Fire Weather Outlook Discussion
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FNUS21 KWNS 211520
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1019 AM CDT Fri Jul 21 2017

Valid 211700Z - 221200Z

...CRITICAL FIRE WEATHER AREA FOR CENTRAL/EASTERN MONTANA...

No major changes are made to the ongoing forecast. The Montana
elevated area is expanded slightly westward and southward to account
for breezy/dry conditions amidst favorable fuels over much of the
state today. Across the elevated area, sustained winds around 10-20
mph and RH values below 20% will increase fire-weather concerns. The
critical area remains unchanged, with the highest confidence in
critical conditions remaining over north-central and eastern
Montana. For more information, see the previous discussion below.

..Picca.. 07/21/2017

.PREV DISCUSSION... /ISSUED 0303 AM CDT Fri Jul 21 2017/

...Synopsis...
The main belt of westerlies is expected to remain across the
northern tier of states today. An upper trough is expected to move
eastward across the Canadian Prairie provinces, as an associated
surface cyclone moves from eastern Montana into the upper Midwest
and a trailing cold front sweeps through portions of the
northern/central Plains.

...Portions of Montana into the far western Dakotas...
Dry west-northwesterly low-level flow will develop in the wake of
the frontal passage today. While temperatures will be somewhat
cooler compared to previous days, sufficient heating of a dry
airmass will result minimum RH values of 10-20% across much of
Montana into the far western Dakotas. The greatest wind speeds are
still expected across north-central into eastern MT, where 20-25 mph
sustained winds are expected this afternoon, resulting in a threat
of critical fire weather conditions. Surrounding the critical area,
elevated to locally critical conditions are expected from northwest
MT into the far western Dakotas, where winds may be slightly weaker
but very low RH values are still expected. Some expansion of the
critical area to the east-southeast may be required in the Day 1
update depending on trends in short-term obs and guidance.

...Snake River Valley of Idaho...
Modestly enhanced west-southwesterly winds still appear possible
across portions of the Snake River valley this afternoon. Sustained
wind speeds of 15-20 mph combined with minimum RH values of 7-15%
will result in a threat of elevated fire weather conditions.

...Please see www.spc.noaa.gov/fire for graphic product...

$$



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