Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
259 FXUS65 KREV 011028 AFDREV Area Forecast Discussion National Weather Service Reno NV 228 AM PST Mon Dec 1 2025 .KEY MESSAGES... * A dry start to the week precedes a weak system on Wednesday, bringing low precipitation chances, a sharp cooldown, and breezy conditions. * Morning lows will be winter like mid to late week, with temperatures plummeting into the teens and 20s for many valley locations Wednesday and Thursday nights. && .DISCUSSION... Current infrared satellite imagery shows increased high-level cloud cover streaming across the Sierra and western Nevada in the wake of a weather system currently moving across the Intermountain West and Rockies. Gusty easterly winds are also taking place this morning along the ridgetops, with current readings in the 45-50 mph range. These gusts will continue to wane into the morning. Otherwise, quiet conditions will persist through Tuesday as high pressure dominates. This stable pattern breaks down Wednesday morning as a moisture- starved trough slides north-to-south across the Great Basin. Short- to-medium range guidance indicates very limited moisture with this system, showing precipitation probabilities generally holding at 10% or less for most valley locations, and capping near 10-15% for the Sierra crest south of Lake Tahoe. Even if showers materialize, little to no accumulation is expected. The primary impact of this mid-week system will be a sharp flip to wintry temperatures and brisk winds. Northerly to easterly winds will increase, with 700-hPa winds topping out around 30-35 kts across the Sierra. This translates to easterly wind gusts peaking near 50-65 mph along the highest peaks of the Sierra, Wednesday morning. These winds will likely generate choppy conditions on Lake Tahoe through the afternoon Wednesday. A very cold air mass filters in behind the cold front, dropping daytime highs by roughly 15 degrees from Tuesday to Wednesday. This sets the stage for the coldest nights of the week. Widespread lows will dip into the teens and 20s, with the colder Sierra valleys, such as Bridgeport, potentially plummeting near 10-15 degrees by early Thursday morning. For the remainder of the week, high pressure appears to favor a drift to the south over the northeastern Pacific, which may open up the storm track into the Pacific Northwest from Friday into next week. Currently we are only anticipating low-end shower chances near the Oregon border, although medium range guidance begins to diverge with about 20-30% of the ensemble solutions pushing the southern edge of the storm track closer to the Sierra by late next weekend. However, most of the scenarios stay on the drier side. Inversions look to weaken this weekend, with temperatures rebounding into the 50s for lower valley locations. -Johnston && .AVIATION... VFR conditions prevail through the TAF period. With high pressure overhead, light winds and valley inversions will characterize the next 24-36 hours. Some light haze is possible in valleys, but slantwise visibility issues should be minimal. Winds remain light and terrain-driven through Tuesday morning. By Tuesday afternoon and especially Wednesday, a passing trough over the Great Basin will increase FL100 winds from the NE around 35-40 kts Wednesday afternoon. Turbulence will be possible particularly around Tahoe Basin terminals. Precipitation chances with this mid- week system are less than 15%. -Johnston && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$