Fire Weather Outlook Discussion
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FNUS21 KWNS 251700
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1159 AM CDT Sun Jun 25 2017

Valid 251700Z - 261200Z

No changes have been made to the ongoing forecast.

..Cohen.. 06/25/2017

.PREV DISCUSSION... /ISSUED 0230 AM CDT Sun Jun 25 2017/

...Synopsis...
Shortwave trough currently moving through central CA will continue
moving north-northeastward into northern CA and southern OR, ahead
of a stronger shortwave trough farther off the northern CA coast.
Increased mid-level moisture and forcing for ascent will contribute
to thunderstorm development across northern CA and central OR
(discussed in more detail below). Farther east, upper troughing
currently extending from the northern Rockies to the Northeast and
covering much of the central and eastern CONUS will persist
throughout the day while gradually shifting eastward.

...Northern CA/Central OR...
Antecedent dry airmass and deep boundary-layer mixing will
contribute to highs in the upper 90s/low 100s and afternoon RH
values in the teens. Despite these dry low levels, aforementioned
lead shortwave trough is expected to move through the region during
the afternoon, helping to moisten the mid levels. Resulting modest
instability coupled with forcing for ascent and favorable orographic
circulations will result in isolated to widely scattered
thunderstorms during the afternoon and evening. Storm motions will
not be particularly fast but the warm and dry boundary-layer and
high cloud bases will contribute to significant sub-cloud
evaporation of any precipitation, resulting in low precipitation
totals at the surface. These dry thunderstorms amidst modestly dry
fuels will support an increased fire weather threat.

...Northern Plains...
Anomalously dry fuels exist across the region due to the
below-average rainfall and dry conditions the area has experienced
for the past 30 days. Northwesterly winds near 15 mph and minimum RH
values around 20-25% will contribute to locally elevated fire
weather conditions this afternoon over the region. Below-average
temperatures should keep RH values above critical values except on a
spotty/localized basis.

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

$$


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