Flash Flood Warning 11, NWS Houston/Galveston, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
855 PM CDT THU AUG 4 2005

.DISCUSSION...
PREVIOUS FORECASTER NAILED IT RATHER WELL AS LATE AFTERNOON SUN
RAISED TEMPS OVER THE NE AND TSTMS ERUPTED THIS EVENING. SOME RATHER
IMPRESSIVE RAINFALL TOTALS OVER HOUSTON...TRINITY AND POLK COUNTIES.
CONVECTION SHOULD AGAIN WANE OVERNIGHT. 18Z GUIDANCE KEEPS THE AREA
DRY FRI/SAT. 00Z UPPER AIR ANALYSIS SHOWS BEST 850 MB MOISTURE NORTH
OF THE REGION AND SPLIT INTO TWO CAMPS - ONE OVER NORTH LOUISIANA
AND POINTS EASTWARD AND THE OTHER OVER NW TEXAS AND THE PANHANDLE.
THE AIRMASS IS CONSIDERABLY DRIER TO THE SOUTH. WILL LOWER POPS
OVERNIGHT ONCE CURRENT CONVECTION DIES OFF BUT WILL NOT MAKE ANY
CHANGES FOR FRI/SAT FOR NOW. 43

PREVIOUS: IN THE SHORT TERM...E & NE PORTIONS OF THE CWA GENERALLY
BETWEEN I-45 AND LA HAS SEEN QUITE A BIT OF SUN AND TEMPS HAVE RISEN
ACCORDINGLY. THINK THIS WILL BE THE PLACE TO WATCH FOR POSSIBLE
INCREASING TSTM DEVELOPMENT. WILL LIKELY MAKE LAST MINUTE TWEAKS TO
EVENING POPS BASED ON AREAL COVERAGE CLOSER TO PRESS TIME.

VERY FEW CHANGES REQUIRED TO THE ONGOING PACKAGE AS THE OVERALL WX
PATTERN CHANGES LITTLE DURING THE NEXT SEVERAL DAYS. SE TX WILL LIE
IN THE GENERAL WEAKNESS BETWEEN THE WESTERN AND SOUTHEASTERN MID
LEVEL RIDGES. PRESSURE GRADIENT IS VIRTUALLY FLAT SUGGESTING
LANDBREEZE/SEABREEZE CIRCULATION WILL BE THE PROMINENT WX FEATURES.
MODELS CONTINUE TO SHOW PWS LINGERING IN THE 1.8-2.1 RANGE FOR THE
NEXT SEVERAL DAYS...BUT DO SHOW A GRADUAL WESTWARD SHIFT OF THE BEST
MOISTURE AXIS THRU THE WEEKEND. FCST CONVECTIVE TEMPS LOOK TO REMAIN
IN THE 87-90 DEGREE RANGE WITH LITTLE CAP TO SPEAK OF. SO...
ANTICIPATE SCT CONVECTION TO INITIATE TOWARD LUNCH TIME FOR THE
NEXT FEW DAYS. SLOW STORM MOVEMENT = LOCALLY HEAVY RAIN IN THE
STRONGER STORMS. ALSO CANNOT RULE OUT A PULSE SEVERE STORM OR TWO
BUT THINK THE BEST WAY TO HANDLE THIS IS IN THE HAZ WX OUTLOOK
VERSUS MENTIONING IN THE ZONES DUE TO THE REMOTE THREAT.

GRADIENT TIGHTENS A BIT EARLY NEXT WEEK SO EXPECT A MORE PROMINENT
SLY FLOW TO ESTABLISH ITSELF. OTHERWISE...GENERAL FCST OF
CLIMO/PERSISTENCE SHOULD WORK OUT WELL.  47

&&

.MARINE...
VERY FLAT PRESSURE GRADIENT WILL PERSIST ACROSS THE WATERS THROUGH
THE WEEKEND. WINDS WILL REMAIN LESS THAN 10 KNOTS...EXCEPT NEAR
THUNDERSTORMS WHERE BRIEF STRONG WIND GUSTS AND HIGHER SEAS ARE
POSSIBLE. WINDS/SEAS WILL PICK UP SLIGHTLY BEGINNING MONDAY IN
RESPONSE TO A TIGHTENING PRESSURE GRADIENT...BUT ARE EXPECTED TO
REMAIN LESS THAN CAUTION CRITERIA.  35

&&

.AVIATION...
EXPECTING GOOD COVERAGE OF SHRA/TSRA ACROSS THE TAF SITES THIS
AFTERNOON. HAVE PUT VCTS AT ALL THE SITES EXCEPT KGLS BEGINNING BY
20Z AND CONTINUING THROUGH ABOUT 01Z. WILL AMEND AS NECESSARY FOR
CONVECTION OCCURRING AT TERMINALS. ACTIVITY WILL DIMINISH AROUND OR
SHORTLY AFTER SUNSET WITH LOSS OF DAYTIME HEATING. SOME SHRA
EXPECTED TO DEVELOP NEAR THE COAST AND MOVE INLAND EARLY FRIDAY.  35

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 95 74 96 74 / 50 50 40 40 30
HOUSTON (IAH)         75 94 75 96 75 / 50 50 40 40 30
GALVESTON (GLS)       81 91 81 91 81 / 30 30 30 30 30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
630 AM CDT THU AUG 4 2005

GMZ330-335-TXZ163-164-176>179-195>200-210>214-226-227-235>238-051200-
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-WHARTON-
630 AM CDT THU AUG 4 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT

SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP
ACROSS SOUTHEAST TEXAS BY MID-DAY. ACROSS CENTRAL AND NORTHERN
AREAS...SLIGHTLY MORE PRECIPITATION COVERAGE IS EXPECTED
AS COMPARED TO SOUTHERN AREAS. DEEPER MOISTURE LOCATED
GENERALLY ALONG AND NORTH OF I-10 WILL ALLOW FOR THE POSSIBILITY
OF LOCALLY HEAVY RAINFALL DURING THE AFTERNOON AND EVENING HOURS.
ISOLATED LOCATIONS COULD EXPERIENCE RAINFALL AMOUNTS OF 2 TO 4
INCHES IN THIS AREA WHERE THE DEEP MOISTURE EXISTS.

THERE IS ALSO A SMALL POSSIBILITY OF ISOLATED PULSE SEVERE
THUNDERSTORMS DURING THE LATE AFTERNOON AND EARLY EVENING HOURS.
THE MAIN THREAT FROM THESE STORMS WOULD BE STRONG WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

LITTLE CHANGE IN THE WEATHER PATTERN IS EXPECTED TO OCCUR. AMPLE
MOISTURE WILL CONTINUE TO LINGER OVER THE AREA AT LEAST THROUGH THE
WEEKEND...LEADING TO SCATTERED AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS.  NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME.