Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 241731
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1131 AM CST WED DEC 24 2014

.AVIATION...
LOW TO MID LEVEL STRATO-CU DECK CONTINUES TO SHIFT SLOWLY ACROSS
MOST SITES LATE THIS MORNING. REGARDLESS...VFR CONDITIONS WILL BE
THE NORM THROUGH THE FORECAST PERIOD.  WINDS WILL BE THE MAIN
CONCERN WITH GUSTY NORTH WINDS TODAY WHICH WILL QUICKLY
DIMINISHING AROUND SUNSET. EXPECT WINDS TO INCREASE OUT OF THE
SOUTH BY MID TO LATE MORNING CHRISTMAS DAY.

48

&&

.PREV DISCUSSION... /ISSUED 948 AM CST WED DEC 24 2014/

UPDATE...
SEE MORNING UPDATE.

DISCUSSION...
12Z SOUNDINGS SHOW DRY AIR ENTRENCHED OVER MUCH OF SOUTH AND
SOUTHEAST TEXAS. SOUNDINGS SUPPORT MAX TEMPS WARMING INTO THE
UPPER 50S. CURRENT FCST ALREADY HAS THIS COVERED. OTHER THAN SOME
MINOR TWEAKS TO SKY GRIDS...PREV FCST IS IN GOOD SHAPE. WEATHER
ACROSS SE TX (TODAY AND THURSDAY) SHOULD NOT IMPEDE TRAVEL PLANS
OR LAST MINUTE SHOPPING. 43

PREV DISCUSSION... /ISSUED 522 AM CST WED DEC 24 2014/

DISCUSSION...

SEE AVIATION.

AVIATION...

STRATO CU DECK 4-6KFT MOVING SE ACROSS NORTHERN TAF SITES THIS
MORNING. WILL SEE SCT-BKN CONDITIONS LATER THIS MORNING IAH AND
SOUTH. NW WINDS WILL INCREASE INTO THE 10-15 KT RANGE WITH HIGHER
GUSTS LATER THIS AM. LIGHT WINDS THIS EVE AND INTO TOMORROW
MORNING. 33

PREV DISCUSSION... /ISSUED 446 AM CST WED DEC 24 2014/

DISCUSSION...
STRATOCU ASSOCIATED WITH THE UPPER TROUGH OVER CENTRAL TEXAS
ROTATING INTO EASTERN TEXAS THIS MORNING...THE TROUGH AXIS WILL BE
EAST OF THE REGION BY EARLY AFTERNOON. THE FOLLOWING DRY NORTHWEST
FLOW PATTERN WILL NOT LAST LONG AS SURFACE RIDGING OVER SOUTHERN
TEXAS TRANSITIONS TO THE CENTRAL GULF COAST/U.S. SOUTHEASTERN
STATES BY CHRISTMAS MORNING AND INITIATES RETURN FLOW. THUS...AFTER
A DRY AND COOL CHRISTMAS EVE DAY WITH THE AFTERNOON ONLY WARMING
INTO THE LOW TO MID 50S... RETURNING ONSHORE WINDS CHRISTMAS DAY
WILL WARM THE DAY FROM THE CHILLED INTERIOR MID 30S/COASTAL MID-
UPPER 40S BACK INTO THE AVERAGE LOWER 60S (NORMAL FOR 30 YEAR LATE
DECEMBER STANDARDS).

WESTERN PACIFIC ENERGY MOVING INTO THE PAC NW TODAY WILL AID IN
DEVELOPING A GREAT BASIN 5H TROUGH GOING INTO FRIDAY...NEARLY
HALTING ITS EASTERN PROGRESSION OVER THE ROCKIES FRIDAY INTO
SATURDAY. AS THE UPPER LEVELS STALL...THE SURFACE LEE LOW WILL
MOVE INTO THE SOUTHERN PLAINS EARLY SATURDAY AND DRAG A WEAK COLD
FRONT INTO CENTRAL TEXAS OVERNIGHT SATURDAY MORNING. DESPITE THE
UPPER TROUGH HANGING BACK INTO THE DESERT SOUTHWEST...THE BACKING
SURFACE HIGH IS FORECAST TO BE STRONG ENOUGH (AROUND 1028 MB) TO
PUSH A MODERATELY STRONG COLD FRONT THROUGH THE CWA LATE SATURDAY.
SLIGHT RAIN CHANCES FOR STREAMER-LIKE SHOWERS FRIDAY DUE TO LOWER
OVERALL MOISTURE PER SLUGGISH PWAT RETURN AND A DOMINANT SW FLOW
PATTERN (PARALLEL TO MID-UPPER WINDS DOWNSTREAM OF WESTERN TROUGH
AXIS) SHUNTING HIGHEST PW AIR TO THE GULF. THE PROBABILITY OF EARLY
SATURDAY (SEA) FOG IS INCREASING AS MID-UPPER 60 F DEW POINT AIR
RIDES OVER SHALLOWER GULF WATER TEMPS IN THE LOWER 60S. THE ADVECTION
OF SEA FOG INTO THE SOUTHERN CWA IS MENTIONABLE WITH RADIATIVE
BEING NOT AS LIKELY PER A PRECEDING DAY OR TWO OF OVERCAST SKIES
AND ROBUST SE-S LOWER LEVEL WINDS. THE HIGHEST CHANCE FOR SHOWERS
AND ISOLATED THUNDERSTORMS WILL BE OVER THE WEEKEND AS THE UPPER
TROUGH FINALLY KICKS OUT INTO THE ARKLATEX BY LATE SUNDAY-EARLY
MONDAY. UPPER LEVEL SUPPORT IS THERE FOR A WIDESPREAD PRECIPITATION
EVENT AS SOUTHEAST TEXAS FALLS UNDER THE RIGHT REAR QUAD OF THE
25H JET...WITH BETTER SATURATION OF THE ENTIRE COLUMN AS PWATS
ARE MODELED TO LIFT TO AROUND 1.3 TO 1.5 INCHES SUNDAY...SLIGHTLY
UNDER 2 STANDARD DEVIATIONS FOR THIS TIME OF YEAR.

THE NWP SUITE BEGINS TO DIVERGE THE LAST FEW DAYS OF THE YEAR INTO
2015 WITH RESPECT TO THE TIMING OF THE 5H PATTERN...BUT ALL THREE
(GFS/ECMWF/CANADIAN) ALL COME UP WITH A FORTIFIED COLDER AND MORE
WET PATTERN DURING THE FINAL DAYS OF THE YEAR. WHILE WINDS MAY
BECOME VARIABLE MONDAY...THE SUITE ALL PUSH A COLD FRONT THROUGH
THE REGION TUESDAY WITH A EFFICIENT WARM AIR ADVECTION UPGLIDE
SCENARIO INCREASING SUBTLE POPS (MAINLY SHOWERS). IF THE GFS IS
THE FAVORED SOLUTION...THEN A 1040-ISH MB HIGH WILL DESCEND FROM
THE CENTRAL PLAINS OVER NEW YEAR`S AND DRAG IN A BITTERLY COLD
CONTINENTAL-IN-ORIGIN AIR MASS INTO SE TX. THE 85H 0C LINE IS
MODELED TO REACH THE COASTLINE AROUND NEW YEAR`S EVE. CURRENTLY
THIS TRANSLATES TO A COLD AND BREEZY EVENING WITH A WIND CHILL
BITE...AMBIENT UPPER 30S TO LOWER 40S WITH AN INLAND 5-10 KT NORTH
WIND/BLUSTERY AT COAST WITH A 15-20 KT WIND TO RING IN 2015. 31

MARINE...
STILL SEEING SCA CONDITIONS OFFSHORE WITH SUSTAINED NW WINDS
22-28 KTS AND 9 FOOT SEAS WELL OFFSHORE. WILL HAVE AN SCA THROUGH
THE MORNING HOURS. WILL HAVE A CAUTION STATEMENT FOR THE BAYS TO
ACCOUNT FOR MORNING 15-20 KTS WINDS. WINDS WILL CONTINUE TO SUBSIDE
DURING THE DAY TODAY. ONSHORE FLOW WILL DEVELOP QUICKLY ON THURSDAY
AND REACH CAUTION CRITERIA AND POSSIBLY SCA CRITERIA WELL OFFSHORE
ON THU NIGHT. ANOTHER COLD FRONT WILL CROSS THE MARINE AREA LATE
SATURDAY. TIDES ARE CURRENTLY ABOUT 1 FOOT BELOW NORMAL IN THE
UPPER BAYS. WILL BE HEADING INTO A LOW TIDE THIS AFTERNOON...BUT
DEPARTURES FROM NORMAL SHOULD BE LESS BY THEN...SO NO LOW WATER
ADVISORY IS EXPECTED. 33

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      53  34  61  49  68 /   0   0   0  10  20
HOUSTON (IAH)              55  35  63  54  71 /   0   0   0  10  20
GALVESTON (GLS)            55  47  62  59  68 /   0   0   0  10  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL NOON CST TODAY FOR THE
     FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY.

     SMALL CRAFT ADVISORY UNTIL NOON CST 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...43
AVIATION/MARINE...48


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