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FNUS21 KWNS 310615

FWDDY1



Day 1 Fire Weather Outlook  

NWS Storm Prediction Center Norman OK

0114 AM CDT Wed Mar 31 2021



Valid 311200Z - 011200Z



...Synopsis...

Early morning water-vapor imagery reveals an upper-level longwave

trough in place over the central U.S. as a surface cold front

continues to push south/southeastward into the Southern Plains and

lower MS river valley. This large-scale trough will undergo gradual

amplification as it translates eastward over the next 24 hours amid

mid-level cold advection over the central Plains to the Midwest. The

resulting height rises and northwesterly flow regime over the Plains

will favor breezy conditions and mostly clear skies over a region

with dry fuels and low humidity. To the west, surface high pressure

over the inter-mountain West and an offshore low will foster another

day of dry offshore winds across southern California that will

introduce fire weather concerns.



...Greater Plains region...

A dry air mass is noted across much of the Plains with dewpoints in

the single digits from eastern MT southward into NE (and only

marginal improvements further south into KS). Although temperatures

will be cooler than previous days, mostly clear skies will help

afternoon RH values fall into the 20-30% range for most locations. A

northwesterly flow regime aloft will feature 30-40 mph mid-level

winds that will likely be able to mix down by late afternoon. The

axis of stronger winds should extend from central SD southeastward

into eastern MO. While a variety of RH/wind combinations are

expected within the broader elevated region, the highest potential

for sustained elevated (and perhaps briefly critical) fire weather

conditions will reside within this corridor.



Further south into west TX, 15-25 mph northeasterly winds behind the

cold front are forecast to gradually weaken through the day.

However, dry air advecting into the region from the north combined

with diurnal heating will allow for a few hours of overlapping

15-20% RH and breezy winds. Elevated fire weather conditions are

expected across the broader west TX region, and transient critical

conditions are possible where RH can fall below 15%.



...Southern California...

Although early-morning observations show weak winds, relative

humidity values in the coastal hills and mountains remain in the

5-15% range with little overnight recovery expected through sunrise

for the higher terrain. Winds are expected to increase after sunrise

and into the afternoon hours with peak sustained winds near 25-30

mph (gusting to 45-55 mph). Downslope warming/drying coupled with

antecedent dry conditions should yield RH values in the single

digits for many locations. While critical wind/RH conditions are

possible, fuels remain marginally receptive and precludes the

introduction of a critical risk area.



..Moore.. 03/31/2021



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



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