Marine Weather and Tide Forecast for Portola, CA

DISCUSSION

A couple of cold fronts will drop through the region over the next week resulting in increased breezes, cooler temperatures, and very low chances for precipitation.

Temperatures: We will see a slight cool down in response to a weak cold front passing through on Sunday. Temperatures will dip to seasonal averages on Sunday, then warm up a bit for Monday-Tuesday.
Another cold front will drop in on Wednesday with a more noticeable drop in temperatures, but even then we will only be slightly below typical temperatures for early December. Daytime highs in Nevada valleys will be in the mid to upper 40s while the Sierra valleys will be in the mid to upper 30s.

Winds: With the weak front on Sunday, plan on increased ridgetop winds that may impact aviation and recreation in the backcountry areas. North to northwest breezes pick up late this afternoon into Sunday with gusts 40 to 60 mph. Peak gusts will be Saturday night overnight into Sunday morning. Breezes will lessen Sunday evening into Monday and also shift out of the northeast. Plan on another bump up in the ridge winds by late Tuesday into Wednesday with similar concerns and impacts to aviation and backcountry recreation.

Precipitation: The dry streak continues through the end of November with little to no potential for significant wetting rains or snow.
We're looking at a meager 10-20% chance of a stray snow shower or flurries near the OR border and northern/eastern Pershing County Sunday morning. There may be better potential with the cold front for Wednesday, but there are discrepancies in the storm track.
Blended guidance is holding at a 10-20% chance of snowfall exceeding 1" in the eastern Sierra/Tahoe basin for now. Cluster analysis highlights a strong ridge anomaly extending over the Eastern Pacific and the Pac NW, which may limit the westward extent of the cold front in question. About half of the solutions show the front tracking in favor of snow showers for portions of western NV, but the other half of the solutions keep it well east into the Great Basin. For the most part, there is no sign of a meaningful precipitation event with the strong ridge blocking the Pacific storm door.

-Edan

AVIATION

VFR conditions along with light breezes will persist through much of today. There is less than a 20% chance of fog formation for KTRK as mid to high level clouds stream across the Sierra and western Nevada ahead of an incoming shortwave for tonight into Sunday.

Precipitation chances appear rather dire for the next several days, but a couple of upper level shortwaves will initiate some stronger winds aloft this afternoon into Sunday and again for Tuesday into Wednesday. Plan on increased westerly FL100/ridge top winds with gusts 35-50 kt around Sunday 03z through 21z with a shift to the NNE Mon 09z through 18z. The increased winds may result in periods of mountain wave turbulence east of the Sierra this afternoon and overnight, and then transition west of the Sierra late Sunday into Monday with the wind shift.

-Edan


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