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FNUS21 KWNS 060701

FWDDY1



Day 1 Fire Weather Outlook  

NWS Storm Prediction Center Norman OK

0100 AM CST Sat Mar 06 2021



Valid 061200Z - 071200Z



...Synopsis...

An upper-level shortwave trough, noted in morning water-vapor

imagery moving onshore across northern California, will continue to

progress to the northeast into the northern Rockies by this

afternoon. In response, a deepening lee trough will strengthen

pressure-gradient winds and support elevated fire weather conditions

across the Plains as well as the Great Basin. Elsewhere across the

CONUS, rain chances across the Southeast and weak winds over

southwestern TX will limit additional fire weather concerns. 



...High Plains...

The overall forecast remains on track and confidence in widespread

elevated fire weather conditions from eastern CO northward into

western SD is high based on recent observations. Regional 00 UTC

soundings and recent surface observations reveal a dry boundary

layer already in place, which will help relative humidity values

fall into the 15-20% range later today. Sustained winds near 20 mph

are expected, and steepening low-level lapse rates will help

downward mixing of 30-35 mph gusts by late afternoon. 



Recent hi-res ensemble guidance continues to show high probabilities

in elevated conditions, and suggests that sustained winds near 20

mph and RH values between 20-25% may extend as far north as western

ND/eastern MT (though slightly higher boundary-layer moisture is

noted in the 00 UTC BIS sounding). Transient critical conditions are

possible across northeast CO and western NE where the potential for

RH near 15% and frequent gusts to 30 mph is highest. Confidence in

sustained, widespread critical conditions is currently not high

enough to warrant a delineation, though trends will continue to be

monitored.



...Great Basin...

Lee troughing to across MT/WY with gradual surface pressure rises

across CA will help strengthen the pressure gradient across the

Great Basin this afternoon. Winds increasing to 15-20 mph are likely

and may coincide with areas of 15-20% RH - especially across

southeast UT where the overlap of favorable wind/RH is highest per

recent guidance. However, ERC values across this region remain below

critical thresholds, suggesting a muted fire weather concern.



..Moore.. 03/06/2021



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



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