Storm Prediction Center Day 1 Fire Weather Outlook
Created: Tue Jul 17 15:31:03 UTC 2018 ( | )
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ZCZC SPCFWDDY1 ALL FNUS21 KWNS 171529 Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1029 AM CDT Tue Jul 17 2018 Valid 171700Z - 181200Z Forecast looks on track and only minor changes were made. Please see the forecast discussion below for more details. ..Nauslar.. 07/17/2018 .PREV DISCUSSION... /ISSUED 0209 AM CDT Tue Jul 17 2018/ ...Synopsis... A weak 500 mb shortwave trough will pass over the northern Great Basin during the afternoon. Mid-level moisture will also move eastward in association with the shortwave trough. At the surface, a thermal trough will develop east of the Cascades down into far northern Nevada. ...Central Washington/Oregon... A thermal low will become established along the lee of the Cascades during peak heating of the afternoon, as temperatures are expected to reach up to 100F in some locales. The thermal low induced pressure gradient will generate downslope sustained surface winds of at least 15-20 mph in tandem with 10-20% RH. Fuels are receptive in this area, with elevated RH/wind criteria being met for fire spread potential. Stronger surface winds (20-25 mph) may occur along the immediate eastward facing slopes of the Cascades along with critically low RH. The brevity of the critical conditions warrant only an elevated delineation at this time. ...Southern Idaho... Strong surface heating during the mid-late afternoon may induce a weak pressure gradient in the Snake River Plain. Sustained surface winds of 15-20 mph are expected along with critical RH. An elevated delineation was added given the receptive nature of fuels in this area. ...Southwest Wyoming... A weak thermal low and associated pressure gradient may develop in the Green River Basin. 15-20 mph sustained surface winds are expected along with 15-20% RH. Though the RH is marginally low and recent rainfall from scattered storms has recently occurred, 10-hr fuels remain receptive to the spread of grass fires. An elevated delineation was added to account for the stronger surface winds overlapping rebounding finer fuels. ...Idaho/Montana border into far western Wyoming... As the aforementioned mid-level shortwave trough progresses eastward, deep-layer ascent and at least marginal buoyancy will foster the development of isolated thunderstorms across the area. Precipitable water values of 0.5-0.75 inches and a relatively deep sub-cloud layer suggests that dry lightning will be possible. Modest mid-level flow will also allow faster storm motions (above 20 knots), reducing accumulating rainfall atop fuels receptive for fire weather spreads. ...Please see www.spc.noaa.gov/fire for graphic product...
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