Monterey Bay Marine Forecast
|Today...E Winds Up To 10 Kt, Becoming Sw This Afternoon. Wind Waves 1 Ft. W Swell 5 To 7 Ft At 14 Seconds.|
|Tonight...E Winds Up To 10 Kt. Wind Waves 1 Ft. W Swell 3 To 5 Ft At 16 Seconds.|
|Sat...N Winds Up To 10 Kt. Wind Waves 1 Ft. W Swell 4 To 6 Ft At 16 Seconds.|
|Sat Night...Ne Winds Up To 10 Kt. Wind Waves 1 Ft. W Swell 4 To 6 Ft At 14 Seconds.|
|Sun...Nw Winds Up To 10 Kt. Wind Waves 1 Ft. W Swell 4 To 6 Ft At 13 Seconds.|
|Sun Night...Se Winds Up To 10 Kt. Wind Waves 1 Ft. W Swell 4 To 6 Ft At 13 Seconds.|
|Mon...N Winds 5 To 10 Kt. Wind Waves 1 Ft. W Swell 6 To 8 Ft.|
|Tue...N Winds 5 To 10 Kt. Wind Waves 1 Ft. W Swell 6 To 8 Ft. Locally Lower Winds And Seas Across Sheltered Portions Of The Bay.|
| 247 AM PST Fri Nov 27 2020 |
Synopsis for the Central California Coast and Bays Including the Monterey Bay, Greater Farallones and Cordell Bank National Marine Sanctuaries - PZZ500
High pressure over the Great Basin will keep light winds through the weekend. Seas are decreasing but another long-period northwest swell may arrive early next week.
| Area Forecast Discussion|
National Weather Service San Francisco Bay Area
456am PST Fri Nov 27 2020
Gusty, dry offshore winds will continue locally in the hills tonight, but will diminish by late morning. Temperatures will quickly cool tonight as a drier airmass settles over the region and lighter winds develop near sea level. High pressure will build from Friday through the weekend, resulting in sunny, mild days and clear, cool nights. Dry weather is expected to continue through next week.
As of 3:10am PST Friday...Water vapor imagery this morning shows the vast majority of the PAC moisture plume being advected into British Columbia by the upper-level trough centered over the Gulf of Alaska. Some of that moisture has made its way into parts of Washington and Oregon, but with the exception of a faint plume over far northern California, the State is under an offshore wind setup, with the axis of an upper-level high just off the coast and an upper-level low centered over the Southwestern US.
One of the main differences between this offshore wind setup and previous ones in recent weeks is that the center of this upper-level low is currently centered much farther south over Arizona. As such, Southern California is experiencing much windier conditions (e.g. the Santa Ana Winds) than our area. Nonetheless, have observed some gusty conditions across the North Bay Mountains and East Bay hills, with max gusts in the of 50mph and 58mph observed over Mt. St. Helena and Mt. Diablo, respectively. Thankfully these winds have not mixed down much below 1500 ft, and the recent rains have helped to somewhat reduce the overnight fire weather concerns.
Primary concerns for the remainder of the morning will be the culmination of gusty winds and the dry air mass in the higher- terrain locations of the Bay Area. Not expecting much in the way of overnight humidity recoveries as short and medium-range guidance prog a continuation of these very dry conditions through the weekend. The good news is that NAM and local WRF both expect these winds to weaken substantially over the next few hours, so should have much calmer winds by late morning. Weakening winds and dry air mass will also contribute to cold conditions over much of the CWA. Expecting widespread mid 30s F and 40s F all along the Coast and Bay Shoreline, while radiative cooling and valley cold air pooling will result in interior valleys starting the day with temps in the upper 20s F to low 30s F. It should be noted that these below-freezing temps will be short-lived and fairly localized in the valleys, so not planning on issuing any freeze warnings through the morning.
Temps will quickly build back up to the 60s F regionwide for the afternoon, and these sunny and dry conditions will be apparent through the remainder of the Holiday weekend owing to the offshore ridge. It should also be noted that given the dryness of the air mass and the calm to light winds expected for the next few days, can expect the next few nigheights to be rather cold. Coastal areas may even see some morning frost depending on how much moisture manages to overcome the dry air mass over land and advect ashore.
ECMWF (European Centre for Medium-Range Weather Forecasts) ENS and GEFS members pick up on the next disturbance moving into the PAC NW Sunday night and into Monday, with the bulk of its moisture remaining well over BC. The passage will at the very least bring back more onshore flow into the region, resulting in a slight departure from the warming trend expected this weekend. Unfortunately, long-range guidance in agreement that ridging will dominate the region through the remainder of next week. The best chance for some precipitation appears to be around late Wednesday/early Thursday when some of the ECMWF ENS members suggest a shortwave trough may undercut the upper-level ridge, but IVT values remain rather low with that passage and the remainder of the GEFS members take an even less aggressive approach. As such, chance of precipitation remains unlikely through next week. Looking at the ECMWF extended weeklies and the GEFS extended, amplified trough-ridge pattern over the eastern PAC looks set to continue, which may translate into our CWA and most of California staying under an upper-level ridge dominant pattern at least through the first part of December.
as of 04:51am PST Friday...High pressure over the Great Basin will keep light winds through the weekend. Seas are decreasing but another long-period northwest swell may arrive early next week.
.MTR WATCHES/WARNINGS/ADVISORIES... .Tday...None.