Severe Thunderstorm Warning 121, NWS Houston/Galveston, TX

SOUTHEAST TEXAS FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
550 PM CDT THU JUN 12 2003

UPDATED ZONE FORECAST TO RAISE POPS TONIGHT AND REMOVE EVE WORDING
AS TSTM THREAT WILL LIKELY EXTEND OVERNIGHT. LINE OF SHOWERS AND
TSTMS IS MOVING SOUTH INTO THE NORTHERN ZONES. HAVE TAPERED POPS
FROM LIKELY ACROSS THE NORTH TO CHC ACROSS THE SOUTH. ONCE HEATING
IS LOST IN A COUPLE OF HOURS NOT SURE HOW WELL LINE WILL HOLD
TOGETHER. COULD SEE SOME PULSE SVR ACTIVITY WITH THE LINE ACROSS THE
NORTHERN AND PORTIONS OF THE CENTRAL ZONES AS THE AIRMASS IS VERY
UNSTABLE.

33/41

PREVIOUS DISCUSSION...
TWO OUTFLOW BOUNDARIES HAVE MERGED ACROSS NRN PORTIONS OF CWA THIS
AFTN PRODUCING A BAND OF HEAVY RAINFALL (2 TO 4 INCHES) AND PULSE
SEVERE STORMS. THIS BOUNDARY WILL PUSH VERY SLOWLY SOUTH THROUGH THE
REMAINDER OF THE AFTN. WILL LEAVE CHANCE POPS IN FOR EARLY EVENING
BEFORE ACTIVITY DIES DOWN AROUND SUNSET.

LATEST ETA/GFS IN GOOD AGREEMENT ON ANOTHER MCS FORMING OVER CENTRAL
TX TONIGHT. HOWEVER...MODELS KEEP THIS SYSTEM WEST OF CWA TONIGHT AS
POOR JET POSITIONING AND WEAK MID LEVEL FLOW INHIBITS EASTWARD
PROGRESS TOWARD SE TX. WILL LEAVE CHANCE POPS NORTH FRIDAY AS A
PRECAUTION BUT WILL GO JUST SLIGHT CHANCE CENTRAL/COAST WITH
SLIGHTLY DRIER AIRMASS IN PLACE AND A LITTLE MORE CAPPING THAN
TODAY. HEAT INDICES WILL PEAK OUT AT AROUND 107 DEGREES AGAIN
FRIDAY...BUT THINK WE WILL REMAIN JUST BELOW ADVISORY CRITERIA.

MODELS CONTINUE TO DEVELOP A WEAK UPPER LOW ACROSS NORTH TX FRI
NIGHT ALONG WITH WIDESPREAD CONVECTION. 12Z ETA/GFS HAVE SLIGHT BUT
SIGNIFICANT DIFFERENCES IN THEIR SOLUTIONS. ETA IS A BIT FASTER AND
FURTHER SOUTH WITH MOVEMENT OF UPPER LOW AND IS FAR MORE AGGRESSIVE
PUSHING HIGHER PWS (OVER 2 INCHES) AND MORE WIDESPREAD TSRA SOUTH
INTO CWA SATURDAY. FOR NOW WILL COMPROMISE SOMEWHAT AND INCREASE
POPS ONLY IN THE NORTH SATURDAY. STRONG OUTFLOW BOUNDARY WILL LIKELY
SET UP OVER CWA SATURDAY AND INTERACT WITH UNSTABLE AIRMASS IN
PLACE...SO SPC SLIGHT RISK FOR DAY 3 LOOKS GOOD. UPPER LOW WILL
MEANDER NEAR EAST TX/LOUISIANA THROUGH EARLY NEXT WEEK WITH SFC
BOUNDARY LINGERING TO PROVIDE CONVECTIVE FOCUS. EVEN SLIGHT SHIFTS
WITH POSITION OF UPPER LOW WILL MAKE A WORLD OF DIFFERENCE WITH RAIN
CHANCES OVER THE AREA. FOR NOW...WILL LEAVE CHANCE POPS IN FCST
THROUGH WEDNESDAY.

FOR MARINE...SCEC CONDITIONS WILL CONTINUE THROUGH FRI NIGHT BEFORE
WINDS SUBSIDE A LITTLE SATURDAY. SEAS MAY TEMPORARILY REACH 7 FEET
OVER THE OFFSHORE WATERS.

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

.PRELIMS...
CLL BB 075/095 074/091 072 233
IAH BB 077/095 077/093 073 322
GLS BB 082/089 081/089 079 222

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.