Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 181151
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
551 AM CST THU DEC 18 2014

.AVIATION...
COMPLICATED AND LOW CONFIDENCE FORECAST FOR THE 12Z TAFS. CURRENT RADAR
TREND AND LATEST HIGH RES MODELS POINT TOWARD AREAS OF RA/SHRA SAGGING
SOUTHWARD TOWARD THE COAST DURING THE DAY TODAY...SO WENT AHEAD AND
INDICATED A BREAK IN THE ACTIVITY CENTRAL AND NORTH. CURRENT CEILINGS
AND VISIBILITIES RANGE FROM IFR AT BOTH CLL AND UTS TO VFR AT GLS.
AREA COULD SEE A COMBO OF MVFR/VFR CEILING DEVELOPMENT DURING THE
DAY TODAY. MODELS INDICATE INCREASING RA/SHRA COVERAGE AFTER 19/00Z
AND ESPECIALLY DURING THE 19/06Z THRU 19/18Z TIME PERIOD AS A STORM
SYSTEM MOVES EASTWARD ACROSS THE AREA. CARRIED PREVAILING SHRA AT
MOST SITES STARTING AT 19/06Z ALONG WITH MAINLY IFR CEILINGS. WE
WILL ALSO NEED TO MONITOR FOR POSSIBLE TSRA DEVELOPMENT TOMORROW...
ESPECIALLY NEAR THE COAST. LOOKS LIKE IMPROVING FLYING CONDITIONS
BEGINNING TOMORROW AFTER 18Z AS A COLD FRONT WORKS ITS WAY THROUGH
THE AREA FROM WEST TO EAST AND BEGINS TO DRY THINGS OUT.  42
&&

.PREV DISCUSSION... /ISSUED 434 AM CST THU DEC 18 2014/

DISCUSSION...
SHOWERS HAVE DEVELOPED THIS MORNING AND EXPANDED A BIT IN COVERAGE
THROUGH THE CENTRAL PARTS OF THE CWA WITH SOME SHOWERS IN THE
COASTAL WATERS. HIGH RES MODELS HAVE BEEN A BIT BEHIND THIS
MORNING WITH TAKING LONGER TO PUSH THE SHOWERS TO THE SOUTH THAN
CURRENT TRENDS. THERE IS ALSO A WARM FRONT THAT WAS ANALYZED THIS
MORNING JUST NORTH OF THE COASTAL SITES FROM AROUND A PSX TO LBX
TO GLS LINE. AT 250 MB THERE WAS ALSO AN IMPRESSIVE JET OF 125 KTS
ANALYZED OVER THE MIDLAND AREA.

THE FORECAST IS FOR THE WARM FRONT TO REMAIN QUASI- STATIONARY
OVER THE COASTAL COUNTIES TODAY BEFORE SAGGING SOUTH AS SHOWERS
AND THUNDERSTORMS FORM ALONG THE BOUNDARY. HIGH TEMPERATURES WILL
BE HIGHLY DEPENDENT ON THE LOCATION OF THE WARM FRONT TODAY. BASED
OFF OF CURRENT TRENDS HAVE GONE SLIGHTLY COOLER TOWARDS THE
NORTHERN AREAS AND CONFINED THE WARMER TEMPERATURES CLOSER TO THE
COAST AS THE WARM FRONT IS EXPECTED NOT TO MAKE IT AS FAR INLAND
AS PREVIOUSLY FORECASTED. HIGH RES AND GLOBAL MODELS ARE IN GOOD
AGREEMENT WITH THE RAIN PUSHING TO THE SOUTH TODAY AND BY THIS
AFTERNOON HAVING MOST OF THE COVERAGE CONFINED SOUTH OF A
COLUMBUS TO SPRING TO CLEVELAND LINE. GFS 300 K SURFACE ALSO SHOWS
MOST OF THE OVERRUNNING WITH BEST MOISTURE CONFINED TO THE COAST
TODAY. LATE THURSDAY EVENING COVERAGE WILL START TO DRASTICALLY
INCREASE THANKS TO A POTENT SHORTWAVE AND MUCH MORE CONDUCIVE JET
PLACEMENT. BOTH NAM AND GFS OMEGA VALUES ARE AGAIN IMPRESSIVE
THANKS TO WIDESPREAD PVA (FROM APPROACHING SHORTWAVE) AND WAA. THE
JET ALSO IS FORECASTED TO BEGIN TO SPLIT FRIDAY MORNING. THE
PLACEMENT OF THE SPLIT IS NOT AS FAVORABLE AS YESTERDAY BUT STILL
PROVIDES MORE THAN SUFFICIENT LIFT. GIVEN THE IMPRESSIVE LIFT AND
MOISTURE VALUES (PWATS ~ 1.50") HAVE RAISED POPS FOR FRIDAY
MORNING. RAIN WILL START TO COME TO AN END FRIDAY AFTERNOON
STARTING IN OUR WESTERN COUNTIES AND PROGRESSING TO THE EAST
THANKS TO THE BEST UPPER LEVEL LIFT AND MOISTURE MOVING OUT OF THE
AREA. A SURFACE LOW WILL ALSO FORM FRIDAY MORNING AND MOVE TO THE
NORTHEAST AND PULL A COLD FRONT THROUGH FOR THE WEEKEND. CLOUDS
LOOK TO REMAIN AROUND FOR THE WEEKEND THOUGH WHICH WILL HELP TO
KEEP TEMPERATURES SLIGHTLY BELOW NORMAL.

ON SUNDAY ANOTHER UPPER LEVEL DISTURBANCE WILL MOVE OVERHEAD BUT
WITH PWATS BELOW 0.8" AND SOUTHEAST TEXAS IN THE CONVERGENT REGION
OF THE UPPER JET NO RAIN IS EXPECTED. BY TUESDAY ANOTHER UPPER
LEVEL LOW WILL PUSH DOWN INTO IOWA ALLOWING A FRONT TO PUSH
THROUGH THE AREA TUESDAY MORNING. BOTH THE GFS AND EURO ARE IN
PRETTY GOOD AGREEMENT BRINGING THE FRONT TO THE COAST BY 6 AM
TUESDAY MORNING. SURFACE HIGH PRESSURE WILL THEN FILTER INTO THE
AREA CHRISTMAS EVE MORNING BUT QUICKLY START TO PULL TO THE EAST.
THIS MEANS THAT AS OF NOW CHRISTMAS LOOKS TO BE ABOVE NORMAL AS
SOUTHEAST WINDS RETURN TO THE AREA. 23

MARINE...
ONSHORE WINDS...AREAS OF RAIN...AND SOME SHOWERS AND THUNDERSTORMS
CAN BE EXPECTED THROUGH FRIDAY. FOG IS POSSIBLE TOO. A COLD FRONT
WILL MOVE THROUGH ON FRIDAY AND WILL BRING AN END TO THE RAINS AND
FOG. MODERATE TO STRONG OFFSHORE WINDS AND ELEVATED SEAS WILL
DEVELOP IN THE WAKE OF THE FRONT...AND ADVISORIES WILL LIKELY BE
NEEDED. WINDS AND SEAS ARE EXPECTED TO COME DOWN LATE SATURDAY OR
SATURDAY NIGHT AS HIGH PRESSURE BUILDS IN FROM THE NORTH AND
NORTHEAST. ONSHORE WINDS RETURN ON MONDAY AND STRENGTHEN MONDAY
NIGHT AHEAD OF THE NEXT COLD FRONT THAT IS EXPECTED TO SWEEP THROUGH
THE AREA ON TUESDAY. 42

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      64  52  55  46  58 /  20  90  80  10   0
HOUSTON (IAH)              68  57  62  46  60 /  60  80  80  20  10
GALVESTON (GLS)            71  61  66  50  58 /  70  80  80  20  10

&&

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

$$

DISCUSSION...23
AVIATION/MARINE...42



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