FXUS64 KHGX 151123
AFDHGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
523 AM CST TUE DEC 15 2009
.DISCUSSION...
ADJUSTED THE DENSE FOG ADVISORY A BIT BY DROPPING LIBERTY COUNTY.
UPDATED FORECAST AND THE NPW JUST SENT OUT.
&&
.PREV DISCUSSION... /ISSUED 433 AM CST TUE DEC 15 2009/
DISCUSSION...
AN APPROACHING UPPER TROUGH WILL SLOWLY WORK ITS WAY ACROSS THE
STATE OVER THE NEXT FEW DAYS. AS IT DOES SO...A COLD FRONT WILL
PUSH OFF THE COAST TODAY AND THEN A COASTAL SURFACE LOW WILL FORM
AND MOVE UP THE COAST WEDNESDAY AND THURSDAY. HIGH PRESSURE WILL
BUILD INTO SOUTHEAST TEXAS LATE THIS WEEK.
THE COLD FRONT WAS MOVING ACROSS THE NORTHWESTERN SET OF COUNTIES
OF THE FORECAST AREA EARLY THIS MORNING. THE NAM12 HAS REFLECTED
THE ACTUAL FRONT QUITE WELL. BY 12Z EXPECT THE FRONT TO BE ALONG A
LINE FROM CONROE TO EAGLE LAKE...BY 15Z FROM HOU TO PSX...AND BY
18Z ALONG OR JUST OFF THE COAST. THE MAIN ISSUE AHEAD OF THE FRONT
WILL BE AREAS OF DENSE FOG. THE MODELS AND OBSERVATIONS INDICATE
THAT THE DENSE FOG WILL BE CONFINED TO MAINLY THOSE LOCATIONS
ALONG AND EAST OF A LINE FROM LIBERTY TO HOUSTON TO EAGLE LAKE.
WILL EXTEND THE DENSE FOG ADVISORY FOR THESE LOCATIONS THROUGH 9
AM. OVER THE IMMEDIATE COAST...THE BAYS...AND THE NEARSHORE WATERS
WILL EXTEND THE DENSE FOG ADVISORY THROUGH NOON.
AFTER THE FRONT PUSHES OFF THE COAST...ISENTROPIC LIFT WILL KEEP
RAIN CHANCES OVER MOST OF THE AREA THROUGH TONIGHT. THE GFS LOOKED
VERY REASONABLE AND WENT WITH ITS GUIDANCE THROUGH THURSDAY FOR
RAIN CHANCES. FOR WEDNESDAY AND THURSDAY...THESE WILL BE LIMITED
MAINLY OVER THE SOUTH HALF OF THE FORECAST AREA. AFTER THE UPPER
TROUGH PUSHES OVERHEAD AND EAST THURSDAY NIGHT...CLEARING SKIES AND
CONTINUED CHILLY CONDITIONS ARE IN STORE THROUGH THE WEEKEND.
40
MARINE...
DENSE SEA FOG WILL PERSIST ACROSS THE BAYS AND NEARSHORE WATERS
INCLUDING THE HOUSTON SHIP CHANNEL UNTIL AT LEAST 15-16Z. THE COLD
FRONT NOW OVER NORTHERN PORTIONS OF SE TX SHOULD CROSS THE BAYS
AROUND THIS TIME AND COASTAL WATERS 17-21Z. VISIBILITIES SHOULD
IMPROVE FAIRLY QUICKLY WITH THE FROPA. WILL EXTEND ADVISORY UNTIL
18Z THOUGH THERE'S A CHANCE IT COULD BE CANCELLED A COUPLE HOURS
EARLY. MODERATE TO STRONG OFFSHORE FLOW WILL DEVELOP IN THE WAKE
OF THE FRONT. THE STRONG WINDS WILL PERSIST THROUGH THURSDAY AS
THE PRESSURE GRADIENT TIGHTENS IN RESPONSE TO YET ANOTHER SFC LOW
DEVELOPS OVER THE WESTERN GULF. HAVE POSTED SCEC FOR THE BAYS AND
SCA FOR THE 00-60 NM WATERS FROM THIS AFTN THROUGH THURSDAY. WINDS
OF 20-30 KTS AND SEAS UP TO 10 FT EXPECTED OVER THE OFFSHORE
WATERS. AS FAR AS THE TIDES GO...THE EXTRA-TROPICAL SURGE MODEL
SHOWS THE HIGHEST TIDE LEVELS OF ABOUT A FOOT ABOVE NORMAL ON
THURSDAY. WINDS APPEAR TO HAVE A MORE NORTHERLY COMPONENT...SO
SIMILAR TO THE LAST SYSTEM THINK TIDE LEVELS WILL REMAIN BELOW
WATCH/WARNING CRITERIA WITH THIS EVENT. MAXIMUM TIDE LEVELS OF
AROUND 3.2 FEET ARE EXPECTED. THE LOW PUSHES EAST OF THE AREA
FRIDAY ALLOWING NORTHERLY WINDS TO DECREASE TO 5-15 KTS. ANOTHER
COLD FRONT WILL CROSS THE WATERS FRI NIGHT RESULTING IN ANOTHER
ROUND OF SCEC/SCA CONDITIONS. 35
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 53 38 52 39 58 / 30 10 20 20 10
HOUSTON (IAH) 58 42 53 41 55 / 60 20 30 40 30
GALVESTON (GLS) 63 48 54 47 53 / 70 30 40 60 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: BRAZORIA...CHAMBERS...FORT BEND...GALVESTON...
HARRIS...JACKSON...MATAGORDA...WHARTON.
GM...DENSE FOG ADVISORY UNTIL NOON CST TODAY 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 SHOULD EXERCISE CAUTION FROM NOON CST TODAY THROUGH
LATE WEDNESDAY NIGHT FOR THE FOLLOWING ZONES: GALVESTON
BAY...MATAGORDA BAY.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 PM CST
THURSDAY 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...40
AVIATION/MARINE...35
