Sunday, September23, 2018 L-36.com


Marine Weather and Tides
Lagunitas-Forest Knolls, CA

Version 3.4
What's New / NOTES
9/17/2018 XTide broke when 1and1 "upgraded" my server. It has been esculated. I am sorry for the problem.

Sunrise 6:58AMSunset 7:05PM Sunday September 23, 2018 4:52 AM PDT (11:52 UTC) Moonrise 5:50PMMoonset 4:28AM Illumination 98% Phase: Waxing Gibbous; Moon at 13 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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PZZ545 Point Reyes To Pigeon Point To 10 Nm- 355 Am Pdt Sun Sep 23 2018
Today..NW winds 10 to 20 kt. Wind waves 2 to 4 ft. NW swell 3 ft at 9 seconds.
Tonight..NW winds 10 to 20 kt. Wind waves 2 to 4 ft. NW swell 4 to 6 ft at 9 seconds.
Mon..W winds 10 kt. Wind waves 2 ft or less. NW swell 3 to 5 ft at 9 seconds.
Mon night..SW winds 10 kt. Wind waves 2 ft or less. NW swell 4 to 5 ft at 9 seconds.
Tue..W winds 10 kt. Wind waves 2 ft or less. NW swell 3 to 5 ft at 9 seconds.
Wed..NW winds 10 kt. Wind waves 2 ft or less. NW swell 3 to 5 ft.
Thu..W winds 10 kt. Wind waves 2 ft or less. NW swell 3 to 4 ft.
...san francisco bar/fourfathom bank forecast..... In the deep water channel...combined seas 3 to 4 ft with a dominant period of 8 seconds. Across the bar...combined seas 4 to 5 ft with a dominant period of 8 seconds. Maximum ebb current of 2.4 knots at 03:25 pm Sunday and 2.2 knots at 03:37 am Monday.
PZZ500 355 Am Pdt Sun Sep 23 2018
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... A trough will remain nearly stationary along the california coast while strong high pressure becomes stationary off the pacific northwest coast. Gusty northwesterly winds will spread across the coastal waters today while onshore winds become gusty over the bays this afternoon and evening. An extension of high pressure will build into the northern great basin tonight and again Monday night into Tuesday. Winds over the coastal waters and bays will be much lighter by later Monday, possibly becoming variable or light southerly early Tuesday morning. Westerly to northwesterly winds return Tuesday afternoon into Thursday.


7 Day Forecast for Marine Location Near Lagunitas-Forest Knolls, CA
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location: 37.98, -122.74     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 231032
afdmtr
area forecast discussion
national weather service san francisco bay area
332 am pdt Sun sep 23 2018

Synopsis An upper level trough moving across far northern
california will likely maintain a cooling trend for inland areas
today. High pressure will begin building inland to our north and
east tonight. This will result in dry offshore winds and fire
weather concerns for the north bay hills from tonight through
Tuesday. Also, expect much warmer conditions by Tuesday and
Wednesday, with temperatures warming well above seasonal
averages. Temperatures will cool late in the week as an upper low
approaches from the west.

Discussion As of 3:30 am pdt Sunday... Water vapor satellite
imagery shows an upper trough beginning to move across the pacific
northwest and far northern california early this morning. Would
typically expect the marine layer to deepen and onshore flow to
increase under such a scenario, but latest observations indicate
this is not happening. In fact, latest fort ord profiler data
shows the marine layer remaining relatively shallow with a depth
of about 1000 feet. Also, onshore pressure gradients have been
trending weaker. In addition, low clouds early this morning are
less extensive compared to 24 hours ago. These factors call into
question previous forecast thinking that the cooling trend would
continue today, especially inland. Based on current trends, the
most likely outcome will be temperatures near persistence in most
areas. And, with less coastal stratus, some coastal areas may
experience slight warming today.

After the upper trough moves off to our east late today, an upper
ridge is forecast to build off the coast of the pacific northwest
and southward along the northern california coast. Also, surface
high pressure will build inland to our north and east by late
tonight, causing winds in the hills to shift from westerly to
north or northeast, especially in the north bay mountains. Locally
gusty offshore winds in the north bay mountains could result in
critical fire weather conditions at higher elevations from tonight
through Tuesday. See fire weather discussion below for details on
the fire weather watch and fire weather concerns.

Building high pressure aloft during the first half of the week and
weak offshore flow will result in a robust warming trend from
Monday through Wednesday. Widespread highs in the 90s are likely
across inland areas by Tuesday and Wednesday. Coastal temperatures
will be more difficult to predict as they will be very dependent
on the strength of offshore flow. Current WRF model indicates
very weak onshore flow will prevail at the surface with light
offshore flow just above. Such a scenario would mean coastal temps
will mostly remain in the 70s to lower 80s. But if offshore flow
is stronger than anticipated, coastal areas could warm well into
the 80s or even a few lower 90s by Tuesday and Wednesday.

The upcoming warm-up will result in uncomfortably warm daytime
conditions across much of our area from Tuesday through Thursday,
but heat risks are expected to remain low to moderate for the most
part due to long autumn nights and cool overnight lows.

A rex block is forecast to develop offshore by midweek as an upper
low begins to undercut the upper high. The models agree that the
low will slowly undercut the ridge and approach the california
coast during the second half of the week. Cooling due to the low's
approach will likely commence as early as Thursday, but only a
slight downturn in temperatures is expected that day. Much more
significant cooling is then anticipated by Friday and Saturday.

Both the ECMWF and GFS generate spotty light precipitation as the
low moves inland by early Saturday. Since this is still 7 days
out, will hold off on adding any rain chances to the forecast.

The longer range models forecast a second upper low to move
onshore by early october. The 00z ECMWF is particularly
interesting with this second system, forecasting widespread
significant rainfall across our area on october 1st and 2nd.

Aviation As of 10:35 pm pdt Saturday... For 06z tafs. The
marine layer remains at around 1400 ft per the fort ord profiler
while satellite imagery shows stratus along much of the coast. A
strong northerly gradient has eroded some of the stratus, making
for an uncertain overnight forecast in terms of timing of ifr cigs
around the bay area and north bay TAF sites. Any CIGS that do
develop are expected to remain in place through 16z-18z tomorrow.

Generally light winds overnight and tomorrow morning before
onshore winds increase in the afternoon to 10-15 kt.

Vicinity of ksfo...VFR through tonight. Ifr CIGS by around 10z-
11z, although confidence is low on timing. Onshore winds tomorrow
afternoon around 15 kt.

Sfo bridge approach... Same as terminal.

Monterey bay terminals... Lifr CIGS overnight with possible patchy
fog in the early morning.

Fire weather As of 3:00 am pdt Sunday... Fire weather watch
remains in effect for the north bay mountains from 11 pm Sunday
night through Tuesday afternoon. North to northeast winds will
develop over napa county tonight and drive humidity lower during
the pre-dawn hours of Monday. This offshore wind event looks
moderate, especially in terms of wind strength, but confidence is
pretty high on offshore pattern developing. Fuels remain
critically dry, so any new starts will be susceptible to the
winds, low humidities and dry fuels. Biggest threat area looks to
be napa county hills, northeast sonoma county and around mt tam.

Winds will ease during the day Monday as temperatures warm up
around 89.

Offshore winds then look to redevelop of similar magnitude Monday
night into Tuesday morning, but with an even drier air mass then
moving in. Overnight humidity recoveries could then well be
confined to around 20 percent or even less. Temperatures are
forecast to continue climbing and widespread 90s are likely across
inland areas Tuesday and Wednesday. But winds are expected to be
light after Tuesday. Cooling is forecast late in the week.

Marine As of 08:15 pm pdt Saturday... Northwest winds will
gradually increase across the coastal waters through tomorrow. The
strongest winds are expected north of point reyes. Winds will
begin to subside into the start of the work week and remain
relatively light through the forecast period. Mixed swell will
continue as well, with a shorter period moderate height northwest
swell and a weak, longer period southerly swell.

Mtr watches warnings advisories
Tday Sca... Pigeon pt to pt pinos 0-10 nm from 9 am
sca... Pt arena to pigeon pt 10-60 nm
sca... Pigeon pt to pt piedras blancas 10-60 nm
sca... Pt pinos to pt piedras blancas 0-10 nm from 9 am
sca... Pt arena to pt reyes 0-10 nm
sca... Mry bay from 2 pm
public forecast: dykema
aviation: as
marine: as
fire weather: dykema blier rww
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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
PRYC1 - 9415020 - Point Reyes, CA 13 mi34 min 58°F1011.9 hPa
46237 - San Francisco Bar, CA (142) 15 mi52 min 58°F4 ft
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 16 mi32 min NW 5.8 G 7.8 55°F 55°F1012.9 hPa
TIBC1 - Tiburon Pier, San Francisco Bay, CA 17 mi35 min SSW 4.1 56°F 1012 hPa
RCMC1 - 9414863 - Richmond, CA 18 mi34 min 64°F
FTPC1 - 9414290 - San Francisco, CA 19 mi40 min 55°F 59°F1012.3 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 21 mi34 min 58°F 1012.3 hPa
PXSC1 22 mi40 min 58°F 55°F
PXOC1 - 9414311 - San Francisco (Pier 1), CA 22 mi34 min 57°F 1011 hPa
OBXC1 24 mi34 min 58°F 56°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 25 mi64 min SSW 1.9 G 5.1
OKXC1 - 9414776 - Oakland (Berth 34), CA 25 mi34 min 57°F 1012 hPa
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 26 mi34 min 60°F 1011.2 hPa
AAMC1 - 9414750 - Alameda, CA 27 mi40 min 57°F 67°F1012.4 hPa
LNDC1 27 mi34 min 58°F 1012 hPa
MZXC1 - 9415102 - Martinez-Amorco CA 33 mi34 min 67°F
46013 - Bodega Bay - 48NM North Northwest of San Francisco, CA 35 mi32 min NW 19 G 23 51°F1011.9 hPa
PCOC1 - 9415144 - Port Chicago, CA 38 mi34 min 59°F 67°F1011.2 hPa
46214 - Point Reyes, CA (029) 39 mi52 min 54°F8 ft
SFXC1 - San Francisco Bay Reserve, CA 41 mi67 min W 4.1 58°F 1011 hPa53°F
RTYC1 - 9414523 - Redwood City, CA 43 mi34 min 56°F 70°F1012.8 hPa
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 45 mi34 min 65°F 1010.4 hPa

Wind History for Point Reyes, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Novato / Gnoss Field, CA15 mi77 minN 010.00 miFair50°F48°F94%1012.2 hPa
Petaluma Municipal Airport, CA20 mi57 minN 010.00 miFair46°F46°F100%1012.2 hPa

Wind History from DVO (wind in knots)
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Last 24hrCalmCalmCalmCalmCalmCalmCalm3SE354NW13N13N7
G13
N7N6N5N5CalmCalmCalmCalmCalmCalm
1 day agoCalmCalmCalmCalmCalmCalmSE4SE4E5SE8SE7NE7N12N12N14N11N10N6NW5N9NW3CalmCalmCalm
2 days agoCalmS4S3CalmCalmCalmCalmSE7SE10E6E7SE85N7N8W5CalmSE5CalmCalmCalmCalmS3Calm

Tide / Current Tables for Bolinas Lagoon, California
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Tide / Current Tables for Point Reyes, California Current
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Weather Map and Satellite Images
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wmap_P
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.
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Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for San Francisco/Monterey Bay Area, CA (7,2,3,4)
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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.