textproduct: Reno

KEY MESSAGES

* A slight 10-20% chance for additional thunderstorms today and on Sunday.

* Colder with additional rain and mountain snow this weekend. Highest snowfall rates late tonight with Sierra Pass travel difficulties.

* Gusty winds continue today and on Sunday.

DISCUSSION

* For the remainder of tonight, light precipitation will continue in northern Mono County northward into eastern Plumas County. From current camera networks, snow levels will remain as low as 6,000 ft into the early morning. Accumulations through daybreak between will be around 1-2 inches. Ongoing light rain showers will additionally continue in portions of western NV into morning, with light accumulations through sunrise. * A deep, cold trough currently (as of 1AM PDT) at 42N/134W will move into the region today. Per latest HREF and Hi-Resoultion guidance, light showers will persist for most of the day from Alpine County northward into Lassen County. Precipitation will then spread south into Mono County by around 5-8 PM PDT. Prior to the arrival of the main trough, southerly flow aloft will increase snow levels to around 7,000 ft through the afternoon. Afterward, snow levels drop to around 5,000-6,500 ft by midnight and down to 4,000-5,500 ft by Sunday morning as the low pressure moves overhead.

* As for winds today, expect southerly winds across the region. Ridgetop wind gusts will be upwards of 80-100 mph, with gusts of 40-50 mph in wind prone areas. Gusts of 25-35 mph are expected elsewhere, with the strongest gusts in the afternoon to around midnight.

* Guidance still shows a period of heavier snowfall rates reaching 2-3"/hour from around 10-11 PM tonight through 3-4 AM Sunday morning in the Sierra. Anticipate slow and difficult travel over Sierra passes as roads will rapidly become snow covered. For the latest forecast snow totals with this storm, please see the current Winter Storm Warnings.

* There is still enough instability (CAPES ~100 J/kg) to not rule out a 20% chance for thunderstorms this afternoon in the eastern Sierra, and a 10% chance in western NV. Storm coverage will be much less compared to Friday afternoon. Main limiting factor may be too much cloud cover.

* Snow levels will be low enough for snow in foothill locations early Sunday morning around western Nevada. Current guidance shows a 30-50% for up to 1" of accumulation above 5000 feet, including Virginia City. We also can not rule a rain/snow mix on the valley floors in western NV on Sunday morning. However, given the recent warm conditions, there is only a 2% chance for anything to accumulate. * For next week, a few showers will linger in the eastern Sierra through Monday morning, with much cooler below average temperatures. Near freezing temperatures are expected in the warmer valleys, with hard freezes (< 28F) in other valleys Monday and Tuesday mornings.

* For next week, drier and warmer conditions are expected on Tuesday. The next system will move through on Wednesday, giving us another chance of precipitation and high winds. -McKellar

AVIATION

* FL100 S-SW winds sustained around 45 kts today. This will translate to winds gusting 20-30 kts at terminal sites in absence of any thunderstorm outflow influences.

* Showers persist in the eastern Sierra today, primarily from northern Mono County into eastern Plumas County. Likely to see increasing snow rates in the Sierra tonight, with several inches of accumulation by Sunday at all Sierra terminals. Western NV terminals will primarily be rain, but could see some snow mix with rain late Saturday night into early Sunday morning. Chances for any accumulation are less than 5% for KRNO, and 10% for KCXP/KMEV. -McKellar

AVALANCHE

Moderate to heavy snow will impact all avalanche center terrain through Monday morning.

* Snow totals, levels, and rates: Up to 2 ft of snow along the highest peaks for SAC and BAC terrain, locally lower (up to 18") for ESAC terrain. Snow levels will hover between 6000-6500 ft this morning before rising to 6750-7500 ft this afternoon and evening. Snow levels quickly plummet below 5000 ft after midnight, rising slightly to 5000-5500 ft (highest near Mammoth) Sunday afternoon. Snowfall rates will be the most intense during the period of lowest snow levels (12am-5am Sunday) with rates of 2-3"/hr. Otherwise, rates of 1"/hr or less expected.

* SLRs and SWE: Snowfall ratios will be lowest around the Tahoe Basin, ranging from 7-10:1 with locally higher for BAC/ESAC terrain (9-12:1). SLRs will increase as the colder air moves in late Saturday night into Sunday morning to 11-13:1, locally up to 14:1 at times. 50th percentile SWE has up to 2.25" along the highest peaks in SAC terrain, otherwise 1-1.5" for BAC and 0.75- 1.25" for ESAC.

* Thunder potential and wind gusts: Best chances for thunder this afternoon and again Sunday afternoon, though chances are less than 20%. Predominantly southerly ridgetop gusts of 80-100 mph.

-Giralte

REV Watches/Warnings/Advisories

NV...Winter Storm Warning from 2 PM Saturday to 11 PM PDT Sunday NVZ002.

CA...Winter Weather Advisory from 2 PM Saturday to 11 PM PDT Sunday CAZ071.

Winter Storm Warning from 2 PM Saturday to 11 PM PDT Sunday CAZ072-073.