National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS64 KBRO 161750
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1250 PM CDT SUN MAR 16 2014

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

&&

.AVIATION...LATEST RADAR TRENDS SHOW SCATTERED SHOWERS DEVELOPING
ASSOCIATED WITH UPPER LEVEL LOW MOVING ACROSS THE AREA. AT THIS
TIME...LOW LIGHTNING ACTIVITY AND LIGHT RAIN IS OBSERVED WITH
THESE SHOWERS. MOST OF THE ACTIVITY WILL CONTINUE TO MOVE NE AT
15 TO 20 KNOTS AND IMPACT THE TERMINALS IN A FEW HOURS. STRONG
NORTH WINDS BEHIND THE FRONT WILL KEEP BREEZE CONDITIONS ACROSS
THE AREA THROUGH THE AFTERNOON. WINDS WILL DIMINISH FOR A FEW
HOURS AFTER SUNSET BUT WILL INCREASE AROUND MIDNIGHT THROUGH
SUNRISE. VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AS DRY AIR
MOVES BEHIND THE FRONT.


&&

.PREV DISCUSSION... /ISSUED 709 AM CDT SUN MAR 16 2014/

DISCUSSION...MADE ADJUSTMENTS TO POPS AND WEATHER FOR EARLY
MORNING HOURS BASED ON LATEST RADAR TRENDS. CONVECTION AHEAD
OF THE FRONT WILL INCREASE ACROSS THE WESTERN PORTION OF THE
VALLEY AND THEN PROGRESS EASTWARD AS UPPER TROUGH MOVES SOUTH.
INCREASE POPS THROUGH MID DAY WITH ISOLATED THUNDERSTORMS. NO
OTHER CHANGES WERE MADE.

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...DENSE SEA FOG IS AGAIN COMPLICATING THINGS AT SOUTH
PADRE ISLAND...WITH THE REGIONAL TAF SITES ONLY SLIGHTLY LESS
AFFECTED. LIGHT WINDS PREVAIL WITH SOME FOG AT ALL SITES. VSBY IS
LOWEST AT HRL WITH HALF A MILE. CEILINGS VARY FROM MVFR AT BRO AND
HRL TO CLEAR AT MFE. CONDITIONS AT ALL SITES CAN BE EXPECTED TO VARY
EARLY THIS MORNING. EXPECT SLOW IMPROVEMENT THROUGH MID MORNING. THE
ARRIVAL OF DRIER AIR AND STRONGER NORTH WINDS WITH A FRONT IN THE
LATE MORNING WILL RAPIDLY IMPROVE CONDITIONS TO VFR...THOUGH HIGHER
CEILINGS WILL REMAIN THROUGH THE DAY.

PREV DISCUSSION... /ISSUED 343 AM CDT SUN MAR 16 2014/

SHORT TERM /TODAY THROUGH MONDAY/...THE BASE OF A SHORT WAVE TROUGH
IS EXHIBITING SOME SPIN OVER WEST TEXAS...WITH JET CIRRUS EVIDENT
MOVING SOUTHWEST TO NORTHEAST OVER SOUTH TEXAS THIS MORNING. A
SURFACE COLD FRONT IS OVER NORTH CENTRAL AND WEST TEXAS...MOVING
SOUTH TOWARD THE CWA. THE FRONT SHOULD PUSH THROUGH THE CWA BY ABOUT
MID DAY...WITH BREEZY NORTH WINDS IN ITS WAKE. HIGH TEMPS WILL MAKE
IT INTO THE 70S ACROSS THE LOWER VALLEY TODAY...BUT WILL BE SOMEWHAT
LESS IN THE UPPER VALLEY...NEAR 70. THE MAIN IMPACTS TODAY WILL BE
EARLY MORNING DENSE FOG NEAR THE COAST...AND SOME WIND...ALTHOUGH NO
ADVISORY HAS BEEN ISSUED. DRY AIR WILL FILTER IN BUT NOT OVERLY SO.
THUS...FIRE WEATHER CONCERNS ARE LOWER THAN PREVIOUSLY ANTICIPATED.
SEE THE SEPARATE PARAGRAPH ON FIRE WEATHER BELOW. A SECOND PIECE OF
SHORT WAVE ENERGY WILL DIVE SOUTH OUT OF THE PLAINS TODAY TO HELP
REINFORCE THE ONE ALREADY OVER WEST TEXAS. THE ENHANCED TROUGH WILL
EXTEND BACK OVER SOUTH TEXAS BY TONIGHT AND ITS BASE WILL MOVE FROM
WEST TO EAST OVER DEEP SOUTH TEXAS OVERNIGHT AS WELL. ISLD SHOWERS
MAY DEVELOP ALONG THE COAST OR OVER THE MARINE AREAS AS THIS HAPPENS
BUT DEEP DRY AND COOL NORTHWEST FLOW WILL PROVIDE A STABLE THERMO
DYNAMIC PROFILE AND RAIN CHANCES WILL BE LIMITED. TEMPS SUNDAY NIGHT
WILL DIP INTO THE 40S TO LOWER 50S...A FULL 10 DEGREES BELOW NORMAL.
SKIES WILL BEGIN TO CLEAR AS PWAT AND COLUMN MOISTURE PLUMMETS. PWAT
BY MONDAY SHOULD BE A HALF INCH OR LESS AND IT WILL BE A SPRING LIKE
DAY ACROSS DEEP SOUTH TEXAS AND THE RGV WITH DAY TIME HIGH TEMPS
STILL ABOUT 10 DEGREES BELOW NORMAL...FROM THE 60S TO THE LOWER 70S
BUT UNDER SUNNY SKIES AND WITH MODERATE NORTHWEST TO NORTH WINDS. IN
GENERAL...HIGH PRESSURE WILL SPREAD OVER THE AREA ONCE THE FRONT
MOVES THROUGH TODAY...WHILE UPSTREAM RIDGING MOVES IN BEHIND AN
EXITING SHORT WAVE TROUGH. RAINFALL CHANCES...WHICH ARE ON THE LOW
SIDE AND ARE MAINLY ASSOCIATED WITH FROPA...WILL VANISH QUICKLY
LATER TODAY.

LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
BREEZY SOUTH TO SOUTHWEST WINDS...AND A MARKED INCREASE IN
TEMPERATURES STILL EXPECTED FOR TUESDAY. ATMOSPHERE WILL BE VERY DRY
ON TUESDAY AFTERNOON WITH DOWNSLOPING SOUTHWESTERLY WINDS AT
850/700MB ONLY ADDING TO THE DRYING AND WARMTH OF THE LOWER
ATMOSPHERE. RIGHT AT THE SURFACE SOUTH TO SOUTHEASTERLY WINDS WILL
ADVECT A LITTLE BIT OF MOISTURE INTO THE BOUNDARY LAYER BUT THAT
WILL QUICKLY MIX OUT IN THE AFTERNOON. SYNOPTIC AND MESOSCALE
PATTERN PRETTY FAVORABLE FOR A HOT DAY AND SHOW THAT IN THE GRIDS
WITH HIGHS IN THE MID TO UPPER 80S IN THE VALLEY AND 90 OR HIGHER IN
ZAPATA COUNTY. WINDS MAY GUST IN THE 25 TO 30 MPH RANGE DURING THE
AFTERNOON AMID A DEEP MIXING LAYER.

LOW LAYER RIDGING GENERALLY INTENSIFIES AND SHIFTS EASTWARD OVER THE
SOUTHEASTERN CONUS PRESENTING THE AREA WITH A MORE EASTERLY FLOW ON
TUESDAY NIGHT INTO WEDNESDAY. 03Z AVHRR SEA SURFACE TEMPERATURE
PRODUCT SHOWS THE SST GRADIENT IS NOT QUITE AS PRONOUNCED TODAY AS
IT HAS BEEN IN THE LAST FEW...BUT STRONG NORTH WINDS PRODUCED BY THE
SUNDAY COLD FRONT WILL PROBABLY INCREASE UPWELLING TIGHTEN THE
TEMPERATURE GRADIENT PROVIDING A FAVORABLE ADVECTION FOG ENVIRONMENT
AND HAVE ADDED FOG TO THE FORECAST FOR TUESDAY MORNING IN COASTAL
LOCATIONS. ONSHORE FLOW WILL LIKELY MODERATE OUR TEMPERATURES JUST A
BIT WITH HIGHS ON WEDNESDAY IN THE LOW TO MID 80S WITH LOWS AROUND
60.

BY THURSDAY 300/500MB RIDGING IS BECOMING INCREASINGLY EVIDENT TO
OUR SOUTH CENTERED AROUND 17N WHILE OVER THE CONUS MORE ZONAL FLOW
WITH SUBTLE LOCAL JET MAXIMUMS CONTINUE. BROAD LOWER LEVEL RIDGING
PERSISTS OVER MOST OF THE SOUTHEASTERN CONUS. THIS ALLOWS OUR LOW
LAYER THICKNESS VALUES TO INCREASE AND CONTINUES A MODERATE EAST TO
EAST SOUTHEASTERLY FLOW. ECMWF STILL PAINTS A WEAK FRONT IN THE AREA
ON THURSDAY BUT IT REMAINS WEAKER STILL...AND HAS LITTLE SUPPORT IN
THE LARGE SCALE SYNOPTIC PICTURE. GFS ENSEMBLE AND DETERMINISTIC GFS
KEEP THE FRONT FROM BEING A PLAYER IN OUR WEATHER. CONTINUED THAT
IDEA IN THE FORECAST ALTHOUGH WE DO GET AN INCREASE IN OUR DEPTH OF
MOISTURE ON THURSDAY WITH 850MB RH VALUES CLIMBING. WE WILL HAVE
PERSISTENT 750MB CAPPING THAT WILL KEEP DEEPER SHOWERS/STORMS FROM
DEVELOPING BUT CONTINUED THE INHERITED SLIGHT CHANCE OF SHOWERS OVER
THE WESTERN HALF OF THE AREA FOR NOW.

FRIDAY INTO SATURDAY THE LOW LEVEL FLOW BECOMES MORE SOUTHEASTERLY
AND WE BEGIN TO LOSE THE MODERATING EFFECTS OF THE ONSHORE BREEZE
ALLOWING TEMPERATURES TO RISE AS OUR LOWER LEVEL THICKNESS VALUES DO
THE SAME. LOW LEVEL RH VALUES FALL AND WE SHOULD HAVE PLENTIFUL
SUNSHINE BOTH FRIDAY AND SATURDAY. BUMPED TEMPERATURES UP A FEW
DEGREES ON SATURDAY AND SUNDAY WITH ECMWF/GFS SHOWING AROUND A 590DM
RIDGE A FEW HUNDRED MILES TO OUR SOUTH WITH A ZONAL JET PATTERN TO
OUR NORTH. 18Z GFS MENTIONED A FRONT SATURDAY/SUNDAY WITH 00Z ECMWF
HOLDING ON TO A HINT OF IT BUT FEEL PRETTY CONFIDENT IN THE
ADVERTISED PATTERN WE WILL STAY FRONT FREE THROUGH SUNDAY AND KEPT
THE FORECAST DRY. /68-JGG/

MARINE...
TODAY THROUGH MONDAY...DENSE FOG IS IN PLACE ON SOUTH PADRE ISLAND
AND SHOULD REMAIN SO UNTIL MID MORNING AS WINDS STAY NEAR CALM. A
COLD FRONT WILL PUSH THROUGH FROM MID TO LATE MORNING OR EARLY AFTN
WHEN ANY REMAINING FOG WILL BE SWEPT AWAY. STRONG NORTHWEST WINDS
WILL DEVELOP IN THE WAKE OF THE FRONT...WITH GUSTS TO GALE FORCE
POSSIBLE OVER THE SOUTHERN FAR OFFSHORE WATERS TONIGHT. WAVE HEIGHTS
WILL BUILD TO 10 FEET OFFSHORE TONIGHT. A MID LEVEL TROUGH AXIS WILL
PASS OVERHEAD TONIGHT INTO MONDAY...WITH MUCH IMPROVED WEATHER TO
FOLLOW ON MONDAY AS HIGH PRESSURE SPREADS OVER THE AREA. HOWEVER...
SMALL CRAFT ADVISORY CONDITIONS MAY STILL PERSIST INTO EARLY MONDAY.

MONDAY NIGHT THROUGH THURSDAY...
PERSISTENT SOUTH WINDS ARE EXPECTED TO DEVELOP TUESDAY MORNING AND
BECOME STRONG AT TIMES THROUGH WEDNESDAY. SMALL CRAFT ADVISORIES MAY
BE NEEDED DURING THE OVERNIGHT HOURS ON THE GULF OF MEXICO AND
DURING THE DAYTIME ON THE LAGUNA MADRE TUESDAY AND WEDNESDAY. MORE
MODERATE EASTERLY WINDS ARE EXPECTED ON THURSDAY WITH GENERALLY
MODERATE SEAS EXPECTED MONDAY NIGHT THROUGH THURSDAY.

FIRE WEATHER...WHILE WIND AND FUEL DRYNESS CRITERIA WILL BE
CRITICAL TODAY...RELATIVE HUMIDITY VALUES WILL REMAIN SLIGHTLY
ABOVE...THAT IS NOT MEETING...THE CRITERIA REQUIRED FOR A RED FLAG
WARNING. NONETHELESS...FIRE DANGER WILL REMAIN HIGHER THAN NORMAL
WITH AN ELEVATED THREAT OF ENHANCED WILDFIRE GROWTH AND SPREAD.

&&

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

     SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR GMZ170.

     GALE WARNING FROM 7 PM THIS EVENING TO 4 AM CDT MONDAY FOR
     GMZ170.

     SMALL CRAFT ADVISORY UNTIL 6 AM CDT MONDAY FOR GMZ150-155-175.

&&

$$

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

67/59