Area Forecast Discussion
Issued by NWS Missoula, MT
FXUS65 KMSO 242104
Area Forecast Discussion
National Weather Service Missoula MT
304 PM MDT SUN MAY 24 2015
.DISCUSSION...Showers crossing the Montana/Idaho border this
afternoon will develop into scattered thunderstorms through sundown.
Given that a few storms in north central Idaho produced small hail
and lightning on Saturday and smilier meteorological conditions
exists today, some storms today will likely have similar
characteristics. If you have plans to be outdoors, be aware of
this threat. Scattered showers will also be present across western
Montana, though the coverage won`t be as widespread as on
Saturday, and lightning potential will be much less.
Monday through Wednesday will feature increased chances for
rainfall and thunderstorms as an upper-level low pressure system
swings into the area. The atmosphere will become more unstable
during the afternoons and evenings, with the chance for more
widespread thunderstorms across central Idaho and western Montana.
The threats will once again be small hail, lightning, and brief
but heavy downpours. Given that Monday is Memorial Day, and many
may have outdoor plans, please prepare for quickly changing
conditions across the Northern Rockies through Monday night. Right
now, rock and mudslides over roadways do not appear to be a
concern, but those living or recreating in areas prone to rock
slides should beware of this potential. Those recreating on area
lakes and rivers should be especially aware of the threat of
lightning and gusty winds near thunderstorms. On Tuesday and
Wednesday, the greatest threat of thunderstorms migrates to
southwest Montana and the Continental Divide, and potential
impacts remain the same.
The upper-low slowly weakens as it drifts over our area Wednesday
and Thursday, though sufficient lingering moisture and instability
will allow for a continuing chance of showers and a few
thunderstorms. Wednesday will be the coolest day of the week, with
a warming trend thereafter.
Looking ahead to the remainder of the week and into the weekend,
models are converging on the idea of a building ridge across the
western US. Consequently, confidence is building in a warm period
arriving by the weekend, with lower-elevation valleys perhaps
approaching 90 degrees. A few afternoon thunderstorms would
likely continue under this pattern as well.
.AVIATION...Scattered rain showers and isolated thunderstorms will
develop around the surrounding terrain of KBTM and KSMN this
afternoon. Main impacts will be partial mountain obscuration and
brief moderate rain.