SPC Day 1 Fire Weather Outlook

By Newsroom America Feeds at 23 Oct 2017

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0150 AM CDT Mon Oct 23 2017 Valid 231200Z - 241200Z ...CRITICAL FIRE WEATHER AREA FOR COASTAL RANGES OF SOUTHERN CALIFORNIA... ...Synopsis... A broad anticyclone will continue to overspread areas of the Intermountain West and Great Basin, with 1042mb centered over northern Idaho by the end of the period. East of the high, a low will rapidly deepen to around 988 mb over the Great Lakes region late in the forecast period, setting up a favorable surface pressure gradient for gusty winds in portions of the central and northern Plains. Meanwhile, the high over the Intermountain West and a weak trough along the California coast will favor an extended period of offshore flow and fire weather concerns across coastal ranges of southern California and the immediate Lower Colorado River Valley vicinity. ...Coastal Ranges of southern California... The aforementioned offshore flow will persist throughout the forecast period, with northeasterly 15-25 mph sustained surface winds gusting to 40-50 mph especially in terrain-favored areas. Meanwhile, a continued dry airmass will remain in place across the region, with already low (near-critical) RH values falling into the single digits in a few locales as temperatures rise into the 90s F during peak heating hours. With dry fuels in place, elevated and critical fire weather delineations remain in place, with critical areas corresponding to regions of strongest surface flow and critical RH. ...Southeastern Montana southeastward to central Kansas... The aforementioned surface pressure gradient between the western high and Great Lakes low will foster widespread areas of 25-35 mph northwesterly surface flow with higher gusts in the afternoon - strongest in areas from west-central South Dakota southward to northwestern Kansas. Both fuels and RH appear to be limiting factors for a higher fire weather threat - fuels only marginally support rapid fire spread and are most favorable in western Nebraska, while RH values will only fall below critical thresholds on a spotty basis. An elevated delineation has been made for this forecast, and morning observations and fuels guidance will be used to determine whether an upgrade to critical and/or spatial adjustments to the ongoing elevated area need to be made. ...Lower Colorado River Valley... Northerly 15-25 mph low-level flow will develop during much of the day in response to a favorable pressure gradient in the across the region. Meanwhile, insolation will aid in temperatures rising into the low 90s F along with very low RH values (around 7-10%). Elevated to locally critical fire weather conditions will exist, especially where fuels are dry. ..Cook.. 10/23/2017 ...Please see www.spc.noaa.gov/fire for graphic product... Read more



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