SPC Day 1 Fire Weather Outlook

By Newsroom America Feeds at 11 Aug 2017

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1144 AM CDT Fri Aug 11 2017 Valid 111700Z - 121200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF OREGON... ...Pacific Northwest to the northern Rockies... Isolated to scattered dry thunderstorm coverage is still anticipated today across portions of the Pacific Northwest and the northern Rockies. 12Z regional sounding sampled a PW gradient across the region, from over an inch along the OR coast to closer to 0.80" at BOI. Highest thunderstorm coverage is expected across central and eastern OR today as storms initiate over both the higher terrain and eastern plains. Slightly lower atmospheric moisture (reflected by lower PW values) is expected farther north in central/eastern WA and farther west in the northern Rockies, which will temper the overall storm coverage in these areas. Given the higher PW values (i.e. greater than 0.75"), a mix of wet and dry storms is likely. However, dry thunderstorm coverage is still expected to be high enough over areas with critically dry fuels to merit a critical fire weather threat. In all, no changes have been made to the ongoing forecast. Additional forecast details are available in the forecast discussion appended below. ..Mosier.. 08/11/2017 .PREV DISCUSSION... /ISSUED 0113 AM CDT Fri Aug 11 2017/ ...Synopsis... A persistent Rex block over the Pacific Northwest will gradually break down today, as a relatively amplified trough approaches the coast. The residual mid/upper low at the base of the block will slowly lift northeast from northern California into Oregon. To its east, a weak/sheared impulse will remain quasi-stationary over Idaho and Wyoming, as a stronger wave drops south from Canada towards northern Montana. ...Pacific Northwest to the northern Rockies... The threat of new fire starts and erratic behavior will increase considerably once again today. The aforementioned low lifting into Oregon will focus convection from the eastern slopes of the Cascades to the Columbia River. While a few cores will produce wetting rainfall (with precipitable-water values around 0.7-0.9 inches), a combination of very dry fuels, scattered storm coverage, and dry/deep boundary-layer profiles supports a critical designation over Oregon. Elsewhere, other disturbances over the region will encourage thunderstorm development along higher terrain; however, storm coverage over sufficiently dry fuels should remain isolated to widely scattered at most. ...Please see www.spc.noaa.gov/fire for graphic product... Read more



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