Friday, September18, 2020
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Marine Weather and Tides
San Lorenzo, CA

Version 3.4
NOTICE
8/26/2020 The 7 day forecast is taking about 5 seconds to load but it will eventually load. NOAA is still working on it.
8/18/2020 NOAA continues to have trouble. Wind guest will occasionally be left off graphs. I am working with NOAA to resolve the issue.
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
10/9/2019 Updated the Marine Zones.
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.

Sunrise 6:52AMSunset 7:12PM Friday September 18, 2020 3:37 AM PDT (10:37 UTC) Moonrise 7:14AMMoonset 7:25PM Illumination 1% Phase: Waxing Crescent; Moon at 1 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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PZZ531 San Francisco Bay South Of The Bay Bridge- 249 Am Pdt Fri Sep 18 2020
Today..W winds 5 to 10 kt, increasing to 10 to 20 kt with gusts up to 25 kt this afternoon.
Tonight..W winds 5 to 15 kt.
Sat..W winds 5 to 15 kt.
Sat night..W winds 5 to 15 kt.
Sun..NW winds 5 to 15 kt.
Sun night..W winds up to 10 kt.
Mon..W winds 10 to 20 kt.
Tue..W winds 10 to 20 kt.
PZZ500 249 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... Predominately 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. Seas remain mixed with a shorter period northwest swell and a moderate period south to southwest swell.


7 Day Forecast for Marine Location Near San Lorenzo, CA
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location: 37.65, -122.22     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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FXUS66 KMTR 181003 AFDMTR

Area Forecast Discussion National Weather Service San Francisco Bay Area 303 AM PDT Fri Sep 18 2020

SYNOPSIS. A weak front will clip the North Bay this morning while mid-level moisture streams across Monterey and San Benito Counties. A few sprinkles along the coast are possible through the early morning hours. 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.

DISCUSSION. As of 3:05 AM PDT Thursday . WNW winds are being 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.

AVIATION. As of 10:50 PM PDT Thursday . Satellite image shows a strong push of stratus into SFO Bay aided by an upper trough approaching the Pacific Northwest. Mid and high clouds which are remnants of a tropical storm are moving through the southern part of the district. Stratus will be spreading into MRY Bay and the inland terminals soon. The question is how low the bases of the stratus deck will be. Marine layer will initially be shallow then deepen during the night as the 500 mb heights fall. Patchy drizzle is possible especially in MRY and SNS. Forecast calls for MVFR/IFR cigs initially, then lifting to MVFR Friday morning.

Vicinity of KSFO . MVFR/IFR cigs with bases near or just below 1000 ft. Cigs becoming MVFR rising to 1000-1500 ft after 13Z clearing after 20Z.

SFO Bridge Approach . Similar to SFO, but with smoke and haze aloft, slant range visibility may be reduced on approach.

Monterey Bay Terminals . Low confidence forecast due to the mid and high clouds blocking the satellite view. IFR cigs have been in and out of WVI so clouds should increase in MRY Bay and spread into MTR and SNS after 07Z possibly later. Clearing after 18Z.

MARINE. as of 10:39 PM PDT Thursday . Low pressure off the Pacific Northwest will bring light winds through Saturday except for stronger winds south of Point Sur. Seas remain mixed with a shorter period northwest swell and a moderate period south to southwest swell.

MTR WATCHES/WARNINGS/ADVISORIES. Tday. SCA . Pt Pinos to Pt Piedras Blancas 0-10 nm



PUBLIC FORECAST: Diaz/AS AVIATION: W Pi MARINE: W Pi

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
AAMC1 - 9414750 - Alameda, CA 9 mi49 min 67°F
RTYC1 - 9414523 - Redwood City, CA 10 mi49 min NW 6 G 7 66°F 73°F1016.2 hPa
LNDC1 11 mi49 min WNW 4.1 G 8 63°F 1015.5 hPa
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 12 mi49 min WNW 6 G 8
OBXC1 12 mi49 min 62°F 62°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 13 mi49 min WNW 8.9 G 11 62°F 1015.4 hPa
PXSC1 14 mi49 min 63°F
PXOC1 - 9414311 - San Francisco (Pier 1), CA 14 mi49 min WNW 1.9 G 5.1 62°F 1014.4 hPa
FTPC1 - 9414290 - San Francisco, CA 17 mi49 min 63°F
PPXC1 - 9414847 - Richmond (Point Potrero), CA 19 mi49 min SW 6 G 7 63°F 1015.7 hPa
RCMC1 - 9414863 - Richmond, CA 21 mi55 min SSW 1.9 G 6 63°F 64°F1015.3 hPa
46237 - San Francisco Bar, CA (142) 24 mi37 min 59°F3 ft
UPBC1 27 mi49 min W 12 G 14
MZXC1 - 9415102 - Martinez-Amorco CA 27 mi49 min WSW 9.9 G 13 65°F 68°F1014.9 hPa
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 28 mi49 min W 9.9 G 12 65°F 1014.8 hPa
PCOC1 - 9415144 - Port Chicago, CA 30 mi49 min WSW 11 G 13 65°F 69°F1014.3 hPa
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 32 mi49 min WNW 6 G 8.9 66°F 1014.5 hPa
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 34 mi27 min W 1.9 G 3.9 61°F1015.9 hPa
SFXC1 - San Francisco Bay Reserve, CA 39 mi52 min W 4.1
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 40 mi27 min SE 1.9 G 5.8 62°F 1015.9 hPa61°F

Wind History for Alameda, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Oakland, Metro Oakland International Airport, CA3 mi44 minW 810.00 miOvercast66°F61°F84%1015.7 hPa
Hayward, Hayward Air Terminal, CA5 mi43 minWNW 710.00 miOvercast67°F60°F79%1016.3 hPa
San Carlos Airport, CA8 mi42 minW 310.00 miOvercast66°F60°F83%1015.9 hPa
San Francisco, San Francisco International Airport, CA8 mi41 minN 010.00 miMostly Cloudy64°F60°F87%1015.3 hPa
Mountain View, Moffett Field, CA18 mi42 minN 010.00 miOvercast64°F59°F83%1015.6 hPa
Half Moon Bay Airport, CA18 mi42 minN 09.00 miOvercast61°F59°F94%1015.9 hPa
Livermore, Livermore Municipal Airport, CA21 mi44 minWSW 610.00 miOvercast64°F60°F87%1014.8 hPa

Link to 5 minute data for KOAK

Wind History from OAK (wind in knots)
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Last 24hrCalmW4S3CalmCalmW5W3SW4W5W9W16W10W13W16W10W11W12W13NW9W10W7W8W8W8
1 day agoCalmCalmSE3SE4CalmS3CalmSW5SW5SW7W6W7W10W12W10W9W9NW5W7CalmSE3CalmSW3S3
2 days agoCalmCalmCalmCalmS3CalmSW4SW6W5W6W8NW9W11W13W13W11W12W4W5W6CalmN3CalmE4

Tide / Current Tables for San Mateo Bridge (east end), San Francisco Bay, California
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San Mateo Bridge (east end)
Click for Map
Fri -- 01:14 AM PDT     8.10 feet High Tide
Fri -- 06:53 AM PDT     Sunrise
Fri -- 07:48 AM PDT     0.08 feet Low Tide
Fri -- 08:14 AM PDT     Moonrise
Fri -- 01:58 PM PDT     7.84 feet High Tide
Fri -- 07:10 PM PDT     Sunset
Fri -- 08:12 PM PDT     0.58 feet Low Tide
Fri -- 08:24 PM PDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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7.38.17.96.85.13.21.50.40.10.82.34.15.97.37.87.46.14.42.61.20.60.92.23.9

Tide / Current Tables for Little Coyote Pt 3.4 mi NNE, South San Francisco Bay, California Current
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Little Coyote Pt 3.4 mi NNE
Click for Map
Fri -- 01:13 AM PDT     -0.00 knots Slack
Fri -- 04:29 AM PDT     -0.98 knots Max Ebb
Fri -- 06:53 AM PDT     Sunrise
Fri -- 07:43 AM PDT     0.00 knots Slack
Fri -- 08:14 AM PDT     Moonrise
Fri -- 10:38 AM PDT     0.83 knots Max Flood
Fri -- 01:44 PM PDT     -0.00 knots Slack
Fri -- 04:53 PM PDT     -0.92 knots Max Ebb
Fri -- 07:11 PM PDT     Sunset
Fri -- 08:02 PM PDT     0.01 knots Slack
Fri -- 08:24 PM PDT     Moonset
Fri -- 10:59 PM PDT     0.84 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.50.1-0.3-0.7-1-0.9-0.7-0.30.10.50.80.80.60.3-0.1-0.5-0.8-0.9-0.8-0.4-00.40.70.8

Weather Map
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wmap_P
GEOS Local Image of CentralWestCoast    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East
Ground Weather Radar Station San Francisco Bay Area, CA
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