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FNUS28 KWNS 222051
FWDD38

Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0351 PM CDT Sat Jul 22 2017

Valid 241200Z - 301200Z

A mid/upper ridge will build across parts of the Desert Southwest,
southern/central Rockies, and southern/central Plains through
mid-week, before potentially shifting westward towards the lower
Colorado Valley late in the week. Along the western periphery of
this ridge, mid-level moisture will slowly spread northward across
the Great Basin and parts of the interior Pacific Northwest/northern
Rockies region. Meanwhile, a series of impulses will cross the
northwest US through the week, with associated occasional frontal
passages at the surface. The combination of these systems and the
aforementioned increasing moisture from the south will boost
thunderstorm chances across parts of the Great Basin, Pacific
Northwest, and northern Rockies this week.

...Dry-Thunderstorm Potential...
An approaching low off the northern California coast and increasing
mid-level buoyancy ahead of this system will promote thunderstorms
from northern California to the northern Rockies on D3/Mon.
Favorably dry fuels and deep/well-mixed boundary-layer profiles
suggest the potential for several thunderstorms with little wetting
rainfall. As such, fire starts from dry lightning strikes will be a
concern. Pockets of more focused convective coverage may support a
critical/scattered designation in later forecasts, but increasing
precipitable-water values and modest storm motions offer too much
uncertainty for a critical designation at this time. As moisture
continues to stream northward, storms will gradually transition to
wetter modes from south to north. Therefore, the 10% area shifts
northward on D4/Tue.

...Gusty Winds / Low RH Potential...
A 40% area is introduced across eastern Montana and vicinity for
D3/Mon, to account for gusty northwesterly flow developing behind a
front late in the day. While the potential for widespread critical
concerns appears uncertain, sustained winds should be strong enough
to combine with low RH/dry fuels to promote at least
elevated/locally critical concerns during the afternoon and evening.

..Picca.. 07/22/2017

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

$$



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