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000
FXUS65 KGJT 092142
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
242 PM MST TUE FEB 9 2010

.SHORT TERM...TONIGHT THROUGH THURSDAY...

STRATUS IN THE SOUTH PRODUCED SOME LIGHT SNOW SHOWERS TODAY...WHILE
NORTHERN VALLEY STRATUS ERODED.

ONLY LIGHT PRECIPITATION FOR THESE PERIODS SHIFTING FROM SOUTH
TONIGHT-WEDNESDAY TO NORTH WEDNESDAY NIGHT-THURSDAY.

THE PACIFIC LOW SOUTH OF SAN FRANCISCO TODAY...WILL DIG DOWN THE
COAST TO SAN DIEGO TONIGHT...THEN EJECT ACROSS THE AZ-SONORA BORDER
ON WEDNESDAY. THIS TILTS THE SUBTROPICAL JET UP INTO SOUTHERN NM
AND SW FLOW ADVECTS IN DEEP MOISTURE STARTING TONIGHT. BOTH GFS AND
NAM EJECT A WEAK POTENTIAL VORTICITY LOBE ACROSS SW CO AFTER
MIDNIGHT TONIGHT. MODELS CONTINUE TO PRODUCE ONLY LIGHT MAINLY
OROGRAPHIC QPF...THOUGH WITH THE SOUTHERN VALLEYS UNDER MOIST
STRATUS DECKS...SEEDER FEEDER PROCESS COULD PRODUCE LIGHT
SNOWFALL THERE TOO. CLOUDS WILL LIMIT DIURNAL TEMPERATURE SPREAD...
EXCEPT ACROSS THE FAR NORTH WHERE COLD VALLEY INVERSIONS WILL
DOMINATE.

VERY WEAK TROUGH PASSAGE OCCURS WEDNESDAY NIGHT SHIFTING THE FLOW
TO NW. MOISTURE DIMINISHES SIGNIFICANTLY THROUGH THE DAY THURSDAY
WITH MOISTURE APPROACHING FROM THE NW LATE IN THE DAY.

.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

A WESTERN U.S. TROUGH WILL BE THE DOMINANT FEATURE THROUGH THE LONG
TERM PERIOD. THIS WILL RESULT IN A PERSISTENT NORTHWEST FLOW OVER OUR
FORECAST AREA. A SERIES OF SHORTWAVES WILL DROP INTO THE NORTHERN
PLAINS/GREAT LAKES REGION AND BRUSH THE NORTHEAST EDGE OF THE
FORECAST AREA. THE CHANCE FOR SHOWERS WILL BE ENHANCED AS EACH WAVE
PASSES...MAINLY ON THE FAVORED NORTHWEST SLOPES ALONG THE CONTINENTAL
DIVIDE. THE STRONGEST DISTURBANCE WILL AFFECT THE AREA ON SAT/SAT
NIGHT. AS A RESULT THE POSSIBILITY OF SNOW WILL DEVELOP OVER MUCH OF
THE FORECAST AREA...WITH BETTER CHANCES OVER THE MOUNTAINS AND NORTH.
DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK.

DUE TO THE SOMEWHAT PERTURBED NORTHWEST FLOW...TEMPERATURES WILL
SLOWLY WARM. VARIABLE CLOUDS WILL KEEP NIGHTTIME TEMPERATURES ON THE
MODERATE SIDE AND NEAR NORMAL. HIGHS WILL TRY TO REACH NORMAL
READINGS...BUT MOST LOCATIONS WILL STAY JUST A LITTLE BELOW.

&&

.AVIATION...

STRATUS CLOUDS IN THE SOUTHERN VALLEYS AND UINTA BASIN HAVE
DIMINISHED THIS AFTERNOON. BUT MOISTURE FROM THE SW WILL INCREASE
OVERNIGHT WITH MVFR CIGS POSSIBLE AFTER MIDNIGHT. AREAS OF -SN WILL
DEVELOP OVER MTNS ALONG AND SOUTH OF I-70 PRODUCING LOCAL IFR CIGS
AND VSBYS. AREAS OF MVFR CIGS WILL PERSIST THROUGH WEDNESDAY WITH
LOCAL IFR CIGS AND VSBYS IN -SN FAVORING THE SOUTHERN MTNS.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.
UT...NONE.

&&

$$

SHORT TERM...JOE
LONG TERM....EH
AVIATION.....JOE+EH