Flash Flood Warning 2, NWS Houston/Galveston, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1250 PM CDT MON MAY 5 2008

.AVIATION...
SWATH OF HEAVIEST RAIN ALONG A NW TO SE LINE FROM KCLL INTO KIAH
WILL CONTINUE TO EFFECT THESE HUBS OVER THE NEXT COUPLE OF HOURS.
RADAR DEPICTING A SLOW EASTERN EXPANSION OF RAIN SHIELD...TRAILER
SCT ACTIVITY OFF TO THE SOUTHWEST FEEDING INTO THIS MAIN LINE. SFC
ANALYSIS HAS A WEAK WARM FRONT MOVING SLOWLY INLAND JUST SW OF
HOUSTON METROPLEX. FEEL THAT HOUSTON AND SURROUNDING HUBS WILL
EXPERIENCE MORE SCATTERED BEHAVIOR SOUTH AND ALONG THIS
BOUNDARY...WITH THE BULK OF HEAVIEST RAIN MOVING FURTHER EAST AND
NORTH. WIDESPREAD RAIN BREAK THROUGH THE EARLY EVENING AS ATMOSPHERE
BECOMES MORE STABLE UNDER A PREDOMINANT MVFR DECK. ANTICIPATING AN
TUESDAY MORNING SOUTHERN TEXAS SHORTWAVE DISTURBANCE TO COME CLOSE
ENOUGH TO SOUTHEASTERN TEXAS TO MENTION VCSH IN THE FAR EXTENDED.
31

&&

.PREV DISCUSSION/UPDATE...
A QUICK UPDATE TO ISSUE A FLOOD WATCH FOR THE NORTHERN 2/3RDS OF
THE AREA WHERE A WIDE SWATH OF 2 TO 3 INCHES OF RAIN HAS FALLEN.
NOT EXACTLY SURE WHICH SCENARIO WILL PLAY OUT BUT A WARM FRONT
OVER THE REGION WILL SLOWLY MOVE NORTH TODAY. AN OUTFLOW BOUNDARY
OVER THE CENTRAL ZONES WILL PROBABLY STAY IN PLACE FOR THE NEXT
SEVERAL HOURS AND TRAINING OF STORMS SHOULD CONTINUE. DIFFERENTIAL
HEATING OVER THE EXTREME NORTHEAST ZONES WILL PROBABLY ALSO SERVE
AS A FOCUS FOR MORE RAIN AND 700 MB STREAMLINE CONVERGENCE ALSO
FAVORS THE NORTHEAST ZONES THIS AFTERNOON. SE TX ALSO LIES IN A
RRQ FURTHER ENHANCING RAINFALL POTENTIAL. PWS ARE NEAR 2 INCHES
AND THE AIR MASS IS UNSTABLE AND SLIGHTLY CAPPED OVER THE SOUTH
WITH LESS CAPPING NORTH. HAVE LEFT SOUTHERN ZONES OUT OF THE WATCH
PRIMARILY BECAUSE THAT AREA HAS NOT HAD HEAVY RAIN THIS MORNING
AND CAN PROBABLY TAKE A FEW INCHES WITHOUT FLOODING. NEW ZONES OUT
SHORTLY. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      77  67  84  69  85 /  90  50  20  10  30
HOUSTON (IAH)              79  67  84  69  84 /  90  40  10  10  20
GALVESTON (GLS)            77  71  80  73  80 /  50  20  10  10  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 4 PM CDT THIS AFTERNOON FOR THE
     FOLLOWING ZONES: AUSTIN...BRAZOS...BURLESON...COLORADO...
     GRIMES...HARRIS...HOUSTON...LIBERTY...MADISON...
     MONTGOMERY...POLK...SAN JACINTO...TRINITY...WALKER...
     WALLER...WASHINGTON.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH THIS EVENING FOR THE
     FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
     CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT
     20 NM.

     SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH THIS EVENING FOR THE
     FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
     CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
     FREEPORT 20 TO 60 NM.

&&

DISCUSSION...43/31

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
947 AM CDT MON MAY 5 2008

TXZ163-164-176>179-195>200-210>214-226-227-235>238-060000-
AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND-
GALVESTON-GRIMES-HARRIS-HOUSTON-JACKSON-LIBERTY-MADISON-MATAGORDA-
MONTGOMERY-POLK-SAN JACINTO-TRINITY-WALKER-WALLER-WASHINGTON-
WHARTON-
947 AM CDT MON MAY 5 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THE COMBINATION OF DEEP MOISTURE AND LIFT IN THE ATMOSPHERE NORTH
OF AN APPROACHING WARM FRONT WILL RESULT IN SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS THIS AFTERNOON.

LOCALLY HEAVY RAINFALL WILL BE POSSIBLE MAINLY NORTH OF THE
INTERSTATE 10 CORRIDOR. RAINFALL AMOUNTS IN THIS AREA WILL
AVERAGE 2 TO 4 INCHES IN THIS AREA...WITH ISOLATED TOTALS OF 4 TO
7 INCHES POSSIBLE. FLOODING OF STREETS...FEEDER ROADS...SECONDARY
ROADS...AND LOW WATER CROSSINGS IS POSSIBLE IN AREAS WHERE THE
HEAVIEST RAIN OCCURS.

FURTHER SOUTH...RAINFALL AMOUNTS WILL AVERAGE AROUND 1/2
INCH...WITH ISOLATED TOTALS OF 1 TO 2 INCHES.

THE THUNDERSTORM ACTIVITY IS EXPECTED TO DIMINISH BY MIDNIGHT AS
THE ATMOSPHERE BEGINS TO STABILIZE AND DRY OUT.

.DAY TWO...TUESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAY THREE...WEDNESDAY

A STRONG UPPER LEVEL LOW PRESSURE SYSTEM AND ASSOCIATED DRYLINE WILL
CROSS NORTH TEXAS WEDNESDAY. A SQUALL LINE IS EXPECTED TO DEVELOP
AHEAD OF THE DRYLINE...HOWEVER STRONG CAPPING IN THE ATMOSPHERE
WILL LIMIT THE SOUTHERN EXTENT OF THE THUNDERSTORM DEVELOPMENT.
IF THE CAP CAN BE BROKEN...THEN A FEW STRONG TO SEVERE THUNDERSTORMS
COULD AFFECT THE NORTHERN HALF OF SOUTHEAST TEXAS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.