Fire Weather Outlook Discussion
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233
FNUS21 KWNS 241633
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1132 AM CDT Wed May 24 2017

Valid 241700Z - 251200Z

Only minor changes have been made to the periphery of the elevated
areas.

Morning observations and latest numerical guidance support the
ongoing forecast of dry and windy conditions across both the
Southwest and the northern Plains. Across the northern Plains,
relative humidity should remain above critical thresholds, despite
the strong winds. Across the southwest, a very dry low-level airmass
will remain in place, although fuel receptiveness and
duration/location of strongest winds will mitigate at higher threat.

..Marsh.. 05/24/2017

.PREV DISCUSSION... /ISSUED 0334 AM CDT Wed May 24 2017/

...Synopsis...
Expansive upper trough currently extending from the upper MS valley
southward to the TX coast is expected to progress eastward into the
more of the eastern CONUS during the period. At the same time, a
shortwave trough currently moving through the base of the upper
trough will move quickly eastward through the lower MS Valley before
pivoting northeastward into the mid-Atlantic. Farther west, upper
ridging will drift across the Plains while another shortwave trough
moves through the northern Rockies and Canadian prairie provinces.
At the surface, low currently moving into the TN valley will
continue northeastward will occluding. An associated cold front will
move across the Southeast, TN Valley, and mid-Atlantic. Ridging is
anticipated across the Plains with strong lee troughing across the
High Plains.

...Southwest...
A tight surface pressure gradient, coupled with deep boundary-layer
mixing and modest westerly flow aloft, will support sustained
westerly winds around 20-25 mph (locally higher) from northern AZ
into north-central NM. Slightly weaker winds are anticipated across
southern AZ and southwest NM. These gusty winds will occur within an
antecedent dry environment supportive of minimum RH values from the
low teens to upper single-digits. Resulting meteorological
conditions are supportive of critical fire weather conditions in
areas where fuels are critically dry. However, the latest fuel
guidance indicates continued above-average fuel moisture across much
of the region. As a result, widespread elevated fire weather
conditions are anticipated with locally critical conditions likely
in areas where fuels are sufficiently dry.

...Northern Plains...
A strong surface pressure gradient associated with a deep surface
low moving across the Canadian prairie provinces and its attendant
cold front will be in place across the region. Strong westerly winds
and quickly drying surface conditions are anticipated in the wake of
the front. Moist fuels and cooler surface conditions are expected to
keep the fire weather risk low across north-central MT. However,
warmer conditions and more favorable fuels are expected farther east
into eastern MT and elevated to locally critical fire weather
conditions are likely as a result.

Additionally, some isolated, high-based thunderstorms are possible
along the front or just ahead of the front. The high-based and
fast-moving nature of these storms will support some threat for
lightning ignitions and an isolated dry thunderstorm area was
introduced as a result.

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

$$



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