041
FXUS65 KMSO 301930
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
130 PM MDT Thu May 30 2024

.DISCUSSION...A moderately unstable atmosphere will lead to
scattered showers, isolated thunderstorms and breezy westerly
winds this afternoon. Convection will be hit and miss, though
those recreating on area lakes should keep an eye in the sky.
Breezy westerly winds gusting up to 20 mph will also create a
light chop on area lakes as well.

Mostly clear skies tonight into Friday morning will allow for
widespread frost to develop for many valleys across the Northern
Rockies. A number of Frost Advisories have been added to the
existing ones, to include the valleys along Highway 93 in Montana,
as well as the Camas Prairie in Idaho. Those with sensitive
gardens may want to prepare them this evening for the potential
frost.

Over the weekend, temperatures remain near average under zonal
flow. A weak disturbance on Saturday will set the stage for
scattered showers but precipitation amounts appear rather light.
Conditions will be drier again on Sunday.

Next Monday, forecast ensemble models continue to show an
atmospheric river impacting the inter-mountain west, bringing
widespread rainfall to the Northern Rockies. There remains quite a
wide range for potential amounts, but the overall mean continues
to indicate anywhere from 0.75"-1.25" falling in the Clearwater
areas of north-central Idaho through Tuesday. Amounts are a bit
lower in western Montana with the mean indicating between
0.25"-0.50". While the probabilities are low, around 10% to 15%,
2 inches of rain isn`t out of the question for locations along
Highway 12 between Lowell and Lolo Pass. The expected rainfall
may pose a risk for isolated locations to experience minor impacts
due to rock and mudslides, along with a noticeable increase in
water levels in area streams and creeks.

The latter part of next week, the majority of models show a
strong ridge building in leading to an extended period of warmer
temperatures with a day or two of thunderstorms mixed in.

&&

.AVIATION...Partly to mostly cloudy conditions will remain over
much of the Northern Rockies through this evening. A moderately
unstable atmosphere is expected to lead to scattered showers and
isolated thunderstorms this afternoon and evening between
30/2000Z-31/0200Z. KGPI and KBTM have between a 15-20% probability
for thunderstorms coming within the vicinity during this time.
Other than the potential for scattered convection, most aviation
sites will experience westerly winds, with a probability between
30-50% gusts will reach around 20kts through 31/0200Z this
evening.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Frost Advisory from 3 AM to 8 AM MDT Friday for Flathead/Mission
     Valleys...Kootenai/Cabinet Region...Lower Clark Fork
     Region...Missoula/Bitterroot Valleys.

ID...Frost Advisory from 3 AM MDT /2 AM PDT/ to 8 AM MDT /7 AM PDT/
     Friday for Eastern Lemhi County...Northern Clearwater
     Mountains...Orofino/Grangeville Region...Western Lemhi
     County.

&&

$$