Tornado Warning 8, NWS Houston/Galveston, TX

SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1025 AM CDT THU JUN 12 2003

EARLY MORNING MCS HAS EXITED AREA WHILE OUTFLOW BOUNDARY ASSOCIATED
WITH STORMS OVER NORTH TX IS NOW APPROACHING NRN ZONES. BECOMING
MORE CONCERNED ABOUT CONVECTIVE POTENTIAL THIS AFTN. NE ZONES
STABILIZED A LITTLE BIT BY EARLIER CONVECTION BUT THE REST OF THE
AREA UNAFFECTED WITH DEWPOINTS RUNNING 76 TO 80F ACROSS SW HALF OF
CWA. THINK OUTFLOW BOUNDARY APPROACHING CWA TO BECOME PREDOMINATE
FOCUS FOR CONVECTION THIS AFTN. EXPECT BOUNDARY TO LIE NW-SE ACROSS
THE AREA BY 18Z. 12Z ETA FCST MODEL SOUNDINGS SHOW CAPES AROUND 3500
J/KG...K-INDICES IN THE MID/UPPER 30S...AND CAPPING ERODING BY EARLY
AFTN. FINALLY...STRONG 300 MB DIFLUENCE WILL CONTINUE ESPECIALLY
OVER NRN ZONES AS JET MAX APPROACHES FROM THE WEST.

WILL GO HIGHEST IN THE NORTHEAST IN AREA OF BEST DIFLUENCE WITH
LOWEST POPS OVER SW WHERE CAPPING WILL HOLD. WILL LOWER TEMPS SOME
OVER THE NORTH DUE TO CLOUDS/PRECIP. WILL ALSO MENTION SEVERE RISK
NRN ZONES TO GO ALONG WITH SPC DAY 1 OUTLOOK. FOR MARINE...WILL KEEP
SCEC GOING ALL WATERS.

35/42

.HGX...SCEC 00-60 NM BAYS AND WATERS.

.PRELIMS...
CLL BB 092/077 096/077 096 443 NE ZONES 543
IAH BB 094/079 095/078 095 333
GLS BB 089/082 089/082 089 333

PREVIOUS DISCUSSION...
SQUALL LINE MOVING E/SE THROUGH SE TX TONIGHT. OBVIOUSLY THIS IS THE
MAIN ISSUE FOR THE FORECAST AS IT WILL STILL BE IMPACTING PORTIONS
OF THE AREA WHEN THE PACKAGE IS ISSUED. WILL HAVE TO BREAK OUT POPS
BETWEEN AM AND PM FOR TODAY AHEAD OF THE LINE. SVR TSTM WATCH
CONTINUES UNTIL 5 AM AHEAD OF THE LINE.

IN THE WAKE OF THE SQUALL LINE...NOT SURE IF THE ATMOSPHERE WILL BE
ABLE TO DESTABILIZE SUFFICIENTLY FOR AFT TSTMS. THINK A SLIGHT CHC
IS WARRANTED...HOWEVER...BETTER CHC MAY OCCUR DURING THE 2ND PERIOD
(EVE AND OVERNIGHT PD) AS WE COULD SEE ACTIVITY AGAIN APPROACH
FROM THE W/NW. BELIEVE THE GREATEST CHC OF THIS OCCURRING WOULD BE
ACROSS THE NW ZONES. SO HIGHEST CHC POPS WILL BE PLACED ACROSS THIS
REGION. WK SHRT WAVES WILL CONTINUE TO MOVE ACROSS THE REGION IN A
MOIST AND UNSTABLE ATMOS...SO CHC POPS LOOK GOOD THROUGH THE
FORECAST PERIOD. MODELS IN AGREEMENT THAT LATE IN THE WEEKEND A SLOW
MOVING CUT-OFF LOW WILL DRIFT SOUTHWARD INTO TEXAS AND BELIEVE THAT
THIS FEATURE WILL PROVIDE AT LEAST A CHC OF RAIN EARLY NEXT WEEK.
STILL FAR OUT IN TIME...SO WILL LEAVE CHC POPS IN THE FORECAST AND
RAISE IF NECESSARY AS CONFIDENCE INCREASES.

CENTRAL AND NORTHERN ZONES MAY HAVE A SVR TSTM THREAT THIS EVE AND
TONIGHT. HOWEVER...WILL NOT MENTION THIS POSSIBILITY YET...AS IT
WILL BE IMPORTANT TO ASSESS THE STATE OF THE ATMOS IN THE WAKE OF
THE MCS TO GET A GOOD HANDLE ON THE SVR WX THREAT.

TEMPS HAVE BEEN A LITTLE ABOVE GUIDANCE AND THIS WILL LIKELY
CONTINUE. ANY LAYER DRYING IN THE WAKE OF THE CONVECTION THIS
MORNING SHOULD BE TEMPORARY. EXPECT HEAT INDICES TO CONTINUE TO RISE
CLOSE INTO THE 102 TO 107 DEGREE RANGE DURING THE AFT HOURS.

FOR THE MARINE AREA...S/SE 15 TO 20 KNOT WINDS WILL CONTINUE WITH
SEAS IN THE 4 TO 6 FOOT RANGE. THEREFORE...WILL CONTINUE TO HAVE
CAUTION STATEMENT AREAWIDE.

33/41

GMZ330-335-TXZ163-164-176>179-195>200-210>214-226-227-235>238-
131200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1055 AM CDT THU JUN 12 2003

...SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF SOUTHEAST
TEXAS THIS AFTERNOON AND EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING MAINLY NORTH OF A LINE FROM COLLEGE STATION TO CONROE TO
LIBERTY. A SERIES OF OUTFLOW BOUNDARIES WILL COMBINE WITH DAYTIME
HEATING TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS OVER
SOUTHEAST TEXAS THIS AFTERNOON AND EARLY EVENING. A FEW OF THE
STORMS COULD BECOME SEVERE...PRODUCING LARGE HAIL OR DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

FRIDAY AND SATURDAY AFTERNOON TEMPERATURES IN THE 90S AND
DEWPOINTS IN THE MID TO UPPER 70S WILL CONTINUE TO PRODUCE HEAT
INDICES ACROSS SOUTHEAST TEXAS IN A 102 TO 107 DEGREE RANGE. AS
TEMPERATURES BEGIN TO FALL AROUND AND SHORTLY AFTER SUNSET EACH
EVENING...HEAT INDICES WILL FALL BELOW 100 DEGREES. A HEAT ADVISORY
IS NOT ANTICIPATED FOR SOUTHEAST TEXAS AT THIS TIME BECAUSE HEAT
INDICES ARE NOT EXPECTED TO MEET THE CRITERIA OF 108 DEGREES FOR TWO
CONSECUTIVE DAYS.

SUNDAY THROUGH WEDNESDAY...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED TODAY.