000
FXUS64 KBRO 132333
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
633 PM CDT THU JUN 13 2013

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

&&

.AVIATION...EARLIER CONVECTION HAS MOVED TO THE FAR WESTERN AND
NORTHERN PARTS OF THE RIO GRANDE VALLEY AND DEEP SOUTH TEXAS.
EXPECT VFR CONDITIONS TO PREVAIL THROUGH THE EVENING WITH CIRRUS
OVERHEAD. MVFR CEILINGS WILL DEVELOP LATE TONIGHT AS MIXING
DECREASES AND CLOUD BASES LOWER. CANNOT RULE OUT SOME SHOWERS
EARLY FRIDAY MORNING BUT EXPECT COVERAGE TO BE SPOTTY. VFR
CONDITIONS ARE EXPECTED TOMORROW WITH CEILINGS RISING BY
MIDMORNING.

&&

.PREV DISCUSSION... /ISSUED 256 PM CDT THU JUN 13 2013/

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ELONGATED 500MB LOW ACROSS NORTHERN MEXICO CONTINUES TO PROVIDE
ISOLATED TO SCATTERED CONVECTION ACROSS PORTIONS OF SOUTH TEXAS THIS
AFTERNOON. THIS FEATURE IS EXPECTED TO DRIFT SLOWLY NORTHWARD INTO
WEST TX TONIGHT INTO FRIDAY. LOW TO MID LEVEL MOISTURE WILL REMAIN
HIGH ACROSS WEST TX INTO NORTHERN MEXICO WITH DRIER AIR ACROSS EAST
TX. WITH THE WEAKNESS IN THE RIDGE ACROSS THE AREA...A SLIGHT CHANCE
OF SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE RIO GRANDE
VALLEY TONIGHT THROUGH FRI NIGHT AS WEAK VORTICITY ROTATES AROUND
THE UPPER LOW ACROSS NORTHEAST MEXICO INTO SOUTH TX. /61/

LONG TERM /SATURDAY THROUGH THURSDAY/...
WEATHER ACROSS OUR AREA WILL LIKELY BE INFLUENCED...AT LEAST
INITIALLY...BY A SHORTWAVE TROUGH STRETCHED FROM THE CAPROCK TO THE
BIG BEND.  THIS FEATURE IS EXPECTED TO DAMPEN AS IT HEADS EAST...AND
ALLOWS BROAD RIDGING ALOFT TO REBUILD OVER OUR AREA BY SUNDAY.

BIG QUESTION IS WHETHER WE WILL CONTINUE TO SEE SPOTTY SHOWERS INTO
SATURDAY AS THIS BIT OF FORCING TRAVERSES OUR REGION.  GIVEN THE
FLOW ALOFT...ANY ADDITIONAL FORCING /PROVIDED BY A FRONT FOR
EXAMPLE/ SHOULD REMAIN NORTH OF THE RED RIVER AND WILL LIKELY NOT
PROVIDE ANY ADDITIONAL SUPPORT.

AMPLE BOUNDARY LAYER MOISTURE IS EXPECTED TO REMAIN ACROSS OUR
REGION...WITH PRECIPITABLE WATER VALUES BETWEEN 1 AND 2 STANDARD
DEVIATIONS ABOVE NORMAL FOR JUNE.  SOME INSTABILITY MAY ALSO BE
PRESENT...BUT FORECAST SOUNDINGS SUGGEST THAT MUCH OF THE AVAILABLE
INSTABILITY WILL NOT BE SURFACE-BASED.  BESIDES...THE BEST FORCING
/SO-TO-SPEAK/ WILL LIKELY BE AFFECTING THE RGV/DEEP SOUTH TEXAS
DURING A DIURNAL MINIMUM IN INSTABILITY.

ALL OF THIS LEADS ME TO PROVIDE A FAIRLY LOW CONFIDENCE
PROGNOSTICATION OF THE LOW POSSIBILITY OF SPOTTY SHOWERS.  RIGHT
NOW...IT LOOKS LIKE THE BEST ODDS OF SEEING MEASURABLE RAIN WILL
OCCUR WEST OF US-281 CONCURRENT WITH SLIGHTLY BETTER FORCING.  OTHER
SHOWERS MAY BE SEEN CLOSER TO THE COAST...WHERE SOME STREAMER
SHOWERS MAY MOVE ONSHORE.  THAT SAID...I HAVE INCREASED SHOWER
PROBABILITIES FOR SATURDAY...WITH TAPERING VALUES THROUGH THE DAY.

LUCKY FOR ALL INVOLVED...FORECAST CONFIDENCE INCREASES BY THE START
OF THE THIRD FULL WEEK IN JUNE.  BROAD RIDGING ALOFT SHOULD KEEP THE
MAIN STORM TRACK WELL TO OUR NORTH...WITH A DEEP FETCH OF EAST TO
SOUTHEAST SURFACE WINDS CIRCULATING AROUND A SURFACE HIGH IN THE
ATLANTIC.  WE SHOULD RETURN TO A DRIER WEATHER PATTERN BY
MONDAY...AS THE AXIS OF BOUNDARY LAYER MOISTURE SHIFTS WEST OF THE
AREA.  AND WITH RIDGING LARGELY EXPECTED TO HOLD...LOOK FOR DRY
CONDITIONS FOR MUCH OF THE UPCOMING WORKWEEK.

A STORM SYSTEM IS EXPECTED TO MOVE ONSHORE IN THE PACIFIC NORTHWEST
BY MID-WEEK...WHICH SHOULD RESULT IN SOME AMPLIFICATION OF THE
RIDGING ACROSS THE LONE STAR STATE.  AS SUCH...THE BIGGEST POTENTIAL
IMPACT FOR THE LONG TERM PORTION OF THE FORECAST SHOULD BE AFTERNOON
TEMPERATURES.  CONFIDENCE IS FAIRLY HIGH THAT TEMPERATURES WILL
REMAIN ABOVE NORMAL /LOWER-MIDDLE 90S/ FOR MID-JUNE...AND THIS TREND
HAS BEEN MAINTAINED WITH THE FORECAST PACKAGE THIS AFTERNOON.  /53/

MARINE...

TONIGHT THROUGH FRIDAY NIGHT...
SEAS WERE NEAR 3 FEET WITH EAST-SOUTHEAST WINDS NEAR 10 KNOTS AT
BUOY020 EARLY THIS AFTERNOON. LIGHT TO MODERATE SOUTHEAST WINDS WILL
PREVAIL ACROSS THE COASTAL WATERS TONIGHT INTO FRIDAY AS WEAK HIGH
PRESSURE PREVAILS ACROSS THE GULF OF MEXICO.  /61/

SATURDAY THROUGH TUESDAY...
MODERATE WINDS AND SEAS ARE GENERALLY EXPECTED THROUGH EARLY NEXT
WEEK.  COMBINED SEAS SHOULD AVERAGE 4 FEET OR LESS /ESPECIALLY THIS
WEEKEND/.  WINDS/SEAS MAY INCREASE SUNDAY THROUGH TUESDAY...AND
COULD NECESSITATE SMALL CRAFT TO EXERCISE CAUTION BY THE END OF THE
WEEKEND OR EARLY NEXT WEEK.  /53/

&&

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

$$

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

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