Area Forecast Discussion
Issued by NWS Missoula, MT
FXUS65 KMSO 222050
Area Forecast Discussion
National Weather Service Missoula MT
250 PM MDT WED OCT 22 2014
...Wet & raw backcountry conditions expected tomorrow...
...Strong gusty winds in the Camas Prairie & Grangeville area
tonight through tomorrow morning...
.DISCUSSION...A wet southwest flow pattern is on tap beginning
tonight and continuing through at least Thursday night. The
moisture content of the atmosphere is above normal due to
subtropical origins and this will be a factor in allowing for
typical up-slope locations to receive anywhere from 0.50 to 1
of total precipitation through Friday morning. A few of the CIPS
analog/pattern matches confirm that Clearwater, Cabinet & Purcell
Mountains and Bitterroot ranges near the Montana and Idaho border
as well as from Glacier National Park south to the Mission
Mountains will see the highest precipitation amounts. Valley
locations will see considerably less precipitation due to down-
sloping effects but still will be able to see up to a 0.25 inches
of rain. Model soundings show the potential for strong gusty winds
to develop in the Grangeville and Camas Prairie area tonight
especially from 2 to 9 am PDT. Therefore we have issued a wind
advisory there for southerly winds 25 to 30 mph with gusts to 45
mph. By Thursday afternoon temperatures will warm into the 50s and
generally breezy conditions will be felt across the region. There
is the chance that Flathead Lake winds could become gusty over 20
mph at times, but confidence is low at this time.
A weak system will track from south to north Friday morning
spreading a few light rain showers from southwestern Montana and
central Idaho north into western Montana. Showers will pretty much
come to and end by Friday night as a brief ridge of high pressure
will build north into western Montana, which will lead to a nice
day on Saturday. Breezy conditions are expected to develop
Saturday afternoon especially for the mountains ahead of the next
system by the end of the weekend.
As the system approaches and moves through Sunday, southwest
winds will increase...especially over higher terrain. Cooler,
showery weather is expected to continue Sunday and into Monday
with snow impacting areas above 4000-5000ft. Another heavier wave
of precipitation will push through beginning Tuesday with
lingering showers lasting through the week.
.AVIATION...Fair flying conditions in store for the rest of the
day across western Montana and central Idaho. Clouds will be on
the increase overnight with rain showers developing by the
morning. All aviation sites will see a chance of rain occasionally
reducing visibilities and lowering ceilings after 1500Z. Gusty
southwest winds will also develop tomorrow afternoon for all
terminals, with gusts approaching 25 to 30 mph after 1800Z.
ID...WIND ADVISORY from 2 AM to 8 AM PDT Thursday for the Camas
Prairie...Grangeville and Highway 95 in the Lower Hells
Canyon/Salmon River Region...Orofino/Grangeville Region.