FXUS64 KEWX 221739
AFDEWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1139 AM CST TUE DEC 22 2009
.AVIATION...
LIFR/IFR CIGS AND VSBYS LIFTING AND BREAKING OUT AS A BRISK SLY LOW
LEVEL FLOW ADVECTS WARMER GULF AIR INTO THE REGION. MOST AREAS
INCLUDING THE TAF SITES WILL BECOME MVFR THEN VFR THIS AFTERNOON
WITH BKN CIRRUS ABOVE. ISOLATED SHRA ARE POSSIBLE MAINLY EAST OF
I35 ACROSS THE COASTAL PLAINS. SLY LOW LEVEL WINDS OF 15-20 KNOTS
WILL PREVAIL THIS AFTERNOON AND EVENING WITH MVFR CIGS QUICKLY
REDEVELOPING AFTER 02Z...AND LOWERING TO IFR AFTER 06Z WITH AREAS
OF 3-5 MILES IN -DZ. IFR CIGS WILL AGAIN LIFT TO MVFR MOST AREAS
BY LATE MORNING WEDNESDAY.
&&
.PREV DISCUSSION... /ISSUED 1025 AM CST TUE DEC 22 2009/
UPDATE...
NO MAJOR CHANGES.
DISCUSSION...
WARM AIR ADVECTION WILL CONTINUE TODAY. BREEZY SOUTHERLY WINDS
WILL KEEP MOISTURE LEVELS HIGH AND SKIES MOSTLY CLOUDY TO OVERCAST
TODAY. TEMPERATURES WILL PEAK IN THE UPPER 60S TO LOWER 70S.
CURRENT FORECAST IS ON TRACK WITH ONLY A FEW MINOR TWEAKS TO
ADJUST FOR CURRENT TRENDS.
PREV DISCUSSION... /ISSUED 540 AM CST TUE DEC 22 2009/
DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION.
AVIATION...
DECOUPLED SURFACE AIR IS PRODUCING LOCALLY DENSE FOG SOUTH OF THE
BALCONES ESCARPMENT...BUT SLIGHTLY BETTER MIXING SHOULD MAKE FOR
MOSTLY IFR/LIFR CONDITIONS FROM LOW CIGS FOR THE TAF SITES THROUGH
LATE THIS MORNING. THE STRATUS DECK SHOULD LIFT INTO MVFR LEVELS
BY MIDDAY WITH VFR SKIES EXPECTED FOR A FEW HOURS LATE IN THE DAY.
THE CIGS SHOULD RETURN QUICKLY IN THE EVENING...AND AN APPROACHING
UPPER DISTURBANCE WILL BEGIN TO SUPPORT DRIZZLE AND OCCASIONAL
CIGS BELOW 500 FEET AFTER MIDNIGHT...MAINLY FOR THE I-35
TERMINALS. A FEW SHOWERS ARE EXPECTED NEAR I-35 AFTER DAYBREAK
WEDNESDAY.
PREV DISCUSSION... /ISSUED 427 AM CST TUE DEC 22 2009/
DISCUSSION...
MOISTURE ADVECTION IS UNDERWAY IN THE LOWER BOUNDARY LAYER WITH
OBSERVED DEWPOINT TEMPERATURES IN THE 50S ACROSS SOUTH CENTRAL
TEXAS AND FORECAST TO INCREASE ITO THE LOWER 60S ALONG AND EAST OF
INTERSTATE 35 TONIGHT. THIS INCREASE IN MOISTURE IS IN RESPONSE TO
A POTENT...DIGGING UPPER TROUGH CURRENTLY PROGRESSING SOUTH ALONG
THE WEST COAST. THIS SYSTEM IS FORECAST TO TURN EAST ACROSS THE
SOUTHERN ROCKIES TONIGHT INTO WEDNESDAY AND PUSH A PACIFIC FRONT
THROUGH OUR AREA LATE WEDNESDAY NIGHT. IN THE MEAN-TIME...WELL
ABOVE NORMAL TEMPERATURES ARE FORECAST THROUGH WEDNESDAY WITH A
MOSTLY CLOUDY OR CLOUDY SKY CONDITION. CHANCES FOR SHOWERS WILL
BE ON THE INCREASE WEDNESDAY AS WELL...AND MAY MIX WITH A FEW
THUNDERSTORMS WEDNESDAY AFTERNOON ACROSS EASTERN SECTIONS OF THE
AREA WHERE SURFACE-BASED INSTABILITIES ARE FORECAST TO BE
GREATEST. CHANCES FOR THUNDERSTORMS WILL BE ON THE INCREASE
WEDNESDAY NIGHT ACROSS MUCH OF OUR AREA DUE TO STRONG CONVERGENCE
AND LIFT ASSOCIATED WITH THE PACIFIC FRONT. A FEW SHOWERS MAY
LINGER ACROSS EASTERN SECTIONS OF THE AREA THURSDAY MORNING BEFORE
CLEARING OUT. A CONTINENTAL POLAR AIRMASS WILL SLIDE DOWN OVER THE
AREA CHRISTMAS EVE...WITH BELOW NORMAL TEMPERATURES FORECAST
CHRISTMAS DAY AND CONTINUING INTO THE WEEKEND. THE 00Z MEDIUM
RANGE MODEL SOLUTIONS ARE IN AGREEMENT SHOWING AN ACTIVE SOUTHERN
BRANCH JET NEXT WEEK... BRINGING UPPER LEVEL ENERGY ACROSS OUR
AREA MONDAY INTO TUESDAY.
OUR NUMBERS ARE GENERALLY CLOSE TO THE 00Z GFSMOS THIS CYCLE...
EXCEPT A CATEGORY OR TWO BELOW THE GUIDANCE BEHIND THE FRONT
THURSDAY INTO FRIDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 70 60 71 49 64 / - 20 30 50 10
AUSTIN BERGSTROM INTL AIRPORT 71 60 72 47 65 / - 20 30 50 10
NEW BRAUNFELS MUNI AIRPORT 72 59 73 48 67 / - 10 20 50 10
BURNET MUNI AIRPORT 70 58 69 47 60 / - 20 20 50 -
DEL RIO INTL AIRPORT 67 52 72 48 66 / - - - 10 -
GEORGETOWN MUNI AIRPORT 70 60 70 48 61 / - 20 30 60 10
HONDO MUNI AIRPORT 72 56 71 48 67 / - - - 30 -
SAN MARCOS MUNI AIRPORT 71 60 73 49 66 / - 20 20 50 10
LA GRANGE - FAYETTE REGIONAL 72 62 73 51 63 / 20 30 40 60 20
SAN ANTONIO INTL AIRPORT 70 58 72 49 67 / - 10 10 50 -
STINSON MUNI AIRPORT 70 58 73 49 68 / - - 10 50 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25/01
