371
FXUS64 KSJT 210931 CCA
AFDSJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
331 AM CST SAT NOV 21 2009
SHORT TERM
MUCH OF THE MID/UPPER CLOUDINESS OVER THE BIG COUNTRY AND HEARTLAND
EARLY THIS MORNING WILL MOVE EAST OF THE REGION BY SUNRISE...AS
UPPER LOW IN CENTRAL TEXAS ALSO MOVES EAST. WINDS WILL BE LIGHT AND
VARIABLE EARLY THIS MORNING...BUT SHIFT TO THE SOUTH AT 5 TO 10
MPH...AS A WEAK LEE TROUGH DEVELOPS.
WENT CLOSE TO GFS MOS GUIDANCE TODAY IN MIDDLE OF THE AIRMASS AND
FULL SUN. GUIDANCE IS USUALLY CLOSE IN SUCH SITUATIONS. HOWEVER
WENT LOWER THAN GUIDANCE TONIGHT....SOUTH OF THE BIG COUNTRY...
WHERE GOOD NIGHTTIME RADIATIONAL CONDITIONS DEVELOP...ESPECIALLY IN
LOW LYING AREAS AND RIVER VALLEYS.
04
LONG TERM
THE FORECAST PATTERN IN THE LONG TERM CONTINUES TO LOOK DRY FOR
OUR AREA. TEMPERATURES SUNDAY WILL BE WARMER THAN TODAY. LOWS
SUNDAY NIGHT WILL ALSO NOT BE AS COOL. BOUNDARY LAYER SHOULD
STAY MIXED ACROSS OUR NORTHERN COUNTIES...AND LOW CLOUD DEVELOPMENT/
ADVANCEMENT IS INDICATED BY EARLY MONDAY MORNING ACROSS MUCH OF
THE AREA SOUTH OF INTERSTATE 20. HIGHS MONDAY ARE EXPECTED TO BE
AROUND 10 DEGREES ABOVE NORMAL WITH SOME THERMAL RIDGING INDICATED
AHEAD OF APPROACHING COLD FRONT.
OVERALL...THE GFS AND ECMWF MODELS INDICATE THAT AN UPPER TROUGH
WILL DEEPEN INTO THE NORTHERN/CENTRAL PLANIS MONDAY...WITH AN
UPPER LOW AND TROUGH PROGRESSING TOWARD THE MID-MISSISSIPPI VALLEY
ON TUESDAY. THOUGH THE GFS AND ECMWF STILL HAVE SOME DIFFERENCES
WITH TIMING AND PLACEMENT...BOTH MODELS SHOW THE ASSOCIATED COLD
FRONT DROPPING SOUTH ACROSS WEST CENTRAL TEXAS MONDAY NIGHT. WILL
BE A DRY COLD FRONTAL PASSAGE FOR OUR AREA...REGARDLESS OF THE
SPECIFIC MODEL DIFFERENCES. COOLER AIRMASS WILL FOLLOW THIS FRONTAL
PASSAGE AND RESIDE IN OUR REGION TUESDAY.
WEDNESDAY AND THURSDAY...THE GFS IS MORE AGGRESSIVE IN DIVING
ANOTHER SHORTWAVE INTO THE MIDWEST AND CARVING OUT A DEEP TROUGH
INTO THE EASTERN PART OF THE COUNTRY BY LATE NEXT WEEK. DEPENDING
ON HOW THIS PATTERN EVOLVES...MAY SEE A REINFORCING SURGE OF
COOLER AIR INTO OUR AREA. APPEARS AT THIS TIME...HOWEVER...THAT
THE BULK OF THE COLD AIR ADVECTION WOULD BE TO OUR NORTHEAST AND
EAST.
19
PRELIMINARY POINT TEMPS/POPS
ABILENE 65 44 71 47 76 / 0 0 0 0 0
SAN ANGELO 67 42 73 47 76 / 0 0 0 0 0
JUNCTION 66 36 73 46 74 / 0 0 0 0 0
SJT WATCHES/WARNINGS/ADVISORIES
NONE.
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