Point Pinos to Point Piedras Blancas out 10 NM Marine Forecast
|Today...Nw Winds 15 To 25 Kt With Gusts Up To 30 Kt. Wind Waves 3 To 4 Ft. Nw Swell 4 To 6 Ft At 9 Seconds And S 2 To 3 Ft At 10 Seconds.|
|Tonight...Nw Winds 15 To 25 Kt With Gusts Up To 35 Kt. Wind Waves 4 To 5 Ft. Nw Swell 3 To 5 Ft At 10 Seconds And S Around 2 Ft At 9 Seconds.|
|Sat...Nw Winds 15 To 25 Kt With Gusts Up To 30 Kt. Wind Waves 3 To 4 Ft. Nw Swell 2 To 4 Ft At 9 Seconds.|
|Sat Night...Nw Winds 15 To 25 Kt With Gusts Up To 30 Kt. Wind Waves 4 To 5 Ft. Nw Swell 5 To 7 Ft At 8 Seconds.|
|Sun...Nw Winds 10 To 15 Kt. Wind Waves 1 To 2 Ft. Nw Swell 4 To 6 Ft At 8 Seconds.|
|Sun Night...Nw Winds 5 To 15 Kt. Wind Waves 1 Ft. Nw Swell 3 To 5 Ft At 8 Seconds.|
|Mon...Nw Winds 5 To 15 Kt. Wind Waves 1 Ft. Nw Swell 2 To 4 Ft And Sw Up To 2 Ft.|
|Tue...Nw Winds 10 To 20 Kt. Wind Waves 1 To 2 Ft. Nw Swell 3 To 5 Ft And Sw Around 2 Ft.|
| 830 AM PDT Fri Sep 18 2020 |
Synopsis for the Central California Coast and Bays Including the Monterey Bay, Greater Farallones and Cordell Bank National Marine Sanctuaries - PZZ500
Light northwest winds with locally stronger northwest winds south of Pigeon Point, into the northern Monterey Bay, and south of Point Sur along the Big Sur coast. Winds are forecast to increase Saturday. Mixed seas prevail with a shorter period northwest swell and a moderate period south to southwest swell.
| Area Forecast Discussion|
National Weather Service San Francisco Bay Area
1045am PDT Fri September 18 2020
A weak front will clip the North Bay today while mid- level moisture streams across Monterey and San Benito Counties. Otherwise, a cool down today and tomorrow followed by near normal temperatures, especially in the interior, this weekend. Another slight cooldown expected primarily across the interior during the early part of next week before temps rebound again.
as of 09:25am PDT Friday... The forecast is still on track for this afternoon. Some areas saw drizzle and patches of moderate fog to start the day. Cloud cover from the remnants of Karina is still pushing into areas as far north as Alameda Co and is being met with more stratiform clouds associated with a low pressure moving into the Pacific Northwest.
measured at higher-terrain stations in the North and East Bays and the SF Peninsula as the cold front associated with the 564dm 500hPa trough off the PAC NW coast continues to slowly inch its way towards the Oregon shoreline. Moisture associated with the trough has evolved into convection and rain over Oregon and Washington State while moisture returns further down in extreme NorCal have been minimal, at best. Back here in the CWA, the moisture that has been moving over the Central Coast for most of the day is associated with the remnants of tropical storm Karina.
While there were some minor concerns for overnight high-based convection with dry lightning (which was a fair concern if we recall the aftermath of the remnants from Genevieve last month), the bulk of the moisture looks to be moved out of the Central Coast by the cold frontal passage by mid-morning. GOES-17 has picked up the lightning strikes over the PAC NW tonight but for us, only seeing a continuation of the moisture transport from Karina in the form of a long stretch of alto-cu and the possibility for some patchy drizzle along our coastal locations through the morning. Nevertheless, will continue to monitor the moisture plume through the rest of the morning.
HRRR-07Z 850hPA winds and temperature capture the wind shift and the frontal passage already being observed in higher-terrain locations. As the surface front clips the entire CWA this morning, some uncertainty exists over how quickly coastal clearing occurs. Fort Ord Profiler has observed an uptick in the marine layer depth within the last couple of hours. That being said, the early-to-mid morning marine layer inversion will likely not be very strong given the cold frontal passage. Could see coastal clearing by mid-to-late morning as a result in a north- south fashion. The possibility for the coastal clearing to occur closer to noon is still on the table, however, given surface low- level mixing may be delayed due to weak winds within the lower atmosphere.
Looking into Friday afternoon and the rest of this upcoming weekend, cold frontal passage will substantially cool down the interior, which for the last couple of days has benefited from greater diurnal heating as smoke has cleared out over much of the CWA since this past Wednesday. Cool down will run through Saturday as the axis of the upper-level trough comes ashore and moves east towards the Canadian Prairies/Montana. As it exits the West Coast, a subtle ridge axis will settle around 125W and allow for a gradual rebound in interior max temps on Sunday. Some locations, like Livermore and San Jose, may observe max temps that are as much as 8 degrees F warmer than Friday.
In terms of air quality for this upcoming weekend, conditions may potentially deteriorate in the North Bay as HRRRx vertically integrated smoke product picks up on the smoke canopy from the August Complex being advected to Napa and Sonoma Counties following the cold frontal passage and the subsequent introduction of more northerly flow.
Model guidance brings a shortwave trough into the PAC NW next Monday around the same location where our upper-level trough is currently located. Interior locations in our CWA will subsequently experience a gradual cooldown through next Wednesday, removing diurnal gains from the weekend. Nevertheless, following this shortwave, high ensemble member confidence in upper-level ridging to return to the West Coast. Not expecting significant building but should see temps return to seasonal average through the second half of next week.
The last couple of GFS and CMC ensemble runs (including the latest 00Z 9/18 runs) have hinted at the possibility of a possible offshore wind event through the end of next week, with the signature being the most pronounced on the GFS members. Nevertheless, these runs are well over 200 hours out for respective ensembles and have little certainty at this time. For now, this is far enough out that it shouldn't raise of too many eyebrows, but should keep an eye on it in the coming days.
as of 08:30am PDT Friday...Light northwest winds with locally stronger northwest winds south of Pigeon Point, into the northern Monterey Bay, and south of Point Sur along the Big Sur coast. Winds are forecast to increase Saturday. Mixed seas prevail with a shorter period northwest swell and a moderate period south to southwest swell.
.MTR WATCHES/WARNINGS/ADVISORIES... .Tday...SCA...Mry Bay from 3 PM SCA...Pigeon Pt to Pt Pinos 0-10 nm from 3 PM SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm