Pigeon Point to Point Piedras Blancas between 60 and 150 NM Offshore Forecast
|Tonight...W Winds 5 To 10 Kt, Becoming W To Nw 5 To 15 Kt, Then Becoming N. Seas 5 To 8 Ft. Chance Of Rain. Areas Of Fog With Vsby 1 Nm Or Less.|
|Sun...N Winds 10 To 20 Kt. Seas 5 To 9 Ft. Areas Of Fog With Vsby 1 Nm Or Less.|
|Sun Night...N Winds Increasing To 20 To 25 Kt. Seas Building To 9 To 11 Ft. Areas Of Fog With Vsby 1 Nm Or Less.|
|Mon...N Winds 15 To 25 Kt. Seas Building To 10 To 17 Ft.|
|Mon Night...N Winds 15 To 25 Kt. Seas Building To 15 To 19 Ft.|
|Tue...N Winds 10 To 20 Kt. Seas 15 To 18 Ft.|
|Tue Night...N Winds Increasing To 20 To 30 Kt. Seas Subsiding To 13 To 15 Ft.|
|Wed...N Winds 20 To 30 Kt. Seas 13 To 14 Ft.|
|Wed Night...N Winds 20 To 30 Kt. Seas 12 To 15 Ft.|
|Thu...N Winds 20 To 30 Kt. Seas 11 To 14 Ft.|
|Thu Night...N Winds 20 To 25 Kt. Seas Subsiding To 9 To 12 Ft.|
| 145 PM PST Sat Dec 5 2020 |
Synopsis for the Central California Coast and Bays Including the Monterey Bay, Greater Farallones and Cordell Bank National Marine Sanctuaries - PZZ500
A weak boundary will create split flow with light southerly winds in the waters north of the Golden Gate and northerly winds in the southern waters the rest of today. Widespread northerly winds will return overnight into Sunday and gradually increase throughout the day. Seas feature a moderate to long period swell that will subside later this weekend. The combination of breezy winds and seas will result in hazardous seas conditions, particularly for smaller vessels. A large, very long period northwest swell will arrive Monday, peak on Tuesday, and bring potential hazards along the immediate coast.
| Area Forecast Discussion|
National Weather Service San Francisco Bay Area
422pm PST Sat Dec 5 2020
Slight cooling trend through the weekend while a weak cold front moves into Northern California. The upper low associated with that cold front will slide southward Sunday night and retrograde back towards the coast through Monday. This pattern will create offshore flow with gusty winds over the mountains during that period. Afterwards, dry weather with mild daytime highs and cool nigheights will persist for the rest of the week.
as of 02:23am PST Saturday...Mid and high-based clouds ahead of the cold front have rolled in to the SF Peninsula in a spectacular fashion and are clipping our entire CWA, along with Northern California and the Sacramento Valley. The weak, dry FROPA is expected to carry into the evening hours, with onshore flow picking up and helping to mix out particulates in some of the urbanized valleys. For the latest on air quality conditions, be sure to refer to AirNow and the Bay Area Air Quality District.
Aside from light winds, the return flow has also begun to increase surface RH values in some of the North Bay and SF Peninsula stations. Unfortunately, not expecting any precipitation out of this FROPA through tonight aside from some very isolated pockets of light coastal/mountain drizzle. Nonetheless, this added moisture has arrived to our area at a good time, as its presence will result in improved overnight humidity recoveries regionwide going into tomorrow morning. The timing of this brief moisture return will also coincide with the development of a cut-off low over the Great Basin tomorrow afternoon. As the system deepens, short and mid-range guidance are all in agreement that upper-level cyclonic flow and the position of the system with respect to our CWA will result in offshore mid-levels winds that will begin to mix down into the North Bay Mountains and East Bay Hills late Sunday night and through Monday. But as previously mentioned, the added moisture over the region will help to mitigate the substantial drying that we would otherwise experience had the onshore flow not come in 24 hours prior.
Moreover, the timing of both the driest conditions and strongest winds in the high-terrain areas over 1000 ft looks set to be just before daybreak. As such, the majority of this offshore wind event will occur during the daytime on Monday. This is not to say that there will not be any fire concerns during that period, as sustained winds are still expected to be in the 15-25mph range at elevations over 1000 ft, with gusts of 30-35mph possible (and up to 40mph possible at the highest peaks). RH values will also eventually drop into the teens as well. But both the local WRF and the NAM are not expecting for the driest conditions to peak until Monday afternoon, when the moisture return from today is advected back out to sea. Thankfully, the cut-off low will then shift further south by late Monday afternoon, so winds will gradually through Monday night and into early Tuesday morning.
The upper-level ridge will begin to build itself back up Monday afternoon and quickly become the dominant synoptic-scale feature again for NorCal. Some weak offshore flow is still expected to linger through Tuesday and as such expecting warming trend early next week. Can expect max temps in the 60s and 70s Monday and Tuesday as a result, before a cooling trend begins on Wednesday as the next upper-level trough approaches the PAC NW and reintroduces NW mid-level flow back into the CWA. Given the longer nigheights and the cooling trend during the second half of next week, may see some cold overnight lows over several interior valley locations (e.g. mid 30s F) while coastal locations will only get down to the 40s F.
Beyond that, still not seeing a potential for substantial precipitation through the first half of the month, although the synoptic pattern does seem to be trending towards more zonal flow by mid-December, which would greatly increase our chances for some more substantial moisture plumes to enter NorCal and the Central Coast. Stay tuned.
as of 01:45pm PST Saturday...A weak boundary will create split flow with light southerly winds in the waters north of the Golden Gate and northerly winds in the southern waters the rest of today. Widespread northerly winds will return overnight into Sunday and gradually increase throughout the day. Seas feature a moderate to long period swell that will subside later this weekend. The combination of breezy winds and seas will result in hazardous seas conditions, particularly for smaller vessels. A large, very long period northwest swell will arrive Monday, peak on Tuesday, and bring potential hazards along the immediate coast.
.MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pt Arena to Pt Reyes 0-10 nm from 3 AM SCA...Pt Arena to Pigeon Pt 10-60 nm from 3 AM