Area Forecast Discussion
Issued by NWS Missoula, MT
FXUS65 KMSO 242028
Area Forecast Discussion
National Weather Service Missoula MT
228 PM MDT TUE MAY 24 2016
.DISCUSSION...Rain has been on a decreasing trend in northwest
Montana so the impact from flooding is also decreasing. The
locations between Columbia Falls, Coram, Whitefish, and West
Glacier that have had flooding issues will continue to see
improvements now that widespread rain has ended. Water will
recede in these areas so flood concerns will greatly diminish
tonight and the flood warning will be allowed to expire. Water
levels on streams and rivers will remain high for much of this
week due to increased runoff from the recent high elevation snow
and a gradual rise in temperatures. Some clearing of cloud cover
is likely tonight so low cloud cover and fog is possible
especially in the areas with recent rainfall.
A moist and marginally unstable atmosphere will persist from
Orofino and Grangeville eastward across western Montana Wednesday.
Local/brief downpours are possible. However, showers will remain
scattered and generally precipitation on the lighter side compared
to the past few days.
A weather system will begin to approach the northern Rockies
Thursday afternoon and evening. This should produce additional
instability and a threat of a few thunderstorms.
A very cool weather system is expected to shift across north
central Idaho and western Montana Friday and Saturday. Newer model
guidance is trending towards more breezy conditions and less
precipitation (but still showers expected most areas). Snow
levels should level sufficiently by Friday afternoon and night to
support snow down to 5000 to 6000 feet. However, in general,
precipitation amounts are expected to be on the light to moderate
Longer range guidance is also showing another weather system
pushing across the northern Rockies on Monday.
.AVIATION...Low cloud cover and showers continue in the region due
to the presence of a broad trough. There is a fairly consistent
cloud shield from around KGIC through K6S5 and KBTM. Ceilings are
lowered in these locations with persistent showers. Some clearing
is taking place in northwest Montana which will allow for just
enough heating for isolated showers to form. Breaks in the clouds
are also expanding south toward Missoula so afternoon showers and
a few thunderstorms are possible during peak heating this
afternoon which will extend south toward KBTM and KSMN. Showers
will decrease during the evening and there is potential for
decreased cloud cover. Simulated satellite imagery for tonight
show clearing of clouds but there is a good chance it will
struggle with the moist surface conditions so low clouds and fog
will also be in the mix during Wednesday morning.