Area Forecast Discussion
Issued by NWS Missoula, MT
FXUS65 KMSO 122053
Area Forecast Discussion
National Weather Service Missoula MT
253 PM MDT Sat Jul 12 2014
.DISCUSSION...Thunderstorms have begun to form across Lemhi County
Idaho and into southwest Montana this afternoon. Storm motion is
quite slow with these storms so in addition to frequent lightning
and gusty winds, localized heavy rain is possible. The population
centers most likely to see thunderstorms are Butte, MT and Salmon, ID.
Tomorrow the ridge of high pressure will strengthen over the
region. This will lead to the warmest conditions so far this year,
with some valley locations approaching 100 degrees in both western
Montana and north central Idaho. Very dry air over the region will
limit thunderstorm potential.
Monday through Tuesday...The threat for showers and thunderstorms
increases as an upper level wave slowly moves through the region.
The thunderstorms could contain heavy rain, gusty winds,
lightning and hail. At this update, the best chance for the
strongest storms will be between 50 miles east and west of the
Idaho/Montana border. The storm motion of these thunderstorms will
be rather slow, so there is potential for flash flooding at any
burn scars including the Lolo Creek Fire Complex & West Mullan
near Superior. Another potential impact could be vegetation damage
if these storms produce hail. Gusty easterly winds will develop
Sunday night and continue into the day on Monday across much of
western Montana into Idaho. Those with recreational plans on area
lakes (i.e. Flathead, McDonald & Whitefish) should take note that
conditions could radically change Monday morning with possible
gusts near 20 mph at times. Another round of showers and
thunderstorms are possible on Tuesday mainly affecting southwest
Montana from Seeley Lake south to Butte. The biggest threat with
these storms will be heavy rain.
Wednesday and Thursday...With the warm upper ridge building back in,
warmer than normal (as much as 10 degrees) high temperatures will
continue and the only chance for a shower or thunderstorms will be
across the higher elevations of the Continental Divide. Forecast
models hint at a possible cool down by the end of the week, but
confidence in this solution remains low at this time.
.AVIATION...Scattered thunderstorms have begun to develop this
afternoon, and may impact KBTM and KSMN between 12/2100Z and 13/0200Z.
Expect lightning, brief heavy rain, and/or gusty winds to be
possible during this time. Elsewhere, VFR conditions will persist
under mostly sunny to partly sunny skies, with the daily late
afternoon breeze kicking up and lasting through sunset.
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