Severe Thunderstorm Warning 30, NWS Brownsville, TX

DEEP SOUTH TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
210 PM CDT SAT SEP 14 2002

88D LOOP SHOWS A FEW SEA BREEZE SHRA OVER SERN CAMERON COUNTY...WITH
A LINE OF SHRA JUST SOUTH OF THE COASTAL WATERS BARELY EXTENDING
INTO EXTREME NORTHEASTERN TAMAULIPAS. THE LINE OF SHRA APPEARS TO BE
ASSOCIATED WITH AN WEAKENING OUTFLOW BNDRY APPROACHING FROM THE
SOUTH. VAD WIND PROFILE SHOWS 10 PERCENT POP IN THE AM ZFP STILL
LOOKS GOOD. IN WV IMAGERY...WEAK MID LEVEL CIRCULATION CAN BE
RESOLVED OVER SOUTHERN TAMAULIPAS. A WEAK UPPER LEVEL RIDGE IS
LOCATED OVER NERN MX...WHICH IS KEEPING THE DEEPER TROPICAL MOISTURE
TO THE SOUTH FOR NOW. ANOTHER WEAK MID LEVEL CIRCULATION CAN BE SEEN
OVER THE BAY OF CAMPECHE MOVING WESTWARD. THIS FEATURE APPEARS TO
HAVE SEPARATED FROM THE H5 TROF OVER THE NORTHERN GULF. MODELS DONT
APPEAR TO RESOLVE THIS FEATURE. TO THE N...POSITIVELY TILTED H5 TROF
EXTENDS FROM THE CENTRAL PLAINS INTO THE DESERT SW. SFC COLD FRONT
WAS MOVING SOUTHWARD THRU KS AND NM AROUND NOON. AVN AND ETA BOTH
INITIALIZE WELL WITH RESPECT TO THE 18Z FRONTAL POSITION.

SHORT TERM...WITH POSITIVELY TILTED H5 TROF TO THE N...MODELS HAVE
BACKED OFF TO A MORE CLIMATOLOGICAL SOLUTION WITH RESPECT TO THE SFC
FRONT TO THE N DURING THE NEXT FEW DAYS. WILL BUMP UP POPS 10
PERCENT TOMORROW...WHICH IS STILL 10 PERCENT BELOW THE MAV
GUIDANCE...THE LOWEST IN THE SUITE OF MOS GUIDANCE. ETA MOS ACTUALLY
GOES FOR 80 PERCENT AT BRO TOMORROW...BUT BELIEVE AVN HAS HANDLE ON
SUBSIDENCE NEAR THE H5 RIDGE AXIS...WHICH SHOULD SUPPRESS WIDESPREAD
CONVECTION TOMORROW. WITH SE SFC FLOW...BELIEVE DIURNALLY DRIVEN SEA
BREEZE CONVECTION WILL ENHANCE AS IT MOVES WESTWARD...SO WILL PLACE
BEST POPS OUT WEST. WILL PLACE PM WORDING FOR CONVECTION DURING THE
NEXT TWO OVERNIGHT PERIODS. WITH DEEPER MOISTURE AVAILABLE MON AND
TUE...WILL GO WITH CHANCE POPS CWA WIDE. AGAIN...BELIEVE CONVECTION
WILL BE DIURNALLY DRIVEN. WILL GO A BIT HIGHER DURING THE OVERNIGHT
HOURS AS LOW LEVEL MOISTURE INCREASES WITH SE FLOW. THIS FAVORS THE
MAV NUMBERS.

LONG TERM...WED STILL LOOKS MOIST AFTER BNDRY TO THE N FALLS
APART...THEN NW FLOW AT H5 BEGINS DRYING OUT THE CWA. WILL GO WITH
LOW END CHANCE POPS WED...THEN SLIGHT CHANCE POPS FOR WEAKER SEA
BREEZE CONVECTION THU AND FRI. MRF TRIES TO BLAST ANOTHER COLD FRONT
THRU THE CWA FRI...BUT WILL DISCARD THIS SOLUTION FOR SOMETHING
CLOSER TO CLIMO. MOISTURE POOLING TO THE SOUTH OF THIS BNDRY SHOULD
ALLOW FOR AT LEAST SLIGHT CHANCE POPS NEXT SAT.

MARINE...AT NOON TIME BUOY020 REPORTED SE WINDS 8-10 KTS WITH SEAS 2
FT AT 7 SEC. AT 1 PM BUOY002 REPORTED SE WINDS 6 TO 10 KTS WITH SEAS
3 FT AT 7 SEC. W3 GUIDANCE CALLS FOR SEAS ARND 2 FT THRU PD WITH LGT
TO MDT SE FLOW. IN THE SHORT TERM...SWAPS GUIDANCE CALLS FOR MOSTLY
2 TO 4 FT TONIGHT THRU SUN. UPPER LEVEL SYSTEM MOVG THRU CNTRL
PLAINS WILL PULL A SFC BNDRY INTO CTNRL TX BY MID DAY SUN. FRONT
SHOULD DISSIPATE OVER THE HEART OF THE STATE BY MON. SFC WIND ACRS
DPSOTEX COASTAL WATERS WILL BE SE AND LGT TO MDT. WITH FLOW OVER NW
GULF BACKING FROM W TO SE TDA...WAA WILL RESULT IN AN INCREASE IN
LOW LEVEL MOISTURE THRU MON. SOME RW MOVED INTO SRN PORTION OF
COASTAL WATERS THIS MORNING ALONG THE LEADING EDGE OF THIS MOISTURE
POOL...AND MORE ARE BEING DETECTED BY RADAR OVER THE NE MEX GULF
WATERS THIS AFTN. MID AND UPPER LEVEL WINDS WILL ADVECT PAC MOISTURE
OVER THE AREA MON THRU THU...LEADING TO SCT TRW/RW SUN THRU THU. THE
NEXT SFC BNDRY APPROACHES THE COASTAL WATERS LATE THU. EXPECT WINDS
AND SEAS TO REMAIN BELOW SCA CRITERIA THRU FCST PD.

.PRELIMINARY NUMBERS...
BRO BB 077/093 077/092 077 05/20/10/30/20
HRL BB 075/094 075/093 075 05/20/10/30/20
MFE BB 076/093 076/092 076 10/30/20/40/30
RGC BB 075/093 075/092 075 10/30/20/40/30
SPI BB 078/087 079/087 079 05/20/10/30/20

SYNOPTIC...MCELROY
AVIATION-MARINE-MESO...SIERRA

INTERNET ADDRESS...WWW.SRH.NOAA.GOV/BRO

.BRO...NONE.