FXUS64 KEWX 011213
AFDEWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
613 AM CST TUE DEC 1 2009
.AVIATION...
MVFR/LOCAL IFR CIGS/VSBYS WILL PREVAIL MUCH OF TODAY AS WIDESPREAD
RA DEVELOPS AHEAD OF THE UPPER LOW. A MIX WITH OR CHANGE TO -SN IS
POSSIBLE TONIGHT INTO EARLY WEDNESDAY NORTH OF A KDRT TO BOERNE TO
KILE LINE. THE UPPER LOW WILL MOVE ACROSS THE AREA TONIGHT INTO
WEDNESDAY MORNING CAUSING THE PRECIPITATION TO END FROM WEST TO
EAST WHICH WILL RESULT IN CIGS LIFTING. WRAPAROUND CLOUDS WILL
PERSIST MAINTAINING LOW VFR CIGS TONIGHT INTO WEDNESDAY MORNING.
NELY WINDS 5 TO 10 KTS TODAY WILL SLOWLY SHIFT TO NWLY TONIGHT.
SOME GUSTS TO 20 KTS ARE POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 503 AM CST TUE DEC 1 2009/
DISCUSSION...
MODELS CONTINUE TO SHOW THE WINTER STORM SYSTEM STRENGTH AND TRACK
TO BE SIMILAR TO EARLIER RUNS. RAINFALL AMOUNTS SO FAR HAVE BEEN
ON THE LIGHT SIDE OF THE FORECAST, BUT THE MAIN IMPULSE SHOULD
MOVE THROUGH LATER TODAY WITH HIGHER TOTALS OF 1-2 INCHES
POSSIBLE. THESE RAINS SHOULD FALL AT RATES BELOW ONE INCH PER
HOUR, ANY RUN-OFF CONCERNS SHOULD BE LIMITED TO URBAN AND POOR
DRAINAGE AREAS. NO THUNDER WAS MENTIONED IN THE FORECAST, BUT AN
ISOLATED CLAP COULD BE POSSIBLE GENERALLY EAST OF I-35 LATE THIS
AFTERNOON.
THE RAIN-SNOW MIX POTENTIAL REMAINS CONSISTENT WITH EARLIER
PROJECTIONS WITH THE BEST CHANCE OF A MIX GENERALLY ALONG AND
NORTH OF A DEL RIO TO BOERNE TO LIBERTY HILL LINE. RAIN MAY MIX
WITH SNOW EARLY IN THE EVENING IN AREAS NW OF DRT WITH THE COLD
MID-LEVEL AIR PUSHING THE RAIN-SNOW MIX LINE TOWARD THE MOUNTAIN
HOME AND LEAKEY AREAS BY MIDNIGHT. AREAS WEST OF LEAKEY AND
MOUNTAIN HOME COULD SEE ALL SNOW AFTER MIDNIGHT, BUT STABILITY IS
EXPECTED TO INCREASE RAPIDLY ON THE BACKSIDE OF THE LOW, LEAVING
ONLY SOME FLURRIES FROM WRAPAROUND ACTIVITY AS TEMPERATURES BECOME
SUPPORTIVE OF ACCUMULATION ON EXPOSED SURFACES. THUS WILL NOT
MENTION ANY ACCUMULATIONS FOR NOW.
WITH THE UPPER LOW DEPARTING LATE WEDNESDAY, COLD TEMPERATURES
WILL DIVE SOUTH WITH THE AID OF A LARGE POLAR TROUGH OVER THE NRN
US. MODEL TRENDS ARE RAPIDLY SHIFTING INTO ANOTHER WINTER WEATHER
EVENT SET FOR FRIDAY MORNING AS A PIECE OF THIS TROUGH CLIPS TX.
THE MODELS ARE CALLING FOR MEASURABLE AMOUNTS OF FROZEN
PRECIPITATION, BUT THE TRENDS ARE STILL SHIFTING THE TROUGH
PLACEMENT AND THE PRECIP POTENTIAL FROM POLAR CLIPPING SYSTEMS
OVER TX ARE USUALLY POOR PRODUCERS OF WINTER PRECIP. WILL ADDRESS
THIS WEATHER SCENARIO IN AN SPS/HWO/GRAPHICAL FORECASTS, BUT WILL
AGAIN DOWNPLAY ACCUMULATION POTENTIALS UNTIL MODEL RUNS SHOW MORE
CONSISTENCY. TEMPERATURES ARE DEFINITELY TRENDING COLDER AS THE
SUCCESSIVE RUNS CONTINUE TO PUSH THE POLAR TROUGH DEEPER AND
FARTHER WEST. A HARD FREEZE MAY BE POSSIBLE SATURDAY MORNING,
ESPECIALLY IF TEMPS ARE AIDED BY FROZEN PRECIP ACCUMULATION ON
FRIDAY.
A PERSISTENT BLOCKING RIDGE PATTERN OVER ALASKA/PACIFIC NW AND THE
PROGRESSIVE ZONAL PATTERN OVER THE SOUTHERN US WILL CONTINUE TO
MAKE FOR A CHALLENGING TASK TO FORECAST BEYOND 4-5 DAYS. AFTER A
BRIEF PERIOD OF EXPECTED STABLE WX LATE FRIDAY INTO SATURDAY, WEAK
DISTURBANCES OVERRIDING THE COLD LOW LEVEL AIR SHOULD PROMOTE COOL
MAX TEMPS AND PATCHY LIGHT RAINS OR DRIZZLE FROM THE WEEKEND INTO
EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 49 41 57 36 53 / 90 80 20 - 10
AUSTIN BERGSTROM INTL AIRPORT 50 40 56 32 54 / 90 80 20 - 10
NEW BRAUNFELS MUNI AIRPORT 51 39 57 34 54 / 90 70 10 - 10
BURNET MUNI AIRPORT 47 37 52 32 48 / 90 80 20 - 10
DEL RIO INTL AIRPORT 50 37 61 37 56 / 80 20 - - 10
GEORGETOWN MUNI AIRPORT 48 40 53 34 50 / 90 90 20 - 10
HONDO MUNI AIRPORT 52 38 59 33 54 / 90 50 - - 10
SAN MARCOS MUNI AIRPORT 51 39 55 33 54 / 90 80 20 - 10
LA GRANGE - FAYETTE REGIONAL 52 43 56 37 54 / 90 90 20 - 10
SAN ANTONIO INTL AIRPORT 51 41 58 36 54 / 90 60 - - 10
STINSON MUNI AIRPORT 51 40 59 35 56 / 90 60 - - 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
18/04
