000
FXUS64 KBRO 081135 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
535 AM CST SUN DEC 8 2013

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...IFR CONDITIONS HAVE DEVELOPED WITH LIGHT RAIN OVER THE
LOWER VALLEY. VISIBILITIES ALTHOUGH STILL VFR COULD BRIEFLY LOWER
TO MVFR THIS MORNING BEFORE THE RAIN PASSES TO THE NORTH. CIGS TO
RISE TO MVFR LATE MORNING AND SHOULD PERSIST THROUGH DAY BEFORE
BEGINNING TO LOWER THIS EVENING AS SOUTH WINDS INCREASE AT AROUND
2000 FEET. THE SOUTH WINDS INCREASE LOW LEVEL MOISTURE AND WARM
SURFACE TEMPERATURES THIS WILL ALLOW FOR LIGHT FOG TO DEVELOP AS
CEILINGS LOWER. TAFS INDICATED MVFR VSBY AND IFR CIGS BY OR
SHORTLY AFTER MIDNIGHT.

&&

.PREV DISCUSSION... /ISSUED 358 AM CST SUN DEC 8 2013/

SHORT TERM /NOW THROUGH MONDAY/...COLD AIR ADVECTION HAS JUST
ABOUT RUN ITS COURSE AND SHOULD BE ABATING SHORTLY AFTER SUNRISE.
TEMPERATURE TRENDS ARE UPWARDS THROUGH MONDAY AS THE NORTHWEST
WINDS STEADILY VEER NORTHEAST LATER TODAY BECOMING EAST TONIGHT
AND MONDAY.

TODAY AND TONIGHT...THE ARCTIC COLD HAS PEAKED BUT LINGERS THIS
MORNING AND SHOULD MOVE OUT OF THE REGION BY NOON. THE WIND CHILL IS
STILL RATHER LOW THIS MORNING SO HAVE EXTENDED THE ADVISORY UNTIL 9
AM WHEN TEMPERATURES BEGIN A SLOW INCREASE AND WINDS FINALLY LOWER.
WEAK CYCLOGENESIS TO TAKE PLACE OVER THE WESTERN GULF LATER TODAY
AND TONIGHT WITH A LOW PRESSURE TROUGH DIGGING INTO THE 4 CORNERS
AREA. THE LOW BEGINS TO DRIFT NORTHWARD APPROACHING THE COASTAL
WATERS. THIS WILL ALLOW WINDS TO VEER NORTHEAST TO EAST AND
INCREASING THICKNESS VALUES. AS A RESULT A SLOW INCREASE IN
TEMPERATURES COMMENCES. ISENTROPIC UPGLIDE DOES STRENGTHEN A BIT
KEEPING A PERSISTENT LOW CLOUD COVER WHICH WILL LIMIT THE HEATING
ACTUALLY TEMPERATURES WILL TAKE ALL DAY TO REACH MAXIMUMS AND MAY
CONTINUE TO INCH UPWARD OVERNIGHT WITH MODELS SUGGESTING MONDAY
MORNING LOWS AT ABOUT THE SAME AS SUNDAY HIGHS. WITH THE THICK CLOUD
COVER THE COLD MORNING TEMPERATURES AND COOL TEMPERATURES OVER THE
GULF HAVE KEPT THE DIURNAL RISE SLOW. RAIN CHANCES TO REMAIN LOW
TODAY WITH SOME INCREASE LATER TONIGHT WITH BEST CHANCE ALONG THE
COAST AND JUST INLAND AS THE ISENTROPIC LIFT STRENGTHENS AS THE LOW
STARTS TO WRAP UP.

MONDAY...AS THE SURFACE LOW/TROUGH APPROACHES THE COASTAL WATERS
MONDAY THICKNESSES CONTINUE TO RISE PUSHING TEMPERATURES UPWARD
ANOTHER NOTCH. IF THE MODELS ARE CORRECT IT COULD BE RATHER NICE
EVEN WITH CLOUDY SKIES AND SOME POSSIBLE LIGHT RAIN ACROSS THE
REGION. HAVE TRENDED WITH THE COOLER MAV NUMBER DUE TO THE CLOUD
COVER AND WILL NOT INDICATE LOW 70S OVER THE LOWER VALLEY JUST YET.
WINDS STAY NORTH AND MAY TURN NORTHWEST AS THE LOW APPROACHES WHICH
FAVORS A POSSIBLE QUICKER FRONTAL PASSAGE WHICH IS HIGHLIGHTED IN
THE THE LONG TERM.  RAIN CHANCES INCREASE AS THE ISENTROPIC LIFT
STRENGTHENS AS THE LOW APPROACHES THE COAST. CONFIDENCE IS LOW ON
HOW MUCH RAIN DEVELOPS THUS KEPT THE RAIN AMOUNTS RATHER LOW.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...EAST PAC RIDGE THAT
HAS BEEN TAPPING THE ARCTIC AIRMASS THE PAST FEW DAYS WILL BE IN
THE PROCESS OF BREAKING DOWN AS SHORTWAVE ENERGY DEEPENS THE
DOWNSTREAM TROUGH OVER THE SOUTHWEST AND BAJA AND A CLOSED LOW
TOPS THE CREST OF THE RIDGE. THIS WILL ESSENTIALLY KNOCK DOWN THE
RIDGE AND FLOW WILL BECOME MORE PROGRESSIVE ACROSS THE CONUS BY
FRIDAY WITH A COUPLE OF SHORTWAVE TROUGH EJECTING INTO THE
SOUTHERN PLAINS FRIDAY AND SATURDAY. FRESH HIGH PRESSURE WILL BE
NOSING INTO THE AREA BEHIND A COLD FRONT WITH COOLING TEMPERATURES
/UPPER 40S AND 50S FOR HIGHS TUESDAY/...AS SOUTHERN STREAM TROUGH
DEEPENS. THIS WILL INDUCE COASTAL TROUGHING WITH SLIGHT CHANCE TO
CHANCE POPS OVER THE COASTAL WATERS WITH LIGHT DRIZZLE OR LIGHT
RAIN IN THE INTERIOR SECTIONS MOST NOTABLY COASTAL SECTIONS. A
SLIGHT WARMING TREND WILL TAKE PLACE DURING THIS TIME FRAME WITH
HIGHS MAKING IT INTO THE MID 50S TO LOWER 60S BY THE END OF THE
WORK WEEK. THE SOUTHERN STREAM TROUGH EJECTS ON FRIDAY WITH POPS
INCREASING TO CHANCE MOST AREAS AND WILL SCOUR OUT MOST MOISTURE
FROM THE COLUMN BY SATURDAY. SKIES WILL BECOME PARTLY CLOUDY
INLAND AREAS BY SATURDAY AFTERNOON WITH ANOTHER COLD FRONT ON THE
HEELS OF THE LONG TERM PERIOD.

MARINE /TODAY THROUGH MONDAY/...HIGH PRESSURE HAS WEAKEN AND
NORTH WINDS AND SEAS CONTINUE TO LOWER. A MODERATE TO EVEN LIGHT
NORTH TO NORTHEAST WINDS TO DEVELOP LATER TODAY INTO TONIGHT.
WINDS TURN NORTHEAST TO EAST A DEVELOPING LOW PRESSURE TROUGH OR
WEAK LOW FORM JUST EAST OR OVER THE SOUTHEASTERN COASTAL WATERS
MONDAY. DEPENDING ON WHERE THE ACTUAL LOW DEVELOPS A STRONGER
PRESSURE GRADIENT IS EXPECTED OVER THE NORTHERN COASTAL WATERS
EAST OF PORT MANSFIELD LATER MONDAY. FARTHER SOUTH WEAKER WINDS
ARE EXPECTED. STRONGER OFFSHORE FLOW DEVELOPS MONDAY NIGHT OR JUST
AFTER THE END OF THE SHORT TERM. LOW RAIN CHANCES TONIGHT AND
MONDAY BUT TEMPERATURES INCREASE ABOUT 10 TO 15 DEGREES.

MONDAY NIGHT THROUGH THURSDAY...COLD FRONT WORKS THROUGH THE COASTAL
WATERS MONDAY NIGHT AND TUESDAY BRINGING STRONG NORTHERLY WINDS AND
HIGHER SEAS. MARINE CONDITIONS WILL BE HAZARDOUS THIS PERIOD WITH
WINDS UP TO 30 KNOTS AT TIMES AND SEAS 7 FEET OR MORE AS WELL.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR TXZ251-
     254>257.

GM...NONE.
&&

$$

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

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