Area Forecast Discussion

KEY MESSAGES

* Periods of mountain snow will create travel disruptions in and across the Sierra through the weekend.

* Rain and a chance of thunderstorms expected this weekend, with light snow falling near valley floors early Sunday morning.

* Warmer and drier weather prevails early next week, with another Pacific storm possible around midweek.

DISCUSSION

A Pacific storm will continue to deliver periods of rain and mountain snow between today and early Sunday morning. Spotty, light showers today will become more widespread on Saturday ahead of an impinging cold front, increasing chances of rain and mountain snow to 70% or higher from midday Saturday to early Sunday morning. A few lightning strikes will also be possible (10-20%) Saturday afternoon as daytime heating couples with deep-layer moisture and strong synoptic lift.

Heaviest Sierra snow is expected above 8000 feet Saturday afternoon into the overnight hours when snowfall rates approach 1"/hour. Highest peaks may see snowfall rates exceed 1"/hour at times. By Sunday afternoon, there is high probability (60%+) of 6" or more of fresh snow along the Sierra (above 8000 ft) with as much as 12-15" along highest peaks (30-50% chance). Pockets of greater snowfall totals may accompany heavier showers or thunderstorms that develop Saturday afternoon. Meanwhile, rain (or a rain-snow mix) will switch to all snow Saturday night for lower Sierra passes and roadways above 6000 feet where there is 30-40% chance of 1"+ of snowfall. As such, be prepared for slick roads and reduced visibilities when traveling in and across the Sierra this weekend.

Snow levels lower further early Sunday morning as the cold front progresses, falling as low as 4500-5000 ft in the Sierra and Sierra Front. This will allow for light snow down to valley floors -- including the Greater Reno-Carson-Minden area -- around or just before sunrise, although no accumulation is expected. However, those in Virgina City may wake up to a dusting of snow Sunday morning.

A brief warming and drying trend is expected early next week, then ensembles hint at another Pacific storm arriving around the middle of next week. -Salas

AVIATION

Isolated showers and low clouds will produce brief periods of MVFR conditions and mountain obscuration into Saturday morning at Sierra terminals. A few showers may spill into W Nevada terminals, although low clouds and mountain obscuration will be the primary issue.

Showers increase in coverage and likelihood Saturday afternoon, resulting in more prolonged periods of MVFR conditions for all terminals. Moreover, there is a low 10-20% chance of thunderstorms Saturday afternoon, which may briefly reduce CIGS/VIS to IFR conditions if storms drift over airfields.

-Salas

REV Watches/Warnings/Advisories

NV...Winter Weather Advisory from 8 AM Saturday to 7 AM PDT Sunday NVZ002.

CA...Winter Weather Advisory from 8 AM Saturday to 7 AM PDT Sunday CAZ072-073.