Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 132037
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
337 PM CDT SUN APR 13 2014

.DISCUSSION...UPDATED FOR LATEST MARINE DISCUSSION BELOW.

&&

.MARINE...WITH EXPECTED STRONG NORTHERLY WINDS BEHIND THE COLD
FRONT MONDAY AFTERNOON THROUGH TUESDAY MORNING...WENT AHEAD AND
HOISTED A SMALL CRAFT ADVISORY FOR THE LAGUNA MADRE AND UPGRADED
TO A GALE WARNING OVER THE OFFSHORE WATERS. GUSTS TO 40 KNOTS IS
LIKELY ACROSS THE OFFSHORE WATERS WITH 30 KNOTS ACROSS THE LAGUNA
MADRE.

&&

.PREV DISCUSSION... /ISSUED 157 PM CDT SUN APR 13 2014/

SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...GOOD PLUME OF SOUTHERLY
MOISTURE FROM THE PACIFIC CONTINUES TO POUR EASTWARD INTO TEXAS THIS
AFTERNOON. LARGE-SCALE TROUGH CONTINUES TO PROGRESS EASTWARD ACROSS
THE US...WITH THE PLUME ON THE VERY SOUTHERN EDGE. THE NEXT COLD
FRONT IS RACING SOUTHWARD THROUGH THE TEXAS PANHANDLE ATTM AND WILL
CONTINUE ITS TREK TONIGHT AND TOMORROW. MORNING KBRO SOUNDING SHOWED
DEEP MOISTURE CONTINUES TO RACE NORTHWARD IN THE LOWER LEVELS...WITH
THE CAP AROUND 3500. DENSE CLOUD COVER WILL OCCUR AGAIN
TONIGHT...BUT SFC WINDS ARE EXPECTED TO REMAIN AROUND 10 KNOTS...SO
FOG FORMATION WILL BE TOUGH TO DEVELOP...EVEN WITH MOISTURE POOLING
AHEAD OF THE FRONT. THE FRONT ARRIVES TOMORROW AFTERNOON DURING PEAK
HEATING. MANY PIECES TRYING TO COME TOGETHER TO BRING THUNDERSTORM
ACTIVITY THIS FAR SOUTH. THE FRONT ITSELF WILL BRING A WELL-DEFINED
FOCUSING MECHANISM FOR LIFTING AT THE SFC. THE FRONT WILL ARRIVE MID
TO LATE AFTERNOON...SO SFC HEATING WILL BE AT A PEAK...ENHANCING SFC
INSTABILITY. MOST OF THE DYNAMICS ALOFT WILL BE WELL OFF TO THE
NORTHEAST INTO LOUISIANA BY THE TIME THE FRONT ARRIVES IN THE
AFTERNOON...SO INSTABILITY ALOFT WILL BE LOWER. MODELS ARE SHOWING
ELEVATED CAPE NUMBERS ABOVE 2000RIGHT ALONG THE COAST WHERE THE
FRONT REACHES THE COASTLINE THROUGH THE AFTERNOON. THE CONCERN IS
DRY AIR ENTRAINING FROM THE MIDLEVELS STRENGTHENING THE CAP. SOME
BRIEF WESTERLY FLOW FRO H7 TO H4 IS NOTED IN GFS DURING THE
AFTERNOON...STRENGTHENING THE CAP OUT WEST. THIS IS A REASONABLE
SOLUTION FOR OUR AREA THIS TIME OF YEAR...SO THE WESTERN VALLEY
COULD VERY WELL MISS OUT ON ANY RAINFALL /AGAIN/. WILL CONTINUE TO
SHOW SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ALONG THE
COAST...AND TAPERING BACK TO ISOLATED WEST OF US 281. DRIER AIR
ARRIVES TOMORROW EVENING...ENDING RAIN CHANCES AND ALLOWING TEMPS TO
FALL INTO THE UPPER 40S AND LOWER 50S BY DAWN TUESDAY.

LONG TERM /TUESDAY THROUGH SATURDAY/...STRONG HIGH PRESSURE WILL
RESIDE OVER SOUTH CENTRAL TEXAS TUESDAY...SUPPORTED BY A MID LEVEL
RIDGE UPSTREAM OVER THE SOUTHWEST. THIS HIGH PRESSURE WILL SHIFT
EAST AND THE RIDGE WILL FLATTEN ON TUESDAY...WITH MOSTLY SUNNY SKIES
AND MODERATE NORTH WINDS...AS WELL AS HIGH TEMPS IN THE 70S...10 TO
15 DEGREES BELOW NORMAL. QUIET WEATHER WILL CONTINUE TUESDAY NIGHT
WITH LIGHT WINDS AND LOW TEMPS IN THE 40S AND 50S...AGAIN 10 TO 15
DEGREES BELOW NORMAL. BY WEDNESDAY A MORE SEASONAL REGIME WILL SET
UP...WITH MODERATE SOUTHEAST WINDS...PARTLY CLOUDY SKIES AND HIGH
TEMPS RECOVERING SOMEWHAT BUT STILL A BIT BELOW NORMAL. MORE CLOUDS
WILL DEVELOP THURSDAY...BECOMING MOSTLY CLOUDY...AS MOISTURE FEEDS
ASHORE...WITH NEAR NORMAL TEMPERATURES OTHERWISE. LOOK FOR 80S
THURSDAY AND MID 60S THURSDAY NIGHT.

THE HERALDED FRONT WILL ARRIVE FRIDAY MORNING...WHOSE HIGH PRESSURE
AIR MASS HAD MOVED OUT OF CENTRAL CANADA AROUND MID WEEK. WINDS WILL
SHIFT TO NORTH WITH A CHANCE OF RAIN...BUT THERE WILL BE A LACK OF
UPPER SUPPORT...WITH MINIMAL CONSEQUENCES FOR THE CWA EXCEPT CLOUDY
SKIES AND A CHANCE OF LIGHT RAIN. AN EJECTING MID LEVEL TROUGH FROM
THE WEST...WITH SOME HELP FROM A SUBTROPICAL JET STREAK...COULD
IGNITE A FEW THUNDERSTORMS OVER THE SIERRA MADRE FRONT RANGE FRIDAY
NIGHT INTO SATURDAY AS IT LIFTS NORTHEAST ACROSS NEW MEXICO. SOME
INSTABILITY APPEARS TO CONTINUE SATURDAY NIGHT AND EVEN SUNDAY NIGHT
OVER THE MOUNTAINS. THE ABOVE IS PREDICATED ON THE CURRENT GFS RUN.
THE OLD ECMWF RUN IS MUCH WEAKER WITH ANY NEW AIR MASS BUT AMPLIFIES
THE CONVECTION AHEAD OF THE EJECTING TROUGH AND THEN KEEPS THE
TROUGH INVOLVED IN WEATHER MAKING WELL INTO THE WEEKEND. THE NEWER
ECMWF RUN JUST IN MATCHES A LITTLE BETTER WITH THE GFS.

MARINE...
TONIGHT THROUGH MONDAY EVENING...BREEZY CONDITIONS CONTINUE FOR THE
MARINE AREAS TODAY...AND SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH
SUNSET. WINDS WILL RELAX NEAR SHORE TONIGHT BUT REMAIN ELEVATED
AROUND 15 KNOTS FOR THE GULF WATERS OVERNIGHT. THE COLD FRONT IS THE
MAIN ISSUE TOMORROW. TIMING IS COMING OUT CONSISTENTLY FOR A LATE
AFTERNOON PASSAGE FOR THE MARINE ZONES. THE FRONT IS EXPECTED TO BE
ACCOMPANIED BY A SQUALL LINE WITH GUSTY NORTH WINDS AND OCCASIONAL
LIGHTNING. BEHIND THE FRONT...GUSTY NORTH WINDS WILL CONTINUE FOR
THE OVERNIGHT HOURS...WITH MORE FREQUENT GUSTS OF 35 KNOTS EXPECTED.
A GALE WATCH HAS BEEN HOISTED FOR THE GULF WATERS...WITH DEFINITE
SMALL CRAFT ADVISORIES FOR THE LAGUNA MADRE BEGINNING WITH FRONTAL
PASSAGE. BREEZY DUE NORTH WINDS WILL KICK SEAS UP TO 6 TO 10 FEET
OFFSHORE AND CAUSING ROUGH WATERS FOR THE LAGUNA MADRE.

TUESDAY THROUGH THURSDAY...STRONG HIGH PRESSURE WILL BUILD OVER THE
LOWER TEXAS COAST TUESDAY...WITH NORTH WINDS OF 25 KNOTS GUSTING TO
GALE FORCE AND WAVE HEIGHTS OF 10 FEET OFFSHORE. THE GRADIENT WILL
RELAX QUICKLY HOWEVER AS HIGH PRESSURE SHIFTS NORTHEAST AND PRESSURE
FALLS OCCUR OVER THE SOUTHERN HIGH PLAINS. SMALL CRAFT ADVISORY
CONDITIONS WILL END TUESDAY NIGHT WHILE WINDS VEER TO SOUTHEAST AND
SEAS LOWER. MODERATE SOUTHEAST WINDS AND SEAS WILL BE THE NORM ON
WEDNESDAY. HIGH PRESSURE FROM CANADA MOVING SOUTH OVER THE PLAINS
WILL STABILIZE THE PRESSURE GRADIENT BY FILLING IN A SOUTHERN PLAINS
STORM SYSTEM...MOVING INTO NORTH TEXAS WEDNESDAY NIGHT...WITH WIND
STRENGTH DECREASING OVER THE MARINE AREAS THURSDAY. THE FRONT COULD
REACH THE LOWER TEXAS COAST THURSDAY NIGHT OR FRIDAY MORNING...WITH
STRONG NORTH WINDS AND HIGHER SEAS ON FRIDAY...THOUGH THERE IS SOME
UNCERTAINTY IN THE MODELS AS TO THE EXTENT OF THE FRONT.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM MONDAY TO 10 AM CDT
     TUESDAY FOR GMZ130-132-135.

     GALE WARNING FROM 3 PM MONDAY TO 10 AM CDT TUESDAY FOR GMZ150-
     155-170-175.

&&

$$

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