Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 182058
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
358 PM CDT SAT OCT 18 2014

.SHORT TERM /NOW THROUGH SUNDAY NIGHT/...
CONVECTIVE LINE CONTINUES TO CHURN RIGHT ALONG THE COAST...WITH
INACTIVE OUTFLOWS DRIFTING FURTHER INLAND. PW IMAGERY SHOWS DEEPEST
MOISTURE JUST STARTING TO MOVE INTO THE WESTERN VALLEY...SO SOME
SHOWER ACTIVITY MAY FINALLY DEVELOP INLAND BEFORE SUNSET. MODELS
GRADUALLY SHIFT THE MOISTURE FURTHER INLAND...AND WITH A WEAK
MIDLEVEL VORT TRYING TO MOVE THROUGH THIS EVENING...SOME SHOWER
ACTIVITY EXPECTED TO DRIFT ACROSS THE REGION OVERNIGHT AND AGAIN
TOMORROW. SOME LIGHT FOG IS POSSIBLE AREAWIDE OVERNIGHT...BUT LARGER
DEPTH OF MOISTURE WILL KEEP FOG FROM GETTING TOO THICK. MODELS
CONTINUE TO SHOW BETTER RAIN CHANCES ACROSS THE WESTERN AREAS INTO
THE BRUSH COUNTRY ON SUNDAY...SO HAVE TAILORED POP CHANCES TO
ACCOUNT FOR THIS. MOISTURE REMAINS INTO SUNDAY NIGHT WITH CONTINUES
SMALL CHANCES FOR POPS. /64/

.LONG TERM /MONDAY THROUGH SATURDAY/...
PERSISTENT EASTERLY FLOW...THANKS IN PART TO A SURFACE RIDGE
CENTERED OVER THE MID-ATLANTIC...WILL ALLOW LOW-LEVEL MOISTURE TO
CONTINUE FLOWING INTO THE REGION.  BY MONDAY...PRECIPITABLE WATER
VALUES ARE EXPECTED TO APPROACH 2 INCHES IN MANY PARTS OF OUR
AREA...WHICH IS BETWEEN 1 AND 2 STANDARD DEVIATIONS ABOVE NORMAL FOR
OCTOBER.  THIS...COMBINED WITH AN INVERTED SURFACE TROUGH EMANATING
FROM A SURFACE LOW IN THE BAY OF CAMPECHE...WILL RESULT IN A
CONTINUED POSSIBILITY OF SEEING SHOWERS AND STORMS EARLY NEXT WEEK.
CONVECTIVE COVERAGE SHOULD BE GREATEST OVER SOUTHERN AND WESTERN
PORTIONS OF THE FORECAST AREA...COINCIDENT WITH THE HIGHEST
PRECIPITABLE WATER VALUES.

AN UPPER LEVEL TROUGH IS EXPECTED TO MOVE ACROSS THE OHIO VALLEY
TUESDAY.  THIS FEATURE SHOULD PUSH A COLD FRONT FROM THE TENNESSEE
AND LOWER MISSISSIPPI VALLEYS TO THE NORTHERN GULF OF MEXICO BY
WEDNESDAY.  MOST OF THE MOMENTUM FOR THIS FRONT SHOULD REMAIN WELL
TO OUR NORTH AND EAST...WHICH RAISES THE QUESTION ABOUT A (WEAK)
FRONTAL PASSAGE IN OUR AREA AROUND MID-WEEK.  LATEST MEDIUM RANGE
MODELS SUGGEST THE POSSIBILITY OF A SURFACE TROUGH PASSAGE
WEDNESDAY-ISH.  WINDS WILL LIKELY BACK TO A MORE NORTHEASTERLY
DIRECTION AND INCREASE IN SPEED AFTER THE PASSAGE OF ANY TROUGH.

REGARDLESS OF WHETHER A FRONT MOVES THROUGH THE FORECAST AREA...A
SURFACE RIDGE...BUILDING SOUTHWARD ACROSS THE UPPER MIDWEST AS THE
WEAK GULF LOW MOVES NORTHEAST...WILL USHER DRIER AIR INTO THE REGION
LATE WEDNESDAY AFTERNOON/EVENING.  THIS WILL EFFECTIVELY BRING AN
END TO THE RAIN.

FORECAST CONFIDENCE WANES A BIT HEADING TOWARD THE END OF THE WEEK.
IT LOOKS LIKE AN UPPER LEVEL LOW WILL MOVE FROM THE PLAINS INTO
TEXAS TOWARD THE END OF THE WEEK.  DISCREPANCIES IN THE LOCATION AND
TIMING OF THIS FEATURE ARE RAMPANT WITHIN THE MEDIUM RANGE MODEL
WORLD THIS AFTERNOON.  THE MORE LIKELY SOLUTION BRINGS THE LOW
TOWARD THE SOUTHEAST TEXAS/SOUTHWEST LOUISIANA COAST BY SATURDAY.
BASED ON THIS TIMING...I DON`T SEE A RETURN OF SIGNIFICANT AMOUNTS
OF LOW-LEVEL MOISTURE IN ADVANCE OF THIS SYSTEM.  AS SUCH...I HAVE
KEPT ANY PRECIPITATION PROBABILITIES BELOW 15 PERCENT (DESPITE WHAT
GUIDANCE FROM THE LATEST MODEL BLENDS SUGGEST).

THANKS TO WFO CORPUS CHRISTI FOR COLLABORATION THIS AFTERNOON.  /53/


&&

.MARINE...

NOW THROUGH SUNDAY NIGHT...
MODEST SOUTHEAST WINDS CONTINUE TO PRODUCE SEAS IN THE 3 TO 4 FOOT
RANGE. WITH LOW PRESSURE DRIFTING AROUND THE BAY OF CAMPECHE AND
HIGH PRESSURE PASSING THROUGH THE LOWER MISSISSIPPI
VALLEY...GENERALLY ONSHORE FLOW WILL CONTINUE THROUGH THE NEXT 36
HOURS. WINDS WILL REMAIN AROUND 15 KNOTS THROUGH THE
PERIOD...KEEPING THE CURRENT SEA STATE THROUGH SUNDAY NIGHT. NO
FLAGS EXPECTED FOR THE REST OF THE WEEKEND. /64/

MONDAY THROUGH THURSDAY...
MODERATE WINDS AND SEAS ARE EXPECTED AS WE HEAD INTO THE LONG TERM
PORTION OF THE FORECAST.  INCREASING WIND SPEEDS AND BUILDING SEAS
WILL LIKELY BE SEEN OVER THE MARINE AREA BY TUESDAY NIGHT...THANKS
TO A TIGHTENING PRESSURE GRADIENT.  THIS MAY RESULT IN EITHER SMALL
CRAFT NEEDING TO EXERCISE CAUTION OR THE ISSUANCE OF SMALL CRAFT
ADVISORIES BY MID-WEEK.  SHOWERS AND STORMS WILL REMAIN POSSIBLE
THROUGH EARLY WEEK...UNTIL DRIER AIR MOVES INTO THE MARINE AREA
WEDNESDAY NIGHT.  /53/

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  74  84  73  84 /  20  20  20  30
BROWNSVILLE          73  85  71  85 /  20  20  20  30
HARLINGEN            71  84  69  85 /  20  30  20  30
MCALLEN              72  85  69  86 /  40  40  20  30
RIO GRANDE CITY      71  85  67  86 /  30  40  30  30
SOUTH PADRE ISLAND   77  83  76  83 /  20  20  20  30

&&

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

$$

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

SHORT TERM FORECASTER... STRAUB
LONG TERM FORECASTER... BUTTS
PSU/GRAPHICASTS... BIRCHFIELD





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