FXUS65 KTFX 241149
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
449 AM MST THU DEC 24 2009

UPDATED AVIATION

.DISCUSSION...

THURSDAY THROUGH SATURDAY...AN UPPER LEVEL HIGH PRESSURE RIDGE OVER 
THE WEST COAST WILL DOMINATE THE WEATHER DURING THE NEXT FEW DAYS. 
HEIGHTS WILL BUILD AND THE AIRMASS WILL REMAIN DRY WHILE SLOWLY 
TRENDING WARMER. NORTH WINDS ALOFT ASSOCIATED WITH THE WEST COAST 
HIGH WILL CONTINUE TO BRING COOL...CANADIAN AIR INTO THE REGION 
UNTIL EARLY SATURDAY MORNING. ALTHOUGH THE AIRMASS WARMS VERY 
SLOWLY...TEMPS WILL STRUGGLE TO RISE. CLEAR SKIES AND LIGHT WINDS 
WILL BRING COLD MORNING TEMPS AND THE FOLLOWING DAY TIME HIGHS WILL 
WILL HAVE TROUBLE OVERCOMING THE LOW OVER NIGHT MINS. ZELZER

SATURDAY NIGHT THROUGH THURSDAY...HIGH PRESSURE WILL REMAIN CENTERED 
OVER SOUTHERN ALBERTA WITH TRANQUIL CONDITIONS REMAINING ACROSS THE 
FORECAST AREA. A WEAK AND MOISTURE-STARVED UPPER-LEVEL SHORTWAVE 
WILL CIRCULATE THROUGH SOUTHWEST MONTANA AND THEN INTO THE PACIFIC 
NORTHWEST. PARTLY TO MOSTLY CLOUDY SKIES AND DRY CONDITIONS ARE 
EXPECTED WITH TEMPERATURES AROUND SEASONAL AVERAGES ON SUNDAY AND 
MONDAY.  LONG-RANGE MODELS SUGGEST A SHORTWAVE TROUGH WILL MOVE INTO 
THE PACIFIC NORTHWEST BY TUESDAY...BRINGING INCREASED PRECIP CHANCES 
ALONG THE CONTINENTAL DIVIDE AND PORTIONS OF SOUTHWEST MONTANA. 
NORTHWEST FLOW WILL ALSO YIELD SLIGHTLY COOLER TEMPERATURES DURING 
THE MIDDLE OF NEXT WEEK. MLS

&&

.AVIATION... 
UPDATED 1200Z.
PATCHY FREEZING FOG HAS DEVELOPED THIS MORNING AT KBZN AND KHLN WITH 
MVFR AND OCCL IFR CONDITIONS AT KBZN THROUGH 1400Z AND MVFR WITH 
POSSIBLE IFR CONDITIONS AT KHLN THROUGH 1500Z. AFTER 
SUNRISE...MIXING WINDS SHOULD ALLOW FOG TO DISSIPATE AT BOTH 
SITES...THEN CLEAR SKIES ARE EXPECTED. REMAINING AREAS CAN EXPECT 
VFR CONDITIONS TO PREVAIL OVER THE 24 HOURS. NORTHWEST FLOW ALOFT 
WILL PERSIST AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION. SCT 
TO BKN MID-HIGH LEVEL CLOUDS WILL MOVE INTO THE AREA LATE THIS 
AFTERNOON AND TONIGHT FROM NORTH TO SOUTH AS WEAK ENERGY MOVES 
THROUGH FLOW ALOFT...HOWEVER DRY CONDITIONS ARE ANTICIPATED 
THROUGHOUT THE PERIOD. MLS

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  14  -1  25  12 /   0   0   0   0 
CTB  12  -6  25   8 /   0   0   0   0 
HLN  10  -2  19  -1 /   0   0   0   0 
BZN  12 -10  21  -4 /   0   0   0   0 
WEY  14 -10  17  -8 /   0  10  10  10 
DLN  13  -5  21  -1 /   0   0   0   0 
HVR   0 -13  11  -9 /   0   0   0   0 
LWT  12  -2  22   5 /   0   0   0   0 

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

WEATHER.GOV/GREATFALLS