Marine Weather and Tide Forecast for Portola, CA

DISCUSSION

Per latest satellite imagery, our upcoming spring storm has assumed a classic comma shape as it continues to churn in the eastern Pacific. The remainder of today and Monday will be seasonably warm and dry as an attendant cold front lags to the west, but Monday afternoon will feature gusty winds in response to the nearing storm.
There is a high likelihood (60-90% chance) of 30-40 mph S/SW gusts developing in the afternoon across NE California and W Nevada -- especially west of US-95. Areas prone to stronger south winds (e.g.
US-395 in Mono Co/near Honey Lake, I-580 near Washoe Lake, and US-95 near Walker Lake) have low, 10-30% chance of gusts exceeding 60 mph at times.

Winds remain strong/gusty on Tuesday, but for areas west of a maturing surface low in west-central NV and east of a Pacific cold front. Strongest winds are favored across Mono, S.Lyon-Mineral, and E.Churchill counties where there is a 50-80% chance of 45+ mph gusts. Farther north and west, there is greater uncertainty in Tuesday's wind potential, which will largely depend on the timing of the aforementioned cold front. Latest guidance continues to suggest a low to moderate (10-30%) of 45+ mph gusts from Tahoe/Reno northward to the OR border. In any case, be prepared for impacts to recreation and travel each of these day and make plans accordingly.

A band of showers along and ahead of the cold front will arrive to the Sierra early Tuesday morning before spilling into western Nevada in the afternoon. Snow levels at the onset of shower activity will be between 6500 and 7500 feet, lowering to 5500-6500 feet Tuesday night. This will allow snow down to pass level for a majority of the storm's duration with heaviest snowfall expected from late morning through the afternoon Tuesday. Snow will become showery Tuesday night before tapering off by Wednesday evening. Snow totals of 4-10" above 6500 feet around Tahoe and 6-12" above 8000 feet in Mono County -- and up to 18" along the crest -- will likely result in travel disruptions Tuesday and Wednesday in and across the Sierra.

A few lightning strikes and strong outflows also cannot be ruled out as increasing instability will bring a 10-20% of thunderstorms Tuesday and Wednesday afternoons -- mainly along the Sierra and along/east of US-95. We'll begin to warm-up and dry out Thursday into the weekend as the storm departs eastward, but a persistent troughing pattern will maintain lower end shower chances each day through next Saturday.

-Salas

AVIATION

* VFR conditions with gusts of 20-25 kts this afternoon for western Nevada valley and Sierra terminals.

* Late Monday into Tuesday, KSVE will start to see showers moving in early Tuesday morning, and by Tuesday afternoon the majority of terminals will see rain, snow, winds and possible lightning.
-HRICH/Salas

REV Watches/Warnings/Advisories
NV...Lake Wind Advisory from 11 AM to 10 PM PDT Monday NVZ002.

Winter Storm Watch from late Monday night through Wednesday afternoon NVZ002.

Lake Wind Advisory from 1 PM to 10 PM PDT Monday NVZ001-003-004.

CA...Lake Wind Advisory from 11 AM to 10 PM PDT Monday CAZ071>073.

Winter Storm Watch from late Monday night through Wednesday afternoon CAZ072-073.