SPC Day 2 Fire Weather Outlook

By Newsroom America Feeds at 7 Oct 15:01

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0158 PM CDT Sat Oct 07 2017 Valid 081200Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NORTHERN CALIFORNIA... ...Portions of the Sacramento Valley and adjacent coastal ranges and the Northern San Joaquin Valley... No changes to the Critical fire weather area were made. The Elevated area was extended a bit further south into the northern San Joaquin Valley to account for an overlap of minimum RH values near 15% and sustained surface winds around 15 mph atop very dry fuels. See previous discussion below for more information on the expected evolution of the fire weather threat over northern California. ...Portions of Northern AZ, northwestern NM, southern UT, and southwest CO... Efficient deep-layer mixing across this area on Day 2/Sunday will promote pre-frontal westerly/southwesterly sustained winds around 15-20 mph. The breezy winds in conjunction with very dry low levels (e.g., minimum RH values at or below 10%) and increasingly receptive fuels will promote elevated to locally critically fire weather conditions. Thus, an Elevated fire weather area was introduced with this update. ..Elliott.. 10/07/2017 .PREV DISCUSSION... /ISSUED 0109 AM CDT Sat Oct 07 2017/ ...Synopsis... ...Portions of the Sacramento Valley and adjacent coastal ranges... Elevated to critical fire weather conditions are expected on Sunday across portions of northern California. A broad upper trough over the western U.S. will deepen over the Great Basin as a jet max slides south across Oregon into northern California and Nevada. This will lead to strong deep layer northerly flow over the region. At the same time, surface high pressure will build over the northern Rockies behind a cold front, leading to tightening pressure gradients across the region. As a result, gusty north to northeasterly offshore winds of 15-30 mph with higher gusts are expected by Sunday afternoon in the early morning hours on Monday. Temperatures will warm into the 80s while RH values fall into the 10-20 percent range. There will be some overnight RH recovery with values climbing into the 20-40 percent range, but wind speeds will remain strong. ...Please see www.spc.noaa.gov/fire for graphic product... Read more



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