Thursday, May25, 2017

Marine Weather and Tides
Point Arena, CA

Version 3.4
What's New / NOTES
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.

Sunrise 5:51AMSunset 8:22PM Thursday May 25, 2017 9:06 AM PDT (16:06 UTC) Moonrise 5:24AMMoonset 7:38PM Illumination 0% Phase: New Moon; Moon at 0 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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7 Day Forecast for Marine Location Near Point Arena, CA
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location: 36.95, -126.32     debug

Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 251500
area forecast discussion
national weather service san francisco bay area
800 am pdt Thu may 25 2017

Synopsis Seasonably cool today into Friday with a deep marine
layer near the coast. Seasonable temperatures on Saturday should
trend warmer inland by Sunday and memorial day Monday. Aside from
the isolated coastal drizzle, dry weather forecast through the
next 7 to 10 days.

Discussion As of 08:00 am pdt Thursday...

only made minor tweaks to the short-term forecast with sky cover.

Satellite reveals an extensive marine layer intruding well inland
through the delta pushing up against the sierra foothills. Fort
ord profiler indicates the marine layer depth has steadily
deepened over the past 24 hours to over 3500 ft this morning and
is approaching 4000 ft. There have also been some reports of
drizzle or even light rain associated with the low clouds in the
north bay. Santa rosa ASOS has reported several one-hundreds of an
inch since midnight.

Upper level low continues to approach the central california coast
and will help to maintain the downward trend in afternoon highs
through the end of the work week. MAX temps for many inland
locations will be anywhere from 5 to perhaps as much as 15 degrees
below normal for late may. The cool weather will be short-lived,
however, as a ridge will be quick to build over the west coast for
the holiday weekend with temperatures rebounding back to normal or
even several degrees above normal. Guidance suggests that the
southern salinas valley may return back to low 90s as early as
Sunday. While the inland areas ride their temperature roller
coaster, coastal locations influenced by low clouds will struggle
to see temperatures change any more than 5 degrees over the
forecast period. The only chance for precipitation over the next 7
days will be for coastal areas that may see isolated drizzle or
light rain.

Prev discussion As of 3:23 am pdt Thursday... Profiler data shows
the marine layer has deepened in excess of 3000 feet with cooler
air aloft keeping the inversion weak. This has allowed deep inland
penetration of marine clouds with a finger now pushing out into
the delta while nearly the entire north bay is completely
inundated as well. Onshore gradient is only 2 mb from sfo to sac
but gusts from 20 to 30 kt are showing up at angel island, concord
and travis which is a sure sign of another cool day for inland
areas with highs struggling to reach 70. In addition to the
extensive cloud cover and onshore push the models continue to show
some drizzle along the coast from half moon bay to big sur this
morning. Forecast grids will continue to show some patchy drizzle
this morning as the Sun comes up, just enough to wet the surfaces
but only expecting trace amounts.

The upper pattern wont change too much on Friday with cyclonic
flow aloft and onshore flow at the surface keeping temps on the
cool side of normal.

As is typical this time of year day to day changes can be hard to
nail down as the subtle marine perturbations can drive the daily
patterns. However the general trend of the holiday weekend shows
near normal temperatures on Saturday then climbing back to above
normal for inland areas on Saturday and Sunday as high pressure
briefly rebuilds. All in all it looks to be a nice holiday weekend
with dry conditions and no excessively hot inland weather. Longer
range trends portend a dry and seasonable pattern through much of
next week as we head into june.

Aviation As of 04:45 am pdt Thursday... Marine layer intrusion
across the region is now extending into the central valley. Bases
are much higher versus yesterday, bringing primarily MVFR toVFR
cigs to regional TAF sites. Expect to see similar ceilings through
16z with mixing out by 18z-19z for bay area sites. Stratus will
remain over the monterey bay TAF sites through most of the day.

Stratus returns tonight. Otherwise, breezy to occasionally gusty
west to southwest winds, especially along the coast in the
afternoon and evening.

Vicinity of ksfo... Breezy southwest winds through the morning
increasing and becoming more westerly by the early afternoon. MVFR
cigs mixing out between 1730-1830z. Stratus returns 05-07z fri.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals... MVFR through the day with brief pockets
of sunlight midday. Breezy onshore winds, especially in the
afternoon and evening.

Marine As of 07:47 am pdt Thursday... Increasing south to
southwest winds along the coastline today... Especially along the
big sur coast. These winds will generate steep fresh swell in the
vicinity. Otherwise light seas. High pressure will redevelop over
the eastern pacific just prior to the memorial day weekend
bringing a return to more typical afternoon and evening onshore
winds to the coastal waters and bays.

Mtr watches warnings advisories
Tday Sca... Pt arena to pigeon pt 10-60 nm
sca... Mry bay from 9 am
sca... Pt pinos to pt piedras blancas 0-10 nm from 9 am
sca... Sf bay from 3 pm
public forecast: rowe rww
aviation: drp
marine: drp
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Airport Reports
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Tide / Current Tables for
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Weather Map and Satellite Images
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Weather Map
IR Satellite Image from GEOS

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Wind Forecast for San Francisco/Monterey Bay Area, CA (12,3,4,5)
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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 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 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.