FXUS64 KCRP 072356
AFDCRP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
556 PM CST MON DEC 7 2009
.DISCUSSION...UPDATED FOR 00Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...SHALLOW COOL AIRMASS WL REMAIN IN PLACE OVRNGT INTO
TUE MRNG ACRS S TX BEFORE ERODING. WARM MOIST LAYER ABV WL RSLT IN
CONT OVC SKIES WITH AREAS OF -DZ/-RA OVRNGT AND BR/FG. MUCH OF THE
AREA ALREADY LIFR...AND REMAINING SITES SHOULD BCM LIFR OVRNGT.
THE AREAS OF -RA/-DZ ALONG AND NE OF A BEA-RKP LINE WL EXPAND SW
AND W THRU THE NIGHT.
SOME MODEL DISCREPANCIES WITH RESPECT TO HOW FAST AIRMASS AND
LIFR/IFR CONDS ERODE DURG THE DAY ON TUE. GNRLY FAVORING THE
FASTER SOLUTIONS OF A GRADUAL TRANSITION FM LIFR TO IFR TO VFR FM
S TO N ACROSS S TX BGN AROUND 15Z THRU 20Z. LOOK FOR NE WINDS
WEAKENING OVRNGT THEN AS AIRMASS ERODES BCMG S TO SSW INCREASING
QUICKLY LATE TUE MRNG INTO THE AFTN.
&&
.PREV DISCUSSION... /ISSUED 307 PM CST MON DEC 7 2009/
SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...WK ISENTROPIC
UPGLIDE WL PERSIST TNT AS A 3-5K FT WARM DEPTH OVERRIDES A 1K FT
SFC-BASED COOL MOIST LYR. THIS SYNOPTIC SETUP WL MAINTAIN THICK
CLOUD CVR AND A CHANCE FOR RAIN. WL PLACE THE HIGHEST POPS OVER
THE WATERS...CLOSER TO THE RETURNING WARM FRONT/COASTAL TROUGH.
WARM WATER DROPLETS FALLING THROUGH THE COOL SFC-BASED LYR WL
PROMOTE FOG DEVELOPMENT AND VERY LOW CEILINGS TNT. THE NEXT ISSUE
WL BE IF THIS SHALLOW COOL LYR ERODES ON TUE. BOTH THE GFS AND
ECMWF SOLNS HAVE BEEN CONSISTENT IN SIGNIFICANTLY ERODING THIS
COOL LYR WHILE THE NAM HOLDS ONTO IT MUCH STRONGER. GIVEN THE
FALLING PRESSURES AREAWIDE IN RESPONSE TO THE APPROACHING S/WV
FROM CALIFORNIA...BLV THAT THE COOL LYR WL ERODE IN LINE WITH THE
GFS/ECMWF SOLNS. BLV ENOUGH MIXING AND SOUTHERLY WINDS WL DEVELOP
ON TUE TO PRODUCE WIDESPREAD 70S FOR HIGHS...WITH AROUND 80 DEGS
FOR HIGHS ACROSS THE SRN AREAS. THE TRAILING PACIFIC COLD FRONT
ASSCTD WITH THIS NEXT S/WV WL PUSH THROUGH AFTER MIDNIGHT TUE. A
RETURN TO DRIER AND MORE NORMAL DECEMBER TEMPS IS THEN EXPECTED.
MARINE...THE MAIN ISSUE TNT WL BE VSBYS. AS THE WARM FRONT
CURRENTLY LOCATED NEAR BUOY 42020 MOVES TWDS THE COASTLINE
TNT...VSBYS ARE EXPECTED TO FALL TO 1 MILE OR LESS AT TIMES.
FALLING PRESSURES THROUGH TUE MORNING WL GRADUALLY DEVELOP THE
WINDS TO A MORE SOUTHERLY DIRECTION AND ALLOW THE WARM FRONT TO
MOVE NORTH OF THE WATERS...IMPROVING VSBYS. BORDERLINE ADVY CONDITIONS
WL BE POSSIBLE JUST AFTER SUNRISE OVER THE OFFSHORE WATERS AS THE
SOUTHERLY GRADIENT CONTINUES TO TIGHTEN. THE GRADIENT SHOULD LAY
BY TUE EVENING BEFORE THE NEXT FNT PUSHES QUICKLY THROUGH AFTER
MIDNIGHT.
LONG TERM (WEDNESDAY THROUGH MONDAY)...COOL/DRY CONDITIONS WILL
PREVAIL BY MIDWEEK AS SURFACE HIGH PRESSURE BUILDS INTO SOUTH TEXAS.
AS THE SURFACE RIDGE AXIS SHIFTS EAST...A COASTAL TROUGH IS PROGGED
TO DEVELOP ALONG THE LOWER TEXAS COAST LATE THURSDAY NIGHT.
OVERRUNNING ACROSS THE REGION IS EXPECTED TO GRADUALLY INCREASE
THROUGH FRIDAY AS MOISTURE TRANSPORT ALONG THE 295K-300K SURFACES
INCREASES. THIS WILL LEAD TO A CHANCE OF LIGHT RAIN FOR THE ENTIRE
REGION LATE THURSDAY NIGHT THROUGH FRIDAY. RAINFALL AMOUNTS SHOULD
GENERALLY REMAIN LIGHT. THE LOW-LEVEL MOISTURE POOLED ALONG THE
COASTAL TROUGH WILL BEGIN TO SHIFT NORTHEASTWARD FRIDAY EVENING AS
AN 850MB TROUGH AXIS ENTERS CENTRAL TEXAS. DRIER BOUNDARY LAYER AIR
IS PROGGED TO FILTER IN BEHIND THE TROUGH AXIS BY LATE FRIDAY NIGHT.
DRY CONDITIONS ALONG WITH NEAR NORMAL TEMPERATURES SHOULD PREVAIL
THROUGH THE WEEKEND AS BOUNDARY LAYER MOISTURE REMAINS LIMITED. THE
MEDIUM RANGE MODELS ARE HINTING AT A SLIGHT CHANCE FOR PRECIPITATION
BY MONDAY AS MOISTURE INCREASES AHEAD OF AN APPROACHING SHORTWAVE.
FOR NOW WILL KEEP THE FORECAST DRY DUE TO THE HIGH UNCERTAINTY WITH
RESPECT TO THE UPPER PATTERN NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 58 78 57 68 48 / 40 20 10 10 10
VICTORIA 55 72 51 65 39 / 50 30 10 10 10
LAREDO 57 80 56 76 50 / 10 10 10 10 10
ALICE 58 80 55 71 46 / 30 20 10 10 10
ROCKPORT 57 74 56 68 48 / 50 30 10 10 10
COTULLA 52 76 49 71 43 / 20 10 10 10 10
KINGSVILLE 58 80 56 72 46 / 30 20 10 10 10
NAVY CORPUS 59 76 59 68 52 / 40 20 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
JR/76...AVIATION
