FXUS64 KSJT 281159
AFDSJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
559 AM CST SAT NOV 28 2009
.DISCUSSION...
EXPECT DEGRADING FLIGHT CONDITIONS OVERNIGHT TONIGHT ACROSS WEST
CENTRAL TEXAS. SEE AVIATION BELOW.
&&
.AVIATION...
LOW-LEVEL MOISTURE WILL CONTINUE TO INCREASE ACROSS WEST CENTRAL
TEXAS DURING THE NEXT 24 HOURS...AS ANOTHER COLD FRONT AND ITS
ASSOCIATED UPPER-LEVEL STORM SYSTEM APPROACHES TEXAS. LOOK FOR VFR
CONDITIONS WITH GUSTY SOUTH TO SOUTHWEST WINDS TODAY. AFTER SUNSET
THIS EVENING...WINDS WILL DIMINISH TO AROUND 10 KNOTS. AFTER
MIDNIGHT TONIGHT...WATCH FOR MVFR TO IFR CEILINGS TO MOVE INTO
WEST CENTRAL TEXAS FROM THE SOUTH AS STRATUS RETURNS. ANALYSIS OF
THE LATEST NAM12 925 MB RELATIVE HUMIDITY AND WIND FIELDS
INDICATES STRATUS WILL BEGIN MOVING INTO OUR SOUTHERN COUNTIES
AROUND MIDNIGHT TONIGHT. MODEL MOS GUIDANCE INDICATES INITIAL
CEILINGS WILL BE AROUND 1500 FEET ABOVE GROUND LEVEL. JUST BEFORE
SUNRISE TOMORROW MORNING...PLAN FOR IFR CEILINGS AT THE
SONORA...JUNCTION ..AND BRADY TERMINALS WITH BASES AROUND 700 FEET
ABOVE GROUND LEVEL. ALSO...PATCH FOG IS LIKELY AT THESE THERE
TERMINALS WITH VISIBILITY DECREASING TO AROUND 5 STATUE MILES BY
AROUND THAT TIME. MEANWHILE...WATCH FOR THE NEXT COLD FRONT TO BEGIN
MOVING INTO THE NORTHWESTERN BIG COUNTRY AROUND SUNRISE TOMORROW
MORNING.
23/HUBER
&&
.PREV DISCUSSION... /ISSUED 406 AM CST SAT NOV 28 2009/
SHORT TERM...
FOR TODAY AND TONIGHT...TEMPERATURES ABOVE SEASONAL NORMALS AND
GUSTY SOUTH TO SOUTHWEST SURFACE WINDS WILL DOMINATE WEST CENTRAL
TEXAS. THE LATEST NAM SURFACE DATA INDICATE AN APPROACHING COLD
FRONT WILL HELP MAINTAIN A TROUGH OF LOW PRESSURE ACROSS THE TEXAS
PANHANDLE AND TRANS PECOS REGION OF WEST TEXAS DURING THE NEXT 24
HOURS. THUS...EXPECT SOUTH TO SOUTHWEST SURFACE WINDS TODAY ACROSS
WEST CENTRAL TEXAS RANGING FROM 10 TO 15 MPH WITH OCCASIONAL GUSTS
AROUND 20 MPH. OVERNIGHT TONIGHT...THE NEXT COLD FRONT WILL BEGIN
MOVING SOUTH ACROSS THE TEXAS PANHANDLE. THE LATEST NAM SURFACE DATA
ARE NOW INDICATING THE FRONT WILL JUST BEGIN TO NOSE INTO OUR
NORTHWESTERN BIG COUNTRY COUNTIES AROUND SUNRISE SUNDAY MORNING. THE
GFS SURFACE DATA ARE IN GOOD AGREEMENT WITH THIS TIMING. SO...I
BELIEVE THIS LOOKS REASONABLE. MEANWHILE...A WEAK UPPER-LEVEL
DISTURBANCE WILL CONTINUE TO TRACK EAST ACROSS TEXAS THIS MORNING.
ANALYSIS OF THE NAM TIME HEIGHT RELATIVE HUMIDITY FIELDS...CENTERED
OVER ABILENE...SAN ANGELO...AND JUNCTION...INDICATE UPPER-LEVEL
CLOUDS SHOULD DECREASE THIS AFTERNOON AS THIS SYSTEM TRACKS FARTHER
EAST OF OUR AREA. HOWEVER...ANALYSIS OF THE NAM12 925 MB RELATIVE
HUMIDITY AND WIND FIELDS INDICATES STRATUS WILL RETURN OVERNIGHT
TONIGHT. AS FOR TEMPERATURES...NUMBERS CLOSE TO MEX MOS LOOK
REASONABLE.
23/HUBER
LONG TERM...
THE MAIN CHALLENGES IN THE LONG TERM FORECAST CONTINUE TO BE A COLD
FRONT EXPECTED ON SUNDAY AND THE POSSIBILITY OF WINTER
PRECIPITATION AS AN UPPER LEVEL STORM SYSTEM APPROACHES AND MOVES
ACROSS THE AREA MONDAY NIGHT THROUGH TUESDAY.
THE MODELS HAVE COME INTO BETTER AGREEMENT OF FROPA TIMING WITH
THE COLD FRONT APPROACHING THE INTERSTATE 20 CORRIDOR MID MORNING
ON SUNDAY...CONCHO VALLEY EARLY AFTERNOON AND THE INTERSTATE 10
CORRIDOR AROUND SUNRISE. A MUCH COLDER AIRMASS WILL MOVE IN ACROSS
WEST CENTRAL TEXAS BEHIND THIS FRONT. A DEVELOPING UPPER LEVEL
STORM SYSTEM ACROSS CALIFORNIA WILL WILL PUSH SOUTH INTO THE
DESERT SOUTHWEST ON SUNDAY AND THEN PUSH EAST INTO NORTHERN MEXICO
AND WEST TEXAS SUNDAY INTO TUESDAY. AHEAD OF THE UPPER LEVEL
SYSTEM WEAK UPPER LEVEL DISTURBANCES WILL MOVE ACROSS THE
AREA...THIS COMBINED WILL RESULT IN CHANCE OF RAIN WITH ISOLATED
THUNDERSTORMS SUNDAY AFTERNOON INTO MONDAY...WITH RAIN CHANCES
ENDING ACROSS THE BIG COUNTRY DURING THE DAY ON MONDAY.
THE CURRENT FORECASTED TRACK OF THE UPPER LEVEL STORM
SYSTEM PLACES THE SOUTHERN HALF OF WEST CENTRAL TEXAS IN A
FAVORABLE LOCATION FOR WINTRY PRECIPITATION. THE CURRENT MODEL SOUNDING
INDICATE THAT MOST OF THE WINTRY PRECIPITATION WILL BE IN THE FORM
OF SNOW BUT SOME SLEET WILL ALSO BE POSSIBLE. AS THIS SYSTEM MOVE EAST OF
WEST CENTRAL TEXAS TUESDAY NIGHT...PRECIPITATION CHANCES WILL END
FROM WEST TO EAST. ATTM SIGNIFICANT SNOWFALL ACCUMULATIONS IS LOW
BUT THIS IS STILL A DEVELOPING SITUATION AND THIS WILL NEED TO BE
MONITORED.
BY MIDWEEK DRIER NORTHWEST FLOW ALOFT WILL BE IN PLACE BUT HAVE
KEPT TEMPERATURES ON THE COOL SIDE AS THE ECMWF CONTINUES TO
ADVERTISE A COLD FRONT TOWARDS THE END OF THE WORK WEEK AND GIVEN
THAT THE ECMWF HAS DONE A BETTER JOB OVER THE LAST COUPLE OF
WEEKS...HAVE GONE TOWARDS THE COLDER ECMWF.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 73 53 56 34 48 / 10 10 40 30 20
SAN ANGELO 75 54 62 36 41 / 10 10 30 40 40
JUNCTION 71 56 61 42 44 / 10 10 30 60 50
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
23/HUBER
