FXUS64 KHGX 260002
AFDHGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
602 PM CST FRI DEC 25 2009
.DISCUSSION...
AVIATION SECTION UPDATED.
&&
.AVIATION...
FAIRLY BENIGN CONDITIONS AT TAF SITES WITH MAINLY VFR CONDITIONS
THROUGH THE TAF PERIOD...AS AIR MASS TOO DRY FOR ANY CONCERN ABOUT
FOG...AND JUST THE POSSIBILITY OF A FEW HIGH CLOUDS THROUGH ABOUT
18Z SATURDAY. SOME INCREASE IN CLOUD COVER POSSIBLE SATURDAY
AFTERNOON. MVFR CIGS AND LIGHT RAIN WILL BE POSSIBLE LATE IN THE
AFTERNOON...ESPECIALLY NEAR THE COAST. 46
&&
.PREV DISCUSSION... /ISSUED 305 PM CST FRI DEC 25 2009/
DISCUSSION...
SFC RIDGE OVER SOUTH TEXAS WILL PERSIST THROUGH TONIGHT. SKIES
SHOULD REMAIN MOSTLY CLEAR OVERNIGHT EXCEPT FOR SOME THIN HIGH
CLOUDS PASSING OVERHEAD WHICH WILL ALLOW FOR GOOD RADIATIONAL
COOLING CONDITIONS. GIVEN THIS FACTOR ALONG WITH THE DRY AIRMASS
IN PLACE (DEWPOINTS CURRENTLY TEENS/LOWER 20S) AND THE LIGHT NE
SFC WINDS...HAVE GONE WITH COLDER METMOS GUIDANCE FOR LOWS
OVERNIGHT. A WIDESPREAD FREEZE IS EXPECTED TONIGHT FOR ALL BUT THE
IMMEDIATE COAST INCLUDING METRO HOUSTON. WFO HGX LOCAL OFFICE
POLICY FOR A HARD FREEZE WARNING RECENTLY CHANGED TO 2+ HOURS WITH
A TEMP OF 24F OR LOWER. FORECAST TEMPS FOR TONIGHT WILL BE RIGHT
ON THE FENCE OVER OUR NE ZONES. AFTER COORD WITH LCH...HAVE HELD
OFF ON ISSUING THE WARNING FOR TONIGHT BUT EVENING SHIFT CAN
MONITOR TEMPS AND ISSUE ONE FOR NE ZONES IF IT LOOKS LIKE TEMPS
WILL DROP LOWER THAN CURRENTLY FORECAST.
A WEAK DISTURBANCE TO THE WEST OF THE BAJA THIS AFTN IS EXPECTED
TO MOVE QUICKLY ACROSS SOUTH TX AND THE WESTERN GULF SAT/SAT
NIGHT. A COASTAL TROUGH IS EXPECTED TO SET UP BY SATURDAY AFTN OVER
THE COASTAL WATERS IN RESPONSE TO THIS FEATURE. ISENTROPIC LIFT
WILL DEVELOP OVER SW ZONES SATURDAY MORNING AND WILL REMAIN
CONCENTRATED OVER SRN HALF OF THE AREA SAT AFTN/EVENING BEFORE
DIMINISHING 06-12Z SUNDAY. GFS BUFR SOUNDINGS SHOW ATMOSPHERE
BECOMING SATURATED BELOW 10KFT AT KIAH/KVCT BY 00Z SUNDAY...BUT A
SIGNIFICANT LOW LEVEL DRY LAYER AT KCLL/KLFK. EXPECT CLOUDS TO
SPREAD ACROSS THE AREA SATURDAY...THICKEN AND LOWER THROUGH THE
DAY...WITH LIGHT RAIN DEVELOPING SRN HALF EARLY AFTN. THE RAIN
WILL BE PRETTY WIDESPREAD NEAR THE COAST...BUT AMOUNTS WILL BE
VERY LIGHT (LESS THAN 1/4 INCH). PRECIP SHOULD WIND DOWN LATE SAT
NIGHT. WILL KEEP LOW POPS IN FCST FOR THE NRN HALF BUT MOST AREAS
NORTH OF HOUSTON WILL REMAIN DRY. WITH THE EXTENSIVE CLOUDINESS...
TEMPS SRN HALF WILL BE MUCH WARMER SAT NIGHT BUT COULD STILL TOUCH
FREEZING OVER THE NORTHEAST. CLEARING WILL TAKE PLACE IN THE WAKE OF
THE SYSTEM SUNDAY MORNING. COOL/DRY CONDITIONS ARE EXPECTED THROUGH
MONDAY AS ANOTHER BUBBLE OF HIGH PRESSURE SETTLES OVER THE AREA.
TEMPS EXPECTED TO DROP TO FREEZING OVER MOST INLAND AREAS SUNDAY
NIGHT AND OVER NE ZONES MONDAY NIGHT. A MORE SIGNIFICANT UPPER
TROUGH IS EXPECTED TO REACH THE BAJA MONDAY AND CROSS TEXAS TUE/TUE
NIGHT. COASTAL TROUGH/SFC LOW WILL DEVELOP OVER THE NW GULF THIS
PERIOD. UPPER FLOW WILL BECOME VERY DIFFLUENT AS THE TROUGH
APPROACHES FROM THE WEST. ISENTROPIC LIFT WILL DEVELOP OVER WRN
ZONES BEGINNING MON NIGHT AND SPREAD AREA WIDE TUE/TUE NIGHT. EXPECT
CLOUDS TO SPREAD ACROSS THE AREA FROM WEST TO EAST MON NIGHT AND
THICKEN AND LOWER TUE MORNING. RAIN EXPECTED TO DEVELOP TUE MORNING
AND PERSIST THROUGH TUE NIGHT. THE INTENSITY SHOULD BE HEAVIER WITH
THIS EVENT...WITH THE POTENTIAL FOR ISOLATED THUNDER NEAR THE COAST.
BUMPED UP POPS TO LIKELY CATEGORY SRN HALF DUE TO HIGH CONFIDENCE.
INITIAL DISTURBANCE PUSHES EAST OF THE AREA WED MORNING BUT HAVE
KEPT LOW POPS IN THE FCST AS TROUGH HANGS BACK TO THE WEST. TEMPS
WILL BE COLD TUESDAY WITH THE CLOUDS/RAIN BUT WARMER WEDNESDAY INTO
THURSDAY AS SOME SUNSHINE RETURNS. A POLAR COLD FRONT IS EXPECTED TO
CROSS SE TX THU NIGHT...WITH FREEZING TEMPS AGAIN NEXT WEEKEND.
35
AVIATION...
WITH HIGH PRESSURE DRIFTING OVERHEAD...VFR CONDITIONS ARE EXPECTED
TO PERSIST THROUGH TONIGHT. AS THE HIGH DRIFTS EASTWARD...EASTERLY
WINDS WILL DEVELOP SATURDAY MORNING. FOR THE KIAH 24 TO 30 HOUR
TIME PERIOD...VFR CEILINGS AND A CHANCE OF RAIN WILL RETURN AS THE
EFFECTS OF A COASTAL LOW OFF THE SOUTH TEXAS COAST BEGIN TO BE
FELT. THERE IS AN OUTSIDE CHANCE FOR MVFR CEILINGS TO DEVELOP AT
THE SITE. 40
MARINE...
WINDS AND SEAS HAVE DIMINISHED BELOW ADVISORY CRITERIA THIS
AFTERNOON. ONLY THE OFFSHORE WATERS HAVE A CAUTION AND EXPECT THE
CONDITIONS TO BETTER THERE BY THIS EVENING. A SURFACE LOW PRESSURE
AREA WILL MOVE NORTHEASTWARD ACROSS THE COASTAL WATERS OVER THE
WEEKEND. SMALL CRAFT CONDITIONS LOOK TO DEVELOP ONCE AGAIN ON
SUNDAY...BUT MAY BEGIN EARLIER IF THE STORM STRENGTHENS MORE THAN
THE MODELS ARE INDICATING ON SATURDAY. DO NOT EXPECT THE CONDITIONS
TO IMPROVE MUCH THROUGH THE MIDDLE OF NEXT WEEK. THE MODERATE
NORTHEASTERLY WINDS MAY VEER ENOUGH TOWARD THE EAST TO BRING HIGHER
THAN NORMAL TIDES EARLY NEXT WEEK. 40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 27 56 33 56 31 / 0 20 20 10 0
HOUSTON (IAH) 29 55 40 58 33 / 0 30 40 10 0
GALVESTON (GLS) 40 51 47 57 40 / 0 40 50 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 6 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...30
AVIATION/MARINE...30
