High Wind and Strong Wind in Montana, October 27, 2021

Area Forecast Discussion
National Weather Service Great Falls MT
1145 PM MDT Tue Oct 26 2021

...Aviation Section Updated...

.SYNOPSIS...

Expect mostly dry weather for the next few days, with strong
winds at times across much of the area later tonight through
Wednesday evening. After a brief warm up later this week, a cold
front will bring some rain, snow, and cooler temperatures for the
weekend.

&&

.UPDATE...

The evening update has been published. Westerly flow aloft
continues to strengthen as a Pacific system moves toward the
Northern Rockies. Winds along the immediate eastern slopes of the
Rocky Mountain Front are already responding to the increased
westerly flow, with a recent wind gust of 69 mph being observed at
Deep Creek in Glacier county. Winds have diminished some in other
areas with the loss of diurnal mixing, but will increase over the
plains on Wednesday. The current high wind products handle the
situation well and will not be changed with this update. Not much
precipitation is expected with this system besides from areas
along the Divide and to a lesser degree over the southwest
mountains. Pops were increased in the East Glacier area for the
near term to cover current trends. Minor adjustments were also
made to winds, temps, and RH for tonight. -RCG

&&

.AVIATION...
1145 PM MDT Tue Oct 26 2021 (27/06Z TAF period)

A gusty west to southwest wind is likely across most terminals this
TAF period, associated with a passing disturbance. Low-level wind
shear will also be likely through early morning at most terminals
until stronger winds are mixed down to the surface. VFR conditions
are expected in most areas, but MVFR or perhaps brief IFR conditions
will be possible across far Southwest Montana through the morning,
given the slight chance for light showers or snow showers. Mountain
obscuration is likely in Southwest Montana and along the divide
through the morning. -AM

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

&&

.PREV DISCUSSION...
/ISSUED 545 PM MDT Tue Oct 26 2021/

Gusty southwest to west winds across central and north-central MT
will continue into this evening. Our next weather system will
begin to push into the area tonight, resulting in increasing
winds through the overnight hours, especially along the Rocky
Mountain Front. Further east across the plains, winds will
gradually pick up through the overnight, though the strong winds
should hold off until around or after sunrise. After sunrise,
thermal mixing should begin to bring down much stronger winds from
a few thousand feet above the surface, which will likely result
in a pretty quick increase in wind speeds for most of the plains.
Winds should peak during the late morning and early afternoon
hours, as winds aloft continue to mix to the surface and mountain
waves roll across the plains. Wind speeds and especially gusts
were tweaked up a bit across much of the northern half of the CWA,
and the High Wind Warning was maintained as-is. The Rocky
Mountain Front and eastern Glacier segment starts earlier (at
midnight) due to the potential for strong winds getting ducted to
the surface overnight. However, Hill, Blaine, and Fergus County
have been dropped from the watch, as there just was not enough
confidence in the potential for hitting high wind criteria. That
said, a few isolated spots could certainly hit wind gusts of
60mph, especially in western Blaine County.

Behind this system, upper level ridging will build in for the
second half of the week, which will result in a warming trend
through the end of the work week and otherwise quiet weather. A
short-wave moving through the ridge Thursday night could trigger
some more strong winds along the immediate Rocky Mtn Front, with
gusts to 50kts or more possible, but it is not expected to extend
further out onto the Plains, so the as of now no extension of the
existing warning or a new high wind warning are anticipated. The
late-week warm-up will be short lived, as an upper level trough
will push in Friday night, bringing in a little bit of moisture
and cooler temperatures for the Halloween Weekend into at least
early next week. -Kredensor/Ludwig

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  38  53  36  60 /   0  10   0  10
CTB  35  50  33  57 /  10  10   0  20
HLN  38  52  36  60 /  10  20   0  10
BZN  32  52  30  58 /  10  20   0   0
WYS  30  39  30  42 /  30  40   0  10
DLN  31  48  30  55 /  20  20   0   0
HVR  36  57  30  60 /   0   0   0  10
LWT  34  51  31  59 /   0  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from 4 AM to 6 PM MDT Wednesday Cascade...
Central and Southern Lewis and Clark...Chouteau...Eastern
Pondera...Eastern Teton...Judith Basin...Liberty...Meagher...
Toole.

High Wind Warning from midnight tonight to 6 PM MDT Wednesday
Eastern Glacier...Northern Rocky Mountain Front...Southern Rocky
Mountain Front.

&&

http://www.weather.gov/greatfalls

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
141 AM MDT WED OCT 27 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1245 PM     NON-TSTM WND GST 6 NW LEDGER             48.31N 111.93W
10/26/2021  M51 MPH          PONDERA            MT   MESONET

            MESONET STATION MTM05 ARC-WTRI CONRAD.

0115 PM     NON-TSTM WND GST 5 N LEDGER              48.34N 111.82W
10/26/2021  M55 MPH          PONDERA            MT   MESONET

            MESONET STATION MTM73 LEDGER N MDA.

0751 PM     NON-TSTM WND GST 1 ENE EAST GLACIER PARK 48.45N 113.20W
10/26/2021  M52 MPH          GLACIER            MT   MESONET

            MESONET STATION MTBRN TWO MEDICINE BRIDGE
            (MT DOT).

0821 PM     NON-TSTM WND GST 8 SE EAST GLACIER PARK  48.36N 113.11W
10/26/2021  M69 MPH          GLACIER            MT   MESONET

            MESONET STATION DCRM8 DEEP CREEK RAWS.

1030 PM     NON-TSTM WND GST 14 W BYNUM              47.98N 112.61W
10/26/2021  M62 MPH          TETON              MT   MESONET

            MESONET STATION DELMT DELLWO (MCSCN).

&&