THE SYNOPTIC PATTERN IN THE PAST TWO MRF
RUNS. THE CNTRL US UPPER TROF SHIFTS EWRD WITH RIDGING OVER THE SRN
ROCKIES BUILDING EWRD INTO TX. SO THESE DAYS WILL LIKELY BE DRY WITH
TEMPERATURES ABOVE SEASONAL NORMALS AND MRF GUIDANCE.

ABI 073/096/076/099 1000
SJT 072/097/072/099 2000
JCT 070/097/071/099 2000

.SJT...NONE.

22/RUBIN

TXZ049-054-064>066-071>073-076>078-098-099-113-114-127-128-139-140-
154-155-168>170-132230-

WEST CENTRAL TEXAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN ANGELO TX
208 PM CDT MON AUG 13 2001

...ISOLATED NONSEVERE THUNDERSTORMS EXPECTED THROUGH THIS EVENING...

THE ATMOSPHERE WILL REMAIN SLIGHTLY UNSTABLE AND WEAKLY CAPPED
THROUGH THIS EVENING...ALLOWING ISOLATED SHOWERS AND THUNDERSTORMS
TO DEVELOP. DUE TO MARGINAL INSTABILITY AND WEAK WINDS ALOFT...
SEVERE THUNDERSTORMS ARE NOT EXPECTED. HOWEVER...A FEW THUNDERSTORMS
MAY PRODUCE OUTFLOW WINDS TO 40 MPH. THUNDERSTORMS WILL LIKELY
DIMINISH BY MID TO LATE EVENING...AS THE ATMOSPHERE STABILIZES.

SPOTTER ACTIVATION IS NOT ANTICIPATED.

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.

14