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KEY MESSAGES

* Snow shower bands will continue to produce winter travel impacts for the eastern Sierra through much of tonight.

* Chilly conditions with breezy winds continue through Monday, with isolated showers Monday afternoon mainly for Mono and Mineral counties.

* After a break between storms Tuesday, another cold front brings a round of gusty winds, valley rain and mountain snow late Wednesday through Thursday.

DISCUSSION

Last night's snow came in quick and heavy, producing 10-18" along the Sierra crest and west of Highway 89, with 4-8" down to lake level in the Tahoe basin, along US-395 in Mono County and central Plumas County around Lake Davis as of this morning. Sierra travel conditions currently range from wet roads during lighter showers, to snow covered roads and slow going with delays, especially along I-80 where heavier bands have persisted. These ongoing snow bands enhanced by thunderstorms in central CA will add several more inches in the warning areas especially around Tahoe, and a few sites near and above pass level could add at least a foot of new snow to this morning's totals. For the advisory area of northeast CA, spotty snowfall of 1-3 additional inches is anticipated for communities and roads west of US-395. Isolated lightning risk remains with a 10-20% chance near the Sierra crest northward to central Plumas/western Lassen counties until around sunset, with most showers winding down through the evening. However, a few showers could linger overnight around the Tahoe basin as the weaker upper low center tracks overhead.

For lower elevations, short-duration showers will continue through the rest of this afternoon, with snow levels hovering around 5000 feet. A few stronger showers could produce brief snow pellets, with about a 10% chance for lightning. Temperatures will remain above freezing through the evening across western NV and breezy SW-W winds (gusts 25-35 mph) should allow most roads to dry before colder temperatures arrive. However, if any moisture remains on the roads overnight, a few slick patches could develop in the pre-dawn hours as lows dip to near freezing.

For Monday, the remnant low drifts southeast across Mineral-Mono counties, with a bit of instability allowing isolated afternoon showers to form in these areas, with a 10-15% chance for lightning west of US-95. Minimal snow accumulation (2" or less) is expected near the crest in Mono County, while snow levels near 6000 feet will keep light precip as rain for lower elevations. Elsewhere, mainly dry but continued cool conditions will prevail with northwest-north breezes, except for a few light showers near the OR border from a separate weak weather system brushing across the Pacific Northwest.

We'll have a short break between storms on Tuesday with highs rebounding to near mid-April averages (lower-mid 60s for lower elevations, lower 50s near the Sierra) and mostly clear skies.

Then for Wednesday-Thursday, another fast moving storm drops in from the Pacific Northwest, bringing a period of gusty winds (current projections 30-40 mph with locally stronger gusts from US-50 northward) followed by a cold front passage. This front currently appears to contain decent forcing, holding together a precip band through Wednesday night/Thursday morning as it pushes south across the region. While the short duration will limit precip totals, it could produce light accumulating snow around Tahoe and a rain-snow mix for foothills of far western NV, setting up a tricky Thursday AM commute given this storm's current timing.

Behind this front will be a chilly and brisk finish to the week, followed by a warmer start to the weekend. However, the progressive synoptic pattern indicates another Pacific storm approaching by the late portion of next weekend. MJD

AVIATION

* FL100 SW wind gusts to 50-60 kt through late tonight, resulting in continued areas of turbulence and periods of LLWS. Surface SW-W wind gusts 20-30 kt at main terminals, diminishing after 01-03Z. Lighter mainly NW winds Monday with afternoon gusts near 15 kt.

* Sierra Terminals: Continued IFR/LIFR for KTRK/KTVL and returning after 22Z at KMMH, with additional 1-4" snow accumulations on runways before most snow winds down between 01-03Z. Spotty MVFR/IFR lingers overnight into Monday AM with either -SHSN or low CIGS. Mainly VFR conditions remainder of Monday except brief MVFR/IFR periods with -SHSN after 20Z at KMMH.

* Western NV Terminals: Isolated rain/snow/pellet showers with brief MVFR periods thru 01-02Z. Lingering lower clouds with terrain obscurations at times overnight. VFR conditions prevail Monday. MJD

AVALANCHE

Snow shower bands will linger through this evening across all avalanche center terrain.

* Snow totals and rates: Additional 2-6" through this evening, with locally up to 9" in heavier bands favoring SAC terrain. Snowfall rates generally up to 0.5"/hour, except for short bursts of 1-2"/hour rates in heavier convective-type snow bands.

* SLRs and SWE: Snow-liquid ratios around 15:1, less dense than last night's snow due to colder air mass and convective nature. Additional SWE (50th percentile) 0.20-0.50" through this evening.

* Thunder potential and winds: 10-20% chance of thunder along the crest through early this evening. Southwest ridge top wind gusts 40-60 mph.

MJD

REV Watches/Warnings/Advisories

NV...Winter Storm Warning until 11 PM PDT this evening NVZ002.

CA...Winter Weather Advisory until 11 PM PDT this evening CAZ071.

Winter Storm Warning until 11 PM PDT this evening CAZ072-073.