FXUS64 KCRP 030111
AFDCRP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
711 PM CST WED DEC 2 2009
.DISCUSSION...SFC HIGH IS SETTLING ACROSS THE AREA AND ALLOWING
WINDS TO RELAX. WINDS ARE BOREDERLINE SCA ACROSS THE OFFSHORE
WATERS BUT SHOULD RELAX AS WELL THROUGH THIS EVENING. ONGOING FCST
LOOKS ON TRACK WITH NO MAJOR CHANGES AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 527 PM CST WED DEC 2 2009/
DISCUSSION...UPDATED FOR 00Z AVIATION DISCUSSION.
AVIATION...VFR CONDITIONS TO GENERALLY PREVAIL THROUGH THE FIRST
16 HOURS OF THE TAF PERIOD. MVFR CIGS WILL BEGIN TO DEVELOP ACROSS
THE REGION AROUND MIDDAY ON THURSDAY. NORTHWEST TO NORTHEAST WINDS
TO GENERALLY REMAIN BELOW 18 KNOTS.
PREV DISCUSSION... /ISSUED 324 PM CST WED DEC 2 2009/
SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...SURFACE HIGH PRESSURE
WILL CONTINUE TO RAPIDLY BUILD INTO SOUTH TEXAS LATE THIS AFTERNOON
GENERATING GUSTY NNWLY WINDS ACROSS THE REGION THROUGH THE EARLY
EVENING HOURS. THE PRESSURE GRADIENT WILL DECREASE OVERNIGHT
GENERATING LIGHT NORTHERLY WINDS. OVERNIGHT LOWS SHOULD DIP INTO THE
UPPER 30S INLAND/LOWER 40S COAST AS A RESULT. CLOUD COVER IS PROGGED
TO INCREASE THURSDAY FROM SOUTH TO NORTH AS ISENTROPIC LIFT
COMMENCES ALONG THE 290K-295K THETA SURFACES. THE SHALLOW COLD AIR
MASS AT THE SURFACE COMBINED WITH INCREASING CLOUD COVER SHOULD
MAINTAIN WELL BELOW NORMAL TEMPERATURES ACROSS SOUTH TEXAS
THURSDAY...WITH HIGHS EXPECTED TO BE IN THE MID 50S AREAWIDE. A
COASTAL TROUGH IS THEN PROGGED TO DEVELOP ALONG THE LOWER TEXAS
COAST LATE THURSDAY NIGHT AHEAD OF AN APPROACHING UPPER LEVEL
TROUGH. THE SURFACE TROUGH AXIS SHOULD ENHANCE ISENTROPIC UPGLIDE
OVER SOUTH TEXAS THURSDAY NIGHT GENERATING INCREASING PRECIP CHANCES
FROM SOUTH TO NORTH...ESPECIALLY AFTER MIDNIGHT ALONG THE SOUTHERN
COASTAL COUNTIES. OVERNIGHT LOWS THURSDAY SHOULD BE SLIGHTLY WARMER
THAN LOWS TONIGHT GIVEN THE EXPECTED INCREASED CLOUD COVER.
LONG TERM (FRIDAY THROUGH WEDNESDAY)...BIG QUESTION FOR FRIDAY WILL
BE HOW MUCH PRECIP WILL WE SEE AND WILL ANY OF IT CHANGE TO SNOW AS
A VERY COLD AIRMASS SETTLES INTO S TX. TEMPS ARE EXPECTED TO FALL
THROUGH THE DAY ON FRI AD WILL BE IN THE 30S ACROSS MUCH OF THE
REGION BY AFTN. MODELS AGREE COMBINATION OF ISENTROPIC LIFT...LOW
CONDENSATION PRESSURE DEFICITS AND LARGE SCALE LIFT ASSOC W/ A
STRONG TROUGH SWINGING INTO THE REGION FROM THE NNW WILL LEAD TO
HIGH PRECIP CHCS ACROSS THE REGION. MODEL SOUNDINGS AND VARIOUS
THICKNESS RULES OF THUMB SHOW THE RAIN/SNOW LINE JUST ENTERING NRN
COS FRI AFTN...BUT WE ARE RIGHT ON THE EDGE AD CONFIDENCE IS NOT
VERY HIGH SNOW WILL QUITE REACH THE AREA. FOR NOW WILL FORECAST
LIKELY LIGHT RAIN ALL AREAS (EXCEPT FAR WEST WHERE ISENTROPIC SFCS
ARE NOT AS FAVORABLE - WENT 40-50 POPS THERE) AND A CHC OF SNOW IN
THE AFTN BUT ONLY FOR THE NRN COS FOLLOWING CLOSELY TO MODEL 540
THICKNESS FOR GUIDANCE ON THAT. EITHER WAY...IT APPEARS TEMPS WILL
REMAIN SLIGHTLY ABOVE FREEZING AT THE SFC AND SNOW ACCUMULATION DOES
NOT APPEAR LIKELY. AGREE W/ HPC WHO LIKES THE FASTER MODELS WRT THE
UPR TROUGH SWINGING EAST AND WILL ONLY SHOW 20-30 POPS IN THE
EVENING FOR THE COASTAL PLAINS ONLY W/ AGAIN THE MENTION OF CHC OF
SNOW MIXED IN FOR AREAS FROM REFUGIO NORTH AND EAST.
THE S/WV WILL ALLOW CLOUDS TO DECREASE RAPIDLY FRI NIGHT BUT WITH
THE H85 FREEZING LINE DIPPING WELL INTO THE AREA AN ADVECTION FREEZE
WOULD LIKELY OCCUR REGARDLESS OF COMPLETE CLEARING ACROSS MUCH OF
THE AREA. MOS VALUES HAVE BEEN DROPPING CLOSER TO WHAT WE HAVE HAD
IN THE FORECAST THE LAST FEW DAYS AND NOW GFS MOS SHOWS SOME MID 20S
FOR NRN COS. LEANED MORE THIS DIRECTION SINCE WE ARE LEANING TOWARD
THE QUICKER TROUGH PROGRESSION AND EXPECT A FREEZE FOR MOST OF THE
AREA MINUS THE IMMEDIATE COAST AND ISLANDS.
THE SPEED AT WHICH THE AIRMASS MODIFIES IS IN QUESTION AS A COASTAL
TROUGH DEVELOPS AND CLOUDS BEGIN TO SWEEP NORTH ACROSS THE AREA LATE
SAT. SO TEMPS BECOME TRICKY AND CONFIDENCE LOW SUN AND BEYOND.
ISENTROPIC LIFT AND DISTURBANCES WILL PROVIDE A CHC OF RAIN/SHOWERS
SAT NIGHT AND SUN. SHOULD SEE A GRADUAL WARM UP THROUGH THE EARLY
NEXT WEEK.
MARINE...SCA CONDITIONS WILL CONTINUE OVER THE MARINE ZONES THROUGH
THE LATE AFTERNOON HOURS AS HIGH PRESSURE RAPIDLY BUILDS INTO THE
COASTAL WATERS. THE WINDS SHOULD FALL BELOW SCA CRITERION OVER THE
BAYS/NEARSHORE WATERS AFTER 00Z...THEN OFFSHORE AFTER 04Z AS THE
SURFACE HIGH PRESSURE SETTLES ACROSS THE REGION. WINDS 20 TO 60 NM
OFFSHORE SHOULD REMAIN IN THE SCEC RANGE AFTER 04Z THROUGH
THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 42 57 43 44 32 / 0 10 50 70 20
VICTORIA 38 56 40 41 27 / 0 0 20 70 20
LAREDO 42 56 40 42 31 / 0 10 30 40 10
ALICE 39 56 40 43 29 / 0 10 40 70 10
ROCKPORT 43 57 41 46 34 / 0 0 30 70 20
COTULLA 39 55 40 42 25 / 0 0 20 40 10
KINGSVILLE 39 56 42 44 29 / 0 10 50 70 20
NAVY CORPUS 45 56 44 49 35 / 0 10 50 70 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: WATERS FROM BAFFIN BAY TO PORT ARANSAS
FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
TE/81...SHORT TERM
JR/19...LONG TERM
