Tornado Warning 68, NWS Houston/Galveston, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
245 PM CST MON NOV 22 2004

DISCUSSION...
OUR HEAVY RAIN/SEVERE WEATHER NIGHTMARE TO CONTINUE FOR ANOTHER DAY.
AT 18Z...A WARM FRONT EXTENDED FROM LAKE CHARLES TO HOUSTON TO
COTULLA. AN AREA OF LOW PRESSURE WAS DEVELOPING ALONG THE FRONT NEAR
COTULLA. THE HEAVIEST RAIN CONTINUED TO FOCUS ALONG AND NORTH OF THE
WARM FRONTAL BOUNDARY. THIS IS LIKELY TO CONTINUE INTO THE EVENING.
IT IS UNCLEAR WHETHER THE AREA WILL SEE THE BREAK IN PRECIP DURING
THE EVENING LIKE LAST NIGHT...BUT AT THIS TIME WILL MAINTAIN HIGH
POPS OVER THE NORTH TONIGHT. SOUTH OF THE BOUNDARY...STORMS ARE
SURFACE BASED AND HAVE THE POTENTIAL TO PRODUCE WEAK TORNADOES.
COVERAGE IS SCATTERED AT BEST AND DONT FORESEE ORGANIZED HEAVY RAIN
THREAT SOUTH OF I-10. WILL MAINTAIN THE FLOOD WATCH EVERYWHERE
BECAUSE OF THE ANTECEDENT RAINFALL.

TUESDAY COULD BE BRUTAL. THE WARM FRONT SHOULD BE PULLED NORTH AS
THE 500 MB LOW IS EJECTED NE AND A SURFACE LOW FORMS OVER NORTH
TEXAS. THE POSITION OF THE SURFACE LOW...AN APPROACHING COLD
FRONT...THE DRYLINE AND TREMENDOUS WIND SHEAR FAVOR THE DEVELOPMENT
OF STRONG TO SEVERE STORMS. SUPERCELLS ARE EXPECTED AHEAD OF THE
SQUALL LINE WHICH SHOULD CROSS THE AREA DURING THE LATE AFTERNOON OR
EARLY EVENING. HELICITY VALUES ARE PROGGED TO REACH 200 M2/S2 BY
LATE AFTERNOON. OTHER INSTABILITY PARAMETERS ARE IN PLACE AS WELL.
THE GROUND IS VERY WET AND IT WONT TAKE MUCH WIND TO KNOCK DOWN
TREES. THE WIND ENERGY WITH THIS SYSTEM LOOKS IMPRESSIVE. SPC HAS
OUTLOOKED SE TX IN MODERATE RISK FOR TUES.

COOLER AND DRIER WEATHER ON THE WAY FOR WED-FRI. ANOTHER UPPER LEVEL
TROUGH WILL PUSH EAST OVER THE WEEKEND. RAIN CHANCES RETURN SAT-SUN
BUT THE SYSTEM IS NOT AS STRONG AS THIS ONE...BUT STILL MORE RAIN ON
THE WAY.

.MARINE...
LITTLE CHANGE EXPECTED FROM THE PREVIOUS PACKAGE. COLD FRONT IS
STILL ON TRACK TO CROSS THE COASTAL WATERS LATE TUESDAY OR EARLY
WEDNESDAY. IN RESPONSE...PRESSURE GRADIENT WILL TIGHTEN AND WINDS
ARE EXPECTED TO REACH ADVISORY CRITERIA OVER THE GULF...AND PERHAPS
CAUTION IN THE BAYS. THERE WILL LIKELY BE A SQUALL LINE DEVELOPING
WITH THE COLD FRONT. WINDS SHOULD BEGIN TO DIMINISH LATE WEDNESDAY
OR EARLY THURSDAY AS THE FRONT MOVES WELL EAST OF THE AREA. 46

&&

.AVIATION...
EXPECT ANOTHER ROUND OR TWO OF SHOWERS AND THUNDERSTORMS AT THE
AIRPORTS OVER THE NEXT 24 HOURS. FOG WILL ALSO ACCOMPANY THE
STORMS...BUT IT IS NOT EXPECTED TO BE QUITE AS THICK AS EARLIER
TODAY. 46

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TORNADO WATCH SOUTH HALF THROUGH 7 PM.
SCEC HIGH ISLAND TO MATAGORDA SHIP CHANNEL 20 TO 60 NM OUT.
FLOOD WATCH HGX CWA THROUGH 6 AM.

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 65 73 52 60 37 / 100  80 30 05 00
HOUSTON (IAH)         67 77 53 62 38 /  90  80 70 05 00
GALVESTON (GLS)       72 79 62 64 48 /  40  80 90 05 00

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
936 AM CST MON NOV 22 2004

TXZ163-164-176>179-195>200-210>214-226-227-235>238-222200-
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-
936 AM CST MON NOV 22 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

.DAY ONE...THIS AFTERNOON.
...A FLOOD WATCH IN EFFECT UNTIL 6 PM...
...TORNADO WATCH IN EFFECT UNTIL 2 PM...

A STATIONARY FRONT ALONG THE COAST MAY WAFFLE AROUND TODAY WITH
DEWPOINTS IN THE MID 60S TO AROUND 70 FLOWING INTO AND OVER THE
FRONTAL BOUNDARY. VERY HEAVY RAINFALL WILL BE POSSIBLE TODAY AS
STORMS DEVELOP AND MOVE NORTHEAST OF THE FRONTAL BOUNDARY.
SOME MAY TRACK OVER THE SAME AREA AS OTHER STORMS LEADING TO GREATER
ACCUMULATIONS. RAINFALL ACCUMULATIONS OF AROUND 1 INCH SHOULD BE
COMMONPLACE NORTH OF THE INTERSTATE 10 CORRIDOR...ISOLATED TOTALS OF 6
TO 8 INCHES MAY BE POSSIBLE.

WIND SHEAR IS IMPRESSIVE AND SOME OF THE STRONGER STORMS COULD
PRODUCE AN ISOLATED TORNADO. THE THREAT FOR STRONG TO SEVERE STORMS
EXISTS THROUGH TUESDAY EVENING.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY...
ON TUESDAY...A COLD FRONT WILL SWEEP THROUGH THE AREA DURING THE
AFTERNOON COLLIDING WITH ABUNDANT GULF MOISTURE AS A POWERFUL UPPER
LEVEL DISTURBANCE ALONG WITH STRONGER SOUTHERLY WINDS COINCIDE
WITH THE FRONTAL PASSAGE. A MODERATE RISK OF SEVERE THUNDERSTORMS WILL
EXIST FOR MUCH OF THE DAY. THE PRIMARY THREAT WILL BE TORNADOES BUT
SOME THREAT OF DAMAGING WINDS AND HAIL WILL EXIST AS WELL. THE THREAT
OF TORNADOES WILL BEGIN AROUND 4 AM NEAR THE COAST AND WILL EXPAND
NORTH THROUGH THE HOUSTON METRO AREA BY 9 AM...AND MAY REACH AREAS AS
FAR NORTH AS HUNTSVILLE AND LIVINGSTON BY LATE MORNING. IN ADDITION...
HEAVY RAIN WILL ALSO ACCOMPANY THE STORMS AND MAY LEAD TO MORE
FLOODING. RAINFALL ACCUMULATIONS OF 2 TO 4 INCHES MAY BE POSSIBLE.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED TODAY AND WILL LIKELY BE
REQUIRED ON TUESDAY.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
137 PM CST MON NOV 22 2004

GMZ335-355-TXZ199-200-210>214-226-227-235>238-230100-
AUSTIN-BRAZORIA-CHAMBERS-COLORADO-FORT BEND-GALVESTON-GALVESTON BAY-
HARRIS-JACKSON-LIBERTY-MATAGORDA-MONTGOMERY-WALLER-
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM-WHARTON-
137 PM CST MON NOV 22 2004

...TORNADO WATCH 880 IN EFFECT UNTIL 7 PM FOR PORTIONS OF SOUTHEAST
TEXAS...

THE STORM PREDICTION CENTER IN NORMAN OKLAHOMA HAS REPLACED TORNADO
WATCH NUMBER 879 WITH A NEW TORNADO WATCH. THE ATMOSPHERE REMAINS
FAVORABLE FOR THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS...SOME OF
WHICH WILL PRODUCE VERY HEAVY RAIN. ALSO...GIVEN THE FAVORABLE WIND
PROFILES...SOME OF THESE STORMS MAY ALSO PRODUCE ISOLATED TORNADOES.
THEREFORE...A TORNADO WATCH WILL REMAIN IN EFFECT UNTIL 7 PM.

IN SOUTHEAST TEXAS...THE COUNTIES INCLUDED IN THE WATCH ARE AUSTIN...
BRAZORIA...CHAMBERS...COLORADO...FORT BEND...GALVESTON...JACKSON...
LIBERTY...MATAGORDA...MONTGOMERY...WALLER...AND WHARTON.

STAY TUNED TO NOAA WEATHER RADIO OR OTHER WEATHER NEWS SOURCES FOR
FURTHER WEATHER UPDATES TODAY.

TXZ178-197-230100-
SAN JACINTO-WASHINGTON-
137 PM CST MON NOV 22 2004

...TORNADO WATCH 879 IS NO LONGER IN EFFECT...

WIDESPREAD RAIN HAS SIGNIFICANTLY STABILIZED THE AIR MASS ACROSS THE
AREA. FOR THAT REASON...THE TORNADO THREAT HAS ALSO DIMINISHED AND
THE TORNADO WATCH HAS BEEN CANCELLED FOR SAN JACINTO AND WASHINGTON
COUNTIES.