Point Pinos to Point Piedras Blancas out 10-60 NM Marine Forecast
|Today...Nw Winds 20 To 25 Kt With Gusts Up To 30 Kt. Wind Waves 9 To 10 Ft. Swell W 12 To 13 Ft At 17 Seconds.|
|Tonight...Nw Winds 15 To 25 Kt With Gusts Up To 30 Kt. Wind Waves 9 To 10 Ft. Swell W 10 To 12 Ft At 16 Seconds.|
|Sun...Nw Winds 10 To 20 Kt With Gusts Up To 25 Kt. Wind Waves 9 To 10 Ft. W Swell 2 To 4 Ft At 25 Seconds And W 6 To 8 Ft At 15 Seconds.|
|Sun Night...Nw Winds 15 To 20 Kt With Gusts Up To 25 Kt. Wind Waves 12 To 14 Ft. W Swell 8 To 10 Ft At 23 Seconds And W 2 To 4 Ft At 14 Seconds.|
|Martin Luther King Jr Day...N Winds 20 To 30 Kt With Gusts Up To 35 Kt. Wind Waves 14 To 16 Ft. W Swell 12 To 13 Ft At 20 Seconds.|
|Mon Night...N Winds 30 To 40 Kt With Gusts Up To 50 Kt. Wind Waves 13 To 15 Ft. W Swell 9 To 11 Ft At 17 Seconds.|
|Tue...N Winds 20 To 30 Kt With Gusts Up To 45 Kt. Wind Waves 8 To 9 Ft. W Swell 4 To 6 Ft.|
|Wed...N Winds 10 To 20 Kt. Wind Waves 6 To 7 Ft. Nw Swell 5 To 6 Ft.|
| 214 AM PST Sat Jan 16 2021 |
Synopsis for the Central California Coast and Bays Including the Monterey Bay, Greater Farallones and Cordell Bank National Marine Sanctuaries - PZZ500
A somewhat large, long period westerly swell will persist through the waters today with gusty northwest winds. Isolated gusts to near gale force speed are possible later today, particularly off of Point Reyes and Point Sur. Winds will shift more northerly Sunday to Sunday night and increase as offshore winds pick up over land. Stronger winds will then persist into early next week with gale force winds likely. A second larger long period northwest swell will arrive late Sunday.
| Area Forecast Discussion|
National Weather Service San Francisco Bay Area
407am PST Sat Jan 16 2021
A warming and drying trend will continue through this weekend as high pressure builds over the state. Two back to back low pressure systems to our east will produce breezy to gusty offshore flow Sunday night through Tuesday evening. Cooling trend from Wednesday through Friday.
as of 03:44am PST Saturday...After some patchy fog in the North Bay during these early morning hours, we are expecting continued warm and dry conditions today into Sunday as we linger under high pressure. Daytime highs will continue to be above normal but not expecting widespread broken records. The airmass for today looks to be a little cooler as 850 mb temps only range from 13-15 degrees C over our region compared to the 14-19 degree range that models had yesterday. Models show the airmass warming up a touch for Sunday with 850 mb temps ranging 15-17 degrees C. Normal daytime highs this time of year would range from the mid 50s to low 60s, but our weekend forecast will be low 60s to mid 70s with warmer inland valleys ranging mid 70s to around 80.
Our attention then turns to the offshore wind event from Sunday night into Tuesday evening. While high pressure remains offshore, we will see two back to back upper level lows slide southward over CA. Our high res local WRF model has been consistent in showing increasing winds during that time period and the GFS model continues to show the SFO-WMC offshore gradient is still ranging -10 to -17 mb. For reference, anytime that gradient shows a difference of more than 9 mb, then we expect offshore flow, but if the difference is 13 mb or greater, it indicates a more significant offshore wind event. With the updated wind forecast, we have decided to update the previous High Wind Watch to a Wind Advisory that expands both in area and time. Initially, it looked like there would be a definite break in the winds between the two lows, but while there may be periods of lighter winds, it made more sense to consider the period encompassing both lows as one offshore wind event. This timing also matches up with the wind products of our neighboring Sacramento and Eureka offices.
Overview of the timing of this wind event: Strong winds will first impact the higher terrain of the North Bay and East Bay hills on Sunday night with downsloping winds then moving into the valley areas of the SF Bay Area by early Monday morning. As the second, stronger low moves southward Monday evening into Tuesday, we expanded the Wind Advisory to include the southern portion of our CWA.
Overview of magnitude of this wind event: Wind gusts over higher peaks and along leeward slopes of our CWA will range 40-60 mph, perhaps locally higher in favored areas. As for valleys, not all locations will see gusty conditions all the time. It's quite possible that valley locations will see light to breezy winds and then get occasional strong gusts throughout this event. It can sometimes be challenging to know exactly where the stronger downslope winds will mix down into the valley. However, we are especially concerned about valley areas on the lee side of the mountains as those downsloping winds could bring gusts of 35 to 50 mph.
As we get into midweek, winds will decrease and we'll be in a cooling trend from Wednesday through Saturday. Our daytime highs will go from mid to upper 60s on Wednesday to the mid to upper 50s by Friday and Saturday. Our extended forecast also remains fairly dry. The GFS is indicating that another low could bring some rain into our region on Friday into Saturday (mainly along the coast) while the ECMWF (European Centre for Medium-Range Weather Forecasts) hints at rain on Saturday. Have seen both of these models oscillate with the past few runs on how much rain could impact our CWA Friday-Saturday so not much confidence in any details, yet.
.BEACHES...as of 08:46pm PST Friday...A moderate, long period northwest swell will arrive along the coastline today resulting in hazardous conditions in the surf zone. Initial forerunners of 3 to 6 feet at 20 to 22 seconds will result in an increased risk of dangerous sneaker waves and rip currents today. As the swell builds through tonight and into Saturday, breaking waves of 15 to 17 feet (locally up to 20 feet at favored breakpoints) can be expected along west to northwest facing beaches.
While these waves are not as large as our previous events in the most recent days, unseasonable warm temperatures this holiday weekend will likely attract more people to the coast. Individuals should be reminded that our coastline and the cold Pacific waters remain dangerous as these larger than normal waves impact the coast. Extreme caution is advised when visiting area beaches.
Additionally, a second very long period and larger west to northwest swell will arrive on Sunday. Additional hazard products will likely be needed once the current ones expire.
.CLIMATE...Record Type: Highs (Old Record Temp/Year)
Jan 16th Jan 17th Jan 18th
Santa Rosa 74/1991 71/1991 74/1976 Kentfield 70/2009 71/1994 70/2014 Napa 76/1920 72/1920 76/1920 Richmond 74/2014 73/2009 71/2018 Livermore 75/1920 70/1986 74/1919 San Francisco 72/2014 73/1991 70/1920 SFO 73/2014 70/1991 68/1948 Redwood City 74/2014 77/1948 74/2009 Half Moon Bay 76/2014* 75/2009 72/2009 Oakland Downtown 78/2014* 74/2014 73/2014 San Jose 73/2014 76/1920 74/1920 Gilroy 76/2014 77/2014 80/2014* Santa Cruz 84/2014 83/2014 83/1920 Salinas Airport 84/2014 86/2014* 81/1994 King City 85/1976 86/2014* 83/2009
as of 04:01am PST Saturday...A somewhat large, long period westerly swell will persist through the waters today with gusty northwest winds. Isolated gusts to near gale force speed are possible later today, particularly off of Point Reyes and Point Sur. Winds will shift more northerly Sunday to Sunday night and increase as offshore winds pick up over land. Stronger winds will then persist into early next week with gale force winds likely. A second larger long period northwest swell will arrive late Sunday.
.MTR WATCHES/WARNINGS/ADVISORIES... .Tday...High Surf Advisory...CAZ006-505-509-530 SCA...Mry Bay SCA...Pt Reyes to Pigeon Pt 0-10 nm SCA...Pigeon Pt to Pt Pinos 0-10 nm SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm SCA...Pt Arena to Pt Reyes 0-10 nm SCA...Pt Arena to Pigeon Pt 10-60 nm