Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 290347
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
947 PM CST WED JAN 28 2015

.UPDATE...

WILL ISSUE A DENSE FOG ADVISORY FOR AREAS SOUTHWEST OF HOUSTON.
VISIBILITIES HAVE BEGUN TO DROP AND WINDS HAVE RELAXED A BIT. 43

&&

.PREV DISCUSSION... /ISSUED 823 PM CST WED JAN 28 2015/

UPDATE...
SEE EVENING UPDATE.

DISCUSSION...
AT 8 PM...SURFACE HIGH PRESSURE WAS LOCATED OVER THE NORTHERN GULF
COAST WITH A TROUGH LOW PRESSURE EXTENDING FROM EASTERN KANSAS
INTO NORTH CENTRAL TEXAS. THE PRESSURE GRADIENT BETWEEN THESE TWO
FEATURES IS RATHER TIGHT SO NOT EXPECTING WINDS TO FULLY DECOUPLE
OVERNIGHT. SFC TEMPS HAVE FALLEN TO NEAR THE DEW PT OVER THE SW
ZONES AND RAP13 FCST SOUNDINGS SHOW A VERY FAVORABLE PROFILE FOR
FOG DEVELOPMENT TONIGHT. THE HRRR IS HINTING AT FOG WITH
VISIBILITIES DROPPING TO BELOW A 1/2 MILE TONIGHT BUT JUST NOT
CONFIDENT ENOUGH TO GO WITH DENSE FOG AT THIS TIME DUE TO THE
SLIGHTLY STRONGER WINDS. WILL WATCH TRENDS CLOSELY AND IF WINDS
RELAX...A DENSE FOG ADVISORY MAY BE REQUIRED FOR THE SW HALF OF
THE REGION. 43

PREV DISCUSSION... /ISSUED 608 PM CST WED JAN 28 2015/

DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.

40

AVIATION...
THE SURFACE HIGH PRESSURE WAS SITUATED OVER THE GULF AT 6 PM AND A
SOUTHERLY FLOW WAS IN PLACE ACROSS SE TEXAS. THE NAM12 TRIES TO
RE-ESTABLISH THE RIDGE INTO THE COASTAL AREAS TONIGHT...AND THE
SURFACE WINDS SHOULD BECOME FAIRLY LIGHT. CLEAR SKIES OVERHEAD
AND A SLIGHTLY HIGHER SURFACE MOISTURE CONTENT WILL LEAD TO THE
POTENTIAL FOR AT LEAST PATCHY FOG FORMATION OVERNIGHT TONIGHT AND
THURSDAY MORNING. IF THE FOG DOES FORM...IT SHOULD BE MORE
PREVALENT OVER THE MORE RURAL SITES. AFTER 15Z...VFR CONDITIONS
ARE EXPECTED.

40

PREV DISCUSSION... /ISSUED 348 PM CST WED JAN 28 2015/

DISCUSSION...
UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE CENTERED OVER THE
SOUTHEASTERN TEXAS GULF HAS MADE FOR A MOSTLY CLEAR DAY ACROSS
THE AREA WITH THE EXCEPTION OF A FEW CIRRUS. MANY AREAS ACROSS
SOUTHEAST TEXAS HAVE MADE IT INTO THE UPPER 70S...AND IN A FEW
AREAS INTO THE LOW 80S. FOG WILL FORM OVERNIGHT AND HAVE ADDED PATCHY
FOG TO THE GRIDS. TOMORROW`S TEMPERATURES WILL A BIT COOLER DUE TO
MORE CLOUD COVER ASSOCIATED WITH THE NEXT COLD FRONT THAT SHOULD
MOVE THROUGH THE AREA THURSDAY AFTERNOON AND NIGHT. NO QPF IS
EXPECTED WITH THE FRONT. THE GFS IS THE FASTEST WITH BRINGING THE
FRONT THROUGH SOUTHEAST TEXAS AND HAVE LEANED MORE TOWARDS A
SOLUTION OF THE NAM/ECMWF DUE TO A LACK OF STRONG UPPER LEVEL
SUPPORT. BEHIND THE FRONT...TEMPS WILL FALL 10-20 DEGREES WITH
FRIDAY MORNING LOWS IN THE 40S AND HIGHS IN THE MIDDLE TO UPPER
50S.

ON SATURDAY A TRANSITION FROM A WESTERLY TO SOUTHWESTERLY FLOW
ALOFT OCCURS AS THE NEXT UPPER LEVEL TROUGH MOVES EASTWARD. THERE
MAY BE A FEW ISOLATED SHOWERS SATURDAY AFTERNOON DUE TO A SHORT
WAVE THAT WILL MOVE INTO THE AREA AHEAD OF THE UPPER LEVEL TROUGH.
GFS AND NAM SOUNDINGS DO NOT SHOW A PARTICULARLY MOIST COLUMN
DURING THE DAY ON SATURDAY. STILL...AN IMPULSE OF ENERGY AHEAD OF
THE MAIN UPPER LEVEL SYSTEM MAY BE ENOUGH FOR A FEW VERY LIGHT
SHOWERS.

THE NEXT COLD FRONT WILL MOVE THROUGH SOUTHEAST TEXAS ON
SUNDAY AFTERNOON AND EVENING. BOTH THE GFS AND ECMWF AGREE ON
FRONTAL TIMING...HAVING IT OFF THE COAST BY MONDAY AROUND 6Z
(MIDNIGHT). PRECIPITATION LOOKS TO MAINLY BE ALONG AND BEHIND THE
FRONT...WITH PRECIP TAPERING BY LATE SUNDAY NIGHT INTO EARLY
MONDAY MORNING. MIN TEMPS BEHIND THE COLD FRONT FOR MONDAY AND
TUESDAY COULD FALL INTO THE UPPER 30S FOR AREAS NORTH OF
INTERSTATE 10.

A FAIRLY UNSETTLED PATTERN REMAINS FOR THE NEXT WORK WEEK DUE TO
AN UPPER TROUGH TO THE SOUTHWEST OF THE AREA. A SERIES OF
DISTURBANCES WILL FORM AHEAD OF THE TROUGH AND MOVE INTO SOUTHEAST
TEXAS...GIVING A LOW TO MODERATE CHANCE OF PRECIP NEXT WEEK. 13

MARINE...
NAM IS STILL FORMING SEA FOG OVERNIGHT WITH THE SREF ALSO
HINTING AT SOME SEA FOG. WATER TEMPERATURES ARE IN THE UPPER 50S
ALONG THE COAST AND DEWPOINTS IN THE GULF ARE CURRENTLY ONLY IN THE
UPPER 50S. DUE TO THIS... CONFIDENCE HAS LOWERED ON THE FORMATION OF
SEA FOG. TIMING OF TOMORROWS FRONT IS STILL IN SOME DISAGREEMENT.
THE GFS PUSHES THE FRONT OFF THE COAST THURSDAY EVENING WHILE THE
EURO IS A TAD SLOWER. THE NAM IS EVEN SLOWER MOVING THE FRONT OVER
THE WATERS FRIDAY MORNING. FOR NOW HAVE LEANED TOWARDS THE EURO
COMPROMISE WHICH WOULD ALLOW WINDS OVER THE WATERS TO REACH CAUTION
CRITERIA FRIDAY MORNING. WINDS WILL THEN QUICKLY VEER TO THE
NORTHEAST AND KEEP AN EASTERLY COMPONENT THROUGH SATURDAY. SOME
ELEVATED TIDES ARE POSSIBLE SATURDAY. SUNDAY EVENING ANOTHER
STRONGER FRONT WILL MOVE OVER THE WATERS. ADVISORY CONDITIONS WILL
BE POSSIBLE. 23

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      53  72  43  57  45 /   0  10  10  10  20
HOUSTON (IAH)              54  73  47  60  46 /   0  10  10  10  10
GALVESTON (GLS)            56  70  51  57  50 /   0  10  10  10  10

&&

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

$$

DISCUSSION...43



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