FXUS64 KEWX 281145
AFDEWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
545 AM CST SAT NOV 28 2009
.DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION BELOW.
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED AT TAF SITES TODAY THROUGH EARLY THIS
EVENING, ALTHOUGH A FEW MVFR CIGS COULD AFFECT HILL COUNTRY
LOCATIONS THIS MORNING. GULF MOISTURE CONTINUES TO INCREASE TO ADD
SOME MID-LEVEL VFR CIGS THIS AFTERNOON AS MIXING RAISES MOST
HEIGHTS TO ABOVE 3000 FT THROUGH EARLY THIS EVENING. CIGS BECOME
DENSE THIS EVENING AND BECOME GRADUALLY LOWER THROUGH THE NIGHT AS
AN UPPER LEVEL DISTURBANCE APPROACHES. SOME LOCALLY DENSE FOG IS
POSSIBLE, BUT WITH THE FAIRLY THICK LAYER OF MOISTURE ADVECTION,
WILL GO WITH 200 FT CIGS AND VSBYS MAINLY ABOVE 1 MILE TOWARD
DAYBREAK.
&&
.PREV DISCUSSION... /ISSUED 418 AM CST SAT NOV 28 2009/
DISCUSSION...
A WARMING TREND IS UNDERWAY...WITH TEMPERATURES TRENDING ABOVE
NORMAL TODAY. SOUTHERLY WINDS IN THE LOWER BOUNDARY LAYER WILL
BRING GULF MOISTURE BACK TO THE AREA TODAY...LIKELY RESULTING IN
ADVECTION-TYPE FOG LATE TONIGHT INTO SUNDAY MORNING.
THE COLD FRONT IS FORECAST TO PUSH INTO OUR NORTHERN COUNTIES
SUNDAY AFTERNOON AND ACROSS OUR CWFA SUNDAY EVENING. ISENTROPIC
UPGLIDE WILL BE ON THE INCREASE BEHIND THE FRONT LATE SUNDAY NIGHT
THROUGH TUESDAY. RAINFALL AMOUNTS OF ONE HALF TO ONE INCH WILL BE
COMMON DURING THIS PERIOD...WITH SPOTTY TOTALS NEAR TWO INCHES
POSSIBLE EAST OF INTERSTATE 35. THE BIG FORECAST QUANDARY IS
WHETHER OR NOT THE HILL COUNTRY AND EDWARDS PLATEAU WILL RECEIVE
FROZEN PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY AS THE UPPER
LOW PULLS OUT OF MEXICO OVER TEXAS. FORECAST SOUNDINGS FROM THE
00Z GFS RUN ARE SNOW-FAVORABLE OVER PORTIONS OF THE HILL COUNTRY
AND EDWARDS PLATEAU ON TUESDAY...WITH A PERIOD OF RAIN AND SLEET
PRIOR TO THE ONSET OF SNOW. HOWEVER...THE 00Z ECMWF SHOWS A MORE
NORTHERLY TRACK OF THE UPPER LOW ON TUESDAY AND WOULD FAVOR FROZEN
PRECIP OVER ONLY A SMALL PORTION OF VAL VERDE COUNTY. THE 06Z GFS
TRENDED FURTHER NORTH WITH THE FORECAST TRACK OF THE UPPER
LOW...CLOSER TO THE 00Z ECMWF SOLUTION. THIS ALL LENDS LOW
CONFIDENCE TO THE FROZEN PRECIP FORECAST LATE MONDAY NIGHT THROUGH
TUESDAY NIGHT. FOR THE AUSTIN SAN ANTONIO CORRIDOR...ONLY A COLD
RAIN IS FORECAST. TEMPERATURES WILL TREND WELL BELOW NORMAL BEHIND
THE FRONT AND WILL HAVE A HARD TIME GETTING OUT OF THE MID TO
UPPER 30S IN THE HILL COUNTRY ON TUESDAY. THE UPPER LOW WILL MOVE
OUT OF TEXAS ON WEDNESDAY AND SURFACE HIGH PRESSURE WILL BUILD
OVER THE AREA.
OUR MAX/MIN TEMP NUMBERS ARE GENERALLY BELOW THE 00Z GFSMOS BEHIND
THE FRONT...ESPECIALLY THE MAX TEMPS ON MONDAY AND TUESDAY WITH
CLOUDS...COLD AIR ADVECTION AND EVAPORATIVE COOLING OF THE FRONTAL
LAYER FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 70 60 70 47 48 / 10 10 30 80 70
AUSTIN BERGSTROM INTL AIRPORT 70 59 71 49 49 / 10 10 30 80 70
NEW BRAUNFELS MUNI AIRPORT 70 59 72 48 49 / 10 10 20 80 80
BURNET MUNI AIRPORT 69 59 66 45 47 / 10 10 40 70 50
DEL RIO INTL AIRPORT 72 57 70 49 49 / - - 20 60 70
GEORGETOWN MUNI AIRPORT 70 61 68 46 48 / 10 10 40 80 60
HONDO MUNI AIRPORT 72 57 72 49 49 / 10 10 20 70 80
SAN MARCOS MUNI AIRPORT 69 59 72 47 48 / 10 10 30 80 70
LA GRANGE - FAYETTE REGIONAL 71 62 74 50 50 / 10 10 30 80 80
SAN ANTONIO INTL AIRPORT 70 60 72 49 49 / 10 10 20 80 80
STINSON MUNI AIRPORT 71 59 73 50 50 / 10 10 20 80 80
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11/18
