Storm Prediction Center Day 2 Fire Weather Outlook
Created: Fri Jul 20 19:25:03 UTC 2018 ( | )
Click for Day 2 FireWX Areal Outline Product (KWNSPFWFD2)
ZCZC SPCFWDDY2 ALL FNUS22 KWNS 201924 Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Fri Jul 20 2018 Valid 211200Z - 221200Z The elevated area across Idaho was expanded farther to the southwest into Oregon/Nevada/California as winds should increase (sustained westerly winds of 15-20 mph) along a frontal boundary associated with the passage of an upper-level trough over the Northern Rockies. RH values should remain below 20% across this area as deeper subtropical moisture will remain to the south across Nevada. A relatively narrow corridor of isolated dry thunderstorm potential remains across the northern Great Basin and into the Northern Rockies on the periphery of this deeper subtropical moisture and along/ahead of the upper-level trough moving over the Northern Rockies. An elevated area was added to portions of the Southern High Plains as very hot/dry/unstable conditions continue. Winds should increase (southerly sustained winds around 15 mph with gusts to 20-25 mph) along a surface pressure trough resulting in elevated fire weather conditions across this area. ..Nauslar.. 07/20/2018 .PREV DISCUSSION... /ISSUED 0622 AM CDT Fri Jul 20 2018/ ...Synopsis... A belt of moderate mid-level flow ahead of an upper level trough in the Pacific Northwest may lead to elevated fire weather concerns across portions of southern Idaho and northern Montana on Saturday. In addition, dry thunderstorms are possible on the northern and western periphery of the monsoonal moisture across the Great Basin and into portions of the northern Rockies. ...Southern Idaho and far southwestern Montana... Deep mixing is expected to transport 15 to 20 mph winds to the surface during the afternoon across much of the Snake River Valley and into the Bitterroot Mountains. In addition, RH values are expected to drop to near critical levels. Models suggest higher winds (20 to 25 mph) are possible, but uncertainties as to the placement of these higher wind speeds and the co-location of critical RH values precludes the inclusion of a critical area at this time. ...Northern Montana... Downslope flow in the lee of the Lewis Range may lead to locally critical fire weather conditions on Saturday. RH values are expected to be critical, but wind speeds are borderline. There is variance between 15 to 25 mph sustained winds among the latest forecast guidance. Therefore, a critical area may be needed during later outlooks, but confidence is not high enough to go higher than elevated at this time. ...Great Basin into portions of the Northern Rockies... Isolated dry thunderstorms are possible along the western and northern periphery of the southwest monsoon. PWAT values will be in the 0.7 to 0.8 inch range across much of this area with at least isolated storm coverage expected. ...Please see www.spc.noaa.gov/fire for graphic product...
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