Flash Flood Warning 8, NWS Houston/Galveston, TX

000 
WGUS74 KHGX 141926
FFSHGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
221 PM CDT THU JUL 14 2005

TXC201-142200-
HARRIS-
221 PM CDT THU JUL 14 2005

...A FLASH FLOOD WARNING CONTINUES UNTIL 500 PM CDT FOR HARRIS
COUNTY...

AT 218 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE STRONG THUNDERSTORMS PRODUCING VERY HEAVY RAINFALL FROM
CHANNELVIEW TO DOWNTOWN HOUSTON TO NEAR ADDICKS. 

RAINFALL RATES OF 2 TO 3 INCHES AN HOUR CAN BE EXPECTED FROM THESE
STORMS. 

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT FOR YOUR CAR TO CROSS
SAFELY. VEHICLES CAUGHT IN RISING WATER SHOULD BE ABANDONED QUICKLY.

PLEASE REPORT FLOODING TO THE COUNTY SHERIFF...LOCAL POLICE...OR
DEPARTMENT OF PUBLIC SAFETY. THEY WILL RELAY YOUR REPORT TO THE
NATIONAL WEATHER SERVICE.

LAT...LON 2965 9554 2964 9507 2973 9495 2982 9494
      2991 9501 2977 9571

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
945 AM CDT THU JUL 14 2005

.DISCUSSION...
12Z DATA CONFIRMS THE OBVIOUS...ABOVE NORMAL PWS AROUND 2.2 INCHES
WITH VIRTUALLY NO CAP ALLOWING CONVECTION TO FIRE ALONG THE COAST.
MORE ORGANIZED CONVECTION OVER NORTHERN ZONES BEING HELPED BY
SUBTLE BUT IDENTIFIABLE SHORT WAVE.  200MB ANALYSIS SHOWS WEAK
SPEED MAX OVER NORTHERN LA AND ANOTHER FROM FAR WEST TEXAS INTO
THE HILL COUNTRY.  RAINFALL 2 TO 3 INCHES ALREADY CONFIRMS THE
OUTLOOK FOR LOCALLY HEAVY RAINFALL.  WE EXPECT CENTRAL ZONES TO BE
THE FOCUS THIS AFTERNOON AS THEY WILL GET BEST SOLAR HEATING AND
OUTFLOW BOUNDARY/SEABREEZE INTERACTION SHOULD PROVIDE FOCUS.
EXPECT ANOTHER ROUND OF STREET FLOODING WHERE THE STRONGER STORMS
FORM DUE TO SLOW STORM MOVEMENT AND HIGH PWS.

MINOR UPDATES TO GRIDS FOR FIRST PERIOD TO LOWER MAX TEMP A NOTCH AND
ADJUST RELATED PARAMETERS.

30

&&

.PREV DISCUSSION... (ISSUED 330 AM CDT THU JUL 14 2005)

DISCUSSION...
CONDITIONS WILL REMAIN FAVORABLE FOR ACTIVE CONVECTIVE DEVELOPMENT
ACROSS SE TX FOR THE NEXT FEW DAYS. AIRMASS WILL REMAIN MOIST AND
UNCAPPED THROUGH AT LEAST SATURDAY WITH PWS FORECAST TO REMAIN AT
OR ABOVE TWO INCHES.

BOTH GFS/ETA INDICATE SOME CHANGES IN THE SYNOPTIC SCALE OVER THE NEXT
24 HOURS. BOTH MODELS FORECAST THE APPROACH OF A WEAK JET MAX AT 250
MB WHICH WILL ACT TO INCREASE UPPER LEVEL DIFFLUENCE OVER SE TX
BEGINNING THIS AFTN. UPPER DIFFLUENCE BECOMES EVEN MORE PRONOUNCED BY
EARLY FRIDAY. MEANWHILE...500 MB TROUGH DEVELOPS OVER CENTRAL TEXAS
TODAY/FRIDAY. MODELS FORECAST WEAK SURFACE TO 850 MB TROUGH CURRENTLY
JUST NORTH OF THE AREA TO REMAIN IN PLACE AND SERVE AS A FOCUS FOR
POOLING MOISTURE AND CONVECTIVE DEVELOPMENT PRIMARILY FOR OUR NRN
ZONES. THE OTHER CONVECTIVE FOCUS FOR OUR AREA WILL BE THE SEABREEZE.

MODEL FORECAST SOUNDINGS SHOW CONVECTIVE TEMPS AGAIN IN THE UPPER
80S/AROUND 90 TODAY SO THINK SETUP WILL BE SIMILAR TO YESTERDAY
WITH ACTIVITY DEVELOPING NEAR THE COAST EARLY THIS MORNING AND THEN
INLAND TOWARD MIDDAY. WILL GO CHANCE POPS THIS MORNING...LIKELY THIS
AFTERNOON. STILL THINK FRIDAY WILL SEE THE MOST WIDESPREAD COVERAGE
OF PRECIP AS THIS IS WHEN WE SEE THE BEST DIFFLUENCE AND LOWEST
CONVECTIVE TEMPS. WENT LIKELY POPS AREA WIDE AND LOWERED TEMPS.

GIVEN SLOW STORM MOTION AND HIGH PWS...WILL MENTION LOCALLY HEAVY
RAIN IN THE FORECAST AND HAZARDOUS WEATHER OUTLOOK TODAY AND FRIDAY.
AN ISOLATED PULSE-TYPE SEVERE STORM IS ALSO POSSIBLE...BUT THE
OVERALL THREAT IS QUITE LOW.

500 MB RIDGE SLOWLY BEGINS TO BUILD ACROSS THE AREA BY EARLY NEXT
WEEK...HOWEVER ATMOSPHERE WILL BE SLOW TO DRY OUT. KEPT WITH TREND OF
LOWERING POPS BEGINNING SUNDAY BUT GENERALLY KEPT POPS IN CHANCE
CATEGORY. TPC FORECAST HAS HURRICANE EMILY IN THE SOUTHWESTERN GULF
MONDAY NIGHT. ANY IMPACTS AT ALL FROM THIS SYSTEM WOULD BE FELT
BEGINNING TUESDAY OR WEDNESDAY.

35

MARINE...
THE PRESSURE GRADIENT IS RELATIVELY WEAK BUT WINDS ARE UP TO 15
KNOTS OFFSHORE. THINK THIS DIURNAL TREND OF WIND SPEEDS HIGHER AT
NIGHT AND LOWER DURING THE DAY WILL CONTINUE. EMILY NOW FORECAST TO
ENTER THE SOUTHWESTERN GULF MONDAY NIGHT AND EFFECTS...IF ANY...WILL
BEGIN TO AFFECT MARINE AREAS ON TUESDAY.  43

AVIATION...
PERSISTENCE SEEMS THE WAY TO GO. LOW CONVECTIVE TEMPS AND HIGH PWS
WOULD INDICATE ANOTHER ACTIVE DAY WITH TSRA AFFECTING TAF SITES
DURING THE MORNING FOR GLS/LBX...EARLY AFTERNOON AT HOU AND MID TO
LATE AFTERNOON IAH/CLL. SOME OF THE STORMS WILL PRODUCE HEAVY RAIN.
TAF SITES TO REMAIN VFR EXCEPT IN AND AROUND TSRA.  43

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      90  76  93  75  93 /  60  30  60  30  50
HOUSTON (IAH)              91  75  91  74  91 /  60  30  60  30  50
GALVESTON (GLS)            89  82  89  81  89 /  50  40  60  30  50

&&

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

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
700 AM CDT THU JUL 14 2005

GMZ330-335-TXZ163-164-176>179-195>200-210>214-226-227-235>238-151200-
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-
700 AM CDT THU JUL 14 2005

...LOCALLY HEAVY RAINFALL POSSIBLE ACROSS SOUTHEAST TEXAS TODAY AND
FRIDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT.
DAYTIME HEATING WILL COMBINE WITH ABUNDANT MOISTURE TO PRODUCE
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST TEXAS
TODAY.

LOCALLY HEAVY RAINFALL IS POSSIBLE TODAY. RAINFALL AMOUNTS
TODAY WILL AVERAGE AROUND 1/2 INCH. HOWEVER...ISOLATED STORMS COULD
PRODUCE RAINFALL AMOUNTS OF 2 TO 3 INCHES IN A SHORT PERIOD OF TIME.
THIS RAINFALL COULD LEAD TO MINOR FLOODING OF STREETS...FEEDER
ROADS...FREEWAY UNDERPASSES...OR OTHER LOW LYING SPOTS.

THERE IS ALSO THE POSSIBILITY OF ONE OR TWO STORMS BRIEFLY BECOMING
SEVERE TODAY.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.
SIMILAR CONDITIONS ARE EXPECTED ON FRIDAY WITH SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS SOUTHEAST TEXAS. LOCALLY
HEAVY RAINFALL AND MINOR FLOODING PROBLEMS WILL AGAIN BE POSSIBLE.

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