189 
FXUS65 KMSO 190931
AFDMSO

WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
230 AM MST THU DEC 19 2002

.SHORT TERM...SHORTWAVE MOVING EAST OF THE FORECAST AREA IS TAKING
THE CLOUDS AND SHOWERS WITH IT THIS HOUR. DECENT CLEARING BEHIND
THIS FEATURE MAY RESULT IN PATCHY VALLEY FOG THIS MORNING. CLEARING
IS IN RESPONSE TO THE BUILDING RIDGE OVER THE PACIFIC NORTHWEST AS A
LOW CONTINUES TO SPIN UP IN THE PACIFIC AT AROUND 42N/135W. THIS
PATTERN WILL KEEP NORTHWEST MONTANA IN NORTHWEST FLOW THROUGH THIS
MORNING...SO FAVORED UPSLOPE LOCATIONS COULD CONTINUE TO SQUEEZE OUT
SOME ISOLATED SNOW SHOWERS. THE RIDGE WILL BE OVER THE INTERMOUNTAIN
WEST AROUND NOON...PUTTING AN END TO THE SNOW. MODEL RH FIELDS DIFFER
OVER THE NEXT 24 HOURS. AVN IS MORE AMBITIOUS ALLOWING MID AND HIGH
LEVEL CLOUDS TO ADVECT INTO THE RIDGE AND BRING MOSTLY CLOUDY SKIES
TO THE AREA. THE ETA HOWEVER IS DRYER...ONLY ALLOWING 300MB MOISTURE
TO MAKE ITS WAY THROUGH THE RIDGE. CURRENT FORECAST IS LEANING MORE
WITH THE DRYER ETA AND WILL CONTINUE THAT TREND. THE RIDGE WILL
CONTINUE TO BE THE MAIN FEATURE FOR THE MISSOULA FORECAST AREA
THROUGH THE SHORT TERM. THE ABOVE MENTIONED LOW WILL MOVE TO THE
SOUTHWEST OREGON COAST LATE FRIDAY MORNING. A SHORTWAVE WILL ROUND
THE BOTTOM OF THE LOW AND MOVE INTO SOUTHERN IDAHO. THIS FEATURE
WILL BRING A SLIGHT CHANCE OF SNOW TO THE SOUTHERN IDAHO ZONES
LATE FRIDAY AFTERNOON THROUGH SATURDAY...MAINLY SOUTH OF THE
SALMON RIVER. THE RIDGE WILL CONTINUE TO BE IN CONTROL OVER THE
REMAINDER OF THE ZONES FOR PARTLY CLOUDY AND COLD CONDITIONS...WITH
LATE NIGHT/EARLY MORNING PATCHY VALLEY FOG.     MEAD

.LONG TERM...EXTENDED MODELS REMAIN FAIRLY CONSISTENT THIS CYCLE.
RESIDUAL TROFINESS SLIDES OVER THE NRN ROCKIES ON SUN SO WILL KEEP
THE CHC OF SNOW SHOWERS GOING. RIDGE BUILDS OVER THE PAC NW/NRN
ROCKIES MON/TUE AND LOOKS STRONGER THAN PREVIOUS RUNS. WILL FINALLY
MAKE THE SWITCH TO DRY FCST FOR THAT PERIOD. NEXT TROF MOVES IN
CHRISTMAS DAY AND SPREADS LIGHT QPF...MAINLY OVER WRN ZONES. NO SENSE
IN GETTING TOO SPECIFIC ON DAY 7 SO WILL BROAD BRUSH CHC POPS. WRIGHT

.MSO...NONE.

...7-DAY SPOT TEMPS AND POPS...
LIB EFB /030 015/029 014/031 2700000
     EBEE 016/027 018/029 020/029 019/028 019/ 32321000033
FCA EFB /030 013/028 012/030 2710000
     EBEE 014/026 016/028 018/027 018/026 018/ 32321000044
POL EFB /032 016/030 016/032 2700000
     EBEE 017/026 020/029 022/028 021/028 021/ 32321000044
MSO EFB /029 014/028 014/030 2700000
     EBBE 017/029 020/030 022/029 021/028 021/ 32331000044
HMM EFB /031 010/030 013/031 2700000
     EBBE 016/030 018/032 020/032 020/030 020/ 32331000044
BTM EFB /024 904/021 902/025 2700000
     EBBE 003/026 007/027 008/026 007/025 007/ 32332000044
ORO BFB /040 023/040 026/040 2700000
     EBEE 028/038 032/040 033/039 031/038 031/ 32321000033
GRV BBE /035 027/036 022/038 2700000
     EBEE 020/033 025/034 025/033 024/031 024/ 32321000033
SMN EEE /028 005/025 010/028 2700022
     EBBE 008/024 011/027 012/028 012/026 012/ 32332000044