Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
769 FXUS65 KREV 182004 AFDREV Area Forecast Discussion National Weather Service Reno NV 104 PM PDT Fri Jul 18 2025 .KEY MESSAGES... * Isolated showers and thunderstorms possible today and tomorrow afternoon south of US-50, especially in Mono and Mineral counties. * Seasonably hot and dry into the weekend with typical afternoon breezes. Hazy skies along the Oregon border from wildfire smoke. * Stronger winds are trending more likely early next week, which may impact travel and recreation, and elevate fire concerns. && .DISCUSSION... The weather button is stuck on loop for today and Saturday with routine afternoon thunderstorms for Mono and Mineral counties, typical summertime temperatures and afternoon breezes. Westerly flow continues transport smoke and haze from the fires in California into portions of the areas. The active Green and Butler wildfires continue to burn resulting in detrimental air quality for portions of Lassen county, northern Washoe County and Surprise Valley. Elsewhere in the Sierra and western Nevada, we have seen bouts of moderate air quality, but for the most part hazy skies have been the impact. We`re looking another couple of days of a 15-20% chance of thunderstorms over Mono and Mineral counties. There is also a small chance (15%) of storms popping up for far northern Washoe county. Heating and sufficient moisture will continue to promote pop up thunderstorms. Main impacts from storm today will be gusty outflow winds, especially with DCAPEs riding around 1000-1300 J/kg by the afternoon. Areas south of Highway 50 have the best shot at storms today, especially with precipitable water values 0.3" and below in the Interstate 80 vicinity. The 0.4-0.5" line runs from Mono Lake across to Walker Lake as of midday today. By Sunday into Monday, a significantly drier air mass pushes into the Sierra and western Nevada as west to southwest flow increases across the region with a trough`s arrival. For context, precipitable water values are running around 0.3-0.5", but the forecast sounding for Reno is showing values dropping to near 0.1" by Sunday afternoon. The much drier conditions combined with the increase in the winds raise concerns for critical fire conditions. See the Fire Weather section for more. Temperatures will cool with the trough`s entrance, but the winds will ramp up to be stronger than our typical day-to-day winds. Widespread wind gusts will be in the 30 to 40 mph range, with even stronger winds in the wind prone areas and the Sierra. -Edan && .AVIATION... Seasonably hot temperatures with widespread VFR conditions and typical afternoon breezes. Main exception is for KMMH where there is a 15-20% chance for thunderstorms between 20Z-04Z this afternoon. Afternoon westerly winds with gusts up to 25 kt are expected today and tomorrow across all terminals. Lingering heat will maintain density altitude concerns for western Nevada terminals. A stronger bout of winds is projected to arrive late Sunday into Tuesday, where afternoon westerly wind gusts may exceed 30kts. -Edan && .FIRE WEATHER... Transient low pressure will encourage winds to become a bit stronger than typical afternoon zephyr breezes Sunday and Monday afternoons as it traverses the Pacific Northwest. Winds appear to be marginal on Sunday with SW/W gusts around 30 mph, but likely surpass critical thresholds Monday afternoon as gusts increase to 35-40 mph. RH reductions to 7-15% are expected each day from the Sierra Front into the W NV Basin and Range. A brief, 1-3 hour period of locally critical fire weather conditions is probable Sunday afternoon from eastern Lassen County into the northern Sierra Front. Duration of critical conditions extends to 2- 4 hours Monday afternoon and expands eastward into the W NV Basin and Range. Overnight recoveries will be poor across western Nevada each night through Monday AM as RH struggles to exceed 35%, but improves Monday night. Winds weaken after Monday with more typical afternoon breezes next week, although thunderstorm chances increase around the middle of next week. -Salas && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$