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Marine Weather and Tides
Version 3.4 |
3/3/2018 - There is a new GOES Satellite for the east coast that required rewriting that part of the code. Please report any issues. 6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported. 5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive. |
Sunrise 6:20AM | Sunset 7:55PM | Monday April 23, 2018 8:01 PM PDT (03:01 UTC) | Moonrise 12:24PM | Moonset 1:51AM | Illumination 63% | ![]() |
Marine Forecasts
EDIT (on/off)  HelpPZZ530 San Pablo Bay Suisun Bay The West Delta And San Francisco Bay North Of The Bay Bridge- 721 Pm Pdt Mon Apr 23 2018 .small craft advisory in effect until 10 pm pdt this evening... Tonight..SW winds 15 to 30 kt...winds decreasing to 10 to 20 kt late. Tue..SW winds 10 to 20 kt...with afternoon gusts to 25 kt possible. Tue night..SW winds 10 to 20 kt...evening gusts to 25 kt. Wed..SW winds 5 to 15 kt. Wed night..SW winds 10 to 20 kt. Thu..SW winds 10 to 20 kt...decreasing to 10 kt. Fri..SW winds 5 to 15 kt. Sat..W winds 5 to 15 kt. Slight chance of showers. | PZZ500 721 Pm Pdt Mon Apr 23 2018 Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Northwest winds will remain light to moderate through most of the week as an area of low pressure approaches the coast. Onshore winds will remain strong and gusty north of the bay bridge this evening, possibly gusty into the overnight hours. Light to moderate seas will prevail through the forecast period with a mixed southerly and northwesterly swell developing late this week. |
7 Day Forecast for Marine Location Near Novato, CA
Hourly EDIT Helplocation: 38.1, -122.59 debug
Area Discussion for - San Francisco/Monterey Bay Area, CA
  (on/off)  Help NOTE: mouseover dotted underlined text for definitionFxus66 kmtr 240043 afdmtr area forecast discussion national weather service san francisco bay area 543 pm pdt Mon apr 23 2018 Synopsis Dry and seasonably warm conditions will continue today. A cooling trend is forecast from Tuesday through the end of the week as an area of low pressure offshore slowly approaches the coast. This low pressure may produce scattered showers from late Friday into Saturday, mainly across the north. Discussion As of 01:27 pm pdt Monday... Sunny skies prevail across most of the bay area this afternoon. The sunshine and light winds have allowed for well above normal temperatures away from the coast. Afternoon temps will likely top out in the 70s to mid 80s. Just like during the summer months, different story at the coast. Weak pressure gradients n-s and e-w have kept low clouds along the coast, mainly san mateo coast southward. Made some late day adjust to the forecast to lower temps around the monterey bay and keep clouds through the afternoon. Otherwise, only minor tweaks were made to the forecast. High pressure will continue to weaken as an upper low currently spinning off the west coast slowly tracks eastward. Night and morning low clouds will continue through Wednesday and possibly mix out completely by Thursday Friday. The lower 500mb heights and cooler 850mb temps will translate to a slight downward trend in daytime high temperatures. Temps by Wednesday will be closer to normal (60s coast, 70s to lower 80s inland) and possibly below normal by Thursday (60s 70s). The track of upper lows are always difficult to forecast, especially in the medium to long range. The 12z model run didn't shed any new light on the rain potential Friday into Saturday. Model consensus brings an upper low into far norcal with some precip possible across the north bay. Confidence is low and will maintain the slight chc of showers sf bay northward. QPF looks to be minimal at this point. Aviation As of 5:43 pm pdt Monday... It's a summer-like afternoon, cooler ocean to warmer hot land temperature (and pressure) contrasts have steepened, coastal stratus and fog are hugging the coastline. The onshore pressure gradient sfo-sac is 1.4 mb while southerly pressure gradients smx-sfo and sns-sjc are a bit stronger at 2.0 mb and 3.3 mb (strong) respectively, under- forecast by recent NAM output and sufficient for the development of a coastally trapped southerly wind reversal if these readings held, however coastal buoys are mostly showing wsw-w wind direction and stratus and fog motion following suite presently. |
The southerly gradients may relax by mid-late evening, however it'll be relatively short-lived as southerly gradients should strengthen again Tuesday into Tuesday night. The marine layer slopes from approx 1000 feet in the bay area to 1400 feet north central coast per profiler data. With exception of ksfo, koak, ksjc, klvk 00z tafs are geared a little more toward ifr CIGS and visibilities developing this evening. Conditions are ideal for ifr lifr vlifr tonight into Tuesday morning along the immediate coast with some inland intrusion through the golden gate. With exception of a strengthening offshore pressure gradient wmc-sfo reaching near 10 mb (nam model showing ~ 4 mb onshore bias) by early Tuesday morning the large scale pattern is otherwise nearly persistence for tonight into Tuesday. The developing offshore gradient may tend to hold areal coverage of stratus and fog at a minimum into the bay area tonight, the offshore gradient will be weaker Tuesday night into Wednesday thus allowing a better set up for stratus and fog intrusion at that time. Vicinity of ksfo...VFR, w-nw wind with occasional gusts to 20-25 knots til 04z. Near high confidenceVFR holds this evening based on present depth of the marine layer (near 1000 feet) and little lower level temperature change tonight. Radiative cooling improves tonight with a clear sky, near surface cooling is a little more pronounced Tuesday morning which may result in a patch or two of fog or low stratus, but for now going with aVFR forecast looks good. Sfo bridge approach... Similar to ksfo. Monterey bay terminals... Visible imagery shows stratus and fog nearby, w-nw wind flow should bring in ifr early this evening. Tempo ifr 00z-03z, prevailing ifr lifr for the overnight hours. Late morning mixing should help result in a return ofVFR for the area terminals. Stratus and fog likely to roll back inland early Tuesday evening. Marine As of 4:57 pm pdt Monday... Northwest winds will remain light to moderate through most of the week as an area of low pressure approaches the coast. Light to moderate seas will prevail through the forecast period with a mixed southerly and northwesterly swell developing late this week. Mtr watches warnings advisories Tday None. Public forecast: mm aviation: canepa marine: as visit us at |
Weather Reporting Stations
EDIT (on/off)  Help NOTE: Click on distance to see the station location on a mapWind History for Richmond, CA
(wind in knots) EDIT (on/off)  Help8 PM | 9 PM | 10 PM | 11 PM | 12 AM | 1 AM | 2 AM | 3 AM | 4 AM | 5 AM | 6 AM | 7 AM | 8 AM | 9 AM | 10 AM | 11 AM | 12 PM | 1 PM | 2 PM | 3 PM | 4 PM | 5 PM | 6 PM | 7 PM | |
Last 24hr | SE | SE | S | S | S G10 | S | S | S | S | S | -- | W | S | S | S | SE | SE | S | S G7 | S G10 | SW G7 | SW G7 | SW | SW |
1 day ago | SE | SE | S | S G9 | S G10 | S G9 | S G7 | S | S G8 | S G6 | SW | NW | NW | NW | SW | W | NW | W G7 | S | S | S G10 | S | SE | SE G5 |
2 days ago | SE G7 | SE G11 | SE G13 | S G13 | S | SE G10 | S G12 | S | S G7 | S | S | W | W | SE | S | SW | NW | NW | S | S | S | S | SE | SE G6 |
Airport Reports
EDIT (on/off)  Help Click EDIT to display multiple airportsAirport | Dist | Age | Wind kt | Visibility | Sky/Weather | Temp | DewPt | Humidity | Pressure |
Novato / Gnoss Field, CA | 4 mi | 67 min | NNW 15 G 20 | 10.00 mi | Fair | 66°F | 55°F | 68% | 1013.5 hPa |
Petaluma Municipal Airport, CA | 11 mi | 67 min | NW 6 | 9.00 mi | Fair | 63°F | 50°F | 64% | 1014.6 hPa |
Napa, Napa County Airport, CA | 18 mi | 68 min | S 10 | 10.00 mi | Fair | 65°F | 55°F | 70% | 1012.8 hPa |
Wind History from DVO (wind in knots)
9 PM | 10 PM | 11 PM | 12 AM | 1 AM | 2 AM | 3 AM | 4 AM | 5 AM | 6 AM | 7 AM | 8 AM | 9 AM | 10 AM | 11 AM | 12 PM | 1 PM | 2 PM | 3 PM | 4 PM | 5 PM | 6 PM | 7 PM | 8 PM | |
Last 24hr | N | SE | N | Calm | N | Calm | Calm | Calm | Calm | Calm | Calm | SE | Calm | Calm | Calm | Calm | E G12 | SE | SE | N | N | N G18 | ||
1 day ago | NE | N | N | N | Calm | Calm | Calm | Calm | NW | Calm | NW | Calm | Calm | Calm | Calm | E | Calm | Calm | Calm | Calm | N | N | N | N |
2 days ago | E | Calm | E | Calm | NW | Calm | Calm | Calm | Calm | S | Calm | Calm | Calm | Calm | Calm | N | Calm | Calm | NW | N G15 | N | Calm |
Tide / Current Tables for Hog Island, San Antonio Creek, San Pablo Bay, California
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of DataHog Island Click for Map Mon -- 02:50 AM PDT Moonset Mon -- 02:59 AM PDT 2.10 feet Low Tide Mon -- 06:23 AM PDT Sunrise Mon -- 07:53 AM PDT 5.48 feet High Tide Mon -- 01:24 PM PDT Moonrise Mon -- 03:32 PM PDT -0.24 feet Low Tide Mon -- 07:54 PM PDT Sunset Mon -- 10:11 PM PDT 5.28 feet High Tide Tide / Current data from XTide NOT FOR NAVIGATION |
12am | 1am | 2am | 3am | 4am | 5am | 6am | 7am | 8am | 9am | 10am | 11am | 12pm | 1pm | 2pm | 3pm | 4pm | 5pm | 6pm | 7pm | 8pm | 9pm | 10pm | 11pm |
3.6 | 2.8 | 2.3 | 2.1 | 2.4 | 3.3 | 4.3 | 5.2 | 5.5 | 5.2 | 4.5 | 3.5 | 2.3 | 1.1 | 0.3 | -0.2 | -0.2 | 0.4 | 1.4 | 2.6 | 3.8 | 4.8 | 5.3 | 5.1 |
Tide / Current Tables for Petaluma River Approach, San Pablo Bay, California Current
EDIT (on/off)  Help One Week of DataPetaluma River Approach Click for Map Mon -- 02:09 AM PDT 0.00 knots Slack Mon -- 02:49 AM PDT Moonset Mon -- 04:26 AM PDT 0.51 knots Max Flood Mon -- 06:23 AM PDT Sunrise Mon -- 07:45 AM PDT -0.00 knots Slack Mon -- 11:22 AM PDT -0.79 knots Max Ebb Mon -- 01:23 PM PDT Moonrise Mon -- 03:22 PM PDT 0.00 knots Slack Mon -- 06:43 PM PDT 0.65 knots Max Flood Mon -- 07:53 PM PDT Sunset Mon -- 10:07 PM PDT -0.00 knots Slack Tide / Current data from XTide NOT FOR NAVIGATION |
12am | 1am | 2am | 3am | 4am | 5am | 6am | 7am | 8am | 9am | 10am | 11am | 12pm | 1pm | 2pm | 3pm | 4pm | 5pm | 6pm | 7pm | 8pm | 9pm | 10pm | 11pm |
-0.4 | -0.3 | -0 | 0.3 | 0.5 | 0.5 | 0.4 | 0.2 | -0.1 | -0.4 | -0.7 | -0.8 | -0.8 | -0.7 | -0.4 | -0.1 | 0.2 | 0.5 | 0.6 | 0.6 | 0.5 | 0.3 | 0 | -0.3 |
Weather Map and Satellite Images
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GOES 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
Wind Forecast for San Francisco/Monterey Bay Area, CA (23,6,7,8)
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Ground Weather Radar Station Sacramento, CA
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Disclaimer: 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 numerious 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. |