000 
FXUS64 KSJT 132112
AFDSJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
312 PM CST WED DEC 13 2000

THE ARCTIC AIR HAS BEEN SCOURED OUT RATHER ABRUPTLY...AT LEAST ACROSS 
THE SOUTHERN HALF OF THE FORECAST AREA. SJT AND JCT HAVE RECOVERED 
INTO THE UPPER 50S AT 20Z...AFTER A CHILLY START. THE COLD AIR IS  
OBVIOUSLY DEEPER OVER THE NORTHERN HALF...BUT SURMISE EVAPORATIONAL 
COOLING (MELTING PROCESS) CONTRIBUTING TO CAUSE. THE MERCURY AT ABI 
READ A RATHER CHILLY 42. OTHERWISE...VISIBLE IMAGERY SHOWED SOME 
RESIDUAL WRAP AROUND STRATO CU ACROSS THE EASTERN PORTIONS OF BIG 
COUNTRY. LOOKING AT WATER VAPOR...NEXT WEATHER MAKER SITUATED NEAR 
44N/129W.   

WHETHER OR NOT TO INTRODUCE POPS WITH NEXT UPPER LEVEL SHORTWAVE TROUGH 
MAIN FORECAST PROBLEM. 

IN THE SHORT-TERM...AM LEANING TOWARD THE COOLER AVN MOS AS FULLY EXPECT 
THE BOUNDARY LAYER TO DECOUPLE OVERNIGHT. FOR THURSDAY...RETURN FLOW 
SETS UP IN RESPONSE TO APPROACHING UPPER LEVEL SHORTWAVE TROUGH. POSITIVE 
THETE-E ADVECTION IN THE 1000-850 MB LAYER SHOULD PROMOTE MOSTLY CLOUDY 
CONDITIONS ACROSS THE SOUTHERN TWO THIRDS OF THE FORECAST AREA...AS 
ADVERTISED BY THE AVN TIME SECTIONS. MORE CLOUDS AREAWIDE FOR THURSDAY 
NIGHT. QUESTION IS...IS THERE ENOUGH MOISTURE FOR PRECIPITATION? RIGHT 
NOW...THE ANSWER IS NO FOR THE LOW LEVEL MOISTURE APPEARS SHALLOW IN 
NATURE. PLENTY OF LIFT PER QG FIELDS...JUST NOT ENOUGH MOISTURE. SKIES 
WILL RAPIDLY CLEAR FROM WEST TO EAST AS THE FAST MOVING UPPER LEVEL 
TROUGH MOVES EAST OF THE AREA.       
 
IN THE EXTENDED...SATURDAY AND SUNDAY LOOK MILD WITH ZONAL FLOW ALOFT.  
850 TEMPERATURES CLIMB INTO THE TEENS. ANOTHER SHOT OF ARCTIC 
AIR DUE IN MONDAY. QUICK WARMUP PROGD FOR TUESDAY AND WEDNESDAY. 

COOR WITH MAF...  

ABI 028/058/047/066 0000
SJT 027/062/045/068 0000
JCT 028/061/044/069 0000

.SJT...NONE.

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