Flash Flooding and Hail in Texas, May 1, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
956 AM CDT TUE MAY 1 2007

.DISCUSSION...
CURRENT FORECAST LOOKS ON TRACK. SHOWERS AND THUNDERSTORMS ARE
ABOUT TO MOVE INTO OUR NORTHERN COUNTIES. PORTIONS OF THIS AREA
RECEIVED SOME LOCALLY HEAVY RAINFALL YESTERDAY...SO WELL HAVE TO
KEEP A CLOSE WATCH ON HOW MUCH RAIN THIS BATCH OF STORMS PRODUCES.
A GENERAL WEAKENING TREND IS BEING INDICATED ON SATELLITE AND
LIGHTNING DATA...SO BELIEVE LOCALLY HEAVY RAINFALL WILL BE THE
PRIMARY SEVERE WEATHER THREAT. ITS HARD TO DETERMINE WHAT AFFECT
THESE STORMS WILL HAVE ON AREAS FURTHER SOUTH AND EAST. CURRENT
THINKING IS THAT THIS ACTIVITY OR ANY BOUNDARIES GENERATED FROM
THIS ACTIVITY IN COMBINATION WITH ANY DAYTIME HEATING MIGHT BE
ABLE TO HELP TO FIRE ADDITIONAL STORMS THIS AFTERNOON ACROSS
PORTIONS OF MAINLY THE CENTRAL AREAS OF SOUTHEAST TEXAS. COASTAL
COUNTIES WILL HAVE THE LOWEST POPS THIS AFTERNOON.

MINOR ADJUSTMENTS ON THE MORNING UPDATE HAVE INCLUDED BOOSTING UP
NORTHERN COUNTY QPF AND LOWERING TODAYS HIGH TEMPERATURES IN THE
SAME AREA. THE FORECAST BEYOND THIS AFTERNOON HAS BEEN LEFT
UNTOUCHED. 42

&&

.PREV DISCUSSION... /ISSUED 541 AM CDT TUE MAY 1 2007/

DISCUSSION...
ONCE AGAIN KEEPING A CLOSE EYE ON THE ACTIVITY TO OUR W/NW WHICH
IS ASSOCIATED WITH THE RATHER WELL-DEFINED BUT SLOW MOVING UPPER
LOW MOVING OUT OF THE TX PANHANDLE. THE NRN PORTIONS OF THE CWFA
LOOK TO BE UNDER THE GUN ONCE AGAIN TODAY AS THE REMNANTS OF THE
MCS MOVE INTO THE AREA. GIVEN THE HEALTHY AMOUNTS THAT FELL PRE-
VIOUSLY AM A BIT CONCERNED WITH THE FCST OF ADDITIONAL RAINS FOR
THIS AFTN. WILL GO AHEAD AND MENTION THE POSSIBILITY OF HVY RAIN
BUT STAY PUT WITH REGARD TO AN FFA TODAY ATTM. NOT REALLY SEEING
MUCH EVIDENCE OF ANY BOUNDARIES AND THE GIVEN THE CURRENT TRENDS
OF MOTION WITH RESPECT TO THE UPPER LOW ITSELF...THE BULK OF THE
RAINS SHOULD OCCUR JUST A BIT FURTHER E/NE OF THE EARLIER PCPN.
FOR THE MIDDLE/LATTER PARTS OF THE FCST...MODELS CONTINUE TO RUN
AMOK. THESE LATEST RUNS HAVE SWUNG BACK TO THE WET WITH THE NEXT
UPPER LOW SPLITTING ITS ENERGY AS IT CROSSES THE STATE. ONE PART
OF THIS FEATURE TO TRAVERSE OVER SE TX AND GUIDANCE NUMBERS HAVE
RISEN ACCORDINGLY. HAVE RAISED POPS FOR THIS TIMEPERIOD (THU/THU
NIGHT) BUT CONFIDENCE IS LOW. THE DAYS FOLLOWING SHOULD BE QUITE
WARM AS RIDGING ALOFT DEVELOPS AHEAD OF A DEEP/POTENT UPPER LOW/
TROF OVER THE WRN U.S. THIS NEXT FEATURE PROGGED TO IMPACT US BY
TUE OF NEXT WEEK (GIVE OR TAKE). 41

AVIATION...
LINE OF STORMS NEARING AN ACT-BMQ LINE AT 1030Z...MOVING TO THE
EAST-SOUTHEAST AT 33 KNOTS. MORE STORMS BEHIND THIS LINE AND
EXPECTING AS THE VORT LOBE ROTATING AROUND THE UPPER LOW TRAVERSES
INTO NORTHEAST TEXAS THESE STORMS TO CONTINUE TO TRACK EAST THROUGH
LATE MORNING THEN MORE EAST OR EAST-NORTHEAST. THIS WOULD BRING THE
STORMS ACROSS THE UTS-CXO TERMINALS 15-16 PERHAPS 17Z TIMEFRAME. THE
SOUTHERN TERMINALS MAY BE CAPPED. WILL GO WITH TEMPOS FOR CXO AREAS
NORTHWARD AND VCTS AT IAH. AFTER THE LOBE LIFTS OUT IT SHOULD END
THE POSSIBILITY OF PRECIP. MVFR/IFR CIGS AGAIN AFTER 06Z AS LLJ
INTENSIFIES.
45

MARINE...
BORDERLINE SCEC FOR THE OFFSHOREWATERS BEYOND 20NM. OTHERWISE
SOUTHEAST WINDS 10 TO 15 KNOTS OR IN THE 15-20 KNOT RANGE AS
PRESSURES FALL OVER THE SOUTHERN PLAINS AND/OR LEE OF THE ROCKIES.
45

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      75  66  83  68  81 /  70  70  30  30  40
HOUSTON (IAH)              80  67  84  68  82 /  50  50  20  20  40
GALVESTON (GLS)            80  71  81  72  79 /  30  30  20  20  40

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 6 PM CDT THIS
     AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO
     THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
     HIGH ISLAND TO FREEPORT 20 TO 60 NM.

&&

DISCUSSION...42

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
759 AM CDT TUE MAY 1 2007

TXZ163-164-176>179-195>200-210>214-226-227-235>238-021300-
AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND-
GALVESTON-GRIMES-HARRIS-HOUSTON-JACKSON-LIBERTY-MADISON-MATAGORDA-
MONTGOMERY-POLK-SAN JACINTO-TRINITY-WALKER-WALLER-WASHINGTON-
WHARTON-
759 AM CDT TUE MAY 1 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT
THE STORM PREDICTION CENTER HAS PLACED PARTS OF SOUTHEAST TEXAS IN
THE SLIGHT RISK AREA FOR SEVERE THUNDERSTORMS TODAY. THIS REGION
IS MAINLY ALONG AND NORTH OF A LINE FROM BRENHAM TO GROVETON.
STORMS THAT DEVELOPED OVERNIGHT ACROSS CENTRAL TEXAS ARE EXPECTED
TO MOVE INTO THE AREA THIS AFTERNOON AND INTERACT WITH THE WARM
FRONT AND DEEP GULF MOISTURE ALREADY IN PLACE. HOWEVER THERE ARE
CONCERNS REGARDING THE STRENGTH OF THE CAP. SHOULD SEVERE STORMS
DEVELOP...THE PRIMARY SEVERE WEATHER THREATS WILL BE STRONG
DAMAGING WINDS AND LARGE HAIL.

HEAVY RAINS YESTERDAY HAVE SATURATED THE GROUNDS OVER THE
NORTHERN HALF OF SOUTHEAST TEXAS. ANY ADDITIONAL DEVELOPMENT LATER
TODAY OVER THESE SAME AREAS COULD PRODUCE LOCALIZED FLOODING ONCE
AGAIN THIS AFTERNOON AND EVENING.

ALL OF THIS ACTIVITY IS EXPECTED TO WEAKEN BY THIS EVENING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY
ANOTHER ROUND OF STORMS IS POSSIBLE THURSDAY AS ANOTHER UPPER
LEVEL STORMS SYSTEM MOVES ACROSS THE STATE. NO HAZARDOUS WEATHER
IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON.