Severe Thunderstorm Warning 89, NWS Houston/Galveston, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
205 PM CDT SUN MAY 8 2005

.DISCUSSION...
SEE AVIATION DISCUSSION FOR NEAR TERM ISSUES. WE SHALL HAVE LIKELY POPS
1ST PERIOD AREAWIDE AS LARGE MCS JUST WEST OF CWFA WILL SHIFT TO OUR
REGION TONIGHT. TORNADO WATCH IN EFFECT MAINLY SOUTH OF 1-10 THROUGH
7 PM THIS EVENING. WE SHALL INCLUDE LOCALLY HEAVY RAIN IN 1ST PERIOD.
HIGH PWATS TO 1.5 INCHES...LOW LEVEL JET AND UPPER LEVEL DIFFLUENCE
(ALONG W/UPPER JET DIVERGENT FIELD) WILL GIVE US WIDESPREAD
CONVECTION ESPECIALLY NEAR ALONG MESO-BOUNDARY LEFT OVER
FROM THE EARLIER MCS THIS MORNING. MESO-ETA STILL SHOWING WEAK ENERGY
MOVING ACROSS NE TX EARLY MONDAY PERHAPS INITIATING SOME CONVECTION
NE ZONES. LATE MONDAY THROUGH THE REST OF THE COMING WEEK LOOKS BENIGN
WITH BUILDING UPPER RIDGE OVER REGION. WARM HUMID DAYS CAN BE EXPECTED
THIS COMING WEEK. GFS HINTING AT A COLD FRONT PUSHING SOUTH ACROSS
REGION LATER IN THE COMING WEEKEND. WE SHALL SEE.

37

&&

.AVIATION...
MAIN FCST ISSUE IS TSTMS. BOUNDARY CURRENTLY STALLED OUT ROUGHLY
ALONG I-10. FAVORABLE JET POSITION AND UPPER IMPULSES MOVING
OVERHEAD WILL FAVOR REDEVELOPMENT OUT WEST AT LEAST THRU THE EVENING
HOURS. THE STRONGER STORMS WILL LIKELY TRACK EWD ALONG THE BOUNDARY.
SVR WX THREAT MAINLY IN THE WARM SECTOR S OF I-10 AND STRONG
WINDS/HAIL BEING MAIN THREAT..THOUGH CANNOT COMPLETELY RULE OUT A
SPINNER OR TWO. THE STORMS IN CNTRL TX MAY END UP FORMING INTO A
LARGE TSTM COMPLEX AS IT MOVES THRU. LOCALLY HEAVY RAIN AT THE
TERMINALS ALSO POSSIBLE. RAINFALL RATES OF 2-3/HOUR HAVE ALREADY
BEEN OBSERVED TODAY...AND WITH TRAINING STORMS ISOLATED 4+ AMOUNTS
ENTIRELY POSSIBLE. CURRENT BET IS FOR THE PRECIP TO GRADUALLY COME
TO AN END LATER THIS EVENING. HOWEVER...ETA - WHICH HAS PERFORMED
GREAT WITH THIS SYSTEM - IS DEPICTING ANOTHER CONVECTIVE BLOWUP
BETWEEN HOU AND SAT AROUND MIDNIGHT AND TAKING THIS COMPLEX TO THE
COAST TOWARD SUNRISE. ONLY DOUBT ABOUT THIS IS THAT THE ATMOS MAY BE
TOO WORKED OVER FROM TODAYS PRECIP. WILL HAVE TO WAIT AND
SEE...OVERALL A LOW CONFIDENCE TAF FCST. 47

&&

.MARINE...
WINDS HAVE BEEN BACKING FOR THE LAST SEVERAL HOURS TO THE ESE AHEAD
OF THE BOUNDARY STALLED INLAND. WINDS HAVE THE POTENTIAL TO BE ALL
OVER THE PLACE TONIGHT DEPENDING ON CONVECTIVE FEATURES AND
BOUNDARIES. WILL GO WITH AVG SE FOR NOW BUT MARINERS SHOULD BE
PREPARED FOR A COUPLE HOURS OF OFFSHORE WINDS IF/WHEN ANY OF THE
STORMS MOVE OFFSHORE. STILL NEED THE SCEC/SCA FLAGS IN THE GULF
TONIGHT DUE TO WINDS AND SEAS. BOTH WILL BE ON A DOWNWARD TREND
BEGINNING MONDAY. GENERAL SUMMERTIME PATTERN THEN SHAPES UP WITH SE
WINDS 10-15KT AND 2-4FT SEAS IN THE FCST FOR THE REMAINDER OF THE
WEEK.  47

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      65  88  67  91  66 /  70  20  10  10   0
HOUSTON (IAH)              68  87  67  90  66 /  70  20  10  10   0
GALVESTON (GLS)            71  80  71  81  69 /  70  30  10  10   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...
TORNADO WATCH FROM 11 AM SUNDAY UNTIL 7 PM SUNDAY FOR THE
      FOLLOWING ZONES...AUSTIN...BRAZORIA...CHAMBERS...
      COLORADO...FORT BEND...GALVESTON...HARRIS...JACKSON...
      LIBERTY...MATAGORDA...WALLER...AND WHARTON.

GM...
.TORNADO WATCH UNTIL 7 PM SUNDAY FOR THE COASTAL WATERS OUT
 TO 20 NM.
.SCA 20-60 NM GULF.
.SCEC 0-20NM GULF.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
327 PM CDT SUN MAY 8 2005

GMZ330-335-TXZ163-164-176>179-195>200-210>214-226-227-235>238-091200-
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-WHARTON-
327 PM CDT SUN MAY 8 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

...A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY AND THIS EVENING FOR
SOUTHERN PORTIONS OF SOUTHEAST TEXAS...

.DAY ONE...TONIGHT...
CONDITIONS REMAIN FAVORABLE FOR THUNDERSTORMS TO TRAIN WEST TO EAST
ALONG A NEARLY STATIONARY BOUNDARY ALONG INTERSTATE 10 THROUGH THE
EVENING HOURS. THERE IS A CHANCE SOME OF THE STORMS WILL PULSE UP TO
SEVERE LEVELS ALONG AND SOUTH OF THE BOUNDARY. HAIL AND DAMAGING WINDS
WILL BE THE MAIN THREAT...THOUGH AN ISOLATED TORNADO IS ALSO
POSSIBLE. DUE TO THE TRAINING NATURE OF THE STORMS...LOCALLY HEAVY
RAIN WILL ALSO BE POSSIBLE. EXPECT LOCATIONS ALONG AND SOUTH OF
INTERSTATE 10 TO RECEIVE 1 TO 2 INCHES OF RAIN...WITH LOCALIZED
AMOUNTS OVER 4 INCHES POSSIBLE WHERE TRAINING STRONG STORMS OCCUR.

THIS ACTIVITY SHOULD WIND DOWN SHORTLY AFTER SUNSET. ONE COMPUTER
MODEL IS SHOWING ANOTHER THUNDERSTORM COMPLEX DEVELOPING BETWEEN SAN
ANTONIO AND HOUSTON TOWARD MIDNIGHT AND THEN MOVE SOUTHWARD AND OFF
THE COAST. HOWEVER THERE IS CONSIDERABLE UNCERTAINTY REGARDING
DEVELOPMENT OF THIS SECOND COMPLEX. THE ATMOSPHERE MAY BECOME TOO
STABLE IN THE WAKE OF THIS EVENINGS STORMS FOR THIS TO OCCUR.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.
NO HAZARDOUS WEATHER IS ANTICIPATED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...
THE SKYWARN SPOTTER NETWORK IS CURRENTLY ACTIVATED THROUGH AT LEAST
THIS EVENING.