Sunday, September23, 2018 L-36.com


Marine Weather and Tides
Petaluma, 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 7:06PM Sunday September 23, 2018 5:41 AM PDT (12:41 UTC) Moonrise 5:49PMMoonset 4:27AM 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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PZZ531 San Francisco Bay South Of The Bay Bridge- 355 Am Pdt Sun Sep 23 2018
Today..W winds 5 kt...increasing to 5 to 15 kt in the afternoon.
Tonight..NW winds 5 to 15 kt.
Mon..NW winds 5 kt...becoming W 5 to 15 kt in the afternoon.
Mon night..NW winds 5 to 15 kt.
Tue..W winds 5 to 15 kt.
Wed..W winds 10 kt.
Thu..W winds 10 kt.
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 Petaluma, CA
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location: 38.22, -122.6     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 231147
afdmtr
area forecast discussion
national weather service san francisco bay area
447 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 4:47 am pdt Sunday... In 72 hours it went from
clear skies (thu) to southerly surge stratus fog (fri) to
widespread coastal stratus fog (sat), and now stratus fog coverage
confined to the immediate coast mainly from san mateo county south
to pt conception including the salinas valley. Satellite also shows
a few patches of stratus and fog near pt reyes.

Inland skies areVFR while on the coast the marine layer remains
compressed favoring vlifr-ifr CIGS and visibilities for the morning.

The 12z tafs are a blend of persistence and WRF model output. A dry
cool frontal boundary, a temporarily steepened northerly pressure
gradient, NW winds and additional compression and downslope drying
has entered the boundary layer reducing the marine stratus and fog
areal coverage as previously described; continuing erosion due to
weak cool air advection, not enough to mix out the marine inversion,
and NW winds should help lift vlifr-ifr toVFR fairly quickly later
on in the morning. Inland skies continueVFR. Low confidence on
stratus and fog coverage tonight into Monday morning.

Vicinity of ksfo...VFR tempo ifr cig 12z-15z. Light westerly wind
increasing by late morning with gusts possible up to 20-25 knots
in the afternoon and evening.VFR forecast tonight and Monday.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals... Vlifr-ifr til 17z-18z,VFR patchy MVFR late
morning into early afternoon. Ifr probably redeveloping tonight and
Monday 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 4:06 am pdt Sunday... 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.

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: canepa
marine: canepa
fire weather: dykema blier rww
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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 21 mi42 min 59°F 1011.1 hPa (-0.4)
RCMC1 - 9414863 - Richmond, CA 23 mi42 min 64°F
TIBC1 - Tiburon Pier, San Francisco Bay, CA 24 mi43 min SSE 7 56°F 1012 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 25 mi42 min 58°F 1012.1 hPa (-0.6)
PRYC1 - 9415020 - Point Reyes, CA 25 mi42 min 58°F1011.7 hPa (-0.4)
MZXC1 - 9415102 - Martinez-Amorco CA 28 mi42 min 59°F 66°F1011.3 hPa59°F
FTPC1 - 9414290 - San Francisco, CA 29 mi48 min 55°F 59°F1012.4 hPa
SFXC1 - San Francisco Bay Reserve, CA 30 mi57 min S 4.1 57°F 1011 hPa52°F
46237 - San Francisco Bar, CA (142) 30 mi42 min 58°F4 ft
PXSC1 31 mi48 min 57°F 55°F
PXOC1 - 9414311 - San Francisco (Pier 1), CA 31 mi42 min 56°F 1011.1 hPa (-0.4)
OKXC1 - 9414776 - Oakland (Berth 34), CA 32 mi42 min 57°F 1012.1 hPa (-0.4)
PCOC1 - 9415144 - Port Chicago, CA 32 mi42 min 59°F 67°F1010.9 hPa (-0.6)
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 32 mi114 min SSW 1.9 G 5.1
OBXC1 32 mi42 min 58°F 57°F
LNDC1 34 mi42 min 58°F 1012.1 hPa (-0.4)
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 35 mi32 min WNW 7.8 G 9.7 55°F 55°F1012.9 hPa
AAMC1 - 9414750 - Alameda, CA 35 mi48 min 58°F 67°F1012.3 hPa
46013 - Bodega Bay - 48NM North Northwest of San Francisco, CA 37 mi32 min NW 18 G 21 51°F1012 hPa
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 40 mi42 min 64°F 1010.2 hPa (-0.4)

Wind History for Richmond, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Petaluma Municipal Airport, CA3 mi47 minN 07.00 miOvercast48°F48°F100%1011.8 hPa
Novato / Gnoss Field, CA6 mi67 minN 01.25 miFog/Mist48°F46°F94%1011.8 hPa
Napa, Napa County Airport, CA17 mi48 minN 410.00 miFair49°F48°F97%1010.8 hPa
Santa Rosa, Santa Rosa Sonoma County Airport, CA23 mi49 minN 010.00 miFair47°F45°F93%1010.8 hPa

Wind History from O69 (wind in knots)
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Last 24hrW4NW3W5W85CalmW765
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W9W9W7NW4NW5NW4CalmCalmCalmCalmCalmCalmCalmCalm
1 day agoCalmCalmCalmCalmCalmCalmCalmN5NW6NW6W10
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4NW4CalmW555W75NW6W5
2 days agoN3CalmCalmCalmCalmCalmCalmCalm55
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5W5CalmCalmCalmCalmCalmCalmCalmCalmCalmCalm

Tide / Current Tables for Upper drawbridge, Petaluma River, San Pablo Bay, 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 Petaluma River Approach, San Pablo Bay, 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 (8,2,3,4)
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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.