Red Flag Warning 5, NWS Brownsville, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
328 AM CST WED DEC 26 2007

.DISCUSSION...MAIN CHALLENGE THIS FORECAST CYCLE IS TIMING AND WEATHER
ASSOCIATED WITH AT LEAST 3 OR 4 COLD FRONTS FROM TODAY THROUGH
NEW YEARS DAY. OVERALL NORTH AMERICAN UPPER FLOW PATTERN CONTINUES
TO BE VERY PROGRESSIVE WITH A VERY FAST GENERAL ZONE FLOW. SHORTWAVES
WITHIN THIS FLOW ARE CROSSING THE CONUS APPROXIMATELY EVERY 72 TO
84 HOURS WHICH BRINGS A COLD FRONT THROUGH DEEP SOUTH TEXAS ABOUT
EVERY 48 HOURS. WITH THE GENERAL WEST TO EAST FLOW OF THESE FRONTS
AND UPPER TROUGHS...COLD AIR TRAPPED OVER THE CENTRAL AND NORTHERN
PLAINS WILL HAVE A HARD TIME REACHING THIS FAR SOUTH.
HOWEVER...VERY DRY AIR ASSOCIATED WITH THE ENSUING AIRMASS WILL
ALLOW FOR COOL TO COLD NIGHTS BUT MILD DAYS WITHIN 24 HOURS OF A
FRONTAL PASSAGE. A QUICK RETURN FLOW WILL MAKE THE DRY AIR SHORT
LIVED UNTIL THE NEXT FRONTAL PASSAGE. THE STRONGEST FRONT OF THE
SERIES IS STILL ON TRACK FOR NEW YEARS DAYS.

TODAY/S FRONT IS ON SCHEDULE TO TRACK ACROSS DEEP SOUTH TEXAS
AND THE RIO GRANDE VALLEY A FEW HOURS EITHER SIDE OF NOON. THE
FRONT CURRENTLY IS APPROACHING THE WESTERN HILL COUNTRY WITH
DEWPOINTS IN THE UPPER 20S. SOUTH WINDS IN ADVANCE OF THE FRONT
HAS ALLOW FOR DEWPOINTS TO SURGE INTO THE 50S AND 60S. SOME
SHOWERS ASSOCIATED WITH THE BRISK LOW LEVEL JET...ARE SHOWING UP
ON RADAR OVER THE COASTAL COUNTIES. THE QUICK MOVEMENT OF THE
SHOWERS AND THE EASTWARD PROGRESS OF THE UPPER TROUGH SHOULD PUSH
MUCH OF THE SHOWERS INTO THE GULF BY SUNRISE...BUT WILL MAINTAIN
THE LOW POPS THROUGH MID MORNING FOR THE FAR EASTERN AREAS. BREEZY
TO WINDY CONDITIONS HAVE DEVELOPED OVERNIGHT WITH THE STRENGTHENING
OF THE LOW LEVEL JET. BREEZY CONDITIONS ALONG THE COAST ARE
EXPECTED TO PERSIST THIS MORNING BEFORE BRIEFLY TAPERING OFF
BEFORE THE FRONT PASSES. BREEZY NORTH WINDS ARE EXPECTED BEHIND
THE FRONT. TEMPERATURES HAVE BEEN RISING OVERNIGHT DUE TO THE LOW
LEVEL JET AND WITH THE LOW CLOUD DECK TO PUSH EAST THIS MORNING
TEMPERATURES SHOULD CLIMB ABOVE GUIDANCE VALUES. DRY AIR SHOULD
FILTER INTO THE REGION WITH THE PREFRONTAL TROUGH MID MORNING WITH
NORTHERN WINDS MOVING OFF THE COAST BETWEEN NOON AND 2 PM.
LOWERING HUMIDITIES AND GUSTY WINDS WILL ALLOW FOR BORDER LINE RED
FLAG WARNING CRITERIA. CONCERNS WITH DRY GRASS AND LITTLE TO NO
RAIN OVER THE LAST SEVERAL WEEKS AND LOCAL SUGAR BURNS AND
FIREWORKS WILL PROMPT A RED FLAG WARNING FROM LATE MORNING THROUGH
THE AFTERNOON. LOW DEWPOINTS AND LOWERING WINDS TONIGHT WILL ALLOW
FOR TEMPS TO DROP AND WILL LIKELY GO A FEW DEGREES UNDER GUIDANCE
AS HAS BEEN THE CASE THE LAST SEVERAL FRONTS.

RETURN FLOW STARTS UP AGAIN THURSDAY ALONG WITH AN INCREASE IN
CIRRUS CLOUDS AS THE SUBTROPICAL JET ADVANCES NORTHWARD. NEXT
FRONT POISED FOR FRIDAY MORNING WITH SIMILAR CONDITIONS AS TODAY/S
FRONT. THE ONLY DIFFERENCE WITH THIS FRONT WOULD BE THE
PERSISTENCE OF HIGH CLOUDS WHICH MAY MAKE THE HIGH TEMPERATURE
FORECAST TRICKY. A LOWERING AND THICKENING OF THE CLOUDS WOULD BE
IN ORDER SATURDAY WITH THE EAST TO SOUTHEAST WINDS RETURNING IN
ADVANCE OF THE NEXT UPSTREAM UPPER TROUGH. THE FRONT ON SUNDAY
LOOKS THE WEAKEST OF THE WEEKLY SERIES WITH THE STRONG FRONT
ADVANCING SOUTH ON NEW YEARS DAY. BOTH MED RANGE MODELS...GFS AND
ECMWF...CONTINUE TO SUGGEST A 1040MB+ SURFACE HIGH TO MOVE INTO
TEXAS WHICH SHOULD USHER IN SOME MUCH COOLER AIR. CONFIDENCE
REMAINS IN THE MEDIUM RANGE AT THIS TIME WITH MODEL IN FAIR
AGREEMENT THIS FAR OUT.

&&

.AVIATION...MVFR CLOUD DECK CURRENTLY MOVING THROUGH WITH WEAK
IMPULSE WILL CLEAR THE LAND PORTIONS OF DEEP SOUTH TEXAS IN THE NEXT
COUPLE HOURS. THE IMPULSE IS ALREADY EAST OF MFE...WHICH IS NOW
SHOWING CLEAR SKIES. MOSTLY CLEAR SKIES WILL REMAIN FOR THE REST OF
THE OVERNIGHT INTO THE EARLY MORNING HOURS. WINDS WILL REMAIN AROUND
10KTS...BUT SHEAR TROUBLES EXIST AS WINDS ARE 30KTS AT 1KFT AND
40KTS AT 3KFT. A COLD FRONT IS EXPECTED TO SWEEP THROUGH BY NOON
TODAY...SWITCHING WINDS TO THE NORTHWEST AND INCREASING TO AROUND
20KTS AT THE SFC.

&&

.MARINE...AT 1AM BUOY020 REPORTED SOUTHEAST WINDS AT 23G29KTS AND
SEAS 6 FEET. PRESSURE GRADIENT CONTINUES TO TIGHTEN DUE TO
APPROACHING COLD FRONT. SMALL CRAFT ADVISORIES CONTINUE FOR THE
OUTER WATERS ZONES WITH SCEC NEEDED FOR NEARSHORE WATERS. WINDS WILL
NOT REACH SCEC FOR THE LAGUNA. THE WINDS WILL BRIEFLY DECREASE JUST
BEFORE THE FRONT ARRIVES. THE COLD FRONT WILL REACH THE REGION NO
LATER THAN NOON LOCAL TIME...WITH WINDS SHIFTING TO THE NORTHWEST
AND INCREASING TO 20 TO 25 KNOTS AGAIN. SCA WILL BE NEEDED FOR ALL
THE COASTAL WATERS ZONES...INCLUDING THE LAGUNA. SEAS WILL
RESPOND...INCREASING TO AROUND 7 FEET AT THE BUOY AND 5 FEET NEAR
SHORE. HIGH PRESSURE WILL QUICKLY MOVE IN BEHIND THE FRONT...LETTING
WINDS QUICKLY DECREASE AND HALTING THE INCREASE OF SEAS. WINDS WILL
TURN TO THE NORTHEAST BY NOON TOMORROW...AND CONTINUE TURNING TO THE
SOUTHEAST BY TOMORROW EVENING. SOUTHEAST FLOW WILL AGAIN INCREASE
THURSDAY NIGHT IN RESPONSE TO THE NEXT IN A SERIES OF COLD FRONTS
MOVING THROUGH THE REGION. THE NEXT FRONT WILL SWEEP THROUGH FRIDAY
MORNING...WITH ANOTHER ROUND OF GUSTY NORTHWEST WINDS AND INCREASED
SEAS.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  74  50  74  58 /  10   0   0  10
BROWNSVILLE          77  48  73  60 /  10   0   0  10
HARLINGEN            76  45  74  59 /  10   0   0  10
MCALLEN              75  45  74  54 /   0   0   0  10
RIO GRANDE CITY      71  42  71  49 /   0   0   0   0
SOUTH PADRE ISLAND   72  55  72  59 /  10   0   0  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...RED FLAG WARNING FROM 11 AM THIS MORNING TO 6 PM CST THIS
     AFTERNOON FOR TXZ248>257.

GM...SMALL CRAFT ADVISORY FOR WINDS FROM NOON TODAY TO 6 PM CST THIS
     AFTERNOON FOR GMZ130-132-135-150-155.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 PM CST THIS AFTERNOON FOR
     GMZ170-175.

&&

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WWW.WEATHER.GOV/BROWNSVILLE

59/64

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BROWNSVILLE TX
942 PM CST TUE DEC 25 2007

TXZ248>257-270345-
ZAPATA-JIM HOGG-BROOKS-KENEDY-STARR-HIDALGO-INLAND WILLACY-
INLAND CAMERON-COASTAL WILLACY-COASTAL CAMERON-
942 PM CST TUE DEC 25 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR DEEP SOUTH TEXAS.

.DAY ONE...TONIGHT.

SMALL CRAFT ADVISORY FOR WINDS ACROSS THE OFFSHORE WATERS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

SMALL CRAFT ADVISORY FOR WINDS WEDNESDAY AS A COLD FRONT MOVES THROUGH.

SMALL CRAFT ADVISORY POSSIBLE THURSDAY NIGHT AND FRIDAY WITH ANOTHER
COLD FRONT.

SMALL CRAFT ADVISORY POSSIBLE WITH A THIRD FRONT NEXT MONDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.