644
FXUS65 KMSO 290712
AFDMSO
Area Forecast Discussion
National Weather Service Missoula MT
112 AM MDT Thu May 29 2025
.DISCUSSION...
KEY MESSAGES:
- Cold front to bring breezy winds this afternoon and evening,
along with thunderstorms capable of gusty outflow winds.
- Hot and dry through the weekend. Temperatures approaching
records for this time of year on Saturday.
- Cool and wet conditions early next week.
A shortwave trough and associated cold front will push through
the Northern Rockies from the west this afternoon and evening.
The well above-normal temperatures ahead of the front, combined
with relatively cooler air behind it, will support an increase in
westerly winds. Peak gusts, up to 30 mph, are expected between 3
PM and 9 PM.
The antecedent instability ahead of the front, along with
increased lift, will favor the development of thunderstorms,
particularly along and east of Highway 93 in western Montana.
Isolated storms may become strong and could produce locally strong
wind gusts up to 50 mph and small hail.
Those planning to recreate on area lakesespecially Flathead
Lakeshould prepare for gusty winds, choppy water, and possible
lightning. Currently, there is a 30 percent chance that gusts
outside of thunderstorms could reach 30 mph.
The breakdown of the ridge will be short-lived, as it is expected
to quickly re- amplify over the region by Friday and Saturday.
Many locations will approach record highs by Saturday, which is
likely to be the warmest day of the year so far. Temperatures are
expected to reach the low to mid-90s across much of the valleys in
western Montana, and even the low 100s in the Riggins area of
north-central Idaho. These temperatures will be roughly 20 degrees
or more above normal for this time of year.
Take extra precautions when spending time outdoors this weekend,
and remember that even with hot air temperatures, water in area
lakes and rivers remains quite cold and flows are still high.
Another cold front is expected to arrive Saturday night into
Sunday, bringing breezy winds and a modest cool-down in
temperatures for Sunday. Forecast models continue to indicate,
with high confidence (greater than 90 percent), that a large low-
pressure system will move into the region by Monday of next week.
Confidence is high in a notable shift toward much cooler
conditions.
However, there is still significant uncertainty in the
track of the main low- pressure system, which will greatly affect
the amount and distribution of precipitation. As of now,
significant precipitation appears most likely across southwest
Montana and along the Continental Divide. Precipitation amounts
remain uncertain for northwest Montana; a more southern track of
the low would likely result in little to no precipitation in that
area. Stay tuned for updates.
&&
.AVIATION...A shortwave trough and associated cold front will
push through the Northern Rockies from the west this afternoon
and evening. Well above-normal temperatures ahead of the front
and cooler air behind it will result in increased westerly winds.
Peak gusts around 2025 knots are expected between 29/2100Z and
30/0300Z this evening.
This front will also bring increased chances for thunderstorms,
with the highest likelihood along and east of Highway 93 in
western Montana. This includes the terminals KGPI, KMSO, KHRF,
KBTM, and KSMN, which may be impacted by convection. The main
threats include brief heavy rainfall, lightning, and isolated
gusty outflow winds up to 40 knots. The best timing for these
impacts is currently between 29/2200Z and 30/0200Z.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&
$$
