Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 201146 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
546 AM CST THU NOV 20 2014

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

&&

.AVIATION...CLOUD COVER WILL REMAIN BKN TO OVC TODAY WITH CIGS
RUNNING 3500 TO 5000. SOME LIGHT DZ IS EXPECTED TO
CONTINUE...ESPECIALLY THIS MORNING ALONG THE COAST...BUT WILL NOT
ADVERSELY AFFECT VISIBILITY OR CIGS. WINDS TODAY WILL BE FROM THE
SE 15G25KTS. LIGHTER WINDS WILL RETURN OVERNIGHT...WITH INCREASED
LLVL SHEAR POSSIBLE IN THE FIRST 1000 FEET DUE TO FORECAST 1000 FT
WINDS OF 30 TO 40KTS AND NEARLY CALM SFC WINDS. CLOUD COVER WILL
CONTINUE OVERNIGHT...BUT WILL GENERALLY REMAIN ABOVE 2000 FEET.

&&

.PREV DISCUSSION... /ISSUED 401 AM CST THU NOV 20 2014/

SHORT TERM /TODAY THROUGH FRIDAY/...SHORT TERM FORECAST WILL BE
DOMINATED BY ONSHORE FLOW FROM THE SOUTHEAST CONTINUING TO PUMP
GULF MOISTURE BACK INTO THE REGION AT LOW LEVELS. MODELS CONTINUE
TO SHOW THAT MOISTURE REMAINS AT LOW LEVELS...GENERALLY BELOW
10000 FEET. LOOKING AT ISENTROPIC LAYERS...BEST UPGLIDE TIMES
ARRIVE LATE THIS MORNING AND AGAIN DURING THE AFTERNOON FRIDAY.
MAIN RESULT WILL BE PATCHY DRIZZLE CONTINUING AREAWIDE
TODAY...WITH DECREASES OVERNIGHT BEFORE RETURNING TOMORROW
MORNING. A LITTLE BIT OF INSTABILITY NOTED IN THE LOWEST LAYERS ON
FRIDAY MAY PROVIDE ISOLATED THUNDER DURING THE AFTERNOON.

EVEN WITH CONSIDERABLE CLOUD COVER EXPECTED TODAY AND TOMORROW...HIGH
TEMPERATURES WILL CONTINUE TO RECOVER BACK TO NEAR NOVEMBER
NORMALS. HIGHS TODAY WILL REACH THE MID TO UPPER 70S...WHICH IS
RIGHT AROUND NORMAL...WHILE FRIDAY RECOVERS A COUPLE MORE DEGREES
TO RIGHT AROUND 80. LOW TEMPERATURES TONIGHT WILL ONLY FALL INTO
THE LOW 60S...WHICH IS RIGHT NEAR NORMAL...AND WILL BE THE
WARMEST NIGHTTIME LOWS IN THE PAST 2 WEEKS.

LONG TERM.../FRIDAY NIGHT THROUGH THANKSGIVING DAY/...THE
EXTENDED IS A TALE OF TWO TRENDS. A WARMING AND BREEZY TREND
CONTINUES AT THE BEGINNING OF THE LONG TERM WITH A SMALL WINDOW FOR
A LINE OF THUNDERSTORMS FOLLOWED BY A COOLING AND MUCH DRIER TREND
ENDING UP WITH A PLEASANT THANKSGIVING DAY.

FRIDAY NIGHT THROUGH SATURDAY...MODELS REMAIN IN GOOD AGREEMENT AND
CONSISTENCY WITH THE ADVERTISED MID LEVEL SHORTWAVE MOVING IN FROM
THE PAC NW AND DIVING SOUTHEAST INTO THE SOUTHWEST DESERTS FRIDAY
AND TRAVERSING TEXAS SATURDAY. CONFIDENCE REMAINS BELOW AVERAGE FOR
A LINE OF THUNDERSTORMS TO MOVE ACROSS THE CWA LATER SATURDAY AS THE
BASE OF THE SHORTWAVE MOVES INTO SOUTH TEXAS. MODELS CONTINUE TO
GENERATE HIGHER POPS AND INDICATE BETTER AVAILABILITY OF MOISTURE AND
JET DYNAMICS TO THE NORTHEAST OF THE RGV AS WELL AS SHOWING SIGNS OF
STRENGTHENING THE CAPPING INVERSION AS THE SOUTHWEST WINDS INCREASE
AOB 850MB. LATEST SWODY2 FROM SPC ALSO INDICATES THE MORE ENHANCED
CHANCE OF SEVERE WEATHER NORTH AND EAST OF DEEP SOUTH TEXAS. STILL
CAN NOT RULE OUT A FEW STRONGER STORMS WITHIN A LINE. POPS ON
SATURDAY AFTERNOON INTO EARLY SAT EVENING REMAIN IN THE 20-30
PERCENT RANGE MAINLY NORTHEAST AND EASTERN AREAS. OTHER SENSIBLE
WEATHER WILL CONSIST OF BREEZY TO WINDY CONDITIONS AND MUCH ABOVE
AVERAGE TEMPERATURES.

SATURDAY EVENING AND SUNDAY...THE PASSAGE OF THE MID LEVEL SHORTWAVE
SWINGS A DRYLINE/PACIFIC FRONT THROUGH THE REGION WITH A MUCH DRIER
AIRMASS IN ITS WAKE. THE DRIER AIR INITIALLY ALLOWS TEMPERATURES
TO LOWER ABOUT 10 DEGREES FROM SATURDAY MORNING. ON SUNDAY A BRIEF
RETURN OF SUMMER AS TEMPERATURES CLIMB INTO MID TO UPPER 80S AND
MAY APPROACH 90 ALONG THE UPPER RIO GRANDE. 850 TEMPS CLIMB TO 18C
AND WEST TO SOUTHWEST DOWNSLOPE COMPRESSES THE ALREADY DRY
AIRMASS.

MONDAY THROUGH THANKSGIVING DAY...THE GENERAL TREND THROUGH THIS
PERIOD WILL BE FOR COOL AND DRIER CONDITIONS. A GRADUAL COOLING
TREND TAKES PLACE AS A BROAD TROUGH TAKES SHAPE OVER THE EASTERN TWO
THIRDS OF THE COUNTRY. THE GFS AND ECMWF SOLUTIONS DIVERGE WITH THE
GFS MORE AGGRESSIVE WITH A RIDGE OVER THE WESTERN HALF OF THE CONUS
WHILE THE ECMWF MAINTAINS A BROAD TROUGH WITH AS A SERIES OF
SHORTWAVES MOVING IN FROM THE PAC NW. WITH THE TROUGH SOLUTION BEING
THE TREND FOR THE LAST FEW WEEKS WILL CONTINUE LEANING IN THIS
DIRECTION AS DOES WPC`S OFFICIAL FORECAST. WITH THE UPPER TROUGH IN
PLACE SOUTH TEXAS WILL BE UNDER A DRY NORTHWEST FLOW WITH COOLER
SURFACE HIGH PRESSURE BUILDING OVER THE REGION. NO DRASTIC
TEMPERATURES BUT EXPECT A LARGE DIURNAL SWINGS TO DEVELOP RANGE WITH
COOL NIGHTS AND MILD DAYS. TEMPERATURES BOTTOM OUT TUESDAY AND
WEDNESDAY BEFORE A SLIGHT RECOVERY ON TURKEY DAY AS WINDS RETURN
FROM THE SOUTHEAST.

MARINE...TODAY THROUGH FRIDAY...SFC HIGH PRESSURE REMAINS ENTRENCHED
ACROSS THE NORTHERN GULF THROUGH THE NEXT 36 HOURS. THE GRADIENT
BEGINS TO INCREASE TODAY...WITH WINDS REACHING 15 TO 20 KNOTS
TODAY AND LIKELY RIGHT AROUND 20 KNOTS THROUGH THE DAY TOMORROW.
SEAS HAVE BEEN FLUCTUATING RIGHT AROUND 4 FEET...AND WILL BEGIN TO
REBUILD DURING THE NEXT 36 HOURS WITH THE INCREASE IN WINDS
FORECAST. LIGHT RAIN AND DRIZZLE WILL CONTINUE FOR THE MARINE
ZONES TODAY AND AGAIN TOMORROW.

FRIDAY NIGHT THROUGH TUESDAY...SOUTHERLY FLOW INCREASES FRIDAY
NIGHT INTO SATURDAY AS LOW LEVEL JET STRENGTHENS IN ADVANCE OF A
STRONG MID LEVEL STORM SYSTEM. ON GOING SMALL CRAFT ADVISORY
CONDITIONS ARE LIKELY AND WILL PERSIST WELL INTO SATURDAY EVENING.
A PACIFIC FRONT MOVES THROUGH THE COASTAL WATERS SATURDAY NIGHT
WITH WINDS BRIEFLY TURNING WEST THEN SOUTHWEST SUNDAY. WINDS AND
SEAS BEGIN TO TAPPER DOWNWARD WITH IMPROVING CONDITIONS. CANADIAN
HIGH PRESSURE THEN BUILDS SOUTHWARD TURNING WINDS TO THE NORTH
MONDAY AND TUESDAY. A SLIGHT INCREASE IN WINDS IS ANTICIPATED
TUESDAY AS THE GRADIENT STRENGTHENS SMALL CRAFT ADVISORIES MAY BE
NECESSARY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

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

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