High Wind in Montana, January 8, 2002

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
900 PM MST MON JAN 7 2002

UPDATES PLANNED FOR ZONES AND STATE

.SHORT TERM...MAIN STORY TONIGHT IS THE WINDS AND MILD TEMPERATURES.
HAVE ALREADY UPDATED A COUPLE OF TIMES TO EXTEND THE HIGH WIND
WARNING. CHECK OF TFX SOUNDING SHOWS A COUPLE OF REASONS FOR STRONG
WINDS. FIRST SOUNDING SHOWS INVERSION NEAR MOUNTAIN TOP LEVEL TO
HELP IN WAVE REFLECTION. THEN BELOW INVERSION IS NEARLY DRY
ADIABATIC LAYER FOR GOOD MIXING. LATEST MESOETA HAS 700 MB WINDS 55
TO 60 KNOTS AT 03Z THEN SLOWLY LOWERS SPEEDS THE REMAINDER OF
TONIGHT. SURFACE DOWNSLOPE GRADIENTS STAY QUITE TIGHT THROUGH THE
NIGHT. WILL BE RAISING SOME WIND SPEEDS FOR TONIGHT. AIRMASS IS
FORECAST TO STAY MILD BUT SOME COLD ADVECTION GOES ON IN THE W LATE
TONIGHT. WILL BE RAISING MOST LOW TEMPERATURES FOR TONIGHT. WOULD
SET RECORD WARM LOWS FOR TUE EXCEPT TEMPERATURES MAY DROP BELOW
RECORDS TUE EVENING. WILL ALSO BE MAKING SOME ADJUSTMENTS TO
PRECIPITATION FORECAST FOR THE NW MOUNTAINS. LATEST ETA HAS SNOW
LEVELS NEAR 8000 FEET IN THAT AREA AT MIDNIGHT BUT LOWER THEM TO
NEAR 6000 FEET BY MORNING. ETA HAS A GOOD START WITH THEIR
INITIALIZATION OF SHORTWAVES OFF THE PAC NW COAST. LATEST ETA IS
STRONGER WITH THE SHORTWAVE MOVING SE THROUGH THE AREA WED AND WED
NIGHT. LATEST MESOETA DEVELOPS SPOTTY PRECIPITATION OVER CENTRAL
MONTANA ON WED. CURRENT FORECAST IS DRY. WILL NOT MAKE A CHANGE FOR
THIS AT THIS TIME BUT MIDNIGHT SHIFT WILL WANT TO TAKE A CLOSER LOOK.
BLANK

.EXTENDED...LATEST AVN IS VERY DIFFERENT FROM LAST NIGHTS MRF AND
ALSO THE PREVIOUS MRF OVER THE WEEKEND BUT IT APPEARS THE LATEST AVN
AND ALSO THE LATEST UKMET ARE TRENDING TOWARDS THE ECMWF RUN FROM 12Z
SUN. THE BIG DIFFERENCE BETWEEN THE AVN AND MRF CONCERNS A SHORTWAVE
LAST NIGHTS MRF DOVE SE THROUGH CENTRAL CAN SAT AND INTO THE DKTS SAT
EVENING. LATEST AVN ALONG WITH THE LATEST UKMET AND 12Z SUN RUN OF
THE ECMWF KEEP A RIDGE OVER CENTRAL CAN ON SAT. THESE 3 MODEL RUNS
HAVE ANTICYCLONIC NW FLOW ALOFT OVER THE AREA EARLY FRI THEN BACK
FLOW ALOFT TO THE SW EARLY SAT AHEAD OF A PACIFIC UPPER TROUGH.
THIS UPPER TROUGH SHOULD MOVE THROUGH THE AREA ON SUN WITH COOLER
TEMPERATURES. LOW LEVEL FLOW SHOULD STILL BE DOWNSLOPE OVER THE
PLAINS SO PLAN TO GO DRY. ON MON SHOULD SEE CYCLONIC NW FLOW ALOFT
OVER THE AREA. AGAIN LOW LEVEL FLOW MAY BE DOWNSLOPE OVER THE PLAINS
BUT WITH NW FLOW ALOFT WILL GO WITH SLIGHT CHANCE OF SNOW SHOWERS.
FOR THE WRN/SW MOUNTAINS AND VALLEYS...SHOULD BE DRY FRI WITH A
CHANCE OF SNOW SHOWERS OVER THE MOUNTAINS SAT NIGHT IN ADVANCE
OF THE UPPER TROUGH. SUN SHOULD SEE SNOW OVER THE MOUNTAINS WITH A
CHANCE OR SLIGHT CHANCE OF SNOW IN THE SW VALLEYS. EXPECT SIMILAR
CONDITIONS MON. BLANK

.CCF NUMBERS
GTF NN 048/055 035/045 032 13001
    NBNNN 048/034 050/038 050/026 034/020 030 11100001122
CTB NN 045/050 031/044 028 13001
    NBNNN 044/032 048/035 047/022 028/016 026 11100001122
HLN NN 040/048 030/044 018 13122
    NUUNE 040/025 046/028 048/025 035/020 032 11100002222
BZN EE 038/045 022/038 015 13122
    EUUNE 035/015 038/018 044/025 034/015 030 11100002222
WEY EE 025/032 012/025 010 13252
    EUUNE 022/002 030/008 035/015 032/005 028 21100003344
DLN EE 036/045 022/036 015 13122
    EUUNE 034/015 038/022 042/024 032/016 030 11100002222
HVR BB 045/052 029/046 020 13001
    BBNNN 048/022 042/033 048/025 033/018 028 11100001122
LWT BE 044/055 025/042 025 13001
    EBNNN 046/028 046/035 052/026 034/016 028 11100001122=

.TFX...HIGH WIND WARNING THROUGH 10 PM THIS EVENING FOR THE
ROCKY MOUNTAIN FRONT AND ADJACENT PLAINS