Tornadoes and Damaging Winds in Texas, April 29, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
938 PM CDT FRI APR 28 2006

.UPDATE...
NOT PLANNING ON MANY CHANGES THIS GO AROUND. ACTIVITY TO THE WEST
CONTINUING TO NUDGE EVER SO CLOSE. A QUICK LOOK AT EARLY ETA RUNS
WOULD SEEM TO INDICATE A SLIGHTLY SLOWER (THAN CURRENT FORECASTS)
TIMING FOR THE CONVECTION ASSOCIATED WITH THE DRYLINE/UPPER TROF.
WILL HAVE TO SEE IF THE OTHER MODEL SOLUTIONS GO WITH THIS TREND.
IN THE MEANWHILE THE LEAD STORMS TO THE WEST SHOULD MAINLY AFFECT
OUR NRN COUNTIES WITH THIS INTIAL ROUND. DEWPOINTS/WINDS STILL ON
THE HIGH SIDE THIS EVENING AND UA PLOTS SHOWING AS RATHER IMPRES-
SIVE UPPER JET (ABOUT 130KT) APPROACHING FROM THE SW. SO IT WOULD
SEEM THAT THE INGREDIENTS ARE COMING TOGETHER BUT THE MAIN QUEST-
ION MARK LOOKS TO BE TIMING. 41
&&

.PREV DISCUSSION... (ISSUED 320 PM CDT FRI APR 28 2006)
KHGX VAD PROFILE SHOWS DEEP SOUTHERLY FLOW IN PLACE ACROSS SE TX
THIS AFTN WITH 45 KNOT LOW LEVEL JET TRANSPORTING PWS OF 1.6-1.7
INCHES INTO THE AREA. A WEAK SURFACE FRONT WAS LOCATED ACROSS
CENTRAL/EAST TX WITH WIDESPREAD ELEVATED CONVECTION OCCURRING
NORTH OF THIS BOUNDARY. MEANWHILE...STORMS WERE BEGINNING TO
DEVELOP ALONG THE DRYLINE IN SOUTHWEST TEXAS FROM THE MIDLAND AREA
SOUTH TO THE TEXAS/MEXICO BORDER. 12Z RUNS OF THE GFS/NAM ARE A
BIT SLOWER WITH THE EVOLUTION OF THE MOVEMENT OF THE DRYLINE AND
UPPER LOW OVER NEW MEXICO. THE MODELS SHOW CONVECTION OVER WEST
TEXAS ORGANIZING INTO AN MCS OVER THE HILL COUNTRY/EDWARDS PLATEAU
THIS EVENING AS IMPRESSIVE 130 KNOT JET STREAK LIFTS NORTHEASTWARD
INTO WEST TX. STRONG UPPER DIFFLUENCE AND 50-60 KNOT LOW LEVEL JET
SHOULD HELP TO SUSTAIN THE CONVECTION AS IT PUSHES EASTWARD TOWARD
OUR CWA LATER TONIGHT DESPITE THE CAPPING IN PLACE AND THE LACK OF
INSTABILITY THAT WILL BE PRESENT. RIGHT NOW THINK SQUALL LINE WILL
REACH SE TX VERY LATE TONIGHT (AFTER 08Z) AND EXIT AREA MID-LATE
MORNING SATURDAY. MODELS CONTINUE TO DEPICT IMPRESSIVE SHEAR
PROFILES OVER SE TX LATER TONIGHT WITH HELICITIES IN EXCESS OF 400
M2/S2 IN SOME CASES.PRIMARY SEVERE THREAT WILL BE DAMAGING
WINDS...WITH A MUCH LOWER RISK OF LARGE HAIL OR ISOLATED TORNADOES
ALSO PRESENT. STORMS WILL PRODUCE BRIEF HEAVY RAINFALL...BUT NOT
OVERLY CONCERNED ABOUT THE RAINFALL THREAT SINCE REGION HAS BEEN
DRY LATELY AND STORMS SHOULD MOVE THROUGH FAIRLY QUICKLY.

WHILE FEEL THE NAM IS TOO SLOW DRYING THE AREA OUT SATURDAY
AFTN/EVENING...DO THINK THERE IS A POSSIBILITY OF THE DRYLINE
HANGING UP OVER OUR EASTERN/COASTAL ZONES SATURDAY AFTN. MOST OF
THE ENERGY WITH THE UPPER TROUGH WILL STILL BE WELL TO THE
WEST...SO IF THE ATMOSPHERE CAN RECOVER FROM MORNING CONVECTION
THERE WILL BE A POSSIBILITY OF ISOLATED TSRA RE-FIRING OVER OUR
FAR ERN ZONES SAT AFTN. WILL MAINTAIN 30 POPS THIS AREA AS A
RESULT. DRYLINE SHOULD EXIT AREA EARLY SAT EVENING WITH PRECIP
ENDING. DRY CONDITIONS WILL FOLLOW FOR SAT NIGHT THROUGH MONDAY.

12Z GFS SIMILAR TO PREVIOUS RUNS DEPICTING A WEAK FROPA TUESDAY WITH
FRONT STALLING ACROSS OUR SRN ZONES INTO WEDNESDAY. PWS INCREASE TO
1.5 INCHES AND ATMOSPHERE REMAINS UNCAPPED SO WILL GO WITH 20/30
POPS THESE PERIODS. A STRONGER FRONT IS EXPECTED TO MOVE ACROSS
SE TX THU/FRI. WILL KEEP LOW POPS GOING FOR THIS PERIOD AS WELL. 35
&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 2 PM SATURDAY FOR THE FOLLOWING
     ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT
     TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
     FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
     FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...AND WATERS FROM
     HIGH ISLAND TO FREEPORT OUT 20 NM.

&&

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
355 PM CDT FRI APR 28 2006

GMZ330-335-350-355-TXZ163-164-176>179-195>200-210>214-226-227-
235>238-291300-
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-
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM-
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM-WHARTON-
355 PM CDT FRI APR 28 2006

...SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST TEXAS LATE
TONIGHT AND SATURDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS.

.DAY ONE...TONIGHT
A LARGE CLUSTER OF THUNDERSTORMS IS EXPECTED TO IMPACT SOUTHEAST
TEXAS LATE TONIGHT AND SATURDAY MORNING. A FEW OF THESE STORMS WILL
HAVE THE POTENTIAL TO BECOME SEVERE. THE PRIMARY SEVERE WEATHER
THREAT WILL BE DAMAGING WINDS...WITH A SMALLER RISK OF ISOLATED
TORNADOES OR LARGE HAIL. THE PRIMARY TIME FRAME FOR THE SEVERE
WEATHER THREAT WILL BE FROM 3 AM TO 10 AM SATURDAY.

SEVERE THUNDERSTORMS ARE ALREADY DEVELOPING THIS AFTERNOON OVER WEST
TEXAS AS AN UPPER LEVEL LOW PRESSURE SYSTEM OVER NEW MEXICO
INTERACTS WITH A MOIST AND UNSTABLE AIRMASS IN PLACE AHEAD OF A
SURFACE DRYLINE. THESE STORMS ARE EXPECTED TO EVOLVE INTO A LARGE
CLUSTER OF THUNDERSTORMS WHICH WILL MOVE EASTWARD AND REACH THE
NORTHWESTERN PORTIONS OF SOUTHEAST TEXAS AFTER MIDNIGHT TONIGHT.

IN ADDITION TO THE SEVERE WEATHER THREAT...THE THUNDERSTORMS WILL
PRODUCE LOCALLY HEAVY RAINFALL. RAINFALL AMOUNTS LATE TONIGHT AND
SATURDAY MORNING WILL AVERAGE 1/2 TO 1 INCH WITH ISOLATED TOTALS
OVER 2 INCHES POSSIBLE. AT THIS TIME...ONLY MINOR FLOODING OF
STREETS OR LOW WATER CROSSINGS IS ANTICIPATED.

.DAY TWO...SATURDAY
THE SQUALL LINE SHOULD MOVE OUT THE REGION LATE SATURDAY MORNING. IF
THE ATMOSPHERE DESTABILIZES AGAIN...ISOLATED THUNDERSTORMS COULD
RE-DEVELOP DURING THE AFTERNOON MAINLY EAST OF INTERSTATE 45. ONE OR
TWO OF THESE STORMS WILL HAVE THE POTENTIAL TO BECOME SEVERE. THESE
STORMS SHOULD DIMINISH AROUND SUNSET.

.DAYS THREE THROUGH SEVEN...SUNDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS ANTICIPATED BETWEEN 3 AM AND 10 AM SATURDAY.