Severe Thunderstorm Warning 192, NWS Houston/Galveston, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1026 AM CDT MON OCT 4 2004

.DISCUSSION...
FORECAST ISSUES FOR TODAY INCLUDE LOW CLOUDS AND FOG OVER THE WESTERN
COUNTIES AND POPS OVER THE NORTHERN COUNTIES THIS MORNING...THEN
TEMPERATURES AND POPS THIS AFTERNOON.

ON THE SYNOPTIC SCALE...SE TX WAS UNDER WEAK HIGH PRESSURE AT 850 AND
700 MB.  THE ENTRANCE REGION OF THE JET WAS OVER THE NORTHERN AREAS
INTO N TX OVER THE CURRENT MCS.  A TROUGH WAS OVER OK AND N TX WITH
MOISTURE POOLING UP ALONG THIS BOUNDARY AT 850 AND 700 MB.  FINALLY...
A VORTICITY MAXIMUM WAS MOVING THROUGH THE STATE AND WAS BEST SHOWN
BY THE ETA.  LOCALLY...THE 12Z SOUNDINGS SHOW MORE INSTABILITY AND
PW/S OVER THE NORTH AND WEST AROUND THE PERIPHERY OF THE HIGH.  LI/S
RANGED FROM -8 AT CRP TO -3 TO -6 AT SHV AND LCH.

THE VWP AND PROFILER DATA HINT AT THE FOG AND STRATUS CURRENTLY OVER
AN AREA FROM SOUTHERN MADISON COUNTY SOUTH-SOUTHWEST TO WESTERN
JACKSON COUNTY WHICH WAS TRAPPED UNDER THE WEAK CAP.  THIS FEATURE WAS
ALSO TRYING TO SPILL EASTWARD AND THE HIGH TOPO MAPS SHOW IT IS PRETTY
MUCH HUGGING THE RIVER VALLEYS. FEEL THAT IT WILL LIFT BY NOON...MAYBE
SOONER IF SOME HOLES CAN DEVELOP.

THE STORMS IN THE NORTH WERE MOVING SOUTHEAST AT ABOUT 25 MPH AND WILL
BE ARRIVING INTO HOUSTON COUNTY BEFORE 16Z.  SOME SMALL HAIL OR STRONG
GUSTY WINDS MAY BE POSSIBLE WITH THE STORMS...YET LIGHTNING WILL BE
THE MAJOR HAZARD AS THE LIGHTNING DATA WAS SHOWING A LOT OF POSITIVE
STRIKES IN THE CIRRUS SHIELD IN ADVANCE OF THE STRONGEST RADAR
ECHOES.

THIS AFTERNOON THE CAP SHOULD BE BROKEN WHEN TEMPERATURES REACH TO
NEAR 90.  THE OUTFLOW MOVING SOUTHEASTWARD WILL ALSO AID IN BREAKING
THE CAP.  THE HIGH ALOFT WAS WEAKER TODAY THAN YESTERDAY THOUGH IT
WILL HAVE SOME INFLUENCE OVER THE OUTFLOW.  STILL THINK THE BEST
RAIN CHANCES WILL BE MORE NORTH THAN SOUTH.  THE WEAK SURFACE FLOW AND
LACK OF CLOUD COVER OVER THE COASTAL AREAS WILL ALSO AID IN A SEA
BREEZE DEVELOPMENT.

WILL UP POPS TO THE LIKELY CATEGORY IN THE NORTH DUE TO CONDITIONS
EXPECTED OVER THE NEXT THREE TO FOUR HOURS.  WILL TWEAK THE CENTRAL
AND COASTAL AREAS UP BUT KEEP IN THE SCATTERED CATEGORY.

PL-40

&&

.AVIATION...
EXPECT THE AREA OF IFR AND MVFR CONDITIONS TO LIFT BY AROUND 17Z.
THE SEABREEZE MAY COLLIDE WITH THE OUTFLOW MOVING IN FROM THE NORTH
TO PROVIDE STORMS THIS AFTERNOON...THOUGH THAT MAY BE LATE IN THE DAY
GIVEN THAT THE INLAND TEMPERATURES ARE FAIRLY COOL AT THE MOMENT.
CURRENT VISIBLE SATELLITE DATA SHOWS A WEAK LINE OF CUMULUS FORMING
ALONG THE COAST FROM WEST GALVESTON BAY SOUTHWESTWARD INTO THE
MATAGORDA BAY AREA.  THE THUNDERSTORM OUTFLOW SHOULD MOVE THROUGH
AREAS NEAR OR EAST OF CLL AROUND 19Z THEN WORK ITS WAY THROUGH IAH IN
THE MID AFTERNOON PERIOD.

40/38

&&

.HGX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 88 68 82 66 83 / 60 50 50 30 40
HOUSTON (IAH)         91 71 84 67 84 / 40 40 50 30 40
GALVESTON (GLS)       88 76 84 75 84 / 30 30 50 30 40

&&

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
700 AM CDT MON OCT 4 2004

TXZ163-164-176>179-195>200-210>214-226-227-235>238-051200-
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-
700 AM CDT MON OCT 4 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT.
A SERIES OF WEAK SURFACE BOUNDARIES WILL COMBINE WITH A MOIST AND
UNSTABLE AIRMASS TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND TONIGHT. HAZARDOUS WEATHER IS NOT ANTICIPATED AT
THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.
LATE WEDNESDAY THROUGH SATURDAY...A SLOW MOVING UPPER LEVEL LOW
PRESSURE SYSTEM WILL COMBINE WITH DEEP TROPICAL MOISTURE FROM THE
GULF AND A SURFACE TROF ACROSS SOUTHEAST TEXAS TO BRING A THREAT FOR
HEAVY RAINFALL. CONSIDERABLE UNCERTAINTY STILL EXISTS ON EXACTLY HOW
MUCH RAIN WILL FALL AND WHERE EXACTLY THE HEAVIEST RAINFALL WILL
OCCUR. THE SITUATION WILL BE MONITORED AND MORE SPECIFIC INFORMATION
WILL BE AVAILABLE IN LATER FORECASTS.

EASTERLY WINDS OVER THE COASTAL WATERS WILL ALSO BRING POSSIBILITY OF
HIGHER THAN NORMAL TIDE LEVELS MAINLY FROM LATE WEDNESDAY THROUGH
FRIDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME.