Fire Weather Outlook Discussion
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FNUS22 KWNS 121715

Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1114 AM CST Tue Dec 12 2017

Valid 131200Z - 141200Z

No changes to the ongoing forecast are needed. See below for more

..Picca.. 12/12/2017

.PREV DISCUSSION... /ISSUED 0128 AM CST Tue Dec 12 2017/

Ridge-trough pattern from west-to-east across the United States will
persist through Wednesday. A shortwave trough will crest the apex of
the ridge and dive south across the eastern Great Basin and central
Rocky Mountains. The result will be a reinforcement of the cold air
in the Great Basin, which will act to maintain the large-scale
surface-pressure field conducive for offshore winds across Southern
California -- albeit weaker than last week.

...Southern California...

Offshore winds will continue for another day. These winds will
maintain very low relative humidity across the region, and poor
overnight recovery. Elevated to locally critical conditions are

One note, even though the overall large-scale surface-pressure
gradient will be weakening with time, forecast soundings indicate
mid-level-lapse rates will be on the order of 7.5-8.0 C/km. These
lapse rates will support plume-dominated fires. Any fire plume
would likely modify/enhance low-level winds in the vicinity of the

...Central United States...

Repeated surface cold front intrusions have scoured what limited
moisture existed across the central United States. This, along with
limited 60-day precipitation has resulted in very dry fuels across
most of the region. Ahead of yet another surface cold front, the dry
airmass and full sunshine will allow for temperature to quickly warm
into the 60s with afternoon relative humidity ranging from around
30% to (possibly) the low teens. Additionally, north surface winds
will strengthen (as the surface-pressure gradient increases) to 15
mph across southern portions of the highlighted area, to near 25 mph
farther north. The result will be widespread elevated to locally
critical fire-weather conditions.

...Please see for graphic product...

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