Sunday, September27, 2020
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Marine Weather and Tides
Pleasanton, 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 6:59AMSunset 6:57PM Sunday September 27, 2020 8:28 AM PDT (15:28 UTC) Moonrise 4:22PMMoonset 1:47AM Illumination 79% Phase: Waxing Gibbous; Moon at 10 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- 237 Am Pdt Sun Sep 27 2020
Today..SW winds up to 10 kt, becoming nw this afternoon.
Tonight..NW winds up to 10 kt.
Mon..W winds around 5 kt.
Mon night..N winds up to 10 kt.
Tue..NW winds up to 10 kt.
Tue night..NW winds up to 10 kt.
Wed..W winds 5 to 15 kt.
Thu..W winds 5 to 15 kt.
PZZ500 237 Am Pdt Sun Sep 27 2020
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... North to northwest winds will decrease today and become easterly on Monday as high pressure builds over the great basin. Winds will be light south to southeast Tuesday before switching around to northwest by midweek. Northwest swell will gradually subside while a light southerly swell also continues.


7 Day Forecast for Marine Location Near Pleasanton, CA
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location: 37.66, -121.89     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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FXUS66 KMTR 271229 AFDMTR

Area Forecast Discussion National Weather Service San Francisco Bay Area 529 AM PDT Sun Sep 27 2020

SYNOPSIS. Red Flag Warnings are in effect for the North and East Bay through Monday evening due to gusty offshore winds and low humidity. Offshore winds combined with strengthening high pressure over California will result in hot and dry conditions across the entire San Francisco Bay Area today and Monday, with very warm temperatures extending south along the Central Coast. Widespread high temperatures in the 90s to around 100 are forecast both days, except upper 70s and 80s close to the ocean. A Heat Advisory is in effect from 11 am today to 7 pm Monday for all interior portions of the San Francisco Bay Area, as well as the San Francisco Bay Shoreline and the city of San Francisco. Coastal areas south of San Francisco will likely begin to cool by Monday afternoon as southerly winds develop near the coast. Cooler conditions will develop in all coastal areas by Tuesday, with only slight cooling expected inland. Inland areas will remain very warm and dry throughout the week.

DISCUSSION. As of 4:10 AM PDT Sunday . Primary forecast concerns in the short term are gusty offshore winds in the hills and widespread very warm to hot temperatures over the next two days.

Since yesterday afternoon surface high pressure has been building strongly to our north and northeast. The ACV-SFO surface pressure gradient currently stands at an impressive 8.5 mb while the WMC- SFO gradient has climbed quickly past 9 mb. These steep offshore gradients are driving gusty north to northeast winds in the hills early this morning. Currently, wind gusts of between 30 and 40 mph are being observed above 1500 feet in the North and East Bay, and Mount Saint Helena (elev. 4300 feet) has been reporting gusts as high as 65 mph early this morning. Although the Sonoma County Airport reported northerly wind gusts up to 25 mph last evening, the nocturnal inversion has been preventing strong winds in the hills from mixing down into the valleys overnight. Expect winds in the valleys of the North and East Bay to pick up later this morning when the inversion mixes out, but only moderate wind speeds are expected at elevations below 1000 feet.

Offshore winds will bring a much drier airmass into our region today. In addition, widespread subsidence warming and drying will occur as an upper ridge centered just offshore amplifies and quickly strengthens along the West Coast today. This warming and drying, along with lack of a seabreeze due to offshore flow, will result in much warmer temperatures across our entire region today. Widespread highs in the 90s to around 100 are expected for most of our forecast area today and high temperatures will be anywhere from 15 to 20 degrees warmer than normal. Even downtown San Francisco is forecast to reach 90. Only areas in very close proximity to the ocean will escape the heat with highs there mostly in the 70s and 80s. The San Francisco Bay Area is generally forecast to be warmer than the Monterey Bay Area due to stronger offshore flow farther to the north. A Heat Advisory goes into effect starting at 11 AM this morning for all inland portions of the SF Bay Area, as well as the City of San Francisco and the SF Bay Shoreline.

Offshore winds will ease in the North and East Bay Hills this afternoon and early evening before increasing once again tonight. Also, relative humidity values will continue to trend downward into Monday. Critical fire weather conditions are expected to persist in the North and East Bay through Monday and Red Flag Warnings are in effect until 9 PM Monday for the entire North Bay as well as the East Bay Hills and Valleys (see Fire Weather Discussion below for details).

The upper ridge is forecast to develop directly over California on Monday which will result in a few additional degrees of warming in most areas. The Heat Advisory that goes into effect across the Bay Area today will continues through 7 pm Monday. Not all areas are expected to warm further on Monday, In fact, cooling is expected across our southern coastal areas on Monday due to the development of southerly winds from Santa Cruz County southward. These southerly winds may be accompanied by a return of a shallow marine layer. The local WRF models forecasts southerly winds to develop as far north as San Francisco by mid afternoon Monday, but this probably won't be early enough in the day to prevent hot temperatures from developing in the City tomorrow.

The upper ridge axis is forecast to shift inland by Tuesday and light onshore flow will like redevelop near our entire coast. This will mean cooling for all coastal areas on Tuesday. Inland areas won't see a whole lot of relief from the heat on Tuesday as marine air probably won't make it very far inland due to a shallow marine layer and only light onshore flow. But most areas should cool by at least a few degrees on Tuesday, enough to lower Heat Risk to some extent.

The upper ridge is forecast to remain locked in place across the Western U.S. through the remainder of the work week. But since the ridge axis will remain slightly to our east, we should maintain light onshore flow which will keep coastal temperatures relatively mild. Inland areas, however, are forecast to remain very warm through Friday. Longer range models agree that the ridge will finally break down next weekend, resulting in milder temps for all areas.

One additional item to keep an eye on as the week progresses is the potential for southerly flow on the west side of the upper ridge to draw tropical moisture northward and across our area by Tuesday or Wednesday. Currently there does not appear any trigger to provide instability to interact with moisture flowing northward, but this will need to be monitored.

AVIATION. As of 5:26 AM PDT Sunday . For the 12z TAFs. Primarily VFR through the region, aside from MVFR cig at KHAF. Some smoke and haze is being reported in East Bay terminals, as strong NNE winds between 1500 and 2500 ft advect smoke from northern CA wildfires. As a result of the strong NNE winds aloft, LLWS 30 kt has been included in tafs for North Bay and East Bay terminals (KSTS/KAPC/KLVK) through 18-19z. Also expecting LLWS issues overnight into Monday morning between 1000 and 2000 ft, affecting these terminals and possibly KOAK/KSFO. Limited to no marine layer influence is forecast overnight. Smoke from Northern California advected into North and East Bay provides chance for slant range vis issues, primarily through the morning hours, but not currently anticipating significant dense smoke issues. VFR is forecast through the TAF period with breezy winds in the afternoon with a few stronger gusts. Winds decrease again overnight with high pressure overhead and little to no cloud cover.

Vicinity of KSFO . VFR with few clouds reported around 1500 ft. Winds light and variable. Haze is possible today with the northerly wind shift moving smoke into the Bay Area and may affect slant-range vis. VFR expected through the TAF period with limited marine layer influence. Winds will become breezy with occasional stronger gusts this afternoon before easing tonight. LLWS in TAF for Monday 12z- 16z with 30 kt NNE winds at 1000 ft. Will continue to monitor.

SFO Bridge Approach . Possible slant-range vis issues with smoke and haze.

Monterey Bay Terminals . VFR through the TAF period. Some haze and smoke may drift in through morning with strong NNE flow aloft, creating possible slant range vis issues. Winds light and variable, becoming breezy onshore in the afternoon. Winds ease tonight with little cloud cover and VFR continuing.

CLIMATE. Here are the record high temperatures for Saturday through Monday .

. SATURDAY . SUNDAY . MONDAY SANTA ROSA . 103 in 2009 . 103 in 2010 . 104 in 2010 KENTFIELD . 99 in 2016 . 103 in 1921 . 102 in 1921 NAPA . 105 in 1963 . 101 in 1958 . 102 in 1966 RICHMOND . 97 in 2019 . 97 in 2010 . 97 in 2010 LIVERMORE . 103 in 1952 . 105 in 1963 . 105 in 2010 SAN FRANCISCO . 94 in 1992 . 93 in 2010 . 95 in 1966 SF AIRPORT . 95 in 1958 . 96 in 2010 . 95 in 2010 REDWOOD CITY . 99 in 1963 . 97 in 2010 . 98 in 2010 HALF MOON BAY . 90 in 1970 . 89 in 1966 . 91 in 1958 OAKLAND DOWNTOWN . 93 in 2016 . 95 in 1973 . 92 in 2010 SAN JOSE . 98 in 2016 . 98 in 1921 . 99 in 2010 GILROY . 104 in 1963 . 108 in 1963 . 101 in 1963 SANTA CRUZ . 101 in 1970 . 103 in 2010 . 100 in 1917 SALINAS . 101 in 2016 . 102 in 2010 . 99 in 1970 KING CITY . 105 in 1963 . 107 in 2010 . 102 in 1973

FIRE WEATHER. As of 4:00 AM PDT Sunday . North to northeast winds have been increasing in the hills of the San Francisco Bay Area, particularly the North Bay, since late Saturday evening. Wind gusts up to 35 mph are currently being observed at the higher elevations of the North and East Bay, with local gusts up to 60 mph above 4000 feet in the North Bay (Mt St Helena). Winds in the hills are forecast to peak between now and late this morning. In addition, gusty winds will mix locally to lower elevations by this morning, but winds in the valleys are not expected to be nearly as strong as in the hills above 1000 feet. RH values have been holding steady overnight, but will likely begin to decrease in the hills by sunrise, and then decrease significantly in all areas through this afternoon. Winds will diminish in the hills this afternoon and early evening, but then increase again tonight and also veer more to the east. Offshore winds are not expected to be quite as strong in the hills on Sunday night compared to Saturday night and winds are forecast to decrease in all areas by midday Monday. However, almost no overnight humidity recovery is expected on Sunday night and RH values will drop as low as the single digits on Monday. The Red Flag Warning that is currently in effect for the entire North Bay, as well as the East Bay Hills and Valleys, will continue through Monday evening.

For the Dolan Fire, north winds this morning are forecast to turn to the east by this afternoon and then to the south by Monday morning. Except for moderate north winds this morning, wind speeds in this area are expected to remain mostly light.

Cooling is forecast for the entire coast on Tuesday as southerly winds develop farther north up the coast. Inland areas will also cool on Tuesday, but by only a few degrees. In fact, very warm and dry conditions are forecast to persist across inland areas through much of the work week. However, after Monday, winds are forecast to remain mostly light.

MARINE. as of 02:37 AM PDT Sunday . North to northwest winds will decrease today and become easterly on Monday as high pressure builds over the Great Basin. Winds will be light south to southeast Tuesday before switching around to northwest by midweek. Northwest swell will gradually subside while a light southerly swell also continues.

MTR WATCHES/WARNINGS/ADVISORIES. Tday. Heat Advisory . Red Flag Warning . SCA . Pt Arena to Pigeon Pt 10-60 nm SCA . Pt Arena to Pt Reyes 0-10 nm until 9 AM SCA . Pt Pinos to Pt Piedras Blancas 0-10 nm until 9 AM SCA . Pigeon Pt to Pt Piedras Blancas 10-60 nm until 9 AM



PUBLIC FORECAST: Dykema AVIATION: Lorber MARINE: W Pi FIRE WEATHER: Dykema

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 20 mi59 min S 1.9 G 1.9 62°F 72°F1013.3 hPa
LNDC1 23 mi59 min SE 2.9 G 2.9 66°F 1012.7 hPa
AAMC1 - 9414750 - Alameda, CA 23 mi59 min E 2.9 G 4.1 64°F 68°F1012.9 hPa
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 25 mi59 min SE 5.1 G 5.1
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 26 mi59 min S 5.1 G 6 74°F 1012.4 hPa
OBXC1 26 mi59 min 66°F 64°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 26 mi59 min SE 1 G 2.9 65°F 1012.7 hPa
PCOC1 - 9415144 - Port Chicago, CA 28 mi59 min SSW 4.1 G 7 65°F 69°F1012.3 hPa
PXOC1 - 9414311 - San Francisco (Pier 1), CA 28 mi59 min NW 1.9 G 1.9 64°F 1011.7 hPa
PXSC1 29 mi59 min 65°F
UPBC1 29 mi59 min W 2.9 G 5.1
MZXC1 - 9415102 - Martinez-Amorco CA 29 mi59 min SSW 2.9 G 2.9 64°F 69°F1012.7 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 30 mi59 min Calm G 1 67°F 1013.2 hPa
FTPC1 - 9414290 - San Francisco, CA 32 mi59 min SSW 2.9 G 2.9 62°F 65°F1012.8 hPa
RCMC1 - 9414863 - Richmond, CA 33 mi59 min Calm G 1 65°F 66°F1012.6 hPa
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 34 mi59 min WSW 1.9 G 2.9 67°F 1012.4 hPa
TIBC1 - Tiburon Pier, San Francisco Bay, CA 34 mi48 min Calm 66°F 1013 hPa
SFXC1 - San Francisco Bay Reserve, CA 38 mi104 min ESE 5.1
46237 - San Francisco Bar, CA (142) 40 mi59 min 60°F5 ft

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Livermore, Livermore Municipal Airport, CA5 mi36 minno data10.00 miFair73°F45°F37%1012.7 hPa
Hayward, Hayward Air Terminal, CA12 mi35 minN 010.00 miFair64°F54°F70%1013.5 hPa
Oakland, Metro Oakland International Airport, CA18 mi36 minNE 410.00 miA Few Clouds64°F55°F75%1012.8 hPa
Mountain View, Moffett Field, CA18 mi94 minN 010.00 miMostly Cloudy61°F55°F83%1012.5 hPa
San Jose, San Jose International Airport, CA20 mi36 minE 410.00 miPartly Cloudy64°F55°F75%1012.8 hPa
San Carlos Airport, CA21 mi42 minN 010.00 miClear61°F55°F83%1013.2 hPa
San Jose / Reid / Hillv, CA22 mi1.7 hrsVar 410.00 miA Few Clouds61°F55°F83%1012.9 hPa
Concord, Buchanan Field, CA24 mi36 minN 010.00 miHaze Smoke63°F55°F76%1011.5 hPa

Link to 5 minute data for KLVK

Wind History from LVK (wind in knots)
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Last 24hrCalmCalmW65S5S7W7W9W12W8W11W4CalmCalmCalmNW3CalmE5E3CalmCalmCalmCalm--
1 day agoW55CalmSW4SW76W9W11W10W12W8CalmSW3W5W6W5CalmNW3CalmCalmE3CalmCalmCalm
2 days agoSW5SW6W9SW8W8W8W13W12W10W10W12W13SW8W4S8SW7SW11SW12SW12SW8SW5SW5SW8SW7

Tide / Current Tables for Alameda Creek, San Francisco Bay, California
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Alameda Creek
Click for Map
Sun -- 02:48 AM PDT     Moonset
Sun -- 05:38 AM PDT     0.02 feet Low Tide
Sun -- 07:01 AM PDT     Sunrise
Sun -- 11:19 AM PDT     5.47 feet High Tide
Sun -- 05:22 PM PDT     Moonrise
Sun -- 05:57 PM PDT     0.65 feet Low Tide
Sun -- 06:56 PM PDT     Sunset
Sun -- 10:23 PM PDT     5.95 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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4.63.52.41.30.50.10.10.71.93.34.75.45.34.73.72.51.50.90.61.32.94.65.85.9

Tide / Current Tables for Dumbarton Point 2.3 mi NE, South San Francisco Bay, California Current
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Dumbarton Point 2.3 mi NE
Click for Map
Sun -- 02:41 AM PDT     -1.13 knots Max Ebb
Sun -- 02:48 AM PDT     Moonset
Sun -- 05:19 AM PDT     0.00 knots Slack
Sun -- 07:00 AM PDT     Sunrise
Sun -- 08:20 AM PDT     1.37 knots Max Flood
Sun -- 11:22 AM PDT     -0.01 knots Slack
Sun -- 03:55 PM PDT     -0.66 knots Max Ebb
Sun -- 05:21 PM PDT     Moonrise
Sun -- 05:33 PM PDT     0.01 knots Slack
Sun -- 06:56 PM PDT     Sunset
Sun -- 08:12 PM PDT     0.97 knots Max Flood
Sun -- 10:47 PM PDT     -0.01 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-0.8-1-1.1-1.1-0.9-0.30.51.11.31.30.90.2-0.2-0.4-0.6-0.6-0.7-0.40.30.810.90.5-0.1

Weather Map
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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.
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Ground Weather Radar Station San Francisco Bay Area, CA
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The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerous of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.