FXUS64 KEWX 231631
AFDEWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1031 AM CST WED DEC 23 2009
.DISCUSSION...
SOUTHERLY WINDS WILL CONTINUE TO ENABLE GOOD WARM AIR ADVECTION
THIS AFTERNOON AHEAD OF THE APPROACHING COLD FRONT. SCATTERED
SHOWERS WILL CONTINUE TO DEVELOP ACROSS EAST TEXAS AND WILL GRADUALLY
DEVELOP FURTHER WEST THROUGHOUT THE DAY. MOST OF THE ACTIVITY THIS
AFTERNOON WILL BE EAST OF HIGHWAY 281 BUT COULD SEE A FEW ISOLATED
SHOWERS ACROSS THE RIO GRANDE PLAINS. BEST AREAL COVERAGE OF SHOWERS
AND THUNDERSTORMS WILL BE OVERNIGHT. HAVE ADJUSTED AFTERNOON HIGHS
UP BY A FEW DEGREES MAINLY ACROSS THE EASTERN HALF OF THE CWA AS
TEMPERATURES HAVE RISEN QUICKER THAN PREVIOUSLY ANTICIPATED. NEW
ZONES OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 553 AM CST WED DEC 23 2009/
AVIATION...
WIDESPREAD STRATUS AND PATCHY BR/FG COVER SOUTH CENTRAL TEXAS AND
THE HILL COUNTRY. MOST CIGS AND VSBYS WILL BE MVFR, EXCEPT IFR OR
WORSE WILL BE OUT WEST AND IN THE FAR EAST. LIFR/VLIFR VSBYS WILL
PERSIST WEST OF A KJCT TO KERV TO KUVA TO MMPG LINE. CIGS AND
VSBYS WILL LIFT MOST AREAS TO VFR AS BR/FG DISSIPATES AND CLOUDS
BECOME SCT LATE MORNING AND AFTERNOON. A FEW SHRA CAN BE EXPECTED
ACROSS EASTERN AREAS TODAY. A COLD FRONT AND UPPER TROUGH MOVE
THROUGH THE AREA TONIGHT WITH A PERIOD OF MVFR CIGS AND VSBYS IN
SHRA/TSRA. SKIES WILL BECOME VFR WITH FEW CLOUDS LATE TONIGHT INTO
THURSDAY. SLY WINDS 5 TO 15 KTS TODAY INTO THIS EVENING WILL SHIFT
TO NWLY 10 TO 20 KTS WITH GUSTS TO 30 KTS OVERNIGHT INTO THURSDAY
WITH THE FRONTAL PASSAGE.
PREV DISCUSSION... /ISSUED 453 AM CST WED DEC 23 2009/
DISCUSSION...
UPPER LOW CENTERED OVER THE 4 CORNERS REGION EARLY THIS MORNING
WITH A LARGE DRY SLOT FEATURE OVER TX LIMITING RAIN POTENTIAL AND
ENHANCING MORNING FOG IN A FEW SPOTS EARLY TODAY. THE MOISTURE
DOES NOT REALLY GET A CHANCE TO FILL BACK INTO THE AREA UNTIL
LATE IN THE AFTERNOON...AND THE CHANCE POPS FOR THE AFTERNOON OVER
EASTERN COUNTIES REFLECT THE POTENTIAL OF MAINLY STREAMER SHOWERS
AND A FEW STORMS GETTING STARTED BEFORE SUNDOWN. THE WEAK MOISTURE
FIELD COULD SUPPORT A FEW SMALL HAIL PRODUCING STORMS AS THE
UPPER LEVEL TROUGH APPROACHES THIS EVENING. HOWEVER...WEAK LOW
LEVEL WIND SHEAR AND LIMITED MOISTURE IS EXPECTED TO RESULT IN
MOSTLY WEAKER STORMS WITH THE STRONGER ACTIVITY POSSIBLE TO THE
NORTH AND EAST. THE BEST RAIN CHANCES ARE FROM 9 PM TO 3 AM WITH
THE PACIFIC FRONT STILL EXPECTED TO SWEEP QUICKLY THROUGH THE
METRO AREAS AROUND MIDNIGHT.
THE SHARP TROUGH WILL BE JUST EAST OF THE FORECAST AREA BY 15Z
THURSDAY WHEN THE STRONGEST POST-FRONTAL WINDS ARE EXPECTED. SOME
OF THE WINDS COULD BRIEFLY APPROACH WIND ADVY CRITERIA IN
LOCALIZED AREAS DURING THIS TIME. DOWNSLOPING WINDS WILL HELP MODIFY
TEMPS AND LOWER RH VALUES LATE IN THE DAY WHEN WINDS BEGIN TO
SUBSIDE. BRIEF ELEVATED FIRE WEATHER CONDITIONS ARE POSSIBLE IN
THE MID AFTERNOON AROUND EAGLE PASS AND CARRIZO SPRINGS AREAS...
BUT COLD AIR ADVECTION SHOULD KEEP MOST RH VALUES IN THE UPPER 20S
OR HIGHER.
THE SHARP UPPER THROUGH ROTATES N INTO THE CENTRAL PLAINS...
MERGING WITH ANOTHER CHUNK OF ENERGY TO DEEPEN INTO A LARGE AND
STRONG UPPER LOW THAT IS SLOW TO MOVE EAST FOR THE WEEKEND. THIS
STORM SYSTEM WILL LIKELY ADD SOME SNOW COVER OVER THE CENTRAL PLAINS
TO ENHANCE COLD AIR ADVECTION ON CHRISTMAS DAY. COOLER THAN GFS
GUIDANCE TEMPS WERE FAVORED FOR THIS WEEKEND. FREEZING MORNING
TEMPS WILL BE POSSIBLE EACH MORNING FRIDAY THROUGH SUNDAY WITH
PROBABLY THE COLDEST AIR ON SATURDAY MORNING. MODELS HAVE BEEN
CONSISTENT WITH KEEPING PRECIP OUT OF THE REGION DURING THIS COLD
PERIOD DESPITE A FAIRLY UNSTABLE ZONAL FLOW PATTERN ALOFT. TEMPS
ARE EXPECTED TO MODERATE INTO EARLY NEXT WEEK WHEN A DISTURBANCE
IS EXPECTED TO SUPPORT A CHILLY OVERRUNNING RAIN SCENARIO TUESDAY
INTO WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 73 46 60 34 50 / 30 50 10 - 10
AUSTIN BERGSTROM INTL AIRPORT 74 47 60 30 52 / 30 50 10 - 10
NEW BRAUNFELS MUNI AIRPORT 75 46 62 32 54 / 20 50 10 - 10
BURNET MUNI AIRPORT 71 43 54 29 48 / 20 50 10 - 10
DEL RIO INTL AIRPORT 70 44 64 35 55 / 10 20 0 0 -
GEORGETOWN MUNI AIRPORT 72 46 56 32 48 / 40 50 10 - 10
HONDO MUNI AIRPORT 73 45 63 30 54 / 10 40 - - -
SAN MARCOS MUNI AIRPORT 75 46 61 31 53 / 30 50 10 - 10
LA GRANGE - FAYETTE REGIONAL 75 49 61 33 52 / 50 70 20 - 10
SAN ANTONIO INTL AIRPORT 73 46 62 33 54 / 20 50 - - 10
STINSON MUNI AIRPORT 74 46 64 32 55 / 20 50 - - 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25/11
