Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 262039

Area Forecast Discussion
National Weather Service Missoula MT
239 PM MDT Sun Mar 26 2017

.DISCUSSION...The upper level ridge over the region will break
down tonight with the passage of a weak cold front. Moist
southwest flow tonight will bring mountain snow showers and valley
rain showers. Tomorrow snow levels will fall, so more locations
will see snow showers, but most valleys will remain rain. Tonight
and tomorrow will be unstable enough for some graupel showers,
though freezing levels are low enough that lightning will be very
isolated, if any occurs at all. The chance of thunder is so low,
no mention was placed in the forecast.

Travelers should expect rapidly changing conditions over mountain
passes tonight, with a slight chance for less than an inch of snow
to affect Lost Trail, Lolo, or Lookout passes by morning.

Relatively cool air will be in place Tuesday in the wake of the
system that moved through Monday. Highs will be around 5 degrees
below seasonal averages, with only scattered mountain showers
remaining, primarily focused in far northwest Montana.

Westerly flow aloft will continue throughout the day Wednesday,
and by Wednesday evening, the next trough of low pressure will
begin moving through. Thursday will likely be a cloudy, cool day,
with widespread precipitation. This system looks similar to
Monday`s, and has continued to trend southward over the last
several days, placing the highest precipitation accumulations
south of I-90. Places like Clearwater and Idaho county ID will
likely see rain or rain equivalent totals in the 0.50 to 1.00
inch range over 24 hours. Cool air will this system will again
lower snow levels to 4000 to 5000 ft, so mountain passes could see
some light accumulations with slushy driving during the AM hours.
Temperatures moderate on Friday, with high pressure building in
for next weekend.


.AVIATION...Increasing clouds and partial mountain obscurations
late this afternoon and evening. The shortwave ridge over the area
will break down tonight causing increasing showers. Valleys, and
area terminals, will have rain showers, but many mountain
locations may see light snow tonight.



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