Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
928 FXUS65 KREV 280918 AFDREV Area Forecast Discussion National Weather Service Reno NV 218 AM PDT Sun Sep 28 2025 .KEY MESSAGES... * Scattered showers and thunderstorms are expected this afternoon with localized flash flooding possible. * Strong low pressure will bring additional showers and storms, gusty winds, and cooler temperatures Monday through midweek. * Unsettled weather may continue Friday into next weekend, but confidence is low. && .DISCUSSION... Shower and thunderstorm activity trends upward this afternoon as large scale ascent overspreads a moist, weakly unstable airmass residing across the region. Favored areas for initial showers and t-storms include the Mono-S.Lyon-Mineral County vicinity northward into the Pine Nut Mountains and Virginia Range where odds are greatest (20-40%). Coverage of showers and t-storms will expand/shift eastward into the W NV Basin and Range through the afternoon before tapering off after sunset. Farther west, most areas will remain dry today, but the environment near the Tahoe Basin into the Greater Reno-Carson-Minden area appears to be at least marginally supportive of a stray shower or thunderstorm during the afternoon, especially if outflows can propagate westward. Slower storm motions and abundant moisture will support isolated flash flooding today, mainly across Mono, S. Lyon, and Mineral counties where coverage/odds are greatest. Thunderstorms will also be capable of gusty outflow winds, small hail, and frequent lightning. Additional showers and thunderstorms are anticipated Monday afternoon with a few t-storms becoming strong to possibly severe given the increasing deep-layer shear. Coverage and favored areas has been difficult to determine due to uncertainty in the placement of an upper trough and if instability is too weak to overcome wind shear. The W NV Basin and Range (east of Alt-95) has consistently been the preferred area for thunderstorm development in CAMs, but latest guidance hints at the possibility of storms farther west across the Sierra and far western Nevada ahead of a weak cold front. In any case, any thunderstorm that is able to mature and organize will likely be capable of marginally severe wind gusts and/or hail. Additional showers (including light snow showers over highest Sierra peaks) or a stray t-storm will be possible Monday night from Tahoe into NE California where the cold front stalls. Winds will also be gusty Monday afternoon outside of thunderstorm influence, so be prepared for choppy waters on area lakes and impacts to travel. A second cold front will approach the region on Tuesday, maintaining shower chances, gusty winds, and cool temperatures through midweek. Unsettled weather may even linger Friday into the weekend as low pressure hangs around, but confidence is low on exact details. -Salas && .AVIATION... Scattered showers and thunderstorms will be the main concern today, especially at KMMH-KHTH where odds (20-30%) are greatest. Thunderstorms may develop as early as 18Z, but the most likely time frame for any storm impacts at these terminals. will be between 20Z and 02Z this afternoon. Thunderstorms will be capable of heavy downpours and brief MVFR conditions, gusty and erratic outflow winds, small hail, and frequent lightning. Elsewhere, thunderstorms will likely stay east of KTRK-KTVL and KRNO-KCXP-KMEV, but outflow winds could initiate thunderstorms farther west near KRNO and KCXP-KMEV between 22Z and 02Z. The more likely outcome for these terminals will be cumulus build-ups with perhaps a stray shower or two in the afternoon. Strong low pressure in the eastern Pacific will strengthen S/SW FL100 winds to 25-35 kts from Tahoe northward after 06Z tonight. This coupled with weakening surface winds may present LLWS and mountain wave turbulence issues tonight, becoming more pronounced/widespread on Monday as winds aloft and at the surface increase. -Salas && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$