Strong non-thunderstorm winds were observed in Idaho as a jet streak moved across the region.
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The episode as NWS MSO wrote it up.
Strong non-thunderstorm winds were observed in Idaho as a jet streak moved across the region.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Missoula, MT wrote its last area forecast discussion before the first event at Nov 20, 2:36 AM PST, 3 hours 39 minutes earlier.
Area Forecast Discussion
National Weather Service Missoula MT
336 AM MST Tue Nov 20 2012
...Significant snow on mountain passes Wednesday into Wednesday Night...
.DISCUSSION...
The Salmon river corridor and the Camas prairie of Idaho will
continue to see breezy to windy conditions throughout the day
before decreasing some this evening. Gusts could still reach the
50 mph mark during the morning hours, so at this time have decide
to continue the high wind warning.
A stream of warm moisture continues to stream into the Northern
Rockies. The region will see a slight decrease in the
precipitation intensity this morning, but will increase during the
afternoon hours. The snow levels remain high so only the highest
peaks will see snow fall, while valleys and mountain passes will
primarily be rain. The strong southwesterly winds are cause
downsloping in the broader valleys of western Montana. These
valleys will see precipitation today, but rainfall will be fairly
light. Tonight the pressure gradient relaxes allowing for a better
chance for the broad valleys to see decent rainfall. The models
are still in agreement that a cold front will swing through the
region on Wednesday into Wednesday night allowing the snowlevels
to drop. During the day snow levels will remain above most valley
locations but the mountain passes should change over to snow. The
mountain passes will experience significant snowfall during the
afternoon and evening hours which will make travel fairly
difficult. Snow levels drop to valley floors Wednesday night, but
precipitation should be on the decrease. Valleys will be limited
to only half of inch to an inch of snow by Thanksgiving morning.
Snow showers will continue into Thursday followed by a brief break
early Friday.
Another moisture feed will begin late Friday that will
initially come as rain with Idaho in the path for high amounts of
rain. Cooler air will move into the region on Saturday, although
moisture will be more limited. The northwesterly flow pattern will
promote off and on snow through the beginning of next week. Colder air
is still possible for early next week but model guidance are
unclear on how cold at this time.
&&
.AVIATION...Steady stream in moisture will remain over the
Northern Rockies today into this evening. Precipitation will
decrease slightly this morning, then increasing during the
afternoon and evening hours. Mountains and passes are
anticipated to be obscured due to low ceilings and steady
precipitation. KGPI should be impacted by rainfall after 20/16z.
KMSO will be surround by precipitation but due to downsloping
effect the valley should not see reductions in visibility until
this evening. The breezy southerly winds at KMSO and KBTM are
anticipated to decrease throughout the day.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...HIGH WIND WARNING until 10 AM PST this morning For the Camas
Prairie...Grangeville and Highway 95.
&&
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https://www.twitter.com/NWSMissoulaThe national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
A non-thunderstorm gust of 70 mph was measured 4 miles south of Grangeville at 6110 feet.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2012Every state in 2012This day in weather historyWarnings in Idaho, November 2012
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 420042.