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KEY MESSAGES

* Strong winds capable of producing damaging gusts will bring widespread travel impacts by air, land and water especially from this evening through early Thursday morning.

* Snow will continue in the Sierra through early Thursday morning, producing hazardous winter driving conditions over the main passes around Tahoe and northeast CA.

* After widespread freezing temperatures early Friday morning, the end of the week into the weekend will see a return of warmer temperatures and lighter winds.

DISCUSSION

Rain and snow has continued to spread across the Tahoe basin and northeast CA, with snow levels generally 7000-8000 feet but dipping below 7000 feet at times. This initial precip area will diminish toward sunset, but quickly resume this evening through late tonight as the main storm and cold front drop in from the north. Snow levels will plunge to valley floors after midnight into early Thursday morning, however the moisture feed will lose much of this punch as the colder air filters in. Winter weather advisories remain in place for the Tahoe basin, where higher elevations received up to a foot of new snow as of this morning, with some of these areas on track to receive at least another foot of snow for the remainder of this storm, with decreasing amounts southward along the Sierra into Mono County. Lighter snow amounts are expected tonight down to lake level around Tahoe and northeast CA foothills west of US-395. Western NV has less than a 20% chance of seeing up to 1" of snow in the foothills near/above 5000 feet as the moisture bands fade out behind the front.

Winds are on the increase with Sierra crest ridge gusts around 80 mph so far. The showers spreading across far western NV have limited the wind increase so far into lower elevations, but by mid-late afternoon the winds will ramp up as these showers diminish. The peak winds will come in advance of the cold front later this evening through the early morning hours, with the greatest potential for damaging gusts in the warning areas between 9 pm and 6 am. For more details on wind speeds and impacts across eastern CA and western NV, see our latest High Wind Warning/Wind Advisory statements.

For Thursday, light snow showers are expected to linger in far northeast CA/northwest NV as the main low pressure area travels across southern Oregon, with spotty accumulations less than 1 inch. Elsewhere, dry and cool conditions prevail (highs mainly in the 40s and 50s) with breezy to locally gusty NW-N winds through the afternoon across the region. For those who got an early start on gardening during the March heat event, be sure to protect sensitive vegetation on Thursday. Widespread freezing temperatures are on tap for Thursday night with lows dropping into the teens and 20s for the Sierra and higher valleys, and 20s-near 30 for lower valleys.

By Friday, high pressure rebuilds off the CA coast, leading to dry conditions with lingering NE-E breezes in lower elevations and increased ridge top gusts near 40 mph over the Sierra crest. Friday will remain on the cool side area due to these winds with highs mainly in the 50s-lower 60s, with lows again dipping near the freezing mark in lower elevations Friday night.

Then for this Easter weekend into early next week, a more substantial warmup will take place with the high pressure ridge moving inland to the Great Basin. Highs will return to the mid 70s for western NV valleys and 60s for Sierra communities Sunday and Monday. This dry air mass will keep cool conditions with light winds for Easter morning activities before the quick warmup during the day.

The next storm to potentially affect the E Sierra/western NV arrives as soon as Tuesday afternoon, continuing through Wednesday. This system is currently looking weaker compared to the current storm, bringing 20-30% chances for showers across northeast CA and the Sierra, and 10-20% chances for western NV, along with temperatures cooling to near early April averages for mid-late week. MJD

AVIATION

* Strong SW winds will bring widespread turbulence/LLWS across all terminals through Thursday morning, with peak surface gusts 40-50+ kt at main terminals and FL100 gusts 80-100 kt. Winds shift to NW with gusts remaining in the 20-30 kt range through Thursday afternoon-early evening before decreasing Thursday night. A short period of gusty east ridge top/FL100 winds to 35 kt continues through Friday, with lighter east winds at the main terminals.

* For the Tahoe area terminals (KTRK/KTVL), SHRA will transition to SHSN tonight as soon as 03Z but the best chances for snow and IFR conditions arrive near/after 08Z as the colder air mass arrives, then diminishing through 12Z with up to 2" of snow accumulating on runways. Farther south at KMMH, the shower chances are lower, with periods of -SHRA/-SHSN mainly between 03Z-09Z and runway snow accumulations of 1" or less.

* For western NV terminals, -SHRA will move through at times into the early evening, and again after 08Z through 12Z, with a 10-20% chance of light snow mixing in but no snow accumulations on paved surfaces.

MJD

AVALANCHE

Rain and snow continues for all avalanche center terrain through Thursday morning.

* Snow levels, rates, and amounts: Large spread in snow levels between avalanche center terrain today. For ESAC, levels rise to 7.5 kft this afternoon before dropping below 6.5 kft after sunset. For BAC, mostly ranging between 5-6 kft, dropping steadily below 5 kft this evening. For SAC and the Tahoe Basin, anywhere from 4.5-5.5 kft today, warming in the afternoon before dropping back off. Rates will be the highest overnight tonight, with up to 1.5"/hr for SAC terrain, otherwise <1"/hr. New snow totals will range from 8-14", locally higher along the Sierra crest of the Tahoe Basin. Otherwise 4-8" for BAC and 2-6" for ESAC.

* SWE and SLRs: SWE will be highest in the Tahoe Basin, with 1-1.25" along the crest. Otherwise, 0.5-1" for the remainder of the area, locally lower as you progress southward. ESAC terrain will see 0.1-0.3" of SWE with 0.2-0.6" for BAC. SLRs will increase as the colder air moves in tonight, from 8-10:1 to 10-12:1.

* Wind gusts: Very strong westerly wind gusts expected, ranging from 100-120 mph, most notably tonight into Thursday.

-Giralte

FIRE WEATHER

Strong to locally damaging downsloping winds are anticipated for this evening into Thursday morning, with High Wind Warnings and Wind Advisories in effect. These winds could limit humidity recoveries for a few hours tonight, especially for west central NV south of US-50 and southern/eastern Mono County, where little or no precipitation has occurred so far with this week's storms. Recent warmth and eroding snowpack exposing areas of vegetation may have allowed some fuels to become receptive to sparks, and high winds could carry sparks into those receptive fuels.

For the western NV Sierra Front, most areas received wetting rainfall since yesterday, while recent and ongoing rain/snow in the Sierra, northeast CA and northwest NV should help reduce fire concerns in these areas. However, in areas that received lighter precipitation, the strong winds tonight could produce an elevated risk of carrying sparks into isolated pockets of drier vegetation. MJD

REV Watches/Warnings/Advisories

NV...Wind Advisory until 11 AM PDT Thursday NVZ001-004-005.

High Wind Warning until 11 AM PDT Thursday NVZ003.

Winter Weather Advisory until 8 AM PDT Thursday NVZ002.

CA...Wind Advisory until 11 AM PDT Thursday CAZ070.

High Wind Warning until 11 AM PDT Thursday CAZ071-073.

Winter Weather Advisory until 8 AM PDT Thursday CAZ072.