FXUS64 KEWX 120301
AFDEWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
901 PM CST FRI DEC 11 2009
.UPDATE...
THUNDERSTORMS IN THE SOUTHEAST.
&&
.DISCUSSION...
A SURFACE TROUGH IS PUSHING INTO THE SOUTHEASTERN COUNTIES FROM
THE GULF AND IS PROVIDING ENOUGH LIFT TO PRODUCE A FEW
THUNDERSTORMS. 00Z AND MODEL SOUNDINGS DO SHOW SUPPORT FOR
CONVECTION TO CONTINUE...SO EXPECT IT WILL BE SHORT LIVED. HAVE
INCLUDED ISO TS IN SE COUNTIES FOR THE NEXT FEW HOURS. HAVE ALSO
MADE MINOR ADJUSTMENTS TO TEMP...DEW POINT...AND WIND GRIDS TO
ACCOUNT FOR HOURLY TRENDS.
&&
.PREV DISCUSSION... /ISSUED 537 PM CST FRI DEC 11 2009/
DISCUSSION...
SEE AVIATION SECTION BELOW FOR 00Z AVIATION FORECAST.
AVIATION...
WARM AIR WILL CONTINUE TO MOVE NORTH OVER THE COOLER SURFACE AIR
AS LOW PRESSURE OFF THE GULF COAST INTENSIFIES TONIGHT...CREATING
AN OVERRUNNING PATTERN WITH LOW CIGS AND BR/FG. IFR CIGS/VSBYS
WILL CONTINUE TO SPREAD NORTH AND WEST. ALL SITES LIKELY TO BE IFR
BY 03Z AND REMAIN THERE THROUGH 18Z SAT. AFTER 18Z SAT I-35 SITES
WILL BE SLOWER TO CLEAR...BUT SHOULD BE MVFR BY 18Z AND REMAIN
THERE UNTIL END OF FCST PERIOD. KDRT WILL BECOME VFR AFTER 18Z.
LIGHT NRLY WINDS WILL CONTINUE OVERNIGHT AND SAT. LGT AND VRBL
WINDS EXPECTED AFTER 00Z SUN WITH BR DEVELOPING TOWARDS THE END
OF THE 30 HR TAFS.
PREV DISCUSSION... /ISSUED 403 PM CST FRI DEC 11 2009/
DISCUSSION...
THE FRONTAL LAYER IS ERODING/MODIFYING AS ISENTROPIC UPGLIDE
CONTINUES OVER THE AREA. LIGHT RAIN WILL INCREASE IN COVERAGE
TONIGHT...EXPANDING NORTH AND WEST ACROSS THE AREA AS A LOW
DEEPENS ALONG THE STALLED FRONT OVER THE NORTHERN GULF AND MOVES
NORTH TOWARD THE COAST. AS THE FRONTAL LAYER CONTINUES TO
MODIFY...FOG WILL BECOME MORE WIDESPREAD. THIS AIRMASS WILL BE
SLOW TO FULLY DIMINISH SATURDAY...ESPECIALLY ALONG AND SOUTH/EAST
OF THE ESCARPMENT. A WARM-UP IS FORECAST THIS WEEKEND...WITH MAX
TEMPS ON SUNDAY 8-20 DEGREES WARMER THAN ON SATURDAY. GULF
MOISTURE WILL RETURN TO THE AREA LATE SUNDAY INTO MONDAY IN
ADVANCE OF THE NEXT COLD FRONT...WHICH IS FORECAST TO PUSH THROUGH
LATE MONDAY NIGHT INTO TUESDAY. THIS AIRMASS WILL BE A MODIFIED
ARCTIC AIRMASS...AND JUST AS COLD AS THE PREVIOUS AIRMASS.
ALTHOUGH THE FROPA FORECAST IS HIGH CONFIDENCE...THE FORECAST FOR
WHAT HAPPENS AFTER THE FROPA IS GENERALLY A LOW CONFIDENCE
FORECAST WITH THE 12Z MEDIUM RANGE MODELS VARYING SIGNIFICANTLY
WITH THE UPPER LEVEL PRESSURE HEIGHT FIELD OVER OUR AREA AND TO
THE WEST. THE 12Z GFS40 IS ADVERTISING A CLEAN FROPA WITH HIGH
PRESSURE BUILDING OVER OUR AREA BOTH AT THE SURFACE AND
ALOFT...WHILE THE ECMWF IS SHOWING RUN-TO-RUN CONSISTENCY WITH AN
UPPER LEVEL TROUGH ON SLOW APPROACH LATE TUESDAY.
OUR MAX/MIN TEMP NUMBERS ARE GENERALLY BELOW THE 12Z
GFSMOS...ESPECIALLY TUESDAY AND TUESDAY NIGHT GIVEN THE POOR
MODELING OF ARCTIC AIRMASSES.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 43 54 48 73 57 / 70 20 - - 10
AUSTIN BERGSTROM INTL AIRPORT 43 53 41 72 55 / 80 20 - - 10
NEW BRAUNFELS MUNI AIRPORT 44 54 45 72 55 / 80 10 - - 10
BURNET MUNI AIRPORT 42 54 45 73 55 / 50 10 - - 10
DEL RIO INTL AIRPORT 46 66 45 73 54 / 10 - 0 - 10
GEORGETOWN MUNI AIRPORT 43 53 45 74 56 / 70 20 - - 10
HONDO MUNI AIRPORT 44 60 43 74 57 / 40 - - - 10
SAN MARCOS MUNI AIRPORT 44 53 45 73 57 / 80 10 - - 10
LA GRANGE - FAYETTE REGIONAL 47 54 46 71 58 / 80 30 10 - 10
SAN ANTONIO INTL AIRPORT 45 58 48 73 58 / 60 10 - - 10
STINSON MUNI AIRPORT 45 57 45 74 57 / 70 10 - - 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/10
