Marine Weather and Tide Forecast for Truckee, CA

DISCUSSION

Winds across northwest NV are shifting to the north and northeast due to a shallow back-door cold front passage. As this front continues pushing south and east, we'll see a colder and very dry air mass spread across the region today. Winds won't be particularly gusty, but just enough to enhance the chill of high temperatures dropping about 6-12 degrees compared to Sunday.
Sierra ridge tops will feel more of the brisk winds with NE-E gusts near 50 mph today through this evening.

Valley inversions with some urban haze will return for Tuesday morning as shortwave ridging sets up overhead. The drier air mass should help prevent a repeat of last week's prolonged freezing fog event around Honey Lake/Susanville, although a few patches of fog or stratus can't be fully ruled out in close proximity to the lake basin. Higher elevations will begin to see a warming trend Tuesday afternoon, while valleys remain chilly due to the inversions.

By midweek, the first in a series of weather systems is projected to reach the Sierra, with increasing SW flow pushing the ridge axis to the eastern Great Basin. This will allow for some valley locations including the main urban areas to warm up to above 50 degrees again, although valleys from Pyramid Lake and Honey Lake northward may have to wait one more day until Thursday to see any appreciable warming.

Precipitation chances are trending a bit higher for Wednesday night-Thursday as some of the medium range guidance swings an upper low with a quick tap of Pacific moisture, although totals still remain on the light side. Unlike previous days which showed only scant moisture with this system, the higher Sierra elevations and passes could see an "appetizer" snow up to a few inches as this system sweeps through.

After a short break in between systems on Friday, we're still keeping an eye on the potential for a stronger storm Friday night into next weekend, as ensembles tease a more active weather pattern. After trending drier yesterday, the most recent blended guidance has edged the precip potential upward again, due to a hint of atmospheric river moisture being drawn in and directed toward the Sierra by Saturday's storm. While this latest storm signal is encouraging to get seasonal precip/snowpack back on track, we'll keep optimism cautious for now. Chances stand at about 40-50% for liquid moisture projections between 1.0 and 1.5" along the crest, yielding at least 1 foot of snow for higher Sierra elevations/passes, and at least 4" down to lake level in the Tahoe basin and northeast CA west of US-395. For western NV, a short period of rain or a rain/snow mix may accompany the storm late Friday night into Saturday, with projected snow levels currently around 5000-5500 feet. Gusty winds will also be in the mix for the start of next weekend, especially for the Sierra ridges.

Overall, the primary storm track is still likely to favor the Pacific Northwest for heaviest precip amounts, especially with subsequent systems on the horizon next week. MJD

AVIATION

Widespread VFR conditions will prevail through midweek. NE-E winds will edge upward today for the main western NV terminals, although gusts should remain below 20 kt. Increasing E/NE FL100 winds with gusts to 45 kt may bring turbulence issues along and west of the Sierra crest through this evening.

First shot of light precip mainly for the Sierra could arrive by late Wednesday night/early Thursday, with a better chance for more notable aviation impacts due to winds arriving by Friday night into Saturday, along with snow chances for the Sierra terminals, and rain showers for western NV terminals. MJD

REV Watches/Warnings/Advisories
NV...None.
CA...None.