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FNUS28 KWNS 222038

Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0338 PM CDT Tue Aug 22 2017

Valid 241200Z - 301200Z

A mid/upper-level trough and associated cold front will impact
portions of the Northwest, northern Rockies, and High Plains on
D3/Thursday into D4/Friday. This weekend, a mid/upper-level ridge
will begin to amplify over portions of the West, resulting in a
return to hot and dry conditions for many areas into early next

...D3/Thursday - D4/Friday: Dry Thunderstorm threat across interior
Northwest/Northern Rockies/Northern High Plains...
On D3/Thursday, a dry thunderstorm threat will persist from eastern
OR into portions of ID/MT, as the mid/upper trough and cold front
move through the region. While coverage may somewhat less compared
to D2/Wednesday, thunderstorm activity may also be somewhat drier
given increasing midlevel flow and storm motions.

On D4/Friday, some dry thunderstorm threat may linger over portions
of ID/MT/northwest WY, as a weak midlevel trough moves eastward and
weakens while the upper ridge begins to rebuild over the area.
Confidence in this scenario is too low for any probabilities at this

...D3/Thursday: Wind/RH potential across central/eastern WA/OR...
While guidance has trended somewhat weaker with wind speeds, it
still appears that dry and breezy post-frontal flow will result in
the potential for elevated to locally critical wind/RH conditions
across portions of the Columbia Gorge and in the lee of the Cascades
on D3/Thursday, where a 40% area has been maintained.

...D3/Thursday - D4/Friday: Wind/RH potential across MT...
An increasing pressure gradient will result in strengthening
southeasterly winds on D3/Thursday across eastern MT. With moisture
return expected to remain rather poor, strong heating will result in
the potential for RH values to fall below 30%. The combination of
wind and RH will result in the potential for elevated fire weather
conditions. The critical threat appears too low for the introduction
of any probabilities for this scenario.

On D4/Friday, locally elevated conditions are possible across much
of MT, but guidance has trended noticeably weaker with the
post-frontal flow, so the existing 40% area for this scenario has
been dropped.

..Dean.. 08/22/2017

...Please see for graphic product...

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