Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
907 FXUS65 KREV 210714 AFDREV Area Forecast Discussion National Weather Service Reno NV 1214 AM PDT Mon Sep 21 2026 .KEY MESSAGES... * Precipitation potential returns today, especially for the Sierra and south of US-50. * Warming up and generally dry conditions are expected mid-week with temperatures 5 to 10 degrees above average. * Increased winds and cooler temperatures return towards the end of the work week. && .DISCUSSION... Upper level low observed in satellite imagery just off the West Coast is expected to move towards the Great Basin today. This system brings a 20-40% chance for showers mainly in areas south of US-50 and the Sierra, especially over Mono and Mineral counties this afternoon per the HREF and RRFS. The ECMWF, GFS and NAM show marginal instability with MUCAPEs up to 500 J/kg near the Tahoe Basin along the Sierra crest. This could lead to a few isolated thunderstorms this afternoon, but thunderstorm chances remain at or below 10%. Very few ensemble members indicate the possibility for high elevation mountain snow mainly above 10500 ft. If there is any snow, it could be a trace up to 0.2 inches based on ensemble data for areas near Mammoth Lakes. Precipitation chances continue through Tuesday, but up to 15% mainly over Lassen and northern Washoe as the upper low continues its northeastward track. For mid-week, temperatures start to increase as weak ridging develops over the West Coast. Temps will increase to 5 to 10 degrees above average with afternoon highs in the mid to upper 90s for western NV, northeast CA and southern Mono valleys, and mid to upper 70s for Sierra communities. Towards the end of the work week, an upper level trough moves towards the PacNW. This will tighten the surface pressure gradient resulting in slightly stronger winds compared to earlier in the week. Gusts are potentially going to be in the 25-40 mph range with a 20-40% chance of gusts greater than 35 mph for wind prone areas along the Sierra Front both on Thursday and Friday. Temperatures are also expected to start cooling off again as this trough brings another generally dry cold front by around Friday. Precipitation chances are very uncertain at the moment, maybe late week into the weekend, but chances are currently below 5%. -HC && .AVIATION... Mostly VFR conditions are expected through the next 24 hrs. Exceptions near SHRA/-TSRA where CIGs and VIS could drop to MVFR, and IFR with the strongest activity near KMMH and KHTH between 18Z-03Z today. There is a 20-40% of showers for the Sierra and areas south of US-50. Mountain obscurations are also possible through tomorrow. Winds will be generally light and VRB overnight and in the morning, then become from the west and southwest with gusts up to 20kts for KMMH/KTVL/KTRK, and from the east and southeast for western NV sites. -HC && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$