252
FXUS65 KMSO 041923
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
123 PM MDT Thu Jul 4 2024


.DISCUSSION...With some unsettled weather over the Midwest and a
massive ridge of high pressure over the eastern Pacific, the
Northern Rockies will stay under northwest flow aloft heading into
the weekend. The implications will be minor. Expect some
increasing northwest winds this evening. Temperatures will
gradually increase. A shortwave trough will bring some chances
(about 20%) for showers and thunderstorms to northwest Montana on
Saturday afternoon.

Impactful weather will start later in the weekend as the ridge of
high pressure over the eastern Pacific shifts eastward.
Confidence is high that a heatwave will affect the Northern
Rockies through next week. The middle of next week looks to be
the hottest period, with valleys in central Idaho hitting the
100-115 degree range and western Montana valleys reaching 90-105
degrees by next Wednesday (July 10th). Expect nighttime
temperatures to cool only into the 50s to 60s, which will make it
difficult for those without air conditioning or other means of
cooling down to find relief from the heat.

As upper level flow transitions back to the southwest later in
the week, embedded moisture will bring chances for afternoon
thunderstorms by about Thursday.


&&

.AVIATION...Expect mostly clear skies today under northwesterly
flow aloft. Winds will increase out of the west or northwest this
afternoon to about 20 knots at KBTM and KMSO. Some instability
will be capable of producing isolated thunder in the vicinity of
KGPI through about 05/0000Z, but confidence was not high enough
to include thunder in the 18Z TAF.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...     Excessive Heat Watch from Tuesday afternoon through Friday
     evening for Kootenai/Cabinet Region...Lower Clark Fork
     Region.

ID...Excessive Heat Watch from Monday afternoon through Friday
     evening for Northern Clearwater Mountains...Southern
     Clearwater Mountains.

     Excessive Heat Warning from noon Tuesday to 11 PM PDT Friday for
     Orofino/Grangeville Region.

     Excessive Heat Warning from noon Monday to 11 PM PDT Friday for
     Lower Hells Canyon/Salmon River Region.

&&

$$