FXUS64 KHGX 041141
AFDHGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
541 AM CST FRI DEC 4 2009
.DISCUSSION...
12Z TAF DISCUSSION.
&&
.AVIATION...
REGIONAL RADAR SHOW AN AREA OF RAIN OVER THE COASTAL BEND MOVING
TOWARDS THE NE. THIS AREA OF RAIN SHOULD AFFECT KLBX...KGLS...KSGR
AND KHOU THIS MORNING. THIS WILL HELP MOISTEN THE ATMOSPHERIC
COLUMN SO THAT WHEN THE NEAR FREEZING AIR AT THE SURFACE DOES
ARRIVE...SNOW SHOULD DEVELOP ALONG THE COAST FOR THE AFTERNOON.
FARTHER NORTH THERE MAY BE A SUBTLE CHANGE OVER FROM RAIN TO SNOW
BUT THE RAIN MAY FALL MORE AS VIRGA ACTING TO MOISTEN AND COOL THE
ATMOSPHERE IN THE PROCESS. THIS MAY LEAD TO PRECIP FALLING AS JUST
SNOW RATHER THAN A TRANSITION. THE LIGHT RAIN FROM THE SW MAY MOVE
INTO KIAH BUT THE RAIN MAY STAY JUST TO THE SOUTH. OTHERWISE ALL
TAFS NORTH OF KIAH WILL JUST HAVE SN WITH NO MENTION OF RAIN. THE
AFTERNOON TIME FRAME FROM 18Z FRI TO 00Z SAT SEEMS TO BE THE BEST
TIME FOR ANY HEAVY SNOWFALL SO WILL KEEP TEMPO GROUP FOR LIFR
VIS/CIGS AS WELL AS MODERATE SNOW. THE UPPER LEVEL TROUGH SHOULD
SWING THROUGH FAIRLY QUICKLY SO THAT BETWEEN 03Z AND 06Z SAT
CEILINGS BEGIN TO LIFT WITH SNOW FLURRIES TAPERING OFF. EXPECT
CLEAR SKIES AFTER 06Z SAT. STRONG NORTHERLY WINDS DURING THE DAY
WILL ALSO HELP LIMIT VIS WITH ANY HEAVIER SNOWFALL. WINDS WILL
DROP OFF OVERNIGHT AS HIGH PRESSURE SETTLES OVER THE REGION.
39
&&
.PREV DISCUSSION... /ISSUED 503 AM CST FRI DEC 4 2009/
..MODERATE TO HEAVY SNOW TO DEVELOP OVER THE REGION TODAY...
DISCUSSION...
COLD HIGH PRESSURE CONTINUES TO SETTLE INTO THE AREA WITH
TEMPERATURES IN THE 40S AT THIS TIME AND THESE WILL BE THE HIGHEST
TEMPS OF THE DAY...BY LATE MORNING THE INLAND AREAS WILL BE IN THE
30S. LIGHT RAIN SHOULD DEVELOP OVER PARTS OF THE AREA THIS MORNING
BUT THE FAR WESTERN PORTIONS OF BRAZOS AND BURLESON MAY SKIP THIS
PHASE OF PRECIP. AS THE VIGOROUS UPPER TROUGH DIGS DOWN INTO
CENTRAL TEXAS THE AFTERNOON THE PROFILES ACROSS SETX SUPPORT RAINS
ENDING AND SWITCHING OVER TO ALL SNOW BY AROUND 1 PM FOR AREAS
WEST OF HIGHWAY 59. AFTER FOCUSING ON THE 00Z RUNS HAVE EXPANDED
THE WINTER STORM WARNING NORTH TO INCLUDE HOUSTON AND MADISON
COUNTIES. SOME THINGS OF CONCERN IS THE POSSIBILITY OF HEAVY BANDS
OF SNOW SETTING UP THIS AFTERNOON FROM SW TO NE THROUGH MAINLY THE
CENTRAL ZONES. HAVE RAISED THE SNOW AMOUNTS TO WIDESPREAD 1-2" AND
ISOLATED 3 TO 4" BUT IF THE BANDS PERSIST THE COUNTIES IN THE
WARNING EAST OF 45 COULD SEE GREATER AMOUNTS. THE WARM GROUND WILL
CERTAINLY HELP TO MELT SNOW THAT FALLS EARLY THIS AFTERNOON BUT
THE STRONG CAA AND MELTING WILL LIKELY LEAD TO BRIDGES AND
ELEVATED ROADS ICING UP LATE THIS AFTERNOON AND EVENING...PERHAPS
BY MID AFTERNOON ACROSS THE NORTH. BREEZY TO WINDY CONDITIONS ON
TAP AND COMBINED WITH THE COLD AFTERNOON TEMPERATURES THE WIND
CHILL INDEX READINGS OF 20-25 DEGREES WILL RULE FROM NOON THROUGH
9-10 AM SATURDAY SO DRESS WARMLY. THE SNOW SHOULD BE COMING TO AN
END BY 6 TO 9 PM AS THE SYSTEM EXITS EAST. THE SNOW COVER AND
CLEARING SKIES WILL LEAD TO A VERY COLD NIGHT WITH TEMPERATURES
ALONG AND NORTH OF 59 IN THE 21-25 DEGREE RANGE BY MORNING.
TEMPERATURES ON SATURDAY WILL CREEP UP SLOWLY IN THE MORNING WITH
MOST OF HEATING GOING INTO MELTING THE SNOW...DURING THE AFTERNOON
TEMPERATURES COULD REACH THE 40S...BUT CONFIDENCE ON SPECIFIC
TEMPS IS NOT VERY HIGH FOR SATURDAY.
HIGH PRESSURE SHIFTS EAST SATURDAY NIGHT AND ANOTHER QUICK SHOT OF
RAIN SUNDAY AFTERNOON FOLLOWED BY ANOTHER ON TUESDAY. THE EVENT
TUESDAY MAY BE CONFINED THE EASTERN HALF OF THE AREA. QUIET
WEATHER WEDNESDAY AND THURSDAY.
45
MARINE...
HIGH PRESSURE CONTINUES TO MOVE INTO TEXAS WITH AN AREA OF LOW
PRESSURE DEVELOPING OFF THE LOWER TX COAST. THE MAIN TRENDS FOR
TODAY WILL BE INCREASING NORTHERLY WINDS IN OFFSHORE AREAS DUE TO
THE DEEPENING AREA OF LOW PRESSURE IN THE GULF OF MEXICO. GENERALLY
SUSTAINED WINDS WILL BE IN THE 25 TO 30 KNOT RANGE BUT COULD SEE
SOME SUSTAINED WINDS TO NEAR GALE FORCE. WIND GUSTS IN EXCESS OF
GALE FORCE WILL BE POSSIBLE AND COULD APPROACH 40 KNOTS IN SOME
OFFSHORE AREAS. SEAS SHOULD BUILD TO 9 TO 12 FEET IN OFFSHORE AREAS
AND ROUGH CONDITIONS WILL LIKELY LAST THROUGH THE EARLY EVENING
HOURS. GALE WARNING HAS BEEN POSTED FOR THE 20-60NM WATERS UNTIL
03Z SAT. SCA CONDITIONS WILL PERSIST INTO SAT MORNING. CONDITIONS
SHOULD IMPROVE RAPIDLY ON SATURDAY AS THE HIGH PRESSURE RIDGE
SETTLES OVER SE TX. WINDS WILL THEN TURN BACK TO THE SE SUN AS A
SURGE OF MOISTURE OVERRIDES THE COLDER AIRMASS ON SUN GIVING ANOTHER
SHOT OF RAIN.
39
AVIATION...
CONDITIONS AT AREA TERMINALS WILL LIKELY DETERIORATE RAPIDLY TODAY.
A STRONG WINTER STORM SYSTEM WILL MOVE OVER SE TX TODAY WHICH WILL
LIKELY SUPPORT RAIN CHANGING TO SNOW DURING THE DAY AS TEMPERATURES
DROP TO FREEZING. BEST CHANCE OF SNOW WILL LIKELY BE IN THE LATE
MORNING THROUGH THE AFTERNOON GENERALLY FROM 15Z THROUGH 00Z SAT.
VISIBILITY WILL LIKELY BE RESTRICTED IN ANY HEAVIER SNOW BANDS
MAKING LIFR/IFR CONDITIONS A HIGH POSSIBILITY ESPECIALLY DURING THE
AFTERNOON HOURS. CONDITIONS WILL LIKELY IMPROVE AFTER 00Z SAT WITH
CEILINGS LIFTING THROUGH 06Z SAT AS THE STORM SYSTEM EXITS SE TX.
WINDS WILL BE STRONG AND GUSTY FROM THE NORTH WHICH WITH SNOWFALL
WILL CONTRIBUTE TO POOR VISIBILITY DURING THIS TIME. WINDS WILL
DECREASE GENERALLY AFTER 03Z SAT.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 36 23 49 37 56 / 90 0 0 10 30
HOUSTON (IAH) 40 24 46 38 57 / 100 20 0 10 50
GALVESTON (GLS) 45 32 52 49 60 / 90 50 0 10 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FREEZE WARNING FROM NOON TODAY TO 9 AM CST SATURDAY FOR THE
FOLLOWING ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...
CHAMBERS...COLORADO...FORT BEND...GALVESTON...GRIMES...
HARRIS...HOUSTON...JACKSON...LIBERTY...MADISON...
MATAGORDA...MONTGOMERY...POLK...SAN JACINTO...TRINITY...
WALKER...WALLER...WASHINGTON...WHARTON.
WINTER STORM WARNING FROM 10 AM THIS MORNING TO 8 PM CST THIS
EVENING FOR THE FOLLOWING ZONES: BRAZORIA...CHAMBERS...FORT
BEND...GALVESTON...GRIMES...HARRIS...HOUSTON...LIBERTY...
MADISON...MONTGOMERY...POLK...SAN JACINTO...TRINITY...
WALKER...WALLER.
WINTER WEATHER ADVISORY UNTIL 8 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: AUSTIN...BRAZOS...BURLESON...COLORADO...
JACKSON...MATAGORDA...WASHINGTON...WHARTON.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING
ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM CST
SATURDAY FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO
THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
HIGH ISLAND TO FREEPORT 20 TO 60 NM.
GALE WARNING FROM 9 AM THIS MORNING TO 10 PM CST THIS EVENING
FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...45
AVIATION/MARINE...39
