Tornado Warning 43, NWS Houston/Galveston, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
840 PM CDT SAT JUN 26 2004

.DISCUSSION...
SO FAR...TONIGHT HAS BEEN QUIETER THAN THE PAST SEVERAL. THERE HAVE
BEEN A COUPLE OF STRONG CELLS OVER THE FAR NORTHWESTERN ZONES WHICH
HAVE SHOWN SOME ROTATION. A LINE OF STRONG TO SEVERE THUNDERSTORMS
HAS DEVELOPED AT THE INTERSECTION OF OUTFLOW BOUNDARIES OVER THE
EXTREME SOUTHERN PART OF THE FORT WORTH CWA...AND THIS LINE IS
SINKING SLOWLY SOUTHWARD TOWARD OUR NORTHERN ZONES. BEST CHANCES FOR
RAIN TONIGHT LOOK TO BE IN THE NORTH IN THE VICINITY OF THIS LINE.
THE COASTAL ZONES LOOK TO HAVE A VERY GOOD CHANCE FOR RAIN AS WELL.
THE QUESTION IS THE CENTRAL ZONES. WITH STORMS EXPECTED TO DEVELOP
ALONG THE COAST...THE INFLOW WILL BE INTERRUPTED SOMEWHAT AND MAY
LIMIT THUNDERSTORM ACTIVITY IN THE CENTRAL ZONES. WITH THIS IN MIND
...WILL LOWER POPS EVER SO SLIGHTLY IN THE CENTRAL AND LEAVE THE
REST OF THE AREA ALONE. 46/30

&&

.PREV DISCUSSION...
SCATTERED THUNDERSTORMS FIRING UP ACROSS CENTRAL AND NORTHERN PORTIONS
OF CWFA THIS AFTERNOON AMD MOVING NORTH AT 15 TO 20 MPH. GPS MET
INTEGRATED PW INDICATE AT OR SLIGHTLY ABOVE 2 INCHES OVER MUCH OF
REGION BUT SLIGHTLY LOWER TO THE NORTHWEST. UPPER LOW OVER HILL
COUNTRY EXPECTED TO GRADUALLY MOVE TO NORTH TEXAS BY SUNDAY. VORT MAX
ASSOCIATED W/UPPER LOW SHOULD SWING ACROSS CWFA TONIGHT. HIGHER
TEMPS DUE TO LESS CLOUD COVER WEST OF OUR REGION WILL PROBABLY RESULT
IN DEVELOPING STORMS WHICH MAY GET ORGANIZED LATE THIS AFTERNOON.
SCATTERED STORMS NOW OVER NORTHERN HALF OF CWFA MAY BECOME MORE
NUMEROUS BY THIS EVENING DUE TO APPROACHING UPPER LEVEL IMPULSE. WE
SHALL CONTINUE WITH FLASH FLOOD WATCH THROUGH 6 AM SUNDAY MORNING.
WITH SATURATED SOIL DUE TO RAINFALL THE PAST SEVERAL DAYS...AND WITH
MANY CREEKS AND RIVERS AT OR NEAR BANKFULL...SLOW MOVING STRONG STORMS
WILL POSE A THREAT. GFS INDICATE UPPER LOW CONTINUING TO MOVE
NORTHEAST OUT OF TEXAS BY MONDAY BUT WEAK UPPER LEVEL TROUGHING
REMAINING. PW VALUES INDICATED TO REMAIN QUITE HIGH NEAR 2 INCHES THE
NEXT FEW DAYS THOUGH. ECMWF INDICATE UPPER RIDGE MOVING OVER REGION BY
THE MIDDLE OF NEXT WEEK AND ALSO THE GFS TO A LESSER EXTENT. TIME
CROSS SECTIONS FOR GFS INDICATE MOIST AIR MASS HANGING ON THE NEXT
SEVERAL DAYS. WE WILL CONTINUE WITH CURRENT FORECAST PACKAGE OF
GRADUALLY LOWERING POPS NEXT WEEK.

PRESSURE GRADIENT ACROSS MARINE WATERS SUPPORTING A LIGHT TO MODERATE
ONSHORE FLOW. THIS IS EXPECTED TO CONTINUE FOR THE NEXT SEVERAL
DAYS. EXCEPT FOR LOCALLY ROUGH SEAS AND HIGHER WINDS IN
THUNDERSTORMS...WINDS AND WAVES HEIGHTS EXPECTED TO BE BELOW CAUTION
LEVELS.

37/47

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
FFA ALL OF SE TX TXZ163-164-176>179-195>200-210>214-226-227-235>238.

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 85 74 87 74 / 90 70 40 50 40
HOUSTON(IAH)          74 85 74 86 74 / 90 60 40 50 40
GALVESTON (GLS)       74 84 75 85 75 / 80 50 40 50 40

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
345 PM CDT SAT JUN 26 2004

TXZ163-164-176>179-195>200-210>214-226-227-235>238-271200-
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-
345 PM CDT SAT JUN 26 2004

...FLOOD WATCH IN EFFECT FOR ALL OF SOUTHEAST TEXAS THROUGH
TONIGHT...

.DAY ONE...TONIGHT...
THE AIR MASS REMAINS VERY MOIST AND UNSTABLE OVER SOUTHEAST TEXAS.
THE UPPER DISTURBANCE OVER THE HILL COUNTRY WILL GRADUALLY MOVE
NORTHEAST AND WILL BE SITUATED OVER NORTH TEXAS BY SUNDAY. SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER SOUTHEAST
TEXAS THROUGH TONIGHT. SLOW MOVING STORMS WILL PRODUCE HEAVY RAINFALL.
GENERAL RAINFALL TOTALS OF 1 TO 3 INCHES WITH ISOLATED AMOUNTS OF 5
INCHES ARE POSSIBLE ESPECIALLY FOR THOSE AREAS NORTH OF INTERSTATE
HIGHWAY 10.

WITH AN ALREADY SATURATED GROUND SURFACE...ADDITIONAL HEAVY RAINFALL
WILL LEAD TO A FLOOD THREAT. RIVER FLOODING THAT WAS EITHER ONGOING OR
DEVELOPING WILL ADD TO THE FLASH FLOOD THREAT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.
THE CURRENT FLOOD THREAT COULD CONTINUE INTO SUNDAY AS CONDITIONS
REMAIN FAVORABLE FOR THE FORMATION OF MORE HEAVY RAINS. A WEAK UPPER
LEVEL TROUGH WILL REMAIN IN PLACE THROUGH MONDAY OVER THE LONE STAR
STATE. A LOWER CHANCE OF PRECIPITATION CAN BE EXPECTED TOWARD THE
MIDDLE OF NEXT WEEK AS AN UPPER LEVEL RIDGE OF HIGH PRESSURE STARTS TO
BUILD IN OVER OUR REGION.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS POSSIBLE TONIGHT.