719
FXUS65 KMSO 080831
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
231 AM MDT Wed May 8 2024

.DISCUSSION...Low pressure east of the Continental Divide is
sending wraparound moisture over the Divide and into western
Montana this morning. Radar returns and satellite imagery point to
increasing widespread precipitation across the Northern Rockies.
The heaviest precipitation is, and will continue to be, over the
Continental Divide as the terrain is providing much of the forcing
for ascent of moist air. Snow levels will be about 4000-4500
feet, keeping precipitation in the form of snow over the Divide
and in Butte and the Georgetown Lake area. Liquid precipitation by
Wednesday evening will likely (80-90 percent chance) exceed 1
inch in the aforementioned areas. In the higher terrain, this
would translate to 8 to 12 inches of snow, with locally higher
amounts along the Divide. Expect winter travel conditions over the
mountain passes traversing the Divide such as Homestake,
MacDonald, Rogers, and Marias Passes through this morning.

This afternoon, the low moves east and takes the moisture with
it. A drying trend will begin this afternoon. 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...Rain, and snow at KBTM, will continue at all Northern
Rockies terminals through about 08/22Z this afternoon.
Precipitation will obscure terrain through this afternoon,
primarily along the Continental Divide. Gusty winds will also
persist through this afternoon, shifting to the north as the low
pressure system east of the Divide moves east. Precipitation will
taper off this evening and winds will relax as high pressure
begins to build.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory until 11 AM MDT this morning for
     Bitterroot/Sapphire Mountains...Butte/Blackfoot Region...
     West Glacier Region.

ID...None.
&&

$$