Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 302037

Area Forecast Discussion
National Weather Service Missoula MT
237 PM MDT MON MAY 30 2016

...Prolonged period of above-normal temperatures mid-week through
early next week...

.DISCUSSION...The exiting low pressure system has moved eastward
faster that previously depicted, which has granted much of north
central Idaho and western Montana a fairly pleasant Memorial Day.
The exception are locations immediately hugging the Continental
Divide, where periodic mountain showers have been occurring.
These will gradually diminish tonight, giving way to the start of
a drying and warming trend for the entire western United States.
Temperatures on Tuesday will warm into the 70s for western
Montana, and low 80s across north central Idaho. With each passing
day, expect temperatures to continue their upward trend by 5 to 10
degrees each day.

On Thursday, we will take a brief pause with the warm-up as the
high pressure ridge flattens out and a pretty strong jet streak
moves through the region. These strong winds will make their way
to the surface and bring a pretty windy day to much of the region.
Area lakes will likely receive increased chop as a result.
Currently, it is looking like widespread wind gusts of 15-25 mph
will be common from late morning to the early evening hours.
Temperatures will continue to be relatively warm: in the mid and
upper 70s.

Friday through the weekend: a very strong high pressure ridge
will develop and bring the FIRST HOT SPELL OF THE YEAR to the
entire Northern Rockies. Valley temps will approach 90 degrees on
Saturday, with even warmer temperatures possible Sunday and
Monday, where they could range in the lower to mid 90s. Lower
Hells Canyon in Idaho will likely be well into the mid 90s, and a
few spots in the vicinity could top out near 100 degrees by

Given that this will be the first hot streak of the year, it will
be prudent to remind ourselves of common heat safety tips, such as
not leaving pets in cars, staying hydrated, and avoiding strenuous
work during the hottest hours of the day. Even though temperatures
will be hot, the temperatures of area lakes and rivers will still
be relatively cold, so hypothermia can be an issue.

A surge of moisture from the southwest is expected to move into
the region late Sunday through next Tuesday, along with a little
breakdown of the ridge. This moist, unstable atmosphere will
combine with all the heat and favor thunderstorm development
across the Northern Rockies. Currently, there is quite a bit of
uncertainty with timing and amount of moisture for this change,
but somewhere late this weekend through early next week this
change is possible.


.AVIATION...Breezy north winds will occur at KMSO through roughly
31/0300Z, with breezy westerly winds occurring at KBTM through
about the same time frame. As the exiting low pressure system
heads even further east of the Divide, what will remain will be
some cloud cover overnight. This will give way to mostly sunny
skies and stable conditions Tuesday under building high pressure.



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