Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX

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FXUS64 KEWX 290548 AAA
AFDEWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1148 PM CST SUN DEC 28 2014

.AVIATION.../06Z TAF CYCLE/

ALL SITES ARE VFR SKC AS OF 29/06Z WITH LIGHT TO CALM WINDS. NWP
OUTPUT CONTINUES TO SUGGEST FOG DEVELOPMENT ALONG THE RIO GRANDE
VALLEY AND SPREADING EASTWARD TOWARDS KSAT 10-16Z TIME FRAME.
TRENDS HAVE BACKED AWAY FROM EASTWARD EXPANSION BUT FEEL KSSF HAS
SLIGHTLY GREATER CHANCE THEN KSAT. HAVE KEPT KAUS/KSAT VFR
THROUGH MORNING HOURS BUT HAVE PLACED HIGH END MVFR FOR KSSF FROM
10-15Z. HRRR OUTPUT AND RAP/NAM BUFR SOUNDINGS CONTINUE TO
INDICATE FOG DEVELOPMENT AT KDRT AND FORECAST FOLLOWS SUITE WITH
3SM VIS RESTRICTIONS 10-16Z DESPITE GFSLAMP GUIDANCE NOT
SUGGESTING FOG. EXPECT VFR CONDITIONS MONDAY AFTER FOG DISSIPATES
THROUGH MUCH OF THE OVERNIGHT INTO EARLY TUESDAY MORNING BEFORE
LOWER CLOUDS RETURN LATE MORNING TUESDAY. /ALLEN/

&&

.PREV DISCUSSION... /ISSUED 922 PM CST SUN DEC 28 2014/

UPDATE...
THE FORECAST HAS BEEN UPDATED FOR THE REMAINDER OF TONIGHT INTO
EARLY MONDAY MORNING. THE MAIN UPDATE WAS TO ADD A MENTION OF
PATCHY FOG ACROSS THE RIO GRANDE PLAINS AND SOUTHERN EDWARDS
PLATEAU. MINOR UPDATES HAVE ALSO BEEN MADE TO THE LATEST
TEMPERATURES...DEW POINTS AND WINDS TO ACCOUNT FOR RECENT
OBSERVATIONS. FINALLY...WE DID DECREASE OVERNIGHT LOW TEMPERATURES
SLIGHTLY ACROSS THE NORTHWESTERN HILL COUNTRY.

PREV DISCUSSION... /ISSUED 335 PM CST SUN DEC 28 2014/

SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
AN UPPER LEVEL TROUGH IS EXITING TO THE EAST OF SOUTH CENTRAL
TEXAS THIS AFTERNOON. SKIES HAVE CLEARED TO NEAR I-35. SKIES WILL
CLEAR ACROSS THE REMAINDER OF OUR AREA BY SUNSET. THIS SETS THE
STAGE FOR WIDESPREAD FREEZING TEMPERATURES BY MONDAY MORNING. WE
HAVE ISSUED A FREEZE WARNING FOR LATE TONIGHT INTO MONDAY MORNING
FOR OUR SOUTHERN TWO TIERS OF COUNTIES...EXCEPT FOR THE SOUTHWEST.
THESE AREAS HAVE NOT YET REACHED FREEZING THIS FALL/WINTER.
MEANWHILE...THE HILL COUNTRY AND ALONG THE ESCARPMENT ALREADY HAVE
SEEN FREEZING TEMPERATURES THIS WINTER SEASON WHILE THE RIO GRANDE
PLAINS WILL FALL TO JUST ABOVE FREEZING. SEE OUR SPECIAL WEATHER
STATEMENT FOR DETAILS FOR THOSE AREAS. A BRIEF WARM UP IS EXPECTED
ON MONDAY ON SOUTH TO SOUTHWEST WINDS. LATE MONDAY NIGHT ANOTHER
COLD FRONT IS EXPECTED TO ENTER THE FAR NORTHERN HILL COUNTRY.
TEMPERATURES SHOULD STAY ABOVE FREEZING MONDAY NIGHT ON MIXING
ALONG AND AHEAD OF FRONT.

LONG TERM (TUESDAY THROUGH SUNDAY)...
THE COLD FRONT WILL SURGE ACROSS THE REMAINDER OF SOUTH CENTRAL
TEXAS TUESDAY MORNING. HIGH TEMPERATURES WILL BE REACHED LATE
MORNING TO MIDDAY AS CLOUDS INCREASE DUE TO MOIST SOUTHERLY FLOW
RIDING OVER COLD ADVECTION IN THE LOWER LEVELS. MODELS ARE IN
BETTER AGREEMENT ON THE PATTERN EVOLUTION IN THE LONG TERM.
ALTHOUGH...SOME DISAGREEMENT REMAINS AND THE FORECAST MAY CHANGE
OVER THE NEXT FEW DAYS. AN UPPER UPPER LEVEL TROUGH DROPPING DOWN
THE WEST COAST ON TUESDAY CLOSES OFF OVER SOUTHERN CALIFORNIA ON
WEDNESDAY INTO THURSDAY AND THEN OPENS UP AND MOVE ACROSS TEXAS
FRIDAY INTO EARLY SATURDAY. ISENTROPIC LIFT DEVELOPS TUESDAY NIGHT
INTO WEDNESDAY LEADING TO AREAS OF LIGHT RAIN INITIALLY ALONG THE
RIO GRANDE...THEN SPREADING ACROSS THE REMAINDER OF THE AREA.
PERIODS OF LIGHT TO OCCASIONALLY MODERATE RAIN OR SHOWERS WILL
CONTINUE THROUGH FRIDAY NIGHT. THERE IS A THREAT FOR WINTER TYPE
PRECIPITATION DURING THE LATE NIGHT INTO MORNING HOURS MAINLY FOR
PARTS OF THE HILL COUNTRY TUESDAY NIGHT THROUGH THURSDAY (NEW
YEARS DAY) MORNING. FORECAST SOUNDINGS SHOW A THICK LAYER ABOVE
FREEZING DEVELOPING ON TOP OF A SHALLOW SUBFREEZING BOUNDARY
LAYER. FREEZING RAIN IS THE LIKELY WINTER TYPE PRECIPITATION THAT
IS EXPECTED WHERE TEMPERATURES DROP BELOW FREEZING. HOWEVER...NO
SIGNIFICANT ICE ACCUMULATIONS ARE EXPECTED. SHOULD THE RAIN BECOME
MORE CONVECTIVE...THEN SOME SLEET MAY BE POSSIBLE OVER A GREATER
AREA. FINALLY...THERE MAY BE A THREAT OF LIGHT SNOW ACROSS WESTERN
EDWARDS PLATEAU PRIOR TO THE DEVELOPMENT OF THE WARM LAYER ALOFT.
BY THURSDAY AFTERNOON...THE LOWER LEVELS WARM ABOVE FREEZING WITH
ONLY A COLD RAIN EXPECTED. AS THE UPPER LOW APPROACHES AND MOVES
ACROSS...SOME THUNDERSTORMS ARE POSSIBLE DUE TO ELEVATED
INSTABILITY THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE RAINS END FROM
WEST TO EAST BY SATURDAY MORNING. FAIR SKIES AND MUCH WARMER
DAYTIME TEMPERATURES ARE EXPECTED NEXT WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              32  61  39  46  36 /   0   0  -   10  10
AUSTIN BERGSTROM INTL AIRPORT  25  60  35  46  36 /   0   0  -   10  10
NEW BRAUNFELS MUNI AIRPORT     29  61  36  48  38 /   0   0  -   10  10
BURNET MUNI AIRPORT            29  61  36  43  32 /   0   0  -   10  20
DEL RIO INTL AIRPORT           34  62  40  56  37 /   0   0  -   10  30
GEORGETOWN MUNI AIRPORT        28  60  35  44  34 /   0   0  -   10  10
HONDO MUNI AIRPORT             28  62  35  51  38 /   0   0  -   10  20
SAN MARCOS MUNI AIRPORT        29  61  36  47  37 /   0   0  -   10  10
LA GRANGE - FAYETTE REGIONAL   31  59  40  50  39 /   0   0  -   10  10
SAN ANTONIO INTL AIRPORT       32  62  39  49  38 /   0   0  -   10  20
STINSON MUNI AIRPORT           32  61  39  51  39 /   0   0  -   10  20

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING UNTIL 9 AM CST MONDAY FOR THE FOLLOWING COUNTIES:
ATASCOSA...DE WITT...FAYETTE...FRIO...GONZALES...KARNES...LAVACA...
UVALDE...WILSON...ZAVALA.

&&

$$

MESOSCALE/AVIATION...15
SYNOPTIC/GRIDS...24




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