Area Forecast Discussion
Issued by NWS Missoula, MT
FXUS65 KMSO 270927
Area Forecast Discussion
National Weather Service Missoula MT
327 AM MDT Wed Jul 27 2016
.DISCUSSION...Model guidance have struggled with the next
shortwave that is expected to pass today, so confidence in the
short-term forecast is lower than it usually would be, which
means there may be more shower activity this morning. This
afternoon`s forecast remains rather consistent with showers and
thunderstorms to develop with the passage of the shortwave today.
Most of the storms are still expected to develop through the
afternoon in northwest Montana, along the divide, and through
Lemhi County Idaho and southwest Montana. Some of the storm
activity along the divide may linger well into tonight as the
shortwave slowly passes. Most of north central Idaho and west
central Montana maintain a mostly storm free forecast.
Storm coverage is still likely to be less on Thursday with
highest chances for storms to be in far northwest Montana,
particularly in the high terrain in and near Glacier NP.
A short lived and weak ridge of high pressure will begin to build
over the Northern Rockies on Friday and linger in the region
through Saturday. This will allow for temperatures to rise a few
degrees above normal for this time of the year, and will primarily
be dry, with exception for the Glacier National Park area for
Friday, and southwestern Montana on Saturday. These two locations
will have just enough moisture and instability in the region to
promote scattered showers and thunderstorms.
As the ridge begins to break down late Saturday afternoon and
evening, winds will increase for much of the Northern Rockies.
Winds gusting to 25-30 mph in the early evening will be possible,
especially across southwestern Montana and Lemhi County in Idaho. This
will also help with the warming, as mentioned above. Saturday will
likely be the warmest day of this week and weekend.
Confidence continues to grow with a slow moving low pressure
system moving across the Pacific NW Sunday through at least the
first half of next week. What this means, is the Northern Rockies
will be slightly below normal in temperatures, and increased
chances for showers and thunderstorms.
A few showers are passing through northwest Montana early this
morning with a shortwave that will continue through the region
today. Much like yesterday, showers and thunderstorms will likely
initiate early in the day due to the early passage of the
shortwave. The locations with highest chances for storms will
again be in northwest Montana, along the divide, and through Lemhi
County Idaho/southwest Montana. Although most of the thunderstorm
activity will decrease through the evening, there are indications
that the shortwave will provide enough instability to keep
thunderstorm chances through 28/0600z.