Truckee, CA Weather

Key Messages

* A slow moving storm will bring widespread wetting rain with thunderstorms and high elevation snow to the region through Thursday evening.

* Cool, but mainly dry, Friday into early next week. A more active storm pattern may return by the end of October.

Discussion

Showers are beginning to fill the radar returns to our west and southeast and will begin to fill the skies over the Sierra today. By this afternoon, many across western Nevada and the Sierra will be seeing raindrops.

TODAY->THURSDAY: STORMY DAYS

* RAIN & THUNDERSTORMS: An ample moisture plume is arriving today, which is why WPC has a 5% risk of heavy rainfall capable of producing flooding from around Reno/Fallon to the south. Widespread rainfall will begin to arrive this afternoon, with a 50-80% chance of up to 0.25" of precipitation. Bands of showers will arrive to the Sierra, then the Tahoe Basin, working over the mountains into western Nevada, then eventually spilling northward to the north of I-80. Localized heavy rain of up to 1" is possible, which may trigger flooding in poor drainage areas and over burn scars. Through this evening, a range of 0.50-1.25" of precipitation is possible, with the highest amounts along the Sierra and leeside Sierra Foothills. The lower end of the range will be found across Reno/Fernley/Carson City/Smith Valley, while even lower amounts of 0.25-0.50" will fall over Fallon/Yerington/Hawthorne. Additional rounds of precipitation are expected to continue overnight into Thursday. Additional precipitation amounts for Thursday over the Sierra will range 0.5-1.25" with the higher amounts found over the northern Sierra and north to the Oregon border, along the Sierra Crest (excluding the Tahoe Basin), over to the east to Churchill County and then to the south over southern Mineral County and to the White Mountains of Mono County. Thunderstorm chances peak at 25-30% this afternoon, decreasing to 15-20% for Thursday.

* HIGH ELEVATION SNOW: Snow levels for today will remain above 8500 feet until nightfall, when they will begin to descend. By Thursday morning, snow levels will have fallen to around 8000 feet, bringing snow to the highest mountain passes. Snow levels will fall by Thursday morning to around 7500 feet, then further fall below 7000 feet for southern Mono County as the moisture lifts to the north. For the entire storm system, a 70% chance for 2" of snow, and a 25% chance for 4" of snow exists for locations above 8000 ft. There may be totals as high as 10", but those totals will only be found on the highest peaks. Any road accumulations will largely be found on the higher passes (Ebbetts, Tioga, Sonora). US-395 may see some snow flying through the air, but accumulations will be limited to the most elevated stretches and totals will remain below 1" of snow.

* TEMPERATURES AND WINDS: This system is bringing with it some cooler air that will bring our high temperatures down to the 50s and low-60s for lower elevations and mid-40s to low-50s for the Sierra. Brisk W-NW winds will reinforce the cooler air, with gusts 25-35+ mph along and north of US-50 by Thursday night.

* PREPARE, STAY AWARE AHEAD OF TRAVEL: Prepare your home by checking the gutters and drains and clearing them if you have not already done so. Make plans to leave early Thursday morning, since the roads will be wet in many areas, which may lead to slower commute times.

Aviation

* Widespread rain and embedded thunderstorms bring periods of MVFR/IFR conditions and mountain obscurations starting around 21/22z today and lasting through much of Thursday. Thunderstorm chances peak at 25-30% this afternoon, decreasing to 15-20% for Thursday.

* Winds will be light overall through Thursday afternoon, though heavier thundershowers may trigger brief gusts to 30+ kts. A cold frontal passage will bring W-NW gusts of 20-25 kts. Thursday night for KRNO/KTRK. HRICH