Fire Weather Outlook Discussion
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908
FNUS22 KWNS 251700
FWDDY2

Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1159 AM CDT Sun Jun 25 2017

Valid 261200Z - 271200Z

...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NORTHWEST NV...
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF EAST-CENTRAL/SOUTHERN
NV...SOUTHWEST UT...NORTHWEST AZ...

No changes have been made to the ongoing forecast.

..Cohen.. 06/25/2017

.PREV DISCUSSION... /ISSUED 0239 AM CDT Sun Jun 25 2017/

...Synopsis...
Upper ridge in place from the Southwest into the northern Rockies is
expected to breakdown on Monday as a shortwave trough moves from
northern CA through the northern Rockies. Farther east, a shortwave
trough will move from the northern Plains/upper Midwest
southeastward into the upper Great Lakes/OH valley, contributing to
an eastward shift of its parent upper trough. At the surface, lower
pressures associated with the northern CA shortwave trough will
contribute to a tightening of the surface pressure gradient across
much of the Intermountain West as well as over the northern Plains.

...Great Basin/AZ...
Aforementioned tightening of the surface pressure gradient along
with modestly enhanced mid-level flow will contribute to gusty
southerly/southwesterly winds in the vicinity of the NV/UT/AZ border
intersection. Very warm and dry conditions are also expected in this
area with minimum RH values in the single digits. Combination of
warm, dry, and windy conditions with dry fuels will support a
critical fire weather threat. Critical fire weather conditions are
also anticipated across northeast NV where winds around 20 mph are
anticipated amidst single-digit RH values and dry fuels.
Above-average temperatures and RH values in the single digits are
anticipated across much of the remainder of the region but winds are
expected to be less than 20 mph, precluding critical fire weather
conditions.

Shortwave trough resulting in the breakdown of the upper ridge will
also support an increase in mid-level moisture across portions of
central/eastern OR and western ID. This mid-level moisture will
exist atop a warm and dry antecedent airmass, contributing to an
environment favorable for dry thunderstorms. Development of these
thunderstorms amidst dry fuels will result in increased fire danger.

...Northern Plains...
Previously discussed tightening of the surface pressure gradient
across the region will result in gusty southeast winds from 20-25
mph from early Monday afternoon through the evening. Above-average
temperatures (i.e. in the upper 80s and low 90s) are also expected,
supporting afternoon RH values around 15-20 percent. While there
will be some dissociation (both spatial and temporally) between the
strongest winds and low RH values, enough overlap exists to support
an elevated to locally critical fire weather threat. A critical
delineation may be needed in subsequent outlooks if guidance
suggests stronger winds will persist farther east.

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

$$



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