868
FXUS65 KMSO 071952
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
152 PM MDT Tue May 7 2024

.DISCUSSION...Breezy conditions have begun to develop across
western Montana and north central Idaho this afternoon in response
to a tightening pressure gradient as low pressure moves through
eastern Montana. The strongest gusts are expected across southwest
Montana through the Missoula/Bitterroot valley eastwards towards
Butte. Gusts of 40 to 50 mph are anticipated through roughly 9pm
MDT. Travel difficulty for high profile vehicles is possible
along with minor tree damage. Wind advisories are in place through
this evening.

Tonight, wrap-around precipitation from the low pressure system
in eastern Montana will move across the Continental Divide into
western Montana and north central Idaho. The heaviest
precipitation is anticipated in the terrain along the Continental
Divide, where liquid precipitation amounts will likely (70 to 90
percent chance) exceed 1.00". Further west, valley locations have
a 40 to 60 percent chance of seeing at least 0.25" of
precipitation. As precipitation develops this evening, snow levels
will lower to roughly 4000-4500 feet. This will bring heavy, wet
snow to the highest terrain along the Continental Divide, where a
foot of snow or more is not out of the question. Forecast snowfall
amounts have trended upwards in southwest Montana. Locations such
as Georgetown Lake, MacDonald Pass, and Homestake Pass may see 9
to 12 inches of snow tonight through tomorrow morning. In
particular, a period of moderate to heavy snow is being shown in
high resolution models between 1am and 6am MDT tomorrow morning.
This could make travel difficult over mountain passes along the
Continental Divide. In addition, snow will likely fall into the
lower elevations of southwest Montana, such as Anaconda and
Butte. Winter-like travel is possible tonight into Wednesday
morning.

Forecast models are very consistent in folding a ridge of high
pressure over western Montana and north central Idaho Thursday
into the weekend. A rapid warm up is anticipated, with
temperatures approaching the upper 70s and low 80s in the valleys
by Saturday and Sunday. In fact, current model guidance shows a
roughly 60 percent chance of Missoula hitting 80 degrees by
Monther`s Day. High pressure will likely remain in place through
early next week. However, by Wednesday, about 30 percent of model
guidance begins to indicate the potential for another trough of
low pressure.


&&

.AVIATION...With a tightening pressure gradient and moisture
moving in with our current weather system, west to northwesterly
gusts of 50-55 mph have already been observed at KBTM this
afternoon, with the expectation of equally strong gusts persisting
through late this evening, tapering off and continuing in the
20-35 mph range overnight. Gusty W-NW winds will be present at all
terminals today and tonight, with gusts reaching into the 40 mph
range for KMSO, KSMN, and KHRF. Lesser gusts to 30 mph will be
possible at KGPI. Precipitation in the form of rain will begin to
impact terminals, save for KBTM, around and after 08/0000Z, with
snow expected to occur and impact KBTM after 08/0600Z through much
of Wednesday morning. Wind shear will be present at KMSO, KHRF,
KBTM, and KSMN this evening.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory from 6 PM this evening to 11 AM MDT
     Wednesday for West Glacier Region.

     Lake Wind Advisory until 8 PM MDT this evening for
     Flathead/Mission Valleys.

     Wind Advisory until 9 PM MDT this evening for
     Bitterroot/Sapphire Mountains...Butte/Blackfoot Region...
     Missoula/Bitterroot Valleys.

     Winter Weather Advisory from 9 PM this evening to 11 AM MDT
     Wednesday for Bitterroot/Sapphire Mountains...
     Butte/Blackfoot Region.

ID...None.
&&

$$