Marine Weather Net

Point Pinos to Point Piedras Blancas out 10 NM Marine Forecast


TONIGHT

NW
WINDS
15 - 25
KNOTS

INDEPENDENCE DAY

NW
WINDS
10 - 15
KNOTS

MON NIGHT

NW
WINDS
10 - 15
KNOTS

TUE

W
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
PZZ565 Forecast Issued: 210 PM PDT Sun Jul 03 2022

SMALL CRAFT ADVISORY IN EFFECT THROUGH LATE TONIGHT
Tonight...Nw Winds 15 To 25 Kt With Gusts Up To 35 Kt. Wind Waves 5 To 6 Ft. Swell S Around 2 Ft At 13 Seconds.
Independence Day...Nw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Wind Waves 3 To 4 Ft. Swell S Around 2 Ft At 13 Seconds.
Mon Night...Nw Winds 10 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 2 To 3 Ft At 8 Seconds And S Up To 2 Ft At 13 Seconds.
Tue...W Winds 5 To 10 Kt. Wind Waves 1 Ft. W Swell 2 To 3 Ft At 9 Seconds.
Tue Night...Nw Winds 10 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 3 To 4 Ft At 10 Seconds.
Wed...Nw Winds 10 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 3 To 4 Ft At 10 Seconds.
Wed Night...Nw Winds 10 To 20 Kt With Gusts Up To 25 Kt. Wind Waves 3 To 4 Ft. Nw Swell 2 To 3 Ft At 10 Seconds.
Thu...Nw Winds 15 To 25 Kt With Gusts Up To 30 Kt. Wind Waves 6 To 7 Ft. Nw Swell 2 To 3 Ft.
Fri...Nw Winds 15 To 25 Kt With Gusts Up To 30 Kt. Wind Waves 6 To 7 Ft.
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Area Forecast Discussion
National Weather Service San Francisco Bay Area
255pm PDT Sunday July 3 2022

Synopsis
Well below normal temperatures through midweek. Marine stratus will continue to impact the area from the evenings through the mornings. A weak cold front passes through on Monday providing the chance for light showers or drizzle, best chances in North Bay. Warming temperatures follow the holiday with hot temperatures possible inland next weekend.

As of 03:00pm PDT Sunday... An unseasonably potent 563dm low pressure trough is currently aligned along the Pacific coastline from Vancouver Island southward through the CAL/MEX border. This broad trough is responsible for the most recent cooling trend, breezy onshore flow, deepening of the marine layer, and even the coastal and upslope focused drizzlefest early Saturday morning. Within this broad parent trough, smaller scale vorticity disturbances are rounding the trough and sweeping through our area bring intermittent periods of unstable weather. Most recently, this was observed on this mornings satellite imagery as it depicted localized fields of stratocumulus developing near and along the marine layer which led to quite a cloudy start to the day. As of this afternoon, our region is currently in between disturbances and skies are beginning to clear. The parting of the skies is only temporary, however, as the next disturbance is set to arrive overnight and bring unsettled conditions to the area throughout the entirety of Independence Day.

This storm system is comparable to a weaker spring storm system but is more interesting in that it is occurring concurrently with the summer time marine stratus/inversion. While typical storm systems result in an initial deepening of the marine layer, which could be used as a near surface reservoir of moisture, they typically advect in cooler than sea surface temperature air aloft, which rapidly destabilizes the atmosphere and mixes out the marine inversion. This system is interesting because it is not quite cold enough aloft to completely mix out the marine inversion, allowing the the two to coexist, and act as a near- surface reservoir of moisture. The slightest forcing or lifting mechanism is then able to act upon the moisture and result in heavy drizzle or light rain, particularly with respect to orographic lift on coastal upslope. This occurred yesterday morning, and the passing of a weak frontal boundary tomorrow may have the same effect, especially near coastal upslope and/or pockets of weak convection. As such, a slight chance to chance of heavy drizzle to light rain expects for periods of the day tomorrow for the North Bay and portions of the Peninsula. Otherwise, tomorrow should be about as cool, cloudier, but not quite as windy.

The question of the day, of course, is what does the forecast for tomorrow's firework displays look like? Well, unfortunately, with interesting weather often comes unsettled weather. Highest resolution nearest term guidance all point towards a similar scenario: both the classical signatures of a weak late season spring storm and a marine intrusion are expected tomorrow evening. Of the two, the marine layer surge is most impactful as it can bring cloud bases under 1000 feet, where as the trough induced cloud coverage generally runs in the 2000-4000 foot range. A quick google search indicates most fireworks trigger at 500-1000 feet for customer grade ones (and likely a bit higher for larger citywide celebrations) meaning the main impacts would come from the marine layer. As such, tomorrow night will be similar to our typical July evenings: the marine layer will gradually expand across the interior by the late afternoon and overtake most urban areas through the night. Given sunset is around 838pm and twilight is around 908pm, within a few miles of the immediate coast will likely see clouds low enough to impact firework viewing as early as 5pm. Areas near the western Bayshore, including the San Francisco downtown event, will likely see low clouds arriving by 8 pm, and areas deeper inland, such as the interior valleys can expect lower clouds to fill in by 11 pm. That said, visibility should remain over a few miles, or enough to see the fireworks, until at least 11pm for nearly all locations. For evening festivities, plan on temperatures in the mid 60s initially but dropping to the mid 50s by the end of fireworks shows. The silver linings to all this are: low fire risk due high humidity and easing winds, the marine stratus still looks beautiful lit up by firework displays, and its still a holiday to enjoy - clouds or not.

Extended forecast remains on track with gradual warming by midweek and much warmer/drier conditions across the interior late week into next weekend. More on that after the 4th.

Marine
as of 03:00pm PDT Sunday...Breezy northwest winds across the coast of Santa Cruz and Monterey counties (especially south of Pigeon Point and Point Sur) as well as near coastal gaps continue through this evening. Winds have diminished in the outer waters and will continue to be calm through mid-week, so expect easing wind waves through early next week before they rebuild mid week. A light long period southerly swell will also be mixed in with these wind driven seas.

NOAA San Francisco Bay Area Office: Watches - Warnings - Advisories
Today:
Small Craft Advisory...Point Arena to Point Reyes 0-10nm until 3pm
Small Craft Advisory...San Francisco Bay
Small Craft Advisory...Monterey Bay
Small Craft Advisory...Pigeon Point to Point Pinos 0-10 nm
Small Craft Advisory...Point Pinos to Point Piedras Blancas 0-10 nm