Thursday, September24, 2020
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Marine Weather and Tides
East Palo Alto, 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 6:57AMSunset 7:03PM Thursday September 24, 2020 8:56 AM PDT (15:56 UTC) Moonrise 2:10PMMoonset 11:48PM Illumination 49% Phase: First Quarter Moon; Moon at 7 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- 814 Am Pdt Thu Sep 24 2020
Today..W winds up to 10 kt, increasing to 10 to 20 kt with gusts up to 25 kt this afternoon. Patchy fog this morning.
Tonight..W winds 10 to 20 kt with gusts up to 25 kt.
Fri..W winds 5 to 15 kt.
Fri night..W winds 5 to 15 kt.
Sat..W winds 5 to 15 kt.
Sat night..W winds up to 10 kt.
Sun..NW winds 5 to 15 kt.
Mon..W winds 5 to 15 kt.
PZZ500 814 Am Pdt Thu Sep 24 2020
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Generally light northwest winds for most of the waters today as a weak frontal system moves through. Locally stronger winds are expected along the big sur coast south of point sur. Winds will then increase across the waters tonight and tomorrow in the post frontal environment. A larger long period northwest swell will continue through tomorrow with swell heights of 9 to 12 feet at periods of 14 to 18 seconds through tomorrow. SWell heights and periods then expected to quickly diminish.


7 Day Forecast for Marine Location Near East Palo Alto, CA
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location: 37.45, -122.1     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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FXUS66 KMTR 241203 AFDMTR

Area Forecast Discussion National Weather Service San Francisco Bay Area 503 AM PDT Thu Sep 24 2020

SYNOPSIS. A weak front moving into far Northern California will allow for a cloudy start for much of the Bay Area this morning. Clearing this afternoon with seasonable temperatures. This trend continues into Friday with no big changes in the weather. Warming trend starts Saturday afternoon with widespread 80s and 90s returning inland. Offshore winds develop Saturday night into Sunday morning, most focused over the North and East Bay hills where a Fire Weather Watch remains in effect. Turning hotter and drier all areas Sunday and Monday as strong high pressure builds with continued light offshore winds that will bring near record breaking heat that may last through Tuesday.

DISCUSSION. as of 3:30 AM PDT Thursday . Lets start with some good news. It is raining in California. Just not around the Bay Area but we've got light rain falling up in Arcata and Crescent City as the tail end of a cold front sweeps into the state. The rain up there will help with Slater, Red Salmon and Fox fires but likely have little impact on the August and North Complex fires. For the Bay Area the synoptic lift associated with the front has organized the marine layer and allowing for a good push of marine clouds along the coast. Expect continued inland push of clouds through this morning throughout the Bay Area. Winds are light but expect persistent onshore breezes today keeping temperatures near or even slightly below normal once the morning clouds peel back.

The models bring another system onto the Oregon coast Friday, again with some rain up near Redwood National Park. Ideally this would be a signal for a change in the upcoming weather pattern but it unfortunately looks like a head fake in the wrong direction. That system will bring some beneficial rains to lingering fires up in OR/WA/ID. Locally that zonal flow aloft will keep onshore winds in place for the Bay Area for at least one more day. Models give some conflicting signals and show some slight cooling of temps may occur on Friday as persistent northwest winds continue but really no impactful weather of note.

The previously mentioned zonal flow and weather systems to our north have perhaps slightly delayed the developing weather pattern for this weekend but for the most part the forecast looks on track. In terms of fire weather humidity values looks slightly higher on Saturday with northerly winds not expected to really mix down much during the day on Saturday. This all appears to be associated with the moist zonal flow to our north and the pattern being less amplified in terms of setting up offshore winds.

However, the period of strongest offshore winds continues to look like it will occur overnight Saturday into Sunday morning. During this time frame a tight surface pressure gradient sets up over northeast California in the vicinity of the Feather River Canyon and around Mt Lassen. This will produce some north/northeast winds that will funnel down and over the North and East Bay hills Saturday night into Sunday morning. 925 mb winds progged around 35 kt with our local 3 km wrf model showing ridge top gusts to around 35 mph. Potential still there for high end gust potential to 50 mph for the wind favored peaks such as Mt Saint Helena, Diablo and Mt Tamalpais. In an odd but not really surprising twist now that we are getting close enough to look at the high resolution models much of the strongest wind potential looks to occur where the LNU and SCU lighting complexes consumed about 800,000 acres in late August. Nonetheless moderate offshore winds with lowering humidity and rising temps is a bad recipe. Upshot is decisions on what to do with Fire Wx Watch will be made after this morning round of conf calls with with land management agencies. Option is still on the table to maintain the watch through Friday before a possible upgrade to Red Flag Warning.

In terms of temperatures, the North and East Bay will see the most warming Saturday afternoon as the northerly downslope winds first develop and readings approach the lower 90s. More serious warming trend occurs on Sunday as humidity values plummet and strong high pressure builds in the form of a 596 dm high centered north and west of Cape Mendocino. At the surface the tightest pressure gradients remain over the Sierra with the 00z ecmwf solution showing a westward trend in the 500 mb trough axis towards a more typical scenario of lee side cyclogenesis in the lee of the Rockies. This sets up a highly amplified pattern across the US with the strong ridge along the West Coast, leading to widespread readings into the 90s and lower 100s while cold air pours into the upper midwest.

As always the challenge will be how hot it gets at the coast. Right now if there looks to be a day where temps would reach or exceed 90 in the City it looks like Monday would be the day as 850 mb temps soar to 25-27 celsius. There wont be strong offshore winds but the strength of the upper ridge and a thermal trough trying to straddle the coast may be just enough to shut off any marine influence. Will be fine tuning the high temp forecasts over the coming days but Sunday through Tuesday look pretty hot. Temps in the valleys should cool fairly well at night with the dry airmass though hill locations will stay steady in the mid 70s to lower 80s. Will assess heat risk potential in the coming days as well.

Long range highly amplified pattern looks to keep the West Coast ridge in place at least through the end of the month. This is not good news for the ongoing fires from Plumas to Sequoia as smoke impacts will continue across the state and bouts of northeast/offshore winds will likely bring some of that smoke back into the Bay Area starting Saturday and lasting into next week. Though the amount of smoke currently being produced is dramatically less compared to the Tuesday after Labor Day.

AVIATION. As of 4:55 AM PDT Thursday . Satellite image shows a northwest flow pushing clouds into the SFO Bay Area and into the East Bay valleys. This is associated with a frontal system that is expected to mix out the clouds late morning and afternoon. Only areal coverage of stratus is expected tonight in a post-frontal environment. Thus far the clouds have stayed out of Monterey Bay but is getting close to MRY.

Vicinity of KSFO . IFR ceiling with bases around 500 feet with tops to 2000 ft. Some drizzle is possible as it has been reported in the hills just to the west. Clearing after 18Z. Breezy this afternoon with west to northwest winds to 20 kt gusting 25-28 kt.

SFO Bridge Approach . Similar to KSFO.

Monterey Bay Terminals . VFR expected, but will have to watch the clouds just outside MRY Bay possibly coming onshore later this morning. Low confidence on tonight as the airmass will be mixed out but cigs could form over the coastal hills and spread into MRY or SNS.

BEACHES. as of 10:34 PM PDT Wednesday . A deep low in the Gulf of Alaska has produced a large long-period swell train that will arrive late Thursday evening and into Friday morning. Swells by then could be up to 10 to 12 ft with a 16 to 18 second period. The main impacts will be increased wave heights breaking near the shoreline and an increased risk of rip currents developing along coastal beaches. With the increase in temperatures inland expected late in the week, beachgoers should be mindful of the increased wave activity and rip currents. The wave activity is forecast to gradually decrease through the weekend, but caution is advised through at least Sunday morning.

MARINE. as of 04:34 AM PDT Thursday . A large long-period swell will arrive tonight and continue through Friday. Forerunners of 18 to 20 seconds are possible today before the larger northwest swell of 9 to 12 feet at 14 to 18 seconds is expected tonight and Friday. A frontal system will move through the Pacific Northwest tonight resulting in generally light northwest winds except for locally gusty winds south of Pigeon Point and along the Big Sur coast. Winds will increase in all waters Friday in the post- frontal environment.

MTR WATCHES/WARNINGS/ADVISORIES. Tday. SCA . Pt Arena to Pt Reyes 0-10 nm from 2 PM SCA . Pigeon Pt to Pt Pinos 0-10 nm from 2 PM SCA . Pt Pinos to Pt Piedras Blancas 0-10 nm



PUBLIC FORECAST: RWW 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
RTYC1 - 9414523 - Redwood City, CA 7 mi57 min SE 1 G 1.9 65°F 73°F1018.6 hPa (-0.0)
AAMC1 - 9414750 - Alameda, CA 25 mi57 min WSW 1.9 G 5.1 61°F 68°F1018.1 hPa (+0.3)
LNDC1 26 mi57 min WSW 5.1 G 7 61°F 1017.8 hPa (+0.0)
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 27 mi57 min SW 6 G 8
OBXC1 28 mi57 min 61°F 61°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 28 mi57 min SSW 4.1 G 6 61°F 1017.8 hPa (+0.0)
PXSC1 29 mi57 min 62°F
PXOC1 - 9414311 - San Francisco (Pier 1), CA 29 mi57 min NNE 1 G 2.9 61°F 1016.7 hPa (+0.0)
FTPC1 - 9414290 - San Francisco, CA 31 mi57 min WSW 8 G 11 60°F 63°F1017.8 hPa (+0.0)
PPXC1 - 9414847 - Richmond (Point Potrero), CA 34 mi57 min S 11 G 14 61°F 1018 hPa (+0.0)
TIBC1 - Tiburon Pier, San Francisco Bay, CA 36 mi46 min Calm 69°F 1018 hPa
46237 - San Francisco Bar, CA (142) 37 mi57 min 59°F4 ft
RCMC1 - 9414863 - Richmond, CA 37 mi57 min SE 4.1 G 8 61°F 65°F1017.4 hPa (+0.0)
MZXC1 - 9415102 - Martinez-Amorco CA 40 mi57 min WSW 7 G 9.9 67°F 69°F1017.1 hPa (+0.3)
UPBC1 41 mi57 min W 7 G 9.9
PCOC1 - 9415144 - Port Chicago, CA 42 mi57 min SW 6 G 8.9 66°F 69°F1016.7 hPa (+0.0)
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 42 mi57 min W 9.9 G 15 69°F 1016.1 hPa (+0.0)
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 42 mi37 min NW 5.8 G 7.8 61°F 1018.5 hPa60°F
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 43 mi57 min WSW 7 G 9.9 66°F 1016.8 hPa (+0.0)
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 44 mi37 min WNW 3.9 G 5.8 59°F1018.2 hPa
ELXC1 - Elkhorn Slough Reserve, CA 48 mi72 min Calm 56°F 56°F
46092 - MBM1 48 mi48 min E 3.9 57°F 57°F1018.1 hPa (+1.3)
46042 - MONTEREY - 27NM West of Monterey Bay, CA 49 mi37 min NW 12 G 14 58°F 57°F1018 hPa58°F

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Mountain View, Moffett Field, CA3 mi2 hrsN 010.00 mi64°F60°F88%1017.9 hPa
San Carlos Airport, CA10 mi70 minN 010.00 miA Few Clouds64°F62°F94%1018.3 hPa
San Jose, San Jose International Airport, CA11 mi64 minN 010.00 miMostly Cloudy67°F61°F81%1017.8 hPa
Hayward, Hayward Air Terminal, CA15 mi63 minSSE 410.00 miMostly Cloudy67°F61°F81%1018.6 hPa
San Jose / Reid / Hillv, CA17 mi67 minN 010.00 miMostly Cloudy66°F62°F88%1018.3 hPa
Oakland, Metro Oakland International Airport, CA18 mi64 minW 810.00 miOvercast65°F61°F87%1017.8 hPa
San Francisco, San Francisco International Airport, CA18 mi61 minWNW 88.00 miOvercast63°F59°F87%1017.7 hPa
Half Moon Bay Airport, CA22 mi62 minNNW 60.25 miFog59°F59°F100%1018.6 hPa
Livermore, Livermore Municipal Airport, CA23 mi64 minWSW 310.00 miMostly Cloudy64°F61°F90%1017.3 hPa

Link to 5 minute data for KPAO

Wind History from PAO (wind in knots)
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Last 24hr--------------------------Calm4NE4N5N10N14N13--NW18--NW14
1 day ago--------------------------Calm344N8N11N16N14N16N14N8
2 days ago--------------------------Calm--N5N6N8NW12--N14NW14NW17
G22
NW14

Tide / Current Tables for Palo Alto Yacht Harbor, California
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Palo Alto Yacht Harbor
Click for Map
Thu -- 01:56 AM PDT     0.13 feet Low Tide
Thu -- 06:58 AM PDT     Sunrise
Thu -- 07:52 AM PDT     6.50 feet High Tide
Thu -- 02:18 PM PDT     3.24 feet Low Tide
Thu -- 03:09 PM PDT     Moonrise
Thu -- 07:01 PM PDT     Sunset
Thu -- 07:18 PM PDT     8.40 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.60.50.10.72.13.95.46.36.56.35.95.34.63.83.33.54.56.17.68.48.27.364.6

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
Thu -- 02:09 AM PDT     0.00 knots Slack
Thu -- 05:04 AM PDT     1.24 knots Max Flood
Thu -- 06:58 AM PDT     Sunrise
Thu -- 08:26 AM PDT     -0.01 knots Slack
Thu -- 12:00 PM PDT     -0.48 knots Max Ebb
Thu -- 02:15 PM PDT     0.00 knots Slack
Thu -- 03:09 PM PDT     Moonrise
Thu -- 04:40 PM PDT     0.75 knots Max Flood
Thu -- 07:01 PM PDT     Sunset
Thu -- 07:27 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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-1.1-0.7-0.10.61.11.21.10.80.3-0.1-0.3-0.4-0.5-0.4-0.10.30.70.70.60.2-0.2-0.5-0.8-1.1

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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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.