Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 271515
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1015 AM CDT SAT JUN 27 2015

.UPDATE...
TALE OF TWO ZONES THIS MORNING...OVERCAST OVER THE NORTHERN ZONES
IN RESPONSE TO THE (BECOMING) STATIONARY BOUNDARY LAYING SOMEWHERE
OVER THE PINEY WOODS/JUST NORTH OF THE CWA WITH THE CONTRAST OF
MAINLY SUNNY SKIES OVER THE SOUTHERN FORECAST AREA. THIS SCENARIO
WILL TIGHTEN THE REGIONAL THERMAL GRADIENT THAT MAY ALLOW THIS
SLOWING BOUNDARY TO SAG INTO THE CENTRAL CWA...AS WELL AS GENERATING
A SEA BREEZE BOUNDARY...AS SOUTHERN COUNTY AFTERNOON TEMPERATURES
WARM INTO THE LOWER 90S. THE MERGER OF THESE TWO FEATURES HAVE
THE POTENTIAL TO SET-UP A HEAVY RAIN EVENT LATTER TODAY AND INTO
THE EARLY SUNDAY MORNING HOURS...NEAR STATIONARY CLUSTERS OF
RAIN/STORMS FOCUSING HIGH RAINFALL RATES OVER THE SAME AREA(S).
31

&&

.PREV DISCUSSION... /ISSUED 652 AM CDT SAT JUN 27 2015/

AVIATION...
LOW CLOUDS AT KCLL AND KUTS AS WELL AS A BROKEN LINE OF TSRA
SKIRTING KCLL WILL TEMPORARILY IMPACT THESE TERMINALS THROUGH 14Z
THIS MORNING. THESE STORMS ARE AHEAD OF A WEAK COLD FRONT
/LOCATED OVER NORTH TEXAS EARLY THIS MORNING/ THAT WILL SLOWLY
PUSH SOUTH THROUGHOUT THE DAY TODAY. ANOTHER ROUND OF CONVECTION
IS EXPECTED FOR THE INLAND TERMINALS ALONG THE FRONT AS WELL AS
FOR COASTAL TERMINALS ALONG A NORTHWARD MOVING SEA BREEZE
GENERALLY AFTER 16-18Z. THE COLD FRONT IS EXPECTED TO STALL NORTH
OF INTERSTATE 10 BY THIS EVENING AND MAY SERVE AS A FOCUSING
MECHANISM FOR ADDITIONAL TSRA/SHRA DEVELOPMENT FOR KSGR/KHOU AND
NORTHWARD SUNDAY MORNING. OTHERWISE...ENVIRONMENTAL CONDITIONS
THIS AFTERNOON WILL BE SUPPORTIVE OF GUSTY WINDS AND LOCALLY HEAVY
RAIN IN ANY THUNDERSTORM WITH VFR CONDITIONS EXPECTED TO PREVAIL
OUTSIDE OF TSRA/SHRA. 14

&&

PREV DISCUSSION... /ISSUED 407 AM CDT SAT JUN 27 2015/

DISCUSSION...
SE TEXAS WAS IN THE WEAKNESS AREA OF A RIDGE THAT EXTENDED FROM
THE ROCKIES TO TEXAS TO ACROSS FL. OTHER WEATHER FEATURES OF NOTE
EARLY THIS MORNING WERE A 200 AND 300 MB LOW LOCATED OFFSHORE OF
THE S TEXAS COAST AND A COLD FRONT THAT WAS THROUGH THE PAN HANDLE
ACROSS N TEXAS. THE MAIN ITEMS OF CONCERN FOR THIS FORECAST
INCLUDE...

- ISOLATED STRONG OR SEVERE STORMS TODAY WITH A WIND THREAT
- LOCALLY HEAVY RAINFALL THREAT TODAY AND TONIGHT

REGARDING THE WIND THREAT...THE NAMBUFR MODEL SOUNDINGS SHOW AN
INVERTED V PROFILE UP TO 850 MB INDICATING A SLIGHT THREAT MAINLY
THIS AFTERNOON.

LOCALLY HEAVY RAINFALL MAY BE MORE ISOLATED DUE TO TRAINING OF
STRONGER STORMS ALONG EITHER THE COLD FRONT OR ANY OUTFLOW
BOUNDARIES THAT MOVE OUT AHEAD OF THE FRONT. PW/S ARE FORECAST TO
REACH BETWEEN 2 AND 2.4 INCHES DEPENDING ON THE MODEL. A
CONSENSUS OF THE HIGHER RESOLUTION MODELS SHOWED THE POTENTIAL
THIS AFTERNOON AND EVENING. DO LIKE THE ASSESSMENT GIVEN THE UPPER
LOW DRIFTING OVER THE WESTERN GULF AND THE FRONTAL BOUNDARY
SINKING SOUTHWARD. FOR THE FORECAST...WENT WITH LOCALLY HEAVY
RAINFALL WITH POPS GREATER THAN OR EQUAL TO 50 PERCENT.

AS OPPOSED TO YESTERDAY...THE FRONT DOES NOT LOOK TO MAKE ITS WAY
ALL THE WAY TO THE COAST ALTHOUGH AN OUTFLOW MAY BRIEFLY PRODUCE
AN OFFSHORE WIND SHIFT OVER GALVESTON BAY AND THE NEARSHORE GULF
WATERS LATE SUNDAY.

THE REMAINDER OF THE FORECAST THE WEAKNESS ALOFT REMAINS OVER THE
AREA THROUGH AT LEAST MID WEEK. THE WEAKENING FRONTAL BOUNDARY
WILL PROVIDE FOR AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS ON
MONDAY THROUGH WEDNESDAY. THE RIDGE BUILDS OVERHEAD A BIT MORE AND
HELPS DRY OUT THINGS ON THURSDAY AND FRIDAY. 40

&&

MARINE...
A LIGHT TO OCCASIONALLY MODERATE SOUTHWEST FLOW IS EXPECTED TO
CONTINUE THROUGH MONDAY AS SURFACE HIGH PRESSURE REMAINS CENTERED
OVER THE GULF OF MEXICO...WITH SHOWER AND THUNDERSTORM CHANCES
PERSISTING OVER THE NEXT SEVERAL DAYS. A FRONTAL BOUNDARY LOCATED
SOUTH OF THE RED RIVER EARLY THIS MORNING WILL CONTINUE TO SAG
TOWARDS SOUTHEAST TEXAS TODAY...STALLING SOMEWHERE NORTH OF INTERSTATE
10 THIS EVENING AND WASHING OUT ON SUNDAY. INCREASING ONSHORE WINDS
AND WAVES EXPECTED BY THE MIDDLE OF NEXT WEEK AS A SERIES OF LOW
PRESSURE SYSTEMS CROSS THE CENTRAL PLAINS. 14

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      90  74  90  74  91 /  60  40  30  10  30
HOUSTON (IAH)              92  75  91  74  91 /  40  60  50  20  40
GALVESTON (GLS)            90  78  89  79  89 /  30  50  50  30  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL NOON CDT TODAY FOR THE
     FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
     CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE
     MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
     TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
     FREEPORT OUT 20 NM.

&&

$$

DISCUSSION...31/33



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