Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 300938

Area Forecast Discussion
National Weather Service Missoula MT
338 AM MDT SAT MAY 30 2015

...Widespread thunderstorms likely Monday...

.DISCUSSION...A shortwave passing through the region has been
resulting in showers and isolated thunderstorms through portions
of north central Idaho, northwest Montana, and west central
Montana this morning. These showers will quickly develop into
thunderstorms this afternoon. There is agreement that some of the
stronger thunderstorms will be in northwest Montana this afternoon
with small hail, heavy rain, and gusty winds. The rest of north
central Idaho and western Montana will also have a chance for
stronger storms, but there should only be a few. Another
shortwave is on track to begin to move through the region Sunday
morning that will initiate showers and isolated thunderstorms that
will expand into southwest Montana during the afternoon. Sunday`s
high temperatures are still expected to be some of the warmest of
the season so far.

Signs continue to point to a very favorable set-up for
strong thunderstorms Monday afternoon and evening across central
Idaho and western Montana. The main impacts from storms continue
to be frequent lightning, small to moderate sized hail, and heavy
downpours that could pose a flash flooding threat. The scenario
for Monday looks much different from the garden variety storms
we`ve seen across the region the past few days. The storms that
form Monday will have the right ingredients to possibly become
severe, so we will be keeping an eye on this potential as time
passes. If you have plans to be outdoors for any reason through
the day Monday into Monday night, please make plans now to adjust
in the case of strong to severe storm development.

Once the energy of the main cold front passes early Tuesday, the
region will remain unstable through the day once more, keeping the
chance for afternoon thunderstorms in the forecast Tuesday. These
do not look to be as strong as the storms expected Monday, but
some could be strong at times.

From midweek onward, the forecast models really seem to disagree
quite a bit on what solution to go with. Given the high amount of
uncertainty, have kept at least a climatological chance for
showers each day into next weekend. Near-normal temperatures are
also anticipated for this time frame as well.


.AVIATION...Scattered thunderstorms streaming across NW Montana
will keep a mention of at least rain showers, if not a vicinity
thunderstorm, for KGPI through the morning hours. Showers are also
possible at KMSO later this morning, though the threat for
lightning is minimal. Thunderstorms will once again increase in
coverage and become widespread this afternoon and evening,
affecting all terminals with gusty winds, rain showers, and
periods of lightning. Best time frame for -TSRA chances will be
30/2100Z through 31/0400Z.



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