Marine Weather Statement 13, NWS Houston/Galveston, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
916 AM CDT MON MAY 28 2007

.DISCUSSION...
WILL UPDATE THE FORECAST TO EXPAND THE FLOOD WATCH UNTIL 00Z FOR
THE ENTIRE CWA...AND ALSO BOOST POPS TO 80 PCT. 12Z ANALYSIS SHOWS
STRONG DIFFLUENCE AT THE 300 MB LEVEL IN RESPONSE TO TROUGH JUST
TO THE WEST. INFLUX OF DEEPER MOISTURE OFF THE GULF COMBINED WITH
VERY LOW CONVECTIVE TEMPS (MID/UPPER 70S) WILL KEEP ROUNDS OF
SHRA/TSRA GOING FOR THE REMAINDER OF THE DAY. WIDESPREAD RAINFALL
AMOUNTS OF 1 TO 2 INCHES WITH ISOLATED TOTALS OF 3 TO 5 INCHES
EXPECTED BY EARLY EVENING. THE AREA OF MOST CONCERN WILL CONTINUE
TO BE OUR WESTERN THIRD WHICH HAS SEEN THE HIGHEST RAINFALL
AMOUNTS OVER THE LAST FEW DAYS. ACTIVITY WILL BE MOSTLY DIURNALLY
DRIVEN AND EXPECT A SIGNIFICANT DECREASE IN TSRA COVERAGE AROUND
SUNSET.

&&

.PREV DISCUSSION... /ISSUED 536 AM CDT MON MAY 28 2007/

DISCUSSION...
BASED ON CURRENT RADAR TRENDS...COOLING CLOUD TOPS PER SATELLITE LOOPS
AND 06Z MODEL GUIDANCE...HAVE UPDATED THE FORECAST PRODUCTS FOR TODAY
TO GO WITH LIKELY RAIN CHANCES FOR ALL INLAND AREAS...SLIGHTLY COOLER
AFTERNOON HIGH TEMPERATURES AND HIGHER QPF VALUES. NO CHANGES HAVE BEEN
MADE TO THE FLOOD WATCH...STILL IN EFFECT UNTIL 5 PM FOR LOCATIONS ROUGHLY
ALONG AND WEST OF A LINE FROM MADISONVILLE TO SEALY TO MATAGORDA. 42

PREV DISCUSSION... /ISSUED 326 AM CDT MON MAY 28 2007/

DISCUSSION...
WEAK UPPER TROUGH PERSISTS ACROSS THE STATE THIS MORNING. THE SLIGHT
EASTWARD MOVEMENT OF THIS SYSTEM SINCE THIS TIME YESTERDAY SHOULD
PLACE PORTIONS OF SOUTHEAST TEXAS AT A BETTER RISK FOR LOCALLY HEAVY
RAINFALL TODAY. REMNANTS OF AN MCS OFF THE CENTRAL AND LOWER TEXAS COAST
ARE PROBABLY HAVING AN INFLUENCE ON SHOWER/THUNDERSTORM DEVELOPMENT
SO FAR...AND ITS HARD TO TELL WHAT AFFECT (IF ANY) THIS WILL HAVE
ON DEVELOPMENT LATER TODAY. SCATTERED SHOWERS HAVE BEGUN TO DEVELOP
ACROSS PORTIONS OF OUR WESTERN COUNTIES WITH THE GREATEST CONCENTRATION
BEGINNING TO SET UP JUST OUTSIDE OUR CWA. PORTIONS OF THIS AREA HAVE
RECEIVED THE MOST RAIN OVER THE PAST SEVERAL DAYS AND IS WHERE OUR
CURRENT FLOOD WATCH REMAINS IN EFFECT. WILL KEEP THIS WATCH GOING
TODAY...ROUGHLY ALONG AND WEST OF A LINE FROM MADISONVILLE TO SEALY
TO MATAGORDA. IF THE NEXT MCS DOES NOT DEVELOP NEAR US AND THE EXPECTED
LOCALLY HEAVY RAINFALL DOES NOT MATERIALIZE TODAY...THE DAY CREW WILL
LIKELY BE ABLE TO CANCEL THE WATCH. FOR TUESDAY AND WEDNESDAY...WILL
CONTINUE TO FORECAST SLIGHTLY HIGHER POPS ACROSS OUR EASTERN COUNTIES
AS THE WEAK TROUGH AXIS MOVES FURTHER OFF TO THE EAST. FOR THURSDAY
AND FRIDAY...IT LOOKS LIKE THE AREA SHOULD GET A DAILY CHANCE OF SHOWERS
AND THUNDERSTORMS. FOR TEMPERATURES...ANTICIPATE LITTLE CHANGE THROUGHOUT
THE WEEK. 42

AVIATION...
SATELLITE AND RADAR IMAGES INDICATE SHOWERS DEVELOPING ACROSS
SOUTHWEST PORTIONS OF THE CWA AND JUST WEST OF THE CWA THIS
MORNING. CEILINGS WERE NEAR 13000FT AT KIAH AND KHOU. LIKELY TO
SEE VFR CONDITIONS AGAIN THIS MORNING BEFORE 15Z EXCEPT ACROSS
WESTERN PORTIONS OF SOUTHEAST TX WHERE CONVECTION CONTINUES TO
DEVELOP. WITH 500MB SHORTWAVE TROUGH ACROSS CENTRAL TX...LAPSE
RATES SHOULD CONTINUE TO BE STEEP ENOUGH FOR SHOWERS TO DEVELOP IN
THE VICINITY BEFORE 15Z AND THUNDERSTORMS IN THE VICINITY AFTER
15Z. WITH PRECIPITABLE WATER VALUES NEAR 1.5 INCHES TODAY...HEAVY
RAIN CAN BE EXPECTED WITH SH/TS. EXPECT MVFR CONDITIONS AFTER 15Z
THROUGH 00Z WITH BRIEF IFR CONDITIONS AS HEAVY RAIN REDUCES
VISIBILITIES IN THE VICINITY. 32

MARINE...
SEAS WERE NEAR 4 FEET WITH SOUTHEAST WINDS NEAR 14 KNOTS AT
BUOY035 AND NEAR 6 FEET WITH SOUTHEAST WINDS NEAR 17 KNOTS AT
BUOY019. WILL CONTINUE SCEC FOR THE FAR OFFSHORE WATERS THIS
MORNING BUT SEAS SHOULD DIMINISH SOMEWHAT THIS AFTERNOON AS THE
PRESSURE GRADIENT WEAKENS SLIGHTLY ACROSS THE WESTERN GULF OF
MEXICO TODAY. HIGH PRESSURE ACROSS THE EASTERN U.S. AND LOW
PRESSURE ACROSS NORTHWEST TX WILL CONTINUE TO PROVIDE A PERSISTENT
ONSHORE FLOW THROUGH THE NEXT COUPLE OF DAYS. THE PRESSURE
GRADIENT IS EXPECTED TO CONTINUE TO WEAKEN WEDNESDAY AND REMAIN
RELATIVELY WEAK THROUGH THE REST OF THE PERIOD AS THE RIDGE ALONG
THE EASTERN U.S. COAST SHIFTS EASTWARD. 32

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      80  68  83  68  85 /  80  30  50  30  40
HOUSTON (IAH)              80  69  82  69  85 /  80  40  60  30  50
GALVESTON (GLS)            80  74  82  74  82 /  80  40  50  30  50

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES:
     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.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 10 AM CDT THIS MORNING
     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...35

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
921 AM CDT MON MAY 28 2007

GMZ330-335-350-355-370-375-TXZ163-164-176>179-195>200-210>214-226-
227-235>238-291200-
AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND-
GALVESTON-GALVESTON BAY-GRIMES-HARRIS-HOUSTON-JACKSON-LIBERTY-
MADISON-MATAGORDA-MATAGORDA BAY-MONTGOMERY-POLK-SAN JACINTO-
TRINITY-WALKER-WALLER-WASHINGTON-
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM-
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM-
WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM-
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM-WHARTON-
921 AM CDT MON MAY 28 2007

...FLOOD WATCH FOR ALL OF SOUTHEAST TEXAS TODAY...
...LOCALLY HEAVY RAINFALL AND POSSIBLE FLOODING OVER SOUTHEAST
TEXAS TODAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT

NUMEROUS SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS SOUTHEAST
TEXAS TODAY AS AN APPROACHING UPPER LEVEL TROUGH COMBINES WITH A
MOIST AND UNSTABLE AIRMASS IN PLACE. WIDESPREAD RAINFALL AMOUNTS
OF 1 TO 2 INCHES...WITH ISOLATED TOTALS OF 3 TO 5 INCHES CAN BE
EXPECTED THROUGH THIS EVENING.

A FLOOD WATCH IS IN EFFECT FOR ALL OF SOUTHEAST TEXAS UNTIL 7 PM
CDT. ADDITIONAL HEAVY RAIN FALLING ON ALREADY SATURATED GROUND
WILL HAVE THE POTENTIAL TO CAUSE SIGNIFICANT FLOODING IN AND
AROUND THE FLOOD WATCH AREA.

.DAYS TWO AND THREE...TUESDAY AND WEDNESDAY

A SLOW MOVING UPPER LEVEL TROUGH WILL COMBINE WITH DEEP MOISTURE TO
PRODUCE PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS PORTIONS OF SOUTHEAST
TEXAS...ESPECIALLY ON TUESDAY. THE STORMS WILL BE SLOW MOVING...WITH
TRAINING LIKELY. ADDITIONAL HEAVY RAINFALL WILL BE POSSIBLE. THE
THREAT FOR THE HEAVIEST RAINFALL IS EXPECTED TO BE LOCATED OVER
THE EASTERN HALF OF SOUTHEAST TEXAS.

.DAYS FOUR THROUGH SEVEN...THURSDAY THROUGH SUNDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.