


Fire Weather Outlook Discussion
Issued by NWS
Issued by NWS
070 FNUS21 KWNS 301656 FWDDY1 Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Mon Jun 30 2025 Valid 301700Z - 011200Z ...Northern California and Southwestern Oregon... An approaching mid-level trough, steep low-level lapse rates and increasing mid-level moisture and instability will aid a mix of wet/dry thunderstorm development across the higher terrain of northern California, with showers and thunderstorms propagating into southern Oregon along and east of the Cascades through this evening. Isolated dry thunderstorm highlights persist where new ignitions are possible atop dry fuels. ...Great Basin... The mid-level trough entering California and associated stronger southerly mid-level flow will overspread the Great Basin today. A deep, well-mixed boundary layer will facilitate gusty surface winds from the south of up to 25 mph across central Nevada, with sustained winds of around 15 mph. The enhanced winds along with low relative humidity will promote an elevated fire weather threat amid receptive fuels. ..Williams.. 06/30/2025 .PREV DISCUSSION... /ISSUED 0215 AM CDT Mon Jun 30 2025/ ...Synopsis... Across the US, sub-tropical ridging will build over the Plains, keeping stronger flow aloft displaced to the north while an upper low will overspread portions of the West Coast. Ahead of the low, breezy southerly winds will advect monsoon moisture northward into parts of CA and OR. Dry thunderstorms and dry/breezy conditions appear likely to support elevated fire-weather potential across the Northwest and Great Basin today. ...Northwest... Weak ascent from an approaching upper trough will allow for isolated to widely scattered thunderstorms across northern CA and southern OR through tonight. Strong heating and dry sub-cloud layers with steep lapse rates below 500mb will support a mixed wet/dry thunderstorm environment capable of occasional dry lightning strikes. Additionally, erratic outflow winds are likely near storms. The increased potential for dry lightning atop receptive fuels, warrants continuation of IsodryT probabilities where fire starts are possible. ...Great Basin... Beneath the upper ridge, very hot surface temperatures are expected over parts of NV and western UT. Southerly surface winds may gust to 15-20 mph through the afternoon, concurrent with widespread RH values below 15%. The presence of breezy low-level winds and the hot/dry conditions will overlap with a progressively drier and receptive fuels across NV. This could support a few hours of elevated fire-weather potential through this evening. ...Please see www.spc.noaa.gov/fire for graphic product... $$