Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 210905

Area Forecast Discussion
National Weather Service Glasgow MT
305 AM MDT Mon Aug 21 2017

.SHORT TERM...for northeast through Tue...

Northeast Montana will be under the influence of an upper-level
trough swinging across southern Saskatchewan this morning. As
such, due to the location of the associated frontal boundary
nearby to our south, we will see cloud cover in the morning.

For those interested in cloud cover and the eclipse, the best
near guidance overnight was CONSShort, so will stick with this. A
surface high expands south over our area today, causing cloud
cover to diminish by late morning. So, CONSShort suggests
widespread partly cloudy skies between 17Z and 19Z. Sky coverage
ranges from 12% to 27% over most areas south of the Missouri
River, and from 15% to 33% north. Expect a forecast update in
mid-morning before the eclipse. Skies will continue to clear from
west during the day the western upper ridge begins to shift east.

Temperatures will remain cooler than normal today due to the
northerly breeze channeling in the cooler air from the north. This
cool influence should last all day for highs ranging from the mid
70s in the northeast to the lower 80s across our southern zones.
The areas with the strongest wind coincide with areas of coolest
temperatures, so no critical fire wx is expected.

Tonight and Tuesday, the upper-level ridge axis shifts from west
of the Canadian Rockies to east of the Canadian Rockies. This
will have the effect of nudging the stationary boundary mostly
east of Northeast Montana by Tuesday afternoon, allowing warmer
air to flow in from the south. Expect highs in the upper 80s in
the south to the upper 70s in the northeast. With no strong wind,
no critical fire wx concerns are expected.


.LONG TERM...Tue night through Mon...

Upper ridge builds over Montana midweek with temperatures warming
into the upper 80s to lower 90s. Upper flow amplifies as an upper
trof pushes into western Canada, with low level lee trof
developing across central Montana. A pressure gradient tightens
with strengthening lee trof, will see increasing southeast winds
Wednesday into Thursday. Fire weather concerns due to the gusty
winds are expected to partially mitigated by dew point rises with
the southeast low level jet across the plains.

As the western Canadian upper trof moves across the Rockies, lee
trof will push through eastern Montana Thursday night into Friday.
Showers and thunderstorms possible with the frontal passage.
Depending on the timing, elevated fire weather concerns are also
possible on Friday with drying airmass with gusty northwest winds
as high pressure pushes out of Alberta.

Cooler and mostly dry conditions expected for the weekend as the
upper ridge begins to rebound to the west. Ebert



VFR expected today and tonight.

An upper-level trough moving east through southern Saskatchewan
sends a dry cold front south through Northeast Montana today.
Broken mid-level clouds are expected to go scattered by afternoon
and then mostly clear tonight.

Wind: north 5-10kt increasing to 10-15kt in the afternoon, then
becoming light and variable tonight.





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