Fire Weather Outlook Discussion
Issued by NWS
Issued by NWS
651 FNUS21 KWNS 231618 FWDDY1 Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1117 AM CDT Sun Jun 23 2024 Valid 231700Z - 241200Z The previous forecast generally remains on track with only minor adjustments made to reflect recent fire reports, morning surface observations, and trends in latest high-res guidance. A dry frontal passage is underway across the Pacific Northwest as mid-level winds increase over the central Cascades (based on the evolution of high-level cirrus over the region). Surface pressure falls in the lee of the Cascades/northern Sierra Nevada should become more apparent in the coming hours with an attendant increase in surface winds. Latest guidance suggests the onset of elevated fire weather conditions will be around 18 UTC along/east of the Sierra Nevada and Cascades with a slightly later onset for the Snake River Plain. Localized critical conditions also remain possible through the Columbia Gorge and along the NV/OR border; however, higher RH with northward extent and displacement from the stronger mid-level flow with southern extent continue to limit confidence in the coverage/duration of critical conditions. ..Moore.. 06/23/2024 .PREV DISCUSSION... /ISSUED 0124 AM CDT Sun Jun 23 2024/ ...Synopsis... An upper-level trough will move through parts of the Northwest today, favorably timed with peak heating. Surface low pressure will deepen in the lee of the northern and Canadian Rockies. Surface winds will increase across the region and into the northern Great Basin. ...Columbia Basin... Winds of 15-20 mph (higher downwind of the Cascade Gaps) are expected by the afternoon. RH may only lower to around 20% in many places due to at least some push of marine air across the Cascades. Given the relatively dry fuels and the expected winds, elevated fire weather is possible. ...OR/NV/CA... Temperatures will be warmer and RH lower farther south. RH could fall to near 10-15% over a broad area. Winds away from the mid-level jet will be slightly weaker, but 15-20 mph is still possible, especially near terrain features. With dry fuels in these areas, fire weather concerns will be elevated. ...Snake River Plain... The southern periphery of the mid-level jet will sag into southern Idaho. This, combined with the strengthening surface pressure gradient, will promote 15-25 mph winds within the valley. RH of 15-20% appears probable. Duration of potentially critical conditions will be minimal and fuels are not yet critically dry. That said, elevated to locally critical fire weather is expected during the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... $$