FXUS64 KHGX 261711
AFDHGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1111 AM CST SAT DEC 26 2009
.DISCUSSION...
WATER VAPOR IMAGERY SHOWS WEAK UPPER DISTURBANCE NOW NEAR MAINLAND
MEXICO AND WILL PUSH QUICKLY ACROSS SOUTH TX AND THE NW GULF THIS
AFTN/TONIGHT. THE LAST COUPLE OF MODEL RUNS HAVE TRENDED MUCH
DRIER WITH COASTAL TROUGH AND BEST ISENTROPIC UPGLIDE REMAINING
OFFSHORE. RAIN CHANCES HAVE NEARLY EVAPORATED IN THE 12Z MOS
GUIDANCE. WILL MAINTAIN LOW POPS (20/30 PCT) MAINLY FOR AREAS
SOUTH OF I-10 THROUGH THIS EVENING FOR THE POSSIBILITY OF A FEW
SPRINKLES OR LIGHT RAIN. VERY LIGHT GENERALLY TRACE AMOUNTS
EXPECTED. TEMPS HAVE WARMED FAIRLY QUICKLY DESPITE THE CLOUD COVER
SO HAVE RAISED MAX TEMPS TO THE MID 50S FOR MOST AREAS. NORTHERN
ZONES LIKELY TO REMAIN MOSTLY CLEAR WHICH SHOULD ALLOW THESE AREAS
TO DROP TO NEAR FREEZING AGAIN TONIGHT. SUNDAY SHOULD BE A NICE
DAY AREAWIDE AS THE CLOUDS CLEAR OUT EARLY.
35
&&
.PREV DISCUSSION... /ISSUED 354 AM CST SAT DEC 26 2009/
DISCUSSION...
A SURFACE LOW IS IN THE PROCESS OF ORGANIZING OFF THE DEEP SOUTH TEXAS
COAST. THIS LOW IS EXPECTED TO MOVE OFF TO THE NORTHEAST TODAY AND TONIGHT
WITH THE MAJORITY OF RAIN REMAINING OFF THE COAST. TODAY'S/TONIGHT'S
RAIN CHANCES RANGE FROM ONLY 10% UP NORTH TO 30% ALONG THE COAST AND 50%
ACROSS THE OFFSHORE WATERS. THICK CLOUD COVER WILL ALLOW AFTERNOON HIGH
TEMPERATURES TO WARM UP TO ONLY A COUPLE DEGREES HIGHER THAN WHAT WAS
OBSERVED YESTERDAY...AND WOULD NOT BE AT ALL SURPRISED IF THE PRELIMS
BELOW END UP BEING TOO WARM. THIS SYSTEM MOVES OFF INTO THE CENTRAL
GULF TONIGHT AND SUNDAY AND HIGH PRESSURE BUILDS BACK INTO THE AREA.
EXPECTED SUNSHINE ON SUNDAY SHOULD BRING HIGH TEMPERATURES UP INTO THE
MID TO UPPER 50S. REINFORCING HIGH PRESSURE ON MONDAY MOVES OFF TO THE
EAST ON MONDAY NIGHT AND TUESDAY AS THE NEXT SHORTWAVE BEGINS TO ORGANIZE
OFF TO OUR WEST. THE NEXT COASTAL TROUGH AND GULF SURFACE LOW GIVES
OUR AREA OUR NEXT BEST CHANCE OF RAIN TUESDAY AFTERNOON THROUGH EARLY
WEDNESDAY MORNING...AND WE CONTINUE TO CARRY LIKELY POPS FOR THIS SETUP.
THERE WILL BE A DRY PERIOD BETWEEN WHEN THIS SURFACE LOW EXITS OFF TO
THE EAST DURING THE DAY ON WEDNESDAY AND WHEN THE NEXT COLD FRONT MOVES
ON THROUGH. FOR NOW...WILL CALL WEDNESDAY NIGHT DRY AND CARRY LOW POPS
ON THURSDAY WITH THE NEXT FRONT. IF THIS TIMING PANS OUT...NEW YEARS
EVE WILL BE DRY AND COLDER AS SURFACE HIGH PRESSURE BUILDS INTO THE
AREA...AND THE FIRST FEW DAYS OF 2010 WOULD END UP BEING DRY WITH
COLD NIGHTS AND COOL DAYS. 42
AVIATION...
CIRRUS CLOUDS ARE SPREADING ACROSS THE REGION FROM THE SOUTHWEST AS
UPPER LEVEL FLOW REMAINS FROM SOUTHWEST. A LOW PRESSURE AREA
DEVELOPING IN THE WESTERN GULF OF MEXICO WILL MOVE EAST NORTHEAST
TONIGHT AND SUNDAY. CLOUDS WILL GRADUALLY LOWER FROM SOUTHWEST TO
NORTHEAST AS MOISTURE INCREASES. TAF SITES ALONG AND SOUTH OF I-10
CEILINGS WILL LOWER TO 3-5 THOUSAND AGL BETWEEN 21Z-06Z WITH A
CHANCE OF R- DURING THIS SAME TIME PERIOD. NORTH OF I-10 CIGS WILL
LOWER TO 5-8 THOUSAND FEET AGL FROM 21Z-06Z BUT NO PCPN IS EXPECTED
IN THIS AREA. AFTER 06Z ANOTHER PUSH OF COOL DRY AIR WILL ENTER INTO
THE REGION DECREASING CLOUD COVER AND ENDING PCPN FOR AREAS NEAR THE
COAST. WINDS FOR NORTHERN TAF SITES WILL BE LIGHT AND VARIABLE
BECOMING NORTHERN 5 TO 10 KNOTS AFTER 06Z. SOUTHERN TAF SITES WILL
SEE EAST TO SOUTHEAST WINDS AROUND 10 KNOTS BECOMING EAST TO
NORTHEAST AFTER 06Z AT 10 TO 15 KNOTS.
MARINE...
RIDGE OF HIGH PRESSURE WILL DRIFT EAST AS SURFACE LOW DEVELOPS IN
WESTERN GULF OF MEXICO. THIS WILL ALLOW WINDS AND SEAS TO INCREASE
TONIGHT REACHING NEAR SCA CRITERIA ON SUNDAY. THE GOM LOW WILL ALSO
BRING A CHANCE OF PRECIPITATION TO THE COASTAL WATERS TONIGHT AND
SUNDAY. A RIDGE OF HIGH PRESSURE WILL BUILD IN FROM THE NORTH ON
MONDAY KEEPING WINDS AND SEAS NEAR SCA CRITERIA. ANOTHER COASTAL LOW
PRESSURE AREA WILL DEVELOP EAST OF BROWNSVILLE TUESDAY AFTERNOON AND
MOVE NORTHEAST UP THE COAST TUESDAY NIGHT AND WEDNESDAY. THIS WILL
INCREASE WINDS AND SEAS AND ALSO SPREAD WIDESPREAD PRECIPITATION
OVER THE UPPER COASTAL WATERS TUESDAY NIGHT AND WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 55 33 56 31 52 / 10 10 0 0 0
HOUSTON (IAH) 56 40 58 33 52 / 20 20 10 0 0
GALVESTON (GLS) 54 47 57 40 52 / 20 30 10 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...35
