Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 241727 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1227 PM CDT SUN AUG 24 2014

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

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
SCATTERED MID LEVEL CLOUDS ACROSS THE COASTAL SECTIONS OF THE CWA
EARLY THIS AFTERNOON. EXPECT VFR CONDITIONS TO PREVAIL THE REST OF
THE AFTERNOON INTO THE EVENING AS 500MB RIDGE ACROSS THE SOUTH
CENTRAL AND SOUTHEAST UNITED STATES CONTINUES TO PROVIDE
SUBSIDENCE ACROSS THE RIO GRANDE VALLEY.
&&

.PREV DISCUSSION... /ISSUED 609 AM CDT SUN AUG 24 2014/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...VFR CONDS WILL PREVAIL THE NEXT 24 HOURS. HIGH
PRESSURE WILL BE IN CONTROL WITH MODERATE SOUTHEAST WINDS THIS
AFTERNOON BECOMING LIGHT OVERNIGHT. DIURNAL CUMULUS WILL DEVELOP
BY MID/LATE MORNING WITH PERHAPS MORE COVERAGE IN THE COASTAL
SECTIONS IF SEABREEZE FRONT DEVELOPS.

PREV DISCUSSION... /ISSUED 430 AM CDT SUN AUG 24 2014/

SHORT TERM /NOW THROUGH MONDAY/...500MB HIGH PRESSURE OVER THE
SOUTHEAST CONUS WILL CONTINUE TO BE IN CONTROL ACROSS OUR AREA IN
THE SHORT TERM. THIS MEANS THAT THE HOT AND MOSTLY DRY FORECAST WILL
CONTINUE. FOR THE MOST PART THE INHERITED FORECAST LOOKED GOOD AND
BELIEVE PERSISTENCE IS A GOOD WAY TO GO. THIS MEANS THAT TEMPS
WILL REMAIN A LITTLE ABOVE NORMAL WITH HIGHS NEAR OR EXCEEDING 100
DEGREES ACROSS A VAST MAJORITY OF THE INLAND AREAS AND LOWS IN THE
UPPER 70S WITH THE EXCEPTION OF THE NORTHERN RANCH LANDS WHICH MAY
FALL INTO THE MID 70S. HEAT INDEX VALUES WILL BE IN THE 105-110 F
RANGE EACH AFTERNOON. SFC HIGH PRESSURE WILL BE SITUATED IN THE
WESTERN GULF SO WINDS WILL REMAIN FROM THE SOUTHEAST WITH SPEEDS
AVERAGING AROUND 15 MPH IN THE AFTERNOONS WHICH WILL QUICKLY
DECREASE AFTER SUNSET. PWATS WILL REMAIN BELOW 1.8 INCHES THIS
PERIOD AND WITH THE LACK OF GOOD 850-700MB MOISTURE SEA BREEZE
SHOWERS WILL BE HARD TO COME BY. HOWEVER...DO HAVE SILENT 10-14
POPS IN THE INTERIOR SECTIONS IN THE AFTERNOON IN CASE ONE OR TWO
SHOWERS DO POP ALONG THE SEA BREEZE WITH MOST IF NOT ALL LOCALES
REMAINING DRY.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...592 DAM HGT CENTER OVER
THE CENTRAL MS VALLEY AT GATE TIME WILL EXTEND SOUTHWEST OVER TX AND
WILL PROVIDE A MEASURE OF STABILITY EARLY ON. HIGH PRESSURE CENTERED
TO THE NORTHEAST OF THAT CENTER WILL DRAW MOISTURE INTO THE NORTHERN
GULF COAST FROM THE EAST...AS A PIECE OF MID LVL ENERGY DIVES SOUTH
ALONG THE EASTERN PERIPHERY OF THE RIDGE TOWARD THE LWR MS VALLEY...
POSSIBLY AND ALSO EVENTUALLY TAPPING INTO WHAT IS CURRENTLY TD4. AT
ANY RATE...THERE WILL BE VERY LITTLE TO DISTURB PERSISTENCE MONDAY
NIGHT AND TUESDAY...WHICH SHOULD REFLECT A CONTINUATION OF SHORT
TERM THINKING.

TUESDAY INTO WEDNESDAY MAY REFLECT A BIT OF A TURNING POINT
HOWEVER...WITH OVERALL MOISTURE SEEING AN UPWARD TREND. NOT ONLY
WILL THE UPPER WEAKNESS BE OVER THE NORTHWEST GULF...WITH LESS LOCAL
INFLUENCE BY SURFACE HIGH PRESSURE...AND UNSETTLED WX CONDITIONS
JUST TO THE NORTHEAST...BUT A PROGRESSIVE SHORT WAVE TROUGH WILL
LIFT EAST FROM THE PACIFIC NORTHWEST INTO THE CENTRAL PLAINS...
PUSHING A COLD FRONT INTO THE SOUTHERN PLAINS AROUND MID WEEK IN
ADVANCE OF THE BUILDING RIDGE OVER THE DESERT SOUTHWEST. SHOWER
ACTIVITY WILL INCREASE JUST TO THE NORTH OF THE CWA...BOTH OVER THE
GULF AND OVER LAND AREAS AS THE MINOR WEAKNESS ALOFT LIES OVERHEAD.
A WEAK SURFACE TROUGH WILL ALSO SET UP JUST TO THE EAST OF THE CWA
OVER THE GULF. MEANWHILE...THE SURFACE FRONT WILL PUSH INTO CENTRAL
AND SOUTH CENTRAL TEXAS AROUND THURSDAY AND THURSDAY NIGHT. THE GFS
FAILS TO PUSH IT THROUGH BY THE END OF THE LONG TERM...BUT THERE
APPEARS TO BE PLENTY OF CONVECTIVE ACTIVITY DEVELOPING OVER THE
HIGHER MEXICAN TERRAIN JUST TO THE WEST OF THE CWA. THERE ARE
DIFFERENCES BETWEEN THE GFS AND ECMWF WITH THE PLAINS SCENARIO. THE
GFS SWINGS THE TROUGH THROUGH THE MIDWEST WITHOUT MUCH FANFARE WHILE
THE ECMWF SEEMS TO DETACH A TRAILING LOW OR SECONDARY TROUGH OVER
THE SOUTHWEST WHICH ENDS UP MEANDERING SLOWLY EAST OVER THE SOUTHERN
HIGH PLAINS AND NORTH TEXAS LATE IN THE WEEK AND KEEPING CONVECTIVE
CHANCES UPSTREAM ALIVE. NONETHELESS...THE EFFECT ON DEEP SOUTH TEXAS
WILL NOT BE THAT GREAT AS A RESULT OF THE NOTED DIFFERENCE...AND HAD
AVERAGE CONFIDENCE OR BETTER IN USING A BLEND OF BOTH MODELS WHICH
REFLECTED SIMILAR WEATHER ELEMENTS THROUGH THE LONG TERM.

TEMPERATURES WILL CONTINUE ABOVE NORMAL WITH HEAT INDEX VALUES IN
THE 103 TO 108 RANGE EACH AFTERNOON. PWAT WILL BE ELEVATED...BUT NOT
EXCESSIVELY SO...BUT STILL ENOUGH TO SUPPORT A DAILY SEA BREEZE ON
WHAT WILL BE LIGHT TO MODERATE WINDS. AVAILABLE LOW LEVEL MOISTURE
WILL SUPPORT A MIX OF CLOUDS AND SUN WITH SCT TO BKN LOW CLOUDS.
OVERNIGHT LOW TEMPERATURES WILL CONTINUE TO BE IN THE 75 TO 80
DEGREE RANGE. DID NOT HAVE ENOUGH CONFIDENCE/REASON TO GO ABOVE
SLIGHT CHANCE POPS IN MOST PERIODS...THOUGH INCREASED SHOWERS OVER
THE MARINE AREAS LOOKS LIKE A GOOD CALL.

MARINE...
NOW THROUGH MONDAY...LATEST MARINE OBSERVATIONS INDICATE MODERATE
SOUTHEAST WINDS ALONG THE LOWER TEXAS COAST WITH SEAS AROUND 3
FEET AT BUOY 42020. SURFACE HIGH PRESSURE ACROSS THE WESTERN GULF
OF MEXICO WILL MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS THROUGH
THE PERIOD. ISOLATED SHOWERS POSSIBLE ACROSS THE LOWER TEXAS
COASTAL WATERS NOW THROUGH SUNDAY NIGHT. SEAS OF 1 TO 3 FT CAN BE
EXPECTED THROUGH THE PERIOD. SMALL CRAFT ADVISORY CONDITIONS WILL
BE UNLIKELY THROUGH SUNDAY NIGHT.

MONDAY NIGHT THROUGH THURSDAY...MID LEVEL RIDGING OVER THE CENTRAL
MISSISSIPPI VALLEY WILL PROVIDE A MEASURE OF STABILITY TO LOCAL
MARINE WEATHER BY SUPPORTING BROAD HIGH PRESSURE OVER THE NORTH GULF
OF MEXICO. LIGHT TO MODERATE EAST TO SOUTHEAST WINDS DURING THE DAY
WILL GENERALLY FADE TO LIGHT OVERNIGHT WITH LOW SEAS THROUGHOUT. NO
ADVISORY CONDITIONS ARE EXPECTED. A MID LEVEL WEAKNESS MOVING EAST
TO WEST UNDER THE RIDGE COULD PLAY A ROLE BEGINNING TUESDAY AS IT
MOVES OVER THE NORTHWEST GULF...INCREASING OVERALL INSTABILITY AND
CONTRIBUTING TO ISOLATED SHOWER ACTIVITY.
&&

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

$$

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