559 FXUS65 KREV 090727 AFDREV Area Forecast Discussion National Weather Service Reno NV 1227 AM PDT Wed Jul 9 2025 .KEY MESSAGES... * Gusty afternoon winds and dry conditions will bring areas of elevated to locally critical fire weather today. Brief chance of isolated PM thunderstorms near the Oregon border today. * Warming trend resumes Thursday, culminating in widespread heat impacts over the weekend. * Triple digit highs likely for lower valleys from Saturday into early next week, with moderate to locally major HeatRisk. && .DISCUSSION... A compact mid-level low tracking across southern Oregon today will enhance surface pressure gradients across northeast California and northwest Nevada. This will result in increased afternoon and evening winds along the Sierra Front and western Basin and Range, with gusts reaching 30-35 mph. When combined with minimum relative humidity values falling below 12%, expect areas of elevated to locally critical fire weather conditions through early evening. There remains a low (5-10%) chance of isolated, high-based convection near the Oregon border this afternoon, mainly across Surprise Valley and far northern Washoe County. Weak instability and subtle ascent ahead of the low may be just enough to spark a few showers or storms. However, convection-allowing models and ensemble lightning density guidance continue to support a limited and short- lived threat. Winds will decrease Thursday as the low shifts east and a weak shortwave ridge builds into the Great Basin. A warming trend resumes with daily temperature increases into the weekend. By Friday, lower valleys are expected to climb into the upper 90s, with Sierra valleys warming into the mid 80s. The primary concern heading into the weekend and early next week will be prolonged and intensifying heat. Both ECMWF and GFS ensemble guidance show 500 mb heights rising toward 595 dam across the Desert Southwest, supporting widespread highs between 100-105 degrees across western Nevada from Saturday through Monday. This will result in moderate to locally major HeatRisk, particularly in lower valleys and urban areas. Overnight lows will also trend warmer, reducing overnight recovery and compounding heat stress potential. Looking ahead, the pattern remains dry with ensemble precipitation probabilities near zero. There are weak signals for monsoonal moisture to clip far southern Nevada or the Sierra Crest by mid-next week, but forecast confidence remains low at this time. -Johnston && .AVIATION... VFR conditions prevail through the period. Low thunderstorm risk (5- 10%) near Fort Bidwell (A28) late today. Triple digit heat returns this weekend, raising potential density altitude issues for aircraft. KRNO/KCXP/KMEV: Breezy west winds 18-25 kt with gusts 30-35 kt this afternoon may lead to light LLWS in the evening. KTRK/KTVL/KMMH: Gusts 20-25 kt this afternoon. -Johnston && .FIRE WEATHER... Afternoon gusts 25-35 mph and RH dropping below 12% will bring a few hours of locally critical fire weather today across the Sierra Front and western NV. The strongest winds will occur from mid-afternoon to early evening, with isolated longer durations in wind-prone zones. A dry cold front tonight brings a wind shift to NW-N, with diminishing speeds. Thursday will be less windy, but poor overnight recoveries and hot/dry conditions return this weekend, especially at mid-slopes and ridgelines. Nighttime RH may dip to 25-30% in western NV valleys by Saturday night. -Johnston && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$