High Wind in Montana, February 10, 2022

Area Forecast Discussion...CORRECTED
National Weather Service Great Falls MT
330 AM MST Thu Feb 10 2022

.SYNOPSIS...

Strong winds will persist through the day today over the plains,
as temperatures remain well above normal. Lesser winds and
slightly cooler temperatures are expected in the southwest. A
disturbance in the northwest flow aloft may bring a period of
light precipitation to the plains tonight into Friday morning,
with the best chance for snow accumulation in the Little Belt and
Snowy Mountains. Temperatures will also cool back closer to normal
on Friday, but high pressure will keep the weekend warm and dry,
but with gusty winds once again.

&&

.DISCUSSION...

Today through Friday...

Strong winds will be the main concern today over much of north
central Montana. West to northwest winds at the low to mid levels
(850-700 mb) will increase into the 45 to 55 kt range today with
the approach of a weak disturbance and the passage of its
associated surface frontal boundary. Surface winds over the plains
that are already quite gusty early this morning will continue to
strengthen and spread east over the plains throughout morning with
the approach of the boundary. Forecast models indicate that this
boundary will likely move south over the plains between 10 am and
2 pm, which will help translate these stronger gusts down to the
surface. Although there should not be a prolonged period of strong
wind gusts over much of the plains area, a few gusts could exceed
60 mph. Have therefore expanded the High Wind Warning to include
all of the plains from 9 am until 8 pm. Gusty ridge top winds may
translate down into the valleys of southwest Montana, but these
gusts will likely remain in the 30 to 40 mph range at the
strongest. These winds should help warm temperatures to between 15
and 20 degrees above normal in the southwest and between 20 and 30
degrees above normal over the plains. These warm, dry, and breezy
conditions will cause increased fire weather concerns, as outlined
in the Fire Weather section of this discussion.

Winds will shift more northwesterly and decrease tonight into
Friday with the passage of the disturbance. However, moisture
with the disturbance and a shift to a more northerly upslope flow
will likely cause a few showers over the northern plains this
afternoon and evening to become more of a widespread light snow
along the north- and east-facing mountain slopes over the plains.
The best chance for accumulating snow will be in the Little Belt
(up to 3 inches on the peaks) and Snowy Mountains (up to 6 inches
on the peaks). The snow should taper off through Friday afternoon.
This will also cause temperatures to cool back closer to normal
for Friday.

Saturday through Sunday...

The upper level high pressure ridge along the Pacific coast will
move back onshore this weekend, putting Montana under a more
anticyclonic northwest flow aloft. As a result, temperatures will
warm back up to between 10 and 20 degrees above normal with dry
conditions. However, a weak disturbance approaching from the
Pacific Northwest will cause mid level winds to increase once
again and develop a surface trough to the lee of the Rockies,
bringing periods of gusty westerly winds. Although these winds
currently do not appear to be quite as strong as those expected
today, this situation will be monitored for any changes over the
next day or so.

Monday through next Thursday...

A low pressure trough moving southeast out of the Gulf of Alaska
is still forecast to move into the Pacific Northwest on Monday,
and it is also still forecast to split as it moves into the Great
Basin. As a result, a weaker low pressure trough will move over
Montana to start the workweek. It will likely bring more gusty
westerly downsloping winds, but forecast models indicate that it
will have enough moisture with it to bring at least mountain
precipitation as well. With uncertainty as to just how strong
these downsloping winds will be, cannot rule out some
precipitation reaching the lower elevations as well. While this
is not a significant change from the previous forecast issuance,
the forecast models now have this trough lingering over the area
into Wednesday, keeping a chance of precipitation around through
then. Temperatures on Monday will remain well above normal, but
the trough will help cool temperatures back closer to normal for
Tuesday and Wednesday. However, the Pacific ridge will start to
move back into the area for Thursday, likely bringing a return to
dry, warm, and breezy conditions.
-Coulston

&&

.AVIATION...
1037 PM MST Wed Feb 9 2022 (10/06Z TAF period)

The primary concern over the TAF period will be gusty surface
winds, LLWS and mountain wave turbulence. Gusty winds are first
expected to develop along the Rocky Mountain Front and adjacent
plains tonight, and spread over the remaining plains tomorrow
during the day. Mountain wave turbulence will be likely, with
LLWS possible across the plains. There will be a chance for some
blowing dust in the vicinity of KCTB in the afternoon. Otherwise,
VFR conditions are expected across the region through tomorrow
afternoon. After that, chances for rain and eventually snow will
develop Thursday night across North-central and then Central
Montana. Mountain obscuration is expected. -AM

Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.

&&

.FIRE WEATHER...

Main period of concern will be today and main area of concern is
over the plains of north central Montana. Mid-level winds will
likely translate down to the surface at times today, mainly late
this morning through the afternoon. Gusts will mostly be in the 35
to 45 mph range, but gusts could reach 65 mph at times, especially
between 9 am and 3 pm immediately ahead of and behind a passing
frontal boundary. Although these gusty winds may cause any new
fire starts to spread, the afternoon relative humidity should
remain above 25 percent, hindering the potential for rapid
spread. Will therefore hold off on any fire weather highlights.

Periods of gusty winds are also expected through the next week or
so, especially on Monday, Tuesday, and next Thursday; however, it
is still uncertain just how dry it will be by then.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  58  26  37  21 /  10  60  30   0
CTB  56  24  36  20 /   0  40  20   0
HLN  53  29  38  19 /  10  20  30   0
BZN  48  23  35  10 /   0  10  30   0
WYS  34  13  33  -3 /   0  10  10   0
DLN  54  25  39  15 /   0   0   0   0
HVR  60  27  35  20 /  20  30   0   0
LWT  52  24  31  17 /  10  60  30   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from 9 AM this morning to 8 PM MST this
evening Blaine...Cascade...Chouteau...Eastern Pondera...Eastern
Teton...Fergus...Hill...Judith Basin...Liberty...Toole.

High Wind Warning until 8 PM MST this evening Eastern Glacier...
Northern Rocky Mountain Front...Southern Rocky Mountain Front.

&&

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