Tornado Warning 52, NWS Houston/Galveston, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
315 AM CST WED NOV 17 2004

.DISCUSSION...
POSITIVE TILTED UPPER TROUGH REALLY BEGINNING TO IMPACT SE TX EARLY
THIS MORNING.  THE MAIN FORECAST PROBLEM OF THE DAY IS THE FLOOD AND
SEVERE WEATHER POTENTIAL.  AS OF NOW...THE FLOOD POTENTIAL LOOKS TO BE
A MODERATE RISK WHILE THE SEVERE IS A SLIGHT RISK.

TACKLING THE SEVERE THREAT FIRST...THE RUC AND ETA12 BOTH SHOWED
SURFACE AND 0 TO 3 KM HELICITY VALUES OF 140 OR BETTER THROUGH THE
EARLY AFTERNOON.  THE AREA MOST LIKELY LOOKS TO BE THE NORTHWESTERN
HALF OF THE FORECAST AREA.  THE MODELS HINT AT THE SURFACE TRIPLE
POINT MOVING OVER THESE LOCATIONS (ALTHOUGH THE WARM FRONT LOOKS TO BE
VERY DIFFUSE).  WILL MENTION THE THREAT OF SEVERE IN ZONES AND GRIDS.

FOR THE FLOOD THREAT...PW/S WILL BE AT OR OVER 1.7 INCHES WITH VERY
GOOD ISENTROPIC LIFT AHEAD OF THE MAIN AREA OF CONVECTION.  AM
EXPECTING SOME TRAINING EFFECTS TO OCCUR AS THE UPPER TROUGH MOVES
CLOSER THROUGHOUT THE DAY.  A LOCAL FLASH FLOOD POTENTIAL TREE
INDICATES A GOOD POTENTIAL FOR FLASH FLOODING.  RAINFALL OVER THE
SOUTHWESTERN COUNTIES HAVE ALREADY TOPPED 4 INCHES IN SOME AREAS OF
WHARTON...MATAGORDA...AND JACKSON COUNTIES.  GIVEN THE HIGH PW/S...THE
STRONG WARM AIR ADVECTION AND PVA...AND UPPER DIVERGENCE...TOTAL
WIDESPREAD RAINFALL AMOUNTS OF 2 TO 4 INCHES LOOK POSSIBLE WITH
ISOLATED LOCATIONS RECEIVING UPWARDS OF 8 INCHES.

THE FORECAST BEYOND THURSDAY LOOKS TO BE ON TRACK AND WILL NOT EXPEND
TOO MUCH ENERGY BEYOND THURSDAY GIVEN THE CURRENT SITUATION.  AFTER A
BRIEF BREAK LATE THURSDAY INTO FRIDAY...ANOTHER SHORTWAVE TROUGH ALOFT
AFFECTS SE TX OVER THE WEEKEND AS THE SUBTROPICAL JET REMAINS
OVERHEAD.

PL-40

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
FFA ALL OF SE TX THROUGH 06Z.
SCA 00 TO 60 NM HIGH ISLAND TO THE MATAGORDA SHIP CHANNEL.
SCEC GALVESTON AND MATAGORDA BAYS.

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 72 61 74 59 74 / 100 60 20 10 10
HOUSTON (IAH)         74 64 76 60 76 / 100 60 40 10 10
GALVESTON (GLS)       75 67 76 65 76 / 100 80 40 10 10

&&

HAZARDOUS WEATHER OUTLOOK...CORRECTED SPOTTER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
925 PM CST TUE NOV 16 2004

TXZ163-164-176>179-195>200-210>214-226-227-235>238-171300-
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-
925 PM CST TUE NOV 16 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

...A FLOOD WATCH IS IN EFFECT FOR THE WESTERN 1/3 OF SOUTHEAST
TEXAS THROUGH 6 PM CST WEDNESDAY...

.DAY ONE...TONIGHT.
A STRONG UPPER LEVEL DISTURBANCE WILL APPROACH SOUTHEAST TEXAS
FROM THE WEST LATE TONIGHT AND TOMORROW. AHEAD OF THIS STORM
SYSTEM...WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
MOVE OUT OF SOUTH CENTRAL TEXAS AND INTO WESTERN PORTIONS OF THE
AREA LATE TONIGHT AND EARLY WEDNESDAY MORNING. LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE BEGINNING LATE TONIGHT AND CONTINUE
THROUGH WEDNESDAY ALONG AND WEST OF A BAY CITY TO BELLVILLE TO
COLLEGE STATION LINE.

THE WIND PROFILE AND INSTABILITY PRESENT OVER THE SOUTHWEST AND
WESTERN PORTIONS OF SOUTHEAST ARE SUFFICIENT FOR THE FORMATION
OF ISOLATED TORNADOES. THIS THREAT IS EXPECTED TO BEGIN LATE
TONIGHT.

TIDE LEVELS ARE EXPECTED TO REMAIN HIGH TONIGHT...AND SOME MINOR
COASTAL FLOODING IS POSSIBLE ESPECIALLY ALONG THE WESTERN SHORE OF
GALVESTON BAY AND THE NORTHERN FACING SHORES OF GALVESTON ISLAND AND
THE BOLIVAR PENINSULA.

.DAY TWO...WEDNESDAY AND WEDNESDAY NIGHT...
SHOWERS AND THUNDERSTORMS ONGOING ACROSS THE WESTERN PORTIONS OF
THE AREA WILL OVERSPREAD CENTRAL AND EASTERN PORTIONS SOUTHEAST TEXAS.
LOCALLY HEAVY RAINFALL IS POSSIBLE. RAINFALL AMOUNTS OF 1 TO 2 INCHES
CAN BE EXPECTED WITH ISOLATED TOTALS OF 3 TO 5 INCHES ACROSS CENTRAL
AND EASTERN AREAS. WESTERN AREAS COULD SEE WIDESPREAD RAINFALL TOTALS
OF 2 TO 4 INCHES WITH ISOLATED 5 TO 7 INCH TOTALS BY THE END OF
WEDNESDAY.

ALONG WITH HEAVY RAINFALL...ISOLATED SEVERE THUNDERSTORMS MAY BE
POSSIBLE ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE AREA. THE MAIN
THREAT WILL BE ISOLATED TORNADOES.

.DAYS THREE THROUGH SEVEN...THURSDAY THROUGH MONDAY...

NO HAZARDOUS WEATHER IS ANTICIPATED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE LATE TONIGHT AND TOMORROW.