Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 312036
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
236 PM CST SAT JAN 31 2015

.SHORT TERM /NOW THROUGH SUNDAY NIGHT/...

IMPACTS...
SHOWERS AND A RUMBLE OF THUNDER TONIGHT...STRONG FRONT SUNDAY NIGHT
WITH SIGNIFICANT MARINE IMPACTS.

RELEVANT FEATURES...
A LARGE CLOSED UPPER LOW CONTINUES TO SWIRL INTO NORTHWESTERN
MEXICO. BROADLY DIFFLUENT JET ACTIVITY AHEAD OF THAT LOW IS
LEADING TO MID LEVEL CLOUDINESS AND MODESTLY STEEPENING LAPSE
RATES OVER THE AREA. SURFACE LOW PRESSURE BUILDING AHEAD OF THE
TROUGH NEAR THE FOUR CORNERS AND THAT IS INTERACTING WITH HIGH
PRESSURE OVER APPALACHIA TO PRODUCE A RATHER BREEZY TO WINDY DAY
ACROSS THE AREA. WEAK PERTURBATIONS IN THE SOUTHWESTERLY FLOW OVER
MEXICO ARE HELPING GENERATE HEAVIER SHOWERS AND A THUNDERSTORM OR
TWO.

TONIGHT...
SUBTLE RIPPLES IN SOUTHWESTERLY JET FLOW OVER MEXICO ARE EXPECTED
TO MOVE OVERHEAD TONIGHT AMID BROADLY DIFFLUENT FLOW. INCREASING
LOW LEVEL MOISTURE ON SOUTHEASTERLIES WILL WORK WITH STEEPENING
UPPER LAPSE RATES TO HELP SPARK A FEW SHOWERS AND POSSIBLY A
RUMBLE OF THUNDER OR TWO...ESPECIALLY NORTH OF THE VALLEY THROUGH
THE OVERNIGHT. RAINFALL AMOUNTS SHOULD BE PRETTY LOW OVERALL BUT A
HEAVIER SHOWER COULD BRING A QUICK 0.25 TO 0.50 INCHES.

SUNDAY...
LOW LEVEL WINDS WILL SHIFT TO THE SOUTHWEST DURING THE DAY SUNDAY
WHICH MAY WORK WITH A FEW BREAKS IN MID AND UPPER LEVEL CLOUDINESS
TO PRODUCE RELATIVELY WARM AFTERNOON TEMPERATURES. CONTINUED HIGHS
AVERAGING AROUND 80 DEGREES AND KEPT RAIN CHANCES LIMITED TO NIL
WITH SOUTHWESTERLY WINDS SFC-850 DRYING THAT LAYER.

SUNDAY NIGHT...
WINDS SPEEDS WILL BACK OFF AS THE COLD FRONT APPROACHES IN THE
EVENING AND PAINTED AN AREA OF FOG STARTING EARLY IN THE EVENING
NEAR THE COAST AND IN PARTS OF THE METRO AREA. THE STRONG FRONT
PUSHES THROUGH IN THE LATE EVENING AND SWEEPS ACROSS THE ENTIRE
FORECAST AREA BY DAYBREAK. SOME SHOWER ACTIVITY AND POSSIBLY A
RUMBLE OF THUNDER OR TWO IS POSSIBLE ALONG AND JUST BEHIND THE
FRONT BUT WIND WILL VERY LIKELY BE THE MOST NOTICEABLE IMPACT FROM
THIS FRONT ASIDE FROM THE MUCH COOLER AND DRIER AIR.

NAM/GFS/ECMWF AND HIGH RES MODELS ARE IN GOOD AGREEMENT ON
SHOWING A VERY STRONG GRADIENT PUSHING ACROSS WITH THE FRONT AND
STRONG SFC- 850MB COLD ADVECTION WHICH WILL HELP MIX DOWN 40 TO 45
KNOT WINDS IN THAT LAYER MAKING GUSTS STRONGER. SURFACE WIND
SPEEDS ON LAND WILL LIKELY BE IN THE 15 TO 20 MPH RANGE...AROUND
25 MPH NEAR THE COAST AND THEN STRONGER OVER THE WATER. BAY AND
NEARSHORE WATER TEMPERATURES HAVE RECOVERED INTO THE LOW 60S...
WHICH IS CLOSE TO THE REPORT OF BUOY 42020 SO EXPECTING OBSERVED
WIND SPEEDS ON ALL WATERS TO BE CLOSER THAN PREVIOUS FRONTS THAT
HAD VERY COLD NEARSHORE WATER PRESENT. WITH SUSTAINED WINDS OF 28
TO 32 KNOTS AND GUSTS PUSHING 35 TO 40 LOOKING LIKE A GOOD BET
ISSUED A GALE WATCH FOR ALL WATERS FROM MIDNIGHT THROUGH MIDDAY
MONDAY. WIND ADVISORIES MAY ALSO BE NECESSARY FOR COASTAL COUNTIES
FOR PART OF THE FRONTAL PASSAGE. /68-JGG/

.LONG TERM /MONDAY THROUGH SATURDAY/...STRONG COLD FRONT WILL
SWEEP THROUGH DEEP SOUTH TEXAS SUNDAY NIGHT AND MONDAY SUPPORTED
BY A NORTHERN STREAM MID LEVEL S/W TROUGH DIVING THROUGH THE
SOUTH CENTRAL PLAINS. A DEVELOPING CUTOFF LOW OVER BAJA LOOKS LIKE
IT WILL HANG BACK AND BECOME MORE OF A PLAYER IN THE POST FRONTAL
ENVIRONMENT...SUPPORTING AN OVERRUNNING SCENARIO THE FIRST TWO TO
THREE DAYS OF THE WEEK...REPLEAT WITH LOW OVERCAST SKIES...LIGHT
RAIN...AND COLDER THAN AVERAGE TEMPERATURES.

BREEZY NORTH WINDS WILL OCCUR OVERNIGHT SUNDAY NIGHT INTO THE
MORNING ON MONDAY WITH SPEEDS OF 25-30 MPH POSSIBLE ALONG THE
COAST BY DAWN MONDAY. WILL BE NOTICEABLY COLDER THAN SUNDAY WITH
HIGH TEMPS MONDAY 20 TO 25 DEGREES COLDER...IN THE MID TO UPPER
50S WITH MID TO UPPER 40S MONDAY NIGHT. AT LEAST MODEST
PRECIPITATION CHANCES WILL ACCOMPANY THE FRONT AND IMMEDIATELY
BEHIND IT WITH BEST CHANCES IN THE MARINE AREAS WITH CHANCES
WANING BY MONDAY AFTERNOON. POPS WILL DECREASE MONDAY AFTER THE
FRONT AS SOME DRIER AIR WILL FOLLOW THE MAIN FRONT IN FROM THE
NORTH...BEFORE A GOOD OVERRUNNING SETUP OCCURS.

ATTENTION TURNS TO CUTOFF LOW MOVING ACROSS NORTHERN MEXICO
TUESDAY AND INTO TEXAS WEDNESDAY. THE AREA WILL BE IN A FAVORABLE
REGION OF UPPER LIFT MONDAY NIGHT THROUGH WEDNESDAY WITH GOOD
CHANCES OF LIGHT RAIN DURING THIS TIME PERIOD. GFS/ECMWF CLOSER IN
THE SOLUTIONS DURING THIS TIME PERIOD WITH THE ECMWF BEING A TICK
SLOWER THAN GFS. HIGH TEMPS TUESDAY WILL AGAIN BE IN THE
50S...WITH TUESDAY NIGHT LOWS NOT DECREASING THAT MUCH...JUST A
FEW DEGREES AS SOME OF THE HEAVIEST RAIN CHANCES OCCUR AND THE
COLDER AIR QUICKLY MODIFIES. RAIN WILL END FROM WEST TO EAST
WEDNESDAY AS SUBSIDENCE BUILDS IN ON THE BACKSIDE OF DEPARTING MID
LEVEL LOW. HIGHS TUESDAY WILL BE SIMILAR TO MONDAY WITH CLOUDY AND
RAINY CONDITIONS BUT MAY SEE THE SUN ON WEDNESDAY WHICH WILL BOOST
HIGHS INTO THE 60S FOR WEDNESDAY. ANOTHER COLD FRONT IS ON TAP FOR
THURSDAY WITH COOLER HIGHS FOR THURSDAY AND FRIDAY BACK INTO THE
LOWER 60S. THE UPSTREAM RIDGE BUILDING OVER THE WEST WILL RESULT
IN THE THURSDAY FRONT BEING MORE OF A GLANCING BLOW AND...WITHOUT
ANYTHING TO THE WEST...A MUCH DRIER PATTERN WILL EVOLVE LATER IN
THE WEEK.

&&

.MARINE...
NOW THROUGH SUNDAY NIGHT...BREEZY SOUTHEAST WINDS ARE FORECAST
THROUGH TONIGHT ON THE GULF OF MEXICO WATERS. MORE MODERATE WINDS
ARE FORECAST SUNDAY AND VERY EARLY SUNDAY EVENING BEFORE A
POWERFUL COLD FRONT SWEEPS ACROSS THE LOWER TEXAS COAST SUNDAY
EVENING. A GALE WATCH HAS BEEN ISSUED FOR FREQUENT GUSTS TO GALE
FORCE FOR ALL LOWER TEXAS COASTAL WATERS. SEAS WILL QUICKLY BECOME
VERY ROUGH BEHIND THE PASSAGE OF THE FRONT.

MONDAY THROUGH WEDNESDAY...A STRONG COLD FRONT WILL MOVE THROUGH
THE LOWER TEXAS COASTAL WATERS LATE SUNDAY NIGHT INTO EARLY MONDAY
MORNING. STRONG NORTH WINDS WITH A FEW HOURS OF GUSTS TO GALE
FORCE WILL DEVELOP SUNDAY NIGHT INTO MONDAY IN THE WAKE OF THE
FRONT. WINDS AND SEAS WILL REMAIN HIGH THROUGH LATE MONDAY AS HIGH
PRESSURE SPREADS RAPIDLY ACROSS THE LOWER TEXAS COAST. A COASTAL
LOW/TROUGH WILL THEN DEVELOP ACROSS THE WESTERN GULF OF MEXICO ON
TUESDAY AS OFFSHORE WINDS VEER MORE TO THE EAST. UNSETTLED WEATHER
WILL HANG ON THROUGH TUESDAY OR WEDNESDAY DUE TO THE PROXIMITY OF
THE OFFSHORE LOW...BUT THE STRONGEST WINDS AND HIGHEST SEAS
ASSOCIATED WITH THE LOW WILL REMAIN JUST BEYOND THE LOCALLY
FORECASTED MARINE ZONES.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  62  77  55  55 /  30  10  40  20
BROWNSVILLE          62  79  55  56 /  30  10  40  20
HARLINGEN            62  81  53  56 /  30  10  40  20
MCALLEN              61  83  53  58 /  40  10  40  20
RIO GRANDE CITY      60  83  53  59 /  50  10  30  20

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...GALE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY MORNING FOR
     GMZ130-132-135-150-155-170-175.

&&

$$

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