Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 221856 AAD
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1256 PM CST THU JAN 22 2015

.DISCUSSION...UPDATED FIRST PERIOD TO REFLECT CURRENT TRENDS
RELATED TO ADVANCE OF COLD FRONT INTO CWA. MAIN CHANGES WERE TO
ADJUST HOURLY TEMPERATURE PROFILE...DOWNPLAY THUNDER AND ADD
PATCHY FOG.

&&

.PREV DISCUSSION... /ISSUED 1156 AM CST THU JAN 22 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...SCATTERED SHOWERS ARE MOVING NORTH ALONG THE COAST
WITHIN A SURFACE WEAKNESS SETTING UP AHEAD OF THE UPSTREAM COLD
FRONT. A HEAVIER SHOWER RECENTLY MOVED THROUGH BRO. MODERATE AND
GUSTY NORTHEAST WINDS ASSOCIATED WITH THE FRONT ARE ON THE WAY...
ALREADY ARRIVING IN THE MID VALLEY. CONVECTIVE SHOWERS WILL BE
REPLACED BY LIGHT RAIN...DRIZZLE...AND POTENTIALLY LOWER VSBY
THROUGH THE AFTERNOON. BASED ON MORNING ACTIVITY AND CURRENT
RADAR RETURNS...BELIEVE WINDOW FOR ANY SIGNIFICANT THUNDER IS
CLOSING...BUT WON`T RULE OUT AN ISOLATED STROKE OF LIGHTNING THIS
AFTERNOON AS THE FRONT REACHES THE SOUTHEAST COAST IN THE NEXT FEW
HOURS...ESPECIALLY OVER THE MARINE DOMAIN. THE STRONGEST LIFT
SHOULD REMAIN NORTH OF THE AREA HOWEVER...WITH OVERRUNNING THE
MAIN DYNAMIC LOCALLY FOR THE NEXT 24 HOURS. THUS...MVFR DUE TO
LOWERED CEILINGS WILL BE THE PRIMARY AVIATION RESTRICTION...
THOUGH BRIEF IFR CAN NOT BE RULED OUT.

PREV DISCUSSION... /ISSUED 741 AM CST THU JAN 22 2015/

DISCUSSION...UPDATED FOR LATEST MARINE DISCUSSION BELOW.

MARINE...POSTED INITIAL SMALL CRAFT ADVISORY FOR THE LOWER TEXAS
COASTAL WATERS BASED ON FORECASTED STRONG WINDS WITH THE ARRIVAL
OF A COLD FRONT LATE THIS AFTERNOON TO EARLY EVENING. REFINEMENTS
POSSIBLE WITH REGULAR MORNING UPDATE.

PREV DISCUSSION... /ISSUED 536 AM CST THU JAN 22 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...THE LAST TRICKLE OF LIGHT RAIN AND SHOWERS FROM MEXICO
IS ENTERING THE COASTAL BEND OF THE LOWER TEXAS COAST AND AWAY FROM
THE TRIO OF MAJOR DEEP SOUTH TEXAS AERODROMES. HOWEVER...THE THREAT
OF ADDITIONAL CONVECTION WILL CONTINUE THROUGH THE MORNING AND EARLY
AFTERNOON HOURS AS A COLD FRONT APPROACHES FROM THE WEST. VFR IS
EXPECTED DURING A MAJORITY OF THIS PERIOD. THE PASSAGE OF THE
FRONT LATER THIS AFTERNOON WILL CAUSE VEERING WINDS AND DEVELOPING
MVFR CONDITIONS INTO THE EARLY EVENING. AVIATION CONDITIONS WILL
FURTHER DETERIORATE LATE THIS EVENING AND THROUGH THE OVERNIGHT
HOURS AS THE PRECIPITATION TYPE SHIFTS FROM SHOWERS TO LIGHT RAIN
AND DRIZZLE AND CEILINGS CONTINUE TO LOWER.

PREV DISCUSSION... /ISSUED 306 AM CST THU JAN 22 2015/

SHORT TERM.../NOW THROUGH FRIDAY/...SCATTERED SHOWERS ARE STREAMING
FROM THE SOUTH AND SOUTHWEST OUT OF NEIGHBORING MEXICO. LIGHT FOG IS
BEING REPORTED BY A FEW SURFACE OBSERVATION SITES...WITH ONLY SLIGHT
REDUCTIONS IN VISIBILITY. A STATIONARY FRONT IS CURRENTLY ANALYZED
ALONG A CORPUS CHRISTI TO ALICE TO LAS TIENDAS LINE WITHIN SOUTH
TEXAS.

TODAY...AFOREMENTIONED STATIONARY FRONT WILL CONVERT TO A COLD FRONT
AND WILL PASS THROUGH DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE ANTICIPATED...
WITH THE STORM PREDICTION CENTER ALSO HAVING THE ENTIRE BRO CWFA IN
A GENERAL RISK OF THUNDERSTORMS. HIGH TEMPERATURES IN THE MID TO
UPPER 70S WERE REALIZED AT THE OFFICIAL SITES WEDNESDAY WITH DECENT
CLOUD COVER OVERHEAD...SO SIMILAR TEMPERATURES ARE EXPECTED TODAY IN
ADVANCE OF THE LATE DAY COLD FRONT.

TONIGHT...PRECIPITATION TYPE WILL CONVERT FROM SHOWERS/THUNDERSTORMS
IN THE EVENING TO LIGHT RAIN FOR THE OVERNIGHT HOURS AS THE COLD
FRONT PUSHES FARTHER EAST AND LEAVES AN OVERRUNNING-TYPE WEATHER
PATTERN FOR THE BRO CWFA. INHERITED LOW TEMPERATURES IN THE MID TO
UPPER 40S APPEARED VERY REASONABLE AND WERE RETAINED FOR THIS CYCLE.

FRIDAY...COLD FRONT MOVES EVEN FARTHER AWAY AND OVERRUNNING RAINFALL
GRADUALLY ENDS FROM WEST TO EAST AS A 500 MB TROUGH APPROACHES...
WITH THE AXIS OF THIS TROUGH ROUGHLY ALONG THE INTERSTATE 69C
CORRIDOR BY THE END OF THE DAY. ALTHOUGH SKIES WILL BECOME PARTLY
CLOUDY FOR THE AFTERNOON HOURS...ENOUGH CLOUDINESS AND PRECIPITATION
AND COLD AIR ADVBECTION WILL BE PRESENT THROUGH MOST OF THE DAY TO
ENSURE TEMPERATURES IN THE MID TO UPPER 50S.

LONG TERM.../FRIDAY NIGHT THROUGH THURSDAY/...EARLY IN THE LONG TERM
THE UPPER LEVEL TROUGH AXIS WILL BE SITUATED RIGHT ALONG THE NE COAST
OF TEXAS. THIS TROUGH WILL DRIFT SURFACE COASTAL LOW NORTH ALONG THE
NORTHERN GULF COAST WITH ABUNDANT MOISTURE SURGING NORTH. NORTHWEST
FLOW WILL BE IN CONTROL FRIDAY NIGHT BECOMING LIGHTER BY THE EARLY
MORNING HOURS ON SATURDAY AS THE TROUGH EXITS THE REGION. DRY AIR
WILL FILTER INTO THE CWA BEHIND THIS TROUGH SATURDAY LIMITING ANY
MORE RAIN CHANCES. LOW TEMPS IN THE EARLY MORNING HOURS WILL BE
RANGING IN THE LOW 40S ACROSS THE RGV AND UPPER 30S ALONG THE
NORTHERN COUNTIES. LESS CLOUD COVER IS EXPECTED SATURDAY AFTERNOON
WITH A FEW HIGH CLOUDS STREAMING ACROSS THE REGION. THIS WILL ALLOW
FOR TEMPERATURES TO WARM UP INTO THE MID 60S. THE MODEL GUIDANCE ARE
TRENDING WARMER IN THE LAST RUN SO LEAN A FEW DEGREES WARMER FOR
SATURDAY. CONTINUE THE SAME TREND FOR THE WEEKEND AND EARLY NEXT
WEEK AS RIDGE TAKES CONTROL OF THE AREA WITH A LIGHT NORTHWEST FLOW
ALOFT AND WEAKER GRADIENT AT THE SURFACE.

A CUT OFF LOW OVER BAJA CA IS STILL BEEN DEPICTED BY THE MODELS WITH
A BROAD RIDGE STRENGTHENING OVER THE PACIFIC NORTHWEST COAST. AS THE
RIDGE SHIFTS EAST...THE CUT OFF LOW WEAKENS BECOMING AN OPEN WAVE AS
IT MOVES INTO BAJA CA MONDAY NIGHT INTO TUESDAY. MOST OF THE UPPER
LEVEL SUPPORT FOR ANY CONVECTION WILL REMAIN IN THE PERIPHERY OF THE
HIGH PRESSURE AS IT MOVES TOWARDS THE CENTRAL PLAINS TUESDAY NIGHT.
THIS WILL NOT BRING MUCH CHANGE TO THE WEATHER PATTERN AS THE MAIN
ACTIVITY REMAINS TO THE NORTH OF THE CWA. SURFACE HIGH PRESSURE WILL
STRENGTHEN INCREASING THE LOW LEVEL MOISTURE IN THE AREA COMING THE
SOUTHERN GULF WITH SOUTHEAST FLOW RETURNING WEDNESDAY.
HOWEVER...MOISTURE CONTENT WILL ONLY INCREASE THE CLOUD COVER ALONG
THE COASTAL COUNTIES WITH NO SIGNIFICANT RAINFALL EXPECTED.

MARINE...NOW THROUGH FRIDAY...BUOY 42020 REPORTED SOUTHEAST WINDS
AROUND 16 KNOTS GUSTING TO AROUND 18 KNOTS WITH SEAS SLIGHTLY UNDER
4 FEET WITH A PERIOD OF 5 SECONDS AT 02 CST/08 UTC. MODERATE WINDS
AND SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST TODAY IN ADVANCE
OF THIS EVENING/S PASSAGE OF A COLD FRONT. ADVERSE MARINE CONDITIONS
WILL DEVELOP AND PREVAIL IN THE WAKE OF THIS COLD FRONT FROM TONIGHT
THROUGH AT LEAST FRIDAY...WITH SMALL CRAFT ADVISORIES LIKELY. WINDS
MAY OCCASIONALLY GUST TO GALE FORCE TONIGHT THROUGH FRIDAY FOR THE
GULF OF MEXICO WATERS EAST OF PADRE ISLAND FROM 0 TO 60 NAUTICAL
MILES OFFSHORE...BUT WITH SEA SURFACE TEMPERATURES RANGING FROM THE
UPPER 50S TO UPPER 60S...A SUSTAINED PERIOD OF GALE FORCE WINDS IS
NOT EXPECTED AT THIS TIME.

FRIDAY NIGHT THROUGH THURSDAY...NORTHWEST FLOW BEHIND THE FRONT
WILL CONTINUE FRIDAY NIGHT WITH HIGH SEAS AND STRONG WINDS. A SCA
WILL LIKELY BE NEEDED DURING THAT TIME. BY SATURDAY MORNING THE
SEAS BEGIN TO DIMINISH WITH LIGHTER WINDS OVER THE GULF WATERS
WITH BENIGN WEATHER PATTERN PREVAILING. THE PRESSURE GRADIENT WILL
REMAIN RELAX THROUGH THE REMAINDER OF THE LONG TERM PERIOD
MAINTAINING LIGHTER WINDS AND LOW SEAS THROUGH THURSDAY. ON
WEDNESDAY THE SOUTHEAST FLOW RETURNS AS HIGH PRESSURE STRENGTHENS
OVER THE GULF. NO SCEC OR SCA IS EXPECTED FOR THE REMAINDER OF THE
LONG TERM PERIOD.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 AM CST FRIDAY FOR GMZ130-
     132-135.

     SMALL CRAFT ADVISORY UNTIL 6 AM CST FRIDAY FOR GMZ150-155-170-
     175.

&&

$$

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