Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 182321 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
621 PM CDT THU SEP 18 2014

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

&&

.AVIATION...DEEP SOUTH TEXAS AVIATION WEATHER REMAINS TRANQUIL
WITH ONLY FEW TO SCT AT 035 AND SOME CIRRUS BLOWOFF FROM STORMS
WELL TO THE NORTH. EXPECT WINDS TO LOWER TO 5 TO 10 KNOTS AFTER
SUNSET AND CONTINUE THROUGH THE NIGHT. AS WITH THIS MORNING...LOW
CLOUDS MAY BRIEFLY BE AN ISSUE AT DAWN...AS INVERSION SETS UP
AROUND 3500...CONVERTING CIGS TO AROUND 2500. A FEW SHOWERS ARE A
POSSIBILITY AT DAWN BUT WILL BE VERY ISOLATED IN NATURE.

&&

.PREV DISCUSSION... /ISSUED 254 PM CDT THU SEP 18 2014/

SHORT TERM... /TONIGHT THROUGH FRIDAY NIGHT/...PLENTY OF RICH GULF
MOISTURE TRAPPED UNDER THE MID LEVEL HIGH PRESSURE RIDGE BUT LITTLE
IN THE WAY OF A SIGNIFICANT TRIGGER TO LIFT THE MOISTURE TO GET
SHOWERS AND THUNDERSTORMS GOING.  BESIDES A FEW STREAMER SHOWERS
THIS MORNING LITTLE IN THE WAY OF CONVECTION HAS FIRED TODAY.
MOISTURE REMAINS SOMEWHAT SHALLOW AND JUST ENOUGH SUBSIDENCE AND
AFTERNOON WARMING DUE TO THE MID LEVEL RIDGE OVERHEAD HAS CURRENTLY
KEPT ANY CONVECTION AT BAY.

TONIGHT...SURFACE DEWPOINTS TO REMAIN RATHER HIGH WITH MID 70S TO
NEAR 80 DEGREES OVERNIGHT. SOUTHERLY FLOW TO SLACKEN OFF AT BIT BUT
MAINTAIN AT LEAST A LIGHT COMPONENT TO KEEP OVERNIGHT LOWS 5 TO 8
DEGREE ABOVE NORMAL. SOME STRATUS CLOUDS TO FORM IN THE BOUNDARY
LAYER OVERNIGHT OR MORE LIKELY BEFORE SUNRISE SO MOSTLY CLEAR TO
PARTLY CLOUDY OVERNIGHT BEFORE SOME AREAS SEE CLOUDINESS INCREASE.
ANY SHOWERS THAT MIGHT FORM WILL LIKELY BE  OFFSHORE AS SOME
STREAMERS MIGHT FORM. WILL BE WATCHING ANY CONVECTION THAT FORMS
OVER THE WEST CENTRAL AND SOUTH CENTRAL TEXAS OVERNIGHT. ANY MCS
THAT DEVELOPS COULD WORK ITS WAY SOUTHEASTWARD POSSIBLY HAVING AN
IMPACT ON OUR AREA FRIDAY.

FRIDAY...UPPER RIDGE SHIFTS SLIGHTLY WESTWARD LEAVING EASTERN AND
SOUTHERN TEXAS ON THE EASTERN PERIPHERY. PERTURBATIONS /PARTS OF THE
REMNANTS OF PACIFIC HURRICANE ODILE/ TO TRAVERSE NORTHWEST TEXAS
PRODUCING CLUSTERS OF THUNDERSTORMS. MODELS ARE IN NOT IN BEST
AGREEMENT IF ANY OF THESE DISTURBANCES WORK THERE WAY INTO OUR CWA.
NAM REMAINS THE MOST AGGRESSIVE WITH A STRONG DISTURBANCE TRACKING
INTO DEEP SOUTH TEXAS UNDER A MORE IMPRESSIVE NORTHWEST FLOW. GFS
AND ECMWF ALTHOUGH KEEP THE STRONGER DISTURBANCES NORTHEAST OF OUR
AREA BOTH INDICATE SOME QPF WITH LOW POPS. ANY COMBINATION OF
OUTFLOW FROM THE NORTHERN THUNDERSTORMS ANY DISTURBANCES WORKING
THERE WAY INTO THE REGION AND SEABREEZE AND DAYTIME HEATING COULD BE
A TRIGGER TO GET A FEW SHOWERS OR THUNDERSTORMS DEVELOPING.
LOCALIZED HEAVY RAIN REMAINS IN THE EQUATION WITH PWATS NOT BUDGING
FROM THE 2 INCH MARK. MODEL CONSENSUS FOCUSES LOW END CHANCE POPS
OVER THE NORTHERN AND EASTERN COUNTIES WITH WESTERN COUNTIES HAVING
THE LEAST CHANCES. A BIT MORE CLOUD COVER TO POSSIBLY KEEP TEMPS
DOWN A DEGREE OR TWO BUT WITH THE HIGHER DUE POINTS HEAT INDICES TO
RANGE FROM 100-105. STILL SUMMER FOR 3 MORE DAYS AT LEAST BY THE
CALENDER.

FRIDAY NIGHT...ANY CONVECTION THAT FIRES DURING THE DAY SHOULD BEGIN
TO DISSIPATE WITH INSTABILITY WEAKENING AS THE TEMPERATURES COOL
OFF. THE WESTERN COUNTIES WILL BE THE FAVORED LOCATIONS THROUGH THE
EVENING. ANOTHER WARM AND MUGGY NIGHT WILL MAKE LOCAL FOOTBALL GAMES
A BIT UNCOMFORTABLE.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...

SATURDAY INTO SUNDAY...MID/UPPER LEVEL RIDGING REMAINS OVER THE AREA
THROUGH SUNDAY PROVIDING SOME SUBSIDENCE. PWATS REMAIN ABOVE 2
INCHES THROUGH EARLY SUNDAY BEFORE DRIER AIR BRIEFLY MOVES INTO THE
MIDLEVELS AND DECREASES PWATS TO AROUND 1.8 INCHES. THE LACK OF A
FOCUS MECHANISM WILL PREVENT WIDESPREAD RAINFALL. HOWEVER...LIGHT
ONSHORE E/SE WINDS SHOULD ALLOW FOR A DAILY SEABREEZE TO DEVELOP AND
FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG
IT.

MONDAY INTO WEDNESDAY....BY MONDAY THE MID/UPPER LEVEL RIDGING
SLIDES WEST AND FLATTENS AS THE NEXT UPPER LEVEL TROUGH SWINGS OVER
THE NORTHEASTERN US...PUSHING THE ASSOCIATED COLD FRONT SOUTH ACROSS
THE PLAINS AND NORTH TEXAS. AT THE SAME TIME DISTURBANCES PUSH WEST
OVER THE GULF OF MEXICO INCREASING EASTERLY FLOW AND MOISTURE...WITH
PWATS SURGING TO 2.2 INCHES MONDAY INTO WEDNESDAY. FRONT CONTINUES
TO APPEAR WEAKER IN THE LAST FEW MODEL RUNS. ECMWF KEEPS THE FRONT
WELL TO OUR NORTH...WHILE THE GFS PUSHES IT A LITTLE FURTHER SOUTH.
LOOKING AT MIDLEVEL WINDS THERE IS LITTLE NORTHERLY FLOW TO PUSH THE
FRONT SOUTH THROUGH THE CWA. BELIEVE WITH LITTLE SUPPORT TO MOVE IT
THROUGH THE CWA...THE FRONT WILL STALL/WASH OUT NORTH OF THE AREA.
HOWEVER...IF THE FRONT MOVES CLOSER TO THE CWA IT COULD ENHANCE
SHOWER AND THUNDERSTORM ACTIVITY FOR THE FIRST HALF OF THE WEEK.
HAVE MAINTAINED POPS AT 20 TO 30 PERCENT FOR THE TIME BEING.

MARINE...
TONIGHT THROUGH FRIDAY NIGHT...A WEAK TO MODERATE GRADIENT TO
PERSIST BETWEEN BROAD HIGH PRESSURE OVER THE GULF AND THE REMNANTS
OF PACIFIC HURRICANE ODILE EXPECTED TO MOVE ACROSS THE TEXAS
PANHANDLE FRIDAY. THE LIGHTER THAN NORMAL SOUTH TO SOUTHEAST FLOW TO
CONTINUE THROUGH FRIDAY EVENING MAINTAINING THE SLIGHT SEAS.
ISOLATED TO SCATTERED SHOWERS OR THUNDERSTORMS ARE POSSIBLE.
STRONGER WINDS AND HIGHER SEAS WILL ACCOMPANY ANY THUNDERSTORM.

SATURDAY THROUGH TUESDAY...LIGHT EAST TO SOUTHEAST WINDS WILL PREVAIL
THROUGH SUNDAY AND SEAS WILL REMAIN LOW. AS HIGH PRESSURE
STRENGTHENS OVER THE PLAINS...MODERATE EAST TO NORTHEAST WINDS WILL
DEVELOP LATE SUNDAY NIGHT INTO MONDAY AND WAVE HEIGHTS BEGIN TO
BUILD. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
THROUGH THE PERIOD.

&&

.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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