Storm Prediction Center Day 1 Fire Weather Outlook
Created: Sun Sep 8 07:03:03 UTC 2024 ( | )
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ZCZC SPCFWDDY1 ALL FNUS21 KWNS 080701 Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0201 AM CDT Sun Sep 08 2024 Valid 081200Z - 091200Z ...Synopsis... Broad troughing over the Pacific Northwest is forecast to intensify as a shortwave perturbation moves onshore across parts of WA and OR today. As the shortwave trough intensifies, flow aloft should also increase as it overspreads the Northwest and Great Basin. Showers and thunderstorms, along with gusty, winds are likely across much of the West, with elevated fire-weather potential. ...Dry Thunder... Beneath the cold core of the upper trough moving inland, a thunderstorm may be ongoing through the morning hours across portions of the Pacific Northwest. Greater storm coverage is expected to develop through the day, as daytime heating and lift from the upper trough interact with deepening mid-level moisture. Model soundings show weak buoyancy atop warm and dry low levels and storm motions greater than 20 kt. With poor precipitation efficiency expected, isolated to widely scattered dry thunderstorms appear likely over receptive fuels. Confidence in dry thunderstorm coverage is greatest across portions of the northern and central Cascades, into eastern ID and far southwestern MT. Scattered thunderstorms are also possible farther south across the southern Great Basin and southern CA. Displaced from the stronger flow aloft, and with access to more robust monsoon moisture, a wetter storm mode is expected. A few drier strikes are still possible outside of the wetter cores within receptive fuels, but the coverage of drier storms appears limited. ...Northern Great Basin and the Cascades... As the trough moves inland, a belt of stronger mid-level flow is expected to intensify over parts of the northern Great Basin and the southern Cascades. The stronger flow aloft will support an increase in surface winds to 15-25 mph. Residual warm temperatures beneath the weakening ridge and the increase in downslope winds will favor drier low levels, with RH minimums below 15% likely. Widespread elevated to near-critical fire-weather conditions are possible across the northern Sierra and Great Basin, where the dry and breezy conditions will overlap with areas of dry fuels. Farther north in the lee of the Cascades, gusty downslope and gap winds may also support brief elevated fire-weather potential as stronger flow aloft develops. However, some humidity recovery will eventually occur as marine influence will increase with time, potentially limiting the coverage and duration of fire-weather concerns. ..Lyons.. 09/08/2024 ...Please see www.spc.noaa.gov/fire for graphic product...