876 
FXUS65 KTFX 182146
AFDTFX

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
245 PM MST TUE DEC 18 2001

.SHORT TERM...TONIGHT THROUGH FRIDAY...
UPPER LEVEL RIDGE MOVES EAST TONIGHT AS NEXT UPPER LEVEL DISTURBANCE
APPROACHES WESTERN MONTANA. THIS DISTURBANCE WILL MOVE ACROSS THE
ARE WEDNESDAY MORNING...BUT PRECIPITATION WILL BE LIMITED. EXPECT
MOSTLY DRY CONDITIONS OVER THE PLAINS OF THE NORTH DUE TO DOWNSLOPE
WINDS. A SLIGHTLY BETTER CHANCE WILL OCCUR OVER THE MOUNTAINS OF
THE SOUTHWEST...BUT BEST DYNAMICS WILL GO NORTH OF THIS AREA. THEN
AS SURFACE LOW MOVES EAST ON THURSDAY...WINDS SWITCH TO THE NORTH...
ESPECIALLY OVER NORTH CENTRAL MT BY 12Z USING THE AVN. THIS WILL
ALLOW FOR UPSLOPE PRECIPITATION TO DEVELOP...ALONG WITH COOLER
TEMPERATURES FOR BOTH THURSDAY AND FRIDAY. THIS SYSTEM NEEDS TO BE
WATCHED...AS SOME FAVORED AREAS ON NORTH FACING SLOPES COULD RECEIVE
A BIT MORE SNOW THEN THEY HAVE SEEN RECENTLY. HOWEVER...ALL SNOW
SHOULD EXIT THE REGION BY FRIDAY AFTERNOON AS SURFACE HIGH WILL MOVE
TOWARDS SOUTH CENTRAL MONTANA.

.EXTENDED FORECAST...SATURDAY THROUGH CHRISTMAS DAY...
MODELS CONTINUE TO AGREE IN GENERAL ON THE GROSS PATTERN THROUGH THE
WEEKEND...WITH DIFFERENCES ARISING EARLY NEXT WEEK. IN GENERAL...
UPPER AIR PATTERN WILL SEEA CLOSED LOW OVER SRN/CRNTRL ROCKIES WITH
A SHORWAVE RIDGE OVER MT GIVING WAY TO ZONAL FLOW. BY MONDAY...THE
MRF BRINGS ANOTHER SHORTWAVE THROUGH SRN CANADA AND DROPS IT INTO AN
OPEN TROUGH OVER THE ERN CONUS. RIDGING FORMS OVER THE ERN PAC AND
GULF OF AK ON CHRISTMAS DAY...ALLOWING A STRONG NW FLOW TO DEVELOP
OVER THE NRN ROCKIES...POSSIBLY BRINGING ARCTIC AIR SOUTHWARD INTO
THE STATE. WILL NOT HIT THIS TOO HARD AS OF YET...BUT WILL COOL
TEMPS SOMEWHAT FOR CHRISTMAS DAY. MPJ

.CCF NUMBERS
GTF BJ 023/040 018/028 015 17001
   EBBNE 025/015 034/020 038/020 038/018 033 35211112111
CTB BE 020/036 015/022 006 17001
   EBBNE 021/010 031/016 035/015 036/015 032 33111112111
HLN BE 020/038 018/030 015 17112
   EBEEE 023/012 028/010 033/016 035/014 028 33211112122
BZN BE 016/035 015/032 012 17222
   EBEEE 021/012 026/008 028/010 030/009 030 22211112122
WEY BE 006/026 010/022 002 17224
   EBEMM 015/905 024/905 027/901 025/002 027 42211113122
DLN BE 016/032 015/030 008 17222
   EBEEE 021/010 028/014 031/016 033/016 033 22211112232
HVR BE 015/037 012/025 005 17002
   EBBNE 023/007 028/010 036/012 036/017 028 33211111112
LWT BJ 018/038 018/030 012 17001
   EBBNE 028/010 034/015 038/018 036/018 030 34211111112

.TFX...NONE.