Flash Flood Warning 76, NWS San Angelo, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
230 AM CDT THU AUG 7 1997

BECOMING LESS CONCERNED ABOUT FLASH FLOOD THREAT AS FRONT CONTINUES
TO MOVE SOUTHEAST INTO CENTRAL TEXAS. WINDS BEHIND THIS COLD FRONT
HAVE GUSTED UP TO 29 KTS AT SJT WITH FRONTAL PASSAGE. BETTER UPPER
SUPPORT BEHIND THE FRONT WILL ALLOW FOR A CHANCE OF SHOWERS AND
MOSTLY CLOUDY SKIES WELL BEHIND THE FRONT MAKING FOR A COOL DAY
ACROSS MUCH OF THE FORECAST AREA TODAY.

CURRENT PRECIPITATION OVER THE EASTERN BIG COUNTRY WILL RESULT IN
LOWER FFG VALUES IN THIS AREA FOR TOMORROW. RADARS ESTIMATE LOCAL
STORM TOTALS UP TO 3 INCHES IN THROCKMORTON AND SHACKELFORD COUNTIES.
SO FAR RAINFALL RATES HAVE BEEN SLOW ENOUGH TO LET VEGETATION AND DRY
GROUNDS SOAK IT UP. PRECIPITABLE WATER VALUES FROM 00Z SOUNDINGS
REMAINED WELL BELOW 150 PERCENT OF NORMAL WHICH SHOULD ALSO HELP TO
MINIMIZE THE FLOODING THREAT. STILL WITH THE GOOD SOAKING THIS
MORNING AND ANOTHER SHORTWAVE HEADING SOUTH FROM COLORADO...WILL
FAVOR MENTION OF LOCALLY HEAVY RAINFALL POSSIBLE. HOWEVER...WATER
VAPOR IMAGERY SHOWS ABUNDANT TROPICAL MOISTURE CONTINUES TO FEED INTO
TEXAS...AND UPPER DIFFLUENCE REMAINS IN PLACE...SO LATER SHIFTS WILL
HAVE TO MONITOR THE SITUATION.

ETA AND NGM SHOW REASONABLE AGREEMENT ON QPF FORECAST THROUGH ABOUT
18 HOURS WITH ETA SHOWING BETTER REPRESENTATION OF THE STRONG COLD
FRONT. BEYOND 18 HOURS THE NGM GOES FORECASTS LIGHTER PRECIPITATION
AMOUNTS THAN THE ETA. PREFER THE ETA IN THE 2ND PERIOD AS DAYTIME
CONVECTION WILL LIKELY KEEP THE FRONT SOUTH OF THE AREA WITH A GOOD
TEMPERATURE GRADIENT ALONG IT AND SURFACE DEWPOINTS IN THE LOW TO MID
70S FEEDING INTO THE BOUNDARY. FAVOR A BLEND OF ETA AND AVIATION
SOLUTIONS WITH HEAVIEST RAINFALL AMOUNTS SOUTHEAST OF THE COUNTY
WARNING AREA OVER CENTRAL TEXAS AND A BROAD AREA OF MODERATE RAINFALL
TO BE ANTICIPATED WITH STRATIFORM RAIN AND SOME ELEVATED CONVECTION
ACROSS THE COUNTY WARNING AREA.

EXPECT AIR TO BECOME STABLE BY MIDNIGHT TONIGHT WITH AREAS OF FOG
DEVELOPING. WILL FAVOR NGM GUIDANCE TEMPS FOR ABI AND WILL APPLY
THOSE TEMPS SOUTH ACROSS THE REST OF THE FORECAST AREA.

ABI 077/068 64
SJT 078/067 65
JCT 078/067 65

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TXZ049-053-054-064>066-071>073-076>078-098-099-113-114-127-128-
139-140-154-155-168>170-080500-

WEST CENTRAL TEXAS THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE SAN ANGELO TX
543 AM CDT THU AUG 7 1997

...SCATTERED TO NUMEROUS NONSEVERE THUNDERSTORMS ARE EXPECTED TO
CONTINUE ACROSS WEST CENTRAL TEXAS TODAY THROUGH THIS EVENING...
...A FLASH FLOOD WATCH IS IN EFFECT FOR THE NORTHERN EDWARDS
PLATEAU...

AN UPPER LEVEL DISTURBANCE WILL INTERACT WITH A COLD FRONT AND
ABUNDANT TROPICAL MOISTURE TO PRODUCE NUMEROUS SHOWERS AND
THUNDERSTORMS ACROSS WEST CENTRAL TEXAS TODAY THROUGH THIS EVENING.
A BROAD AREA OF SHOWERS WITH EMBEDDED THUNDERSTORMS WILL MOVE VERY
SLOWLY SOUTHEAST ACROSS THE AREA AFFECTING MUCH OF WEST CENTRAL
TEXAS THROUGHOUT THE DAY.

WITH COOL DAYTIME TEMPERATURES AND LIGHT UPPER LEVEL WINDS...SEVERE
THUNDERSTORMS ARE NOT EXPECTED. HOWEVER...LOCALLY HEAVY RAINFALL
AMOUNTS WILL LIKELY PRODUCE FLOODING OF POOR DRAINAGE AREAS. THE
MOST LIKELY AREAS TO RECEIVE FLOODING WILL BE OVER THE NORTHERN
EDWARDS PLATEAU WHERE SHOWERS AND THUNDERSTORMS HAVE ALREADY
PRODUCED UP TO 2 INCHES OF RAINFALL. RAINFALL IS EXPECTED TO
DIMINISH ACROSS THE AREA BY LATE THIS EVENING.

SPOTTER ACTIVATION IS NOT ANTICIPATED. FOR THE SOUTHWEST TEXAS AND
NEW MEXICO OUTLOOK SEE PRODUCT LBBSPSMAF. FOR THE WESTERN PARTS OF
NORTH TEXAS... NORTH CENTRAL TEXAS... AND SOUTH CENTRAL TEXAS
OUTLOOKS SEE PRODUCTS OKCSPSOKC... FTWSPSFTW... AND SATSPSSAT.

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