


Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
932 FXUS65 KREV 191918 AFDREV Area Forecast Discussion National Weather Service Reno NV 1218 PM PDT Tue Aug 19 2025 .KEY MESSAGES... * Warm and dry conditions remain through Thursday. * Hot temperatures bring a risk for widespread heat impacts from Friday into Saturday. * Monsoonal moisture brings back showers and thunderstorms to the forecast through the weekend. && .DISCUSSION... Until Thursday, expect gradual heating to build to its zenith on Friday, when 100+ degree temperatures will visit western Nevada valleys. Sierra valleys will entertain upper 80s to lower 90s Thursday through Saturday. Overnight lows will remain elevated due to clouds developing and dewpoints increasing associated with the incoming moisture. The heating may be intense and persistent enough to bring heat advisories late week. As the moisture gradient draws nearer for Friday, showers and storms take over the narrative into the weekend. By Friday, showers and storms will populate the skies as far north as the Tahoe Basin and along I-80 toward Fernley, where chances of 10-15% exist. Farther south, near Mammoth Lakes, chances are the highest at 25-30% for Friday. As we head into the weekend, the moisture increase will bring about increasing chances for showers and t-storms. By Saturday, the threat migrates northward all the way into Oregon and Idaho. This will increase chances over the Tahoe Basin to 35-40% and Mammoth Lakes to 60-65%. Sunday we will see much of the same, with a increase in storm chances across much of the region. Hazards to stay aware of will be periods of heavy rain, small hail, frequent lightning and strong gusty outflow winds. The last two, frequent lightning and outflow winds, will increase fire weather concerns, especially Friday as the moisture source starts toward the region. Storms may be capable of tossing lightning, creating new fire starts in receptive and dry fuels, and winds could carry the flames or sparks. See the Fire Weather section below for details. Taking a glance into next week, showers and storms will hang around, but temperatures will be on the decline as a trough approaches from the northwest and modifies the ridging pattern. HRICH && .AVIATION... * VFR conditions prevail through midweek for all area terminals. The main impact for aviators will be afternoon gusts of 15-25 kts between the hours of 20-03z today. As we head into mid-late week, increased daytime heating will likely induce density altitude concerns across western Nevada terminals. HRICH && .FIRE WEATHER... * Today, low relative humidities and gusty afternoon winds will be the effective drivers behind isolated elevated fire weather conditions across the region. Our main concern today is for holdover fires that may be impacted by afternoon gusts, mainly during the hours of 1 to 7 PM. Gusts will be lighter starting Wednesday, ahead of the increasing moisture settling in for the weekend. * Friday, as moisture surges northward along the edge of the ridge pattern, a favorable setup for thunderstorms emerges. As the shower potential builds in, a chance for lightning to strike outside of wet storm cores increases. As the dewpoints increase into the weekend, this threat will become negligible since the main storm threat will become heavy rain. HRICH && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$