603
FXUS65 KMSO 061854
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1254 PM MDT Tue May 6 2025

.DISCUSSION...

KEY MESSAGES:

-  Warmer and drier conditions through Wednesday

-  Slightly cooler, isolated thunderstorms southwest MT and
   breezy all locations for Thursday

-  Friday into Saturday likely warmest temperatures so far this
   year, causing significant increase river/stream flows

-  Scattered thunderstorms Saturday and Sunday afternoons,
   potentially a few strong storms.

High pressure ridging returns today lasting through Wednesday
resulting in warmer and drier conditions. High temperatures by
Wednesday will be 10-15 degrees above normal. Additionally, east
winds will be gusty up to 25 mph at times, lighter on Wednesday.

A weak disturbance knocks down the ridge on Thursday causing the
upper level flow to become southwesterly. This feature will bring
a few showers to the region Wednesday night into Thursday morning.
Temperatures will cool a few degrees, but the biggest impact will
be the breezy conditions with gusts up to 35 mph across northwest
Montana. By late afternoon, the axis of showers will be over the
Anaconda Mountains and near Butte, an isolated thunderstorm will
be possible. Any showers or an isolated thunderstorm during the
afternoon will be capable of gusty and erratic outflow winds 30 to
40 mph.

Ridging builds back in Friday and Saturday likely bringing the
warmest temperatures so far this year by Saturday. In fact, there
is a 40% probability of reaching 90F in Missoula, 50-70%
probability of 90F for the lower elevations of north-central
Idaho. Stream and river flows will rise significantly with the
accelerated snowmelt.

There is a potential for scattered thunderstorms Saturday and
Sunday afternoons as mid level moisture increases from the
southwest. Current projected instability and shear profiles along
with high cloud bases allow for the potential of a few strong
thunderstorms with gusty wind concerns.

Nearly all ensemble models (about 90%) show a large scale trough
over the Pacific Northwest early next week (May 12-14) with a
return to seasonable temperatures and showery conditions.


&&

AVIATION...High pressure ridging will build in today and Wednesday
allowing for VFR conditions. Easterly winds are present with
gusts to 25 kts throughout today, and will diminish by sunset.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

$$