Flash Flood Warning 72, NWS Houston/Galveston, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
340 AM CST SUN NOV 21 2004

DISCUSSION...
SLOW NORTHWARD MOVING WARM FRONTAL BOUNDARY EXTENDING FROM NEAR EDNA
TO HOUSTON TO NEAR MOSS HILL. STRONG ISENTROPIC LIFTING ESPECIALLY SW
ZONES PRODUCING COPIOUS RAINFALL. FLASH FLOOD WARNINGS CONTINUING OVER
JACKSON/WHARTON COUNTIES EARLY THIS MORNING WHERE STRONG CLUSTER OF
THUNDERSTORMS PERSISTS. PWATS OVER CWFA ABOUT 1.5 TO 1.6 INCHES.
FLOOD DECISION TREE AND PRECIP ESTIMATE OBVIOUSLY POINT TO FLOODING
POTENTIAL FOR OUR REGION TODAY. WITH SOIL QUITE SATURATED FROM
RAINFALL THE PAST FEW DAYS...AND ANTICIPATED CONTINUING WIDESPREAD
RAINFALL OVER CWFA...WE SHALL ISSUE A FLOOD WATCH SHORTLY FOR TODAY.
WARM AIR AND MOISTURE ADVECTION BOTH EVIDENT AT 850 AND 700 MB
LEVELS (WITH GOOD INFLOW AT 850 MB).  MODELS SHIFTING FOCUS OF
RAINFALL TO THE NORTHWEST TONIGHT. WARM FRONTAL BOUNDARY EXPECTED TO
GRADUALLY PUSH NORTH TODAY. THIS SHOULD SHIFT RAINFALL FOCUS TO
NORTHERN ZONES BUT STILL A GOOD CHANCE AREAWIDE WITH HIGH PWATS AND
UPPER LEVEL JET NEARBY. THIS SCENARIO WILL CONTINUE THROUGH EARLY
NEXT WEEK. UPPER LOW WILL MOVE TO WEST TEXAS EARLY TUESDAY AND THEN
RAPIDLY SWING NORTHEAST WHILE OPENING INTO A TROUGH.  DRYING WEST TO
EAST EXPECTED BY TUESDAY AFTERNOON. COLD FRONT WILL PUSH THROUGH
REGION TUESDAY NIGHT. WEDNESDAY AND REST OF WEEK WILL SEE DRY AND
COOL WEATHER. A COLD FRONT IS INDICATED BY GFS TO MOVE ACROSS TEXAS
SUNDAY.

AVIATION...EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS OVER
CWFA TODAY WITH CEILINGS AT OR SLIGHTLY BELOW IFR CONDITIONS.
VISIBILITIES TEMPORARILY LOWERING TO BELOW IFR CONDITIONS IN
PASSING SHOWERS.

MARINE...WE SHALL HAVE CAUTION FOR BAYS AND 0-20 NM COASTAL WATERS
WITH SCA 20-60 COASTAL WATERS. SOUTH TO SOUTHEAST WINDS HAS BEEN
INCREASING IN RESPONSE TO TIGHTENING OF PRESSURE GRADIENT NEAR THE
COAST. WAVE HEIGHTS GRADUALLY INCREASING THE LAST FEW HOURS AND NOW
RUNNING 5 FEET 20-60 NM REGION.

37/45
&&

.HGX WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH ALL HGX CWFA UNTIL 6 PM TODAY.
SCEC BAYS AND 0-20 NM COASTAL WATERS.
SCA 20-60 NM COASTAL WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 73 66 74 66 73 / 80 80 60 80 70
HOUSTON (IAH)         77 68 76 68 76 / 80 60 50 60 70
GALVESTON (GLS)       78 72 77 71 78 / 80 40 30 50 70

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
435 AM CST SAT NOV 20 2004

TXZ163-164-176>179-195>200-210>214-226-227-235>238-211200-
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-
435 AM CST SAT NOV 20 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

...HEAVY RAINFALL AND SOME SEVERE THUNDERSTORMS POSSIBLE THIS
WEEKEND AND ON INTO MONDAY AND TUESDAY ACROSS SOUTHEAST TEXAS...

.DAY ONE...TODAY AND TONIGHT
A WARM FRONT PUSHING NORTH ACROSS SOUTHEAST TEXAS ALONG WITH PASSING
UPPER LEVEL DISTURBANCES WILL RESULT IN SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS. LOCALLY HEAVY RAIN IS POSSIBLE. WITH THE
ALREADY SATURATED GROUNDS...SOME FLOODING MAY BE POSSIBLE.
ALSO...SOME OF THE STORMS MAY BECOME SEVERE. A LONG DURATION FLOOD
WATCH MAY BE ISSUED LATER TODAY.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.
THROUGH TUESDAY...WIDESPREAD RAINFALL ACCUMULATIONS OF 1 TO 3 INCHES
WITH ISOLATED TOTALS APPROACHING 5 INCHES WILL BE POSSIBLE. WITH THE
GROUND ACROSS MUCH OF SOUTHEAST TEXAS NEARLY SATURATED...A FLOOD
THREAT MAY DEVELOP.

SEVERE THUNDERSTORMS MAY ALSO DEVELOP ACROSS SOUTHEAST TEXAS AND THE
ADJACENT COASTAL WATERS SUNDAY ON INTO MONDAY AND TUESDAY. THE MAIN
THREAT WILL PROBABLY BE STRONG DAMAGING WINDS AND ISOLATED TORNADOES.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED THIS WEEKEND.