High Wind in Montana, January 4, 2001

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
900 PM MST WED JAN 3 2001
...UPDATES PLANNED FOR ZONES AND STATE...
AS FOR HIGH WIND WARNING PLAN TO RIDE WITH IT EVEN THOUGH CRITERIA MAY
NOT BE MET. LATEST WIND APPLICATION PROGRAM FROM 00Z THU ETA RUN HAS
ONLY A PEAK GUST OF 44 KNOTS AT CTB TONIGHT. WINDS NOT VERY STRONG NOW
BUT MAY PICK UP WITH SHORTWAVE PASSAGE LATER THIS EVENING. ANOTHER
BOTHERSOME THING IS SURFACE CHART SHOWS MAIN PRESSURE FALLS HAVE MOVED
INTO ERN MT AND SASK. UPSHOT IS THAT ALTHOUGH HAVE DOUBTS EVENT WILL
OCCUR DO NOT HAVE ENOUGH CONFIDENCE TO CANCEL WARNING. LATEST ETA
ACTUALLY INDICATES A BETTER THREAT FOR HIGH WINDS ON FRI RATHER THAN
TONIGHT. LATER SHIFTS WILL NEED TO WATCH THIS. OTHERWISE WILL BE MAKING
SOME CHANGES TO FORECASTS BASED ON THIS MORNINGS/THIS EVENINGS MODEL
RUNS. IN THE SW WILL ADD SOME LOCAL GUSTY SW WINDS FOR THU NIGHT AND
FRI. WILL ALSO DROP LOW FOR BZN FOR TONIGHT AS THEY ARE ALREADY BELOW
FORECASTED LOW. BUT THEY SHOULD NOT FALL MUCH FARTHER. OVER THE ROCKY
MOUNTAIN FRONT WILL NEED TO ADD LIKELY POPS FOR THU NIGHT INTO FRI FOR
THE MOUNTAINS. LATEST ETA HAS EVEN MORE QPF FOR AREA THAN THIS MORNINGS
MODEL RUNS. SNOW LEVELS ARE QUITE HIGH OVERNIGHT SO MAY NOT NEED A
HIGHLIGHT. LATEST ETA/NGM SPREAD QPF OVER THE NRN PLAINS IN MOIST WARM
AIR ADVECTION PATTERN THU NIGHT. HOWEVER PRECIPITATION WILL BE FIGHTING
DOWNSLOPE AT THE SURFACE. WILL LEAVE DRY FORECAST ALONE BUT CURRENT ZERO
PCT POPS MAY BE TOO OPTIMISTIC. WILL ALSO BASICALLY REVERSE MOSTLY
CLOUDY FORECASTS FOR THU AND PARTLY CLOUDY FORECASTS FOR THU NIGHT FOR
THE PLAINS. DUE TO EXPECTED GUSTY WINDS WILL RAISE FORECAST LOWS FOR GTF
AND LWT FOR TONIGHT SEVERAL DEGREES. BLANK

EXTENDED DISCUSSION...AGAIN TODAY MODELS IN PRETTY GOOD AGREEMENT WITH
ONE ANOTHER ON GENERAL WEATHER TRENDS AND ALSO SHOWING DECENT
CONSISTENCY WITH THEIR PREVIOUS RUNS ON THESE TRENDS. MODELS INDICATE
FAST-MOVING SHORTWAVE MOVING THROUGH THE AREA FRI NIGHT. DOWNSLOPE
SHOULD PREVENT PRECIPITATION OVER THE PLAINS SO WILL GO WITH MOSTLY DRY
CONDITIONS THERE. THERE SHOULD BE DRY NW FLOW ON SAT WHICH WILL
TRANSITION TO SW FLOW THEREAFTER AS UPPER RIDGE MOVES E OF AREA.
QUESTION IS WHEN TO INTRODUCE NEXT THREAT OF PRECIPITATION. 00Z WED MRF
RUN INDICATED A THREAT ON MON BUT LATEST AVN RUN IS SLOWER WITH NEXT
SHORTWAVE AND ACCOMPANYING MOISTURE. TODAYS 12Z UKMET RUN IS IN GOOD
AGREEMENT WITH AVN RUN AT 120 HRS WITH SHORTWAVE STILL OFF THE W COAST
MON MORNING. ON THE OTHER HAND LATEST NOGAPS IS FASTER WITH SHORTWAVES.
HAVE OPTED TO GO WITH AVN/UKMET SOLUTIONS SO WILL HOLD OFF ON MENTION OF
PRECIPITATION UNTIL TUE. BLANK

CCF NUMBERS
GTF NN 038/049 032/055 035 160000
CTB NN 034/044 028/048 032 160000
HLN BE 025/045 022/040 025 160001
BZN BB 017/042 015/036 020 160001
WEY BB 002/025 905/028 005 161101
DLN BB 022/040 020/040 022 160001
HVR NN 037/045 026/052 030 160000
LWT NN 037/045 028/050 032 160000