Severe Thunderstorm Warning 165, NWS Houston/Galveston, TX

SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
230 PM CDT SAT AUG 9 2003

WHAT IS LEFT OF THE MCS WHICH HAS BEEN MOVING THROUGH NORTHERN AND
CENTRAL TEXAS TODAY IS NOW ENTERING NW ZONES OF SE TX. ISOLATED
SHOWERS AND THUNDERSTORMS ARE DEVELOPING ALONG THE SEA BREEZE ACROSS
COASTAL SECTIONS. A LARGE THICK CIRRUS SHIELD HAS HELPED KEEP THE
HIGH TEMPS DOWN A LITTLE ACROSS THE REGION TODAY WHEN COMPARED TO
YESTERDAY. HOWEVER...DW PTS HAVE BEEN HIGHER AND THEREFORE HEAT
INDEX VALUES ARE STILL A LITTLE ABOVE 105 DEGREES. THINK TOMORROW
WILL BE A LOT LIKE TODAY AS FAR AS HIGH LEVELS OF LOW-LEVEL MOISTURE
...SO WILL EXTEND THE HEAT ADVISORY THROUGH SUNDAY.

MAIN FORECAST ISSUE IS THE CHC OF RAIN. THE CLUSTER OF STORMS ACROSS
THE NW PORTIONS OF THE AREA HAVE MOVED OFF OF THE ORIGINAL
DISTURBANCE THAT IGNITED THEM. THIS SIGNIFICANT DISTURBANCE WILL
PUSH INTO SE TX THIS EVENING AND MOVE SOUTH OF THE AREA BY MORNING.
LATEST GFS SPLITS THIS DISTURBANCE AS IT APPROACHES THIS EVENING
WITH THE MORE SIGNIFICANT ENERGY MOVING ALONG THE WESTERN EDGE OF SE
TX AND WESTWARD. WILL FOLLOW THIS IDEA AND HAVE SLIGHTLY HIGHER POPS
ACROSS THE WESTERN ZONES TONIGHT...BUT KEEP SCT POPS AREAWIDE
TONIGHT BECAUSE OF THIS DISTURBANCE. BELIEVE THAT THE AREA WILL
STILL HAVE A SVR TSTM THREAT TONIGHT BECAUSE OF THE MID-LEVEL ENERGY
AND HIGH INSTABILITY.

PATTERN CHANGE STILL EXPECTED EARLY NEXT WEEK WHICH WILL LIKELY
RESULT IN GRADUALLY LOWER HIGH TEMPERATURES AND AT LEAST CHC POPS.
MID/UPPER LEVEL TROF AXIS WILL RETROGRADE AROUND MID LEVEL RIDGE
WHICH BUILDS TO THE NORTH. PW VALUES WILL REMAIN HIGH (AROUND 2
INCHES) SO SCT POPS WILL BE FORECAST THROUGH THE EXTENDED.

33/40

.HGX...HEAT ADVISORY ALL ZONES THROUGH SUNDAY.

PRELIMS...
CLL BB 075/096 074/094 074 542
IAH BB 076/095 075/094 074 442
GLS BB 081/090 080/089 080 432

GMZ330-335-TXZ163-164-176>179-195>200-210>214-226-227-235>238-101200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
920 AM CDT SAT AUG 9 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

...SLIGHT CHANCE OF SEVERE THUNDERSTORMS THIS AFTERNOON AND TONIGHT...

.DAY ONE...TODAY AND TONIGHT.
AN EXCESSIVE HEAT ADVISORY IS IN EFFECT FOR ALL OF SOUTHEAST TEXAS
TODAY. ABOVE NORMAL TEMPERATURES ALONG WITH HIGH RELATIVE HUMIDITIES
WILL YIELD HEAT INDEX VALUES BETWEEN 105 AND 111 DEGREES THIS
AFTERNOON.

SCATTERED THUNDERSTORMS MAY DEVELOP ALONG THE SEABREEZE AND OLD
OUTFLOW BOUNDARIES FROM YESTERDAYS STORMS THIS AFTERNOON.
STORMS THAT DO DEVELOP COULD INTENSIFY QUICKLY AND BE CAPABLE OF
PRODUCING DAMAGING WINDS AND HAIL.

A THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP NORTH OF THE REGION
THIS EVENING AND POSSIBLY MOVE INTO SOUTHEAST TEXAS OVERNIGHT. AT
THIS TIME IT APPEARS THE MAIN SEVERE WEATHER THREAT OVERNIGHT WILL BE
DAMAGING WINDS. LOCATIONS ALONG AND WEST OF INTERSTATE 45 THE HAVE
BETTER CHANCES OF SEEING SEVERE WEATHER ASSOCIATED WITH THIS
COMPLEX...MAINLY AFTER 11 PM.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. THE EXCESSIVE HEAT
ADVISORY WILL PROBABLY NOT NEED TO BE RE-ISSUED AS SLIGHTLY COOLER
DAYTIME TEMPERATURES AND INCREASED CLOUDCOVER IS EXPECTED.
OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE REQUIRED THIS AFTERNOON AND TONIGHT.