Saturday, June23, 2018 L-36.com


Marine Weather and Tides
San Francisco, CA

Version 3.4
What's New / NOTES
5/20/2018 -- NOAA is having problems with the data feed that I use to draw the graphs. They are aware of the issue and working to resolve it. Sometimes changing the location by about a mile will give a correct graph. 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.

Sunrise 5:47AMSunset 8:36PM Saturday June 23, 2018 8:10 PM PDT (03:10 UTC) Moonrise 3:35PMMoonset 2:03AM Illumination 82% Phase: Waxing Gibbous; Moon at 11 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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PZZ530 San Pablo Bay Suisun Bay The West Delta And San Francisco Bay North Of The Bay Bridge- 652 Pm Pdt Sat Jun 23 2018
.small craft advisory in effect from 5 am pdt Sunday through Sunday evening...
Tonight..SW winds 10 to 20 kt.
Sun..SW winds 15 to 25 kt.
Sun night..SW winds 15 to 25 kt. Patchy fog after midnight.
Mon..SW winds 10 to 20 kt. Patchy fog in the morning.
Mon night..SW winds 10 to 20 kt. Patchy fog after midnight.
Tue..SW winds 15 to 25 kt. Patchy fog.
Wed..SW winds 10 to 20 kt. Patchy fog.
Thu..W winds 10 to 20 kt. Patchy fog.
PZZ500 652 Pm Pdt Sat Jun 23 2018
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... High pressure over the eastern pacific and a thermal trough over inland california will keep gusty northerly winds across the coastal waters through tonight. Gusty winds will generate steep wind waves creating hazardous sea conditions, particularly for small vessels. Winds will subside tonight as a southerly surge pushes northward shifting the winds along the inner coastal waters out of the south. Winds will pick up again on Monday as an upper trough moves through to the north.

7 Day Forecast for Marine Location Near San Francisco, CA
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location: 37.81, -122.44     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 240117
afdmtr
area forecast discussion
national weather service san francisco bay area
617 pm pdt Sat jun 23 2018

Synopsis Very warm to hot temperatures are forecast for the
interior today as high pressure dominates the weather pattern.

Additionally, offshore winds will develop and result in heightened
fire weather concerns for portions of the region today through
Sunday. Cooling is then expected by Sunday and into early in the
upcoming week with increased onshore flow.

Discussion As of 2:45 pm pdt Saturday... A 594dm 500mb high
pressure dome of hot, dry air is amplifying along the west coast
early this afternoon. 850mb temperatures are expected to push into
the 25-26c range within the next few hours as the ridge builds
inland. This warm air advection and subsidence of this air mass
will translate into one of the hottest days of the year for most
inland locations, with temperatures on average 12 to 20 degrees
above seasonal normals. Many of the hottest locations, such as the
inland east bay, pinnacles national park, and the northern reaches
of the north bay have already broken triple digits as of early
this afternoon with several more hours of sunlight remaining. 104f
at arroyo seco raws is the highest temperature reported as of 2pm
and is expected to push beyond 105f by the end of the day.

Temperatures are noticeably cooler closer to the coast, running
only 3 to 6 degrees above normal, but temperatures ramp up quickly
away from the coast. These temperatures are around 2 standard
deviations above the norm, which generally does not translate to
record temperatures (usually 3+ standard deviations are required),
however, concords record of 102f set in 2017 will likely be
challenged in the next few hours. Kccr (concord airports asos
identifier) is currently sitting at 101f as of 2pm, with more
warming ahead.

A heat advisory (sfonpwmtr) is in effect as a result of these
temperatures thru the daylight hours of the day. Stay out of
direct sunlight, stay hydrated, listen to your body for signs of
heat exhaustion, check on vulnerable pets, plants, and populations
through the day, and never leave your child in a hot vehicle.

Also considering visiting the coastal areas today as temperatures
will be much more mild for coastal areas. If you do choose to
visit ocean coastal areas remember that the water is still very
cold!
in addition to the heat, dry gusty N NE winds will develop
through the weekend aimed primarily and the north and east bay
hills mountains. Mount diablo has already gusted to 60mph as of
445am this morning, and several other locations in the
aforementioned areas have reached 40 mph. Winds were expected to
weaken slightly during the day today (and have) but will pick up
again this evening into tomorrow morning. As a result of the heat
and dry offshore flow, relative humidity values will drop into
the upper single digits to low teens in the warmest windiest
locations by this afternoon. This means that there is a greatly
increased risk that any new fires that start will spread rapidly.

As a result, a red flag warning is in effect (sforfwmtr) for these
areas through tomorrow. Be mindful of any outdoor activities that
could ignite new fires, such as discarded hot or burning objects
from cars, lighting campfires, barbecues, or fireworks, driving
cars over dry grass, or using anything with a motor including lawn
equipment.

Satellite imagery showed the development of a southerly surge
along our coast early this morning. This is a moist cool maritime
air mass that generally jets up the coast in the back side of our
heat spikes heat waves. The arrival of this southerly surge was
not unexpected, however, it did arrive a bit sooner than any model
had indicated. The southerly surge was halted as it approached
point sur once it was no longer sheltered from the dry northerly
flow waiting for it past the lighthouse. This dry northerly flow
rapidly entrained dry air into the shallow southerly surge, drying
it out, and weakening its momentum. The msl analysis showed the
center of a weak circulation driving this surge off the coast,
which stalled and then further cut off the surge by undercutting
it with more dry around midday. That said, we are expecting the
shallow southerly surge to eventually break through the resistance
at the lighthouse and creep up the coast towards the monterey
peninsula. No significant impacts are expected to come from this
southerly surge until it deepens and pushes farther northward
tomorrow. Then and only then is it expected to bring a return
towards a maritime-dominated air mass over most of the san
francisco and monterey bay areas, with cooler temperatures and
cloudy skies near the coast. A return to near normal temperatures
are then expected through the upcoming week as weak onshore flow
redevelops under a benign quasi zonal setup.

Aviation As of 6:17 pm pdt Saturday... Surface winds over the
coastal waters are currently driven by mainly two opposing pressure
gradients, an ongoing healthy 7.9 mb northerly acv-sfo gradient
and a steadily climbing 4.4 mb southerly smx-sfo gradient; a surface
ridge is located over the central coast and trough over the bay area.

Also in the mix for tonight will be a steadily strengthening offshore
wmc-sfo pressure gradient nearing 10 mb (after correcting for onshore
bias) possibly keeping the more locally onshore sfo-sac gradient
tempered near neutral into Sunday morning.

Good chancesVFR will prevail at all area terminals this evening
except areas of MVFR vsbys in haze and patchy ifr in fog and stratus
reaching northward on the immediate coastline. Based on the gradient
picture, hi-res models are missing onset of a southerly wind reversal
thus TAF wind forecasts are low to moderate confidence at best. Strong
land to ocean temperature contrasts, development of locally driven
onshore wind and newly developing southerly surge will determine winds
and eventually fog and stratus intrusion behavior late tonight into
Sunday.

Wrf model output also indicates gusty n-ne low levels winds spreading
over sonoma and napa counties late tonight and Sunday morning which
may cause a brief period of low level wind shear; worth mentioning
but not enough to add llws to ksts 00z TAF at this time, elsewhere
to the south and east lighter low level winds are forecast. Offshore
component to the winds tonight will be monitored closely as this
will determine strength of potential low level winds entering the
bay area.

Vicinity of ksfo... Near high confidenceVFR prevails this evening,
westerly wind near 15 knots. Depending how the southerly pressure
gradient overlaps the south bay and along the sf peninsula late
tonight and Sunday morning surface winds may shift to 190 or 200
deg, with a general increase in wind late tonight and Sunday.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals... The leading edge of a southerly wind
reversal has reached santa cruz, visible imagery shows fog and
stratus rapidly developing along the northern monterey bay. Hi-res
models are several hours slow with present development thus taf
forecasts are lower confidence here in the nearest term. In
general still think there's good chancesVFR will hold this
evening as the present patterns settles in this evening and
overnight. Adjusted tafs to follow general idea of hi-res models
rh and wind forecasts, but started arrival times earlier. Eddy
circulation developing over the monterey bay embedded within larger
scale wmc-sfo offshore gradient may shift kmry winds around to an
easterly direction for a while tonight.

Fire weather As of 3:18 am pdt Saturday... A red flag warning
remains in effect for the north and east bay hills from 11 am
through 8 pm this evening. The main concern will be for hot
inland temperatures and low relative humidity along with moderate
and dry northerly winds. To be clear the weather set-up is very
different and not nearly as critical in terms of winds to the
north bay firestorm last october.

Temperatures will continue to warm this afternoon further drying
out fuels that are running near average in terms of seasonal
dryness. Even more widespread afternoon highs in the 90s and low
100s are expected. As temperatures warm, dry northerly winds will
come down the sacramento valley and spread over napa county
by late this morning with wind gusts between 35-45 mph. Winds
will ease in the afternoon before the north and east bay hills see
another round of increased north winds late this evening into
Sunday. During this time little to no relative humidity recovery
is expected and overnight lows will be warm in the 70s and 80s.

Afternoon highs on Sunday will remain warm to hot, but onshore
flow will return late in the day providing some cooling.

Those spending time outside this weekend are urged to be vigilant
with sources of ignition. Any new fire starts, especially in the
grassy fuels will spread rapidly.

Marine As of 5:08 pm pdt Saturday... High pressure over the
eastern pacific and a thermal trough over inland california will
keep gusty northerly winds across the coastal waters through
tonight. Gusty winds will generate steep wind waves creating
hazardous sea conditions, particularly for small vessels. Winds
will subside tonight as a southerly surge pushes northward
shifting the winds along the inner coastal waters out of the
south. Winds will pick up again on Monday as an upper trough moves
through to the north.

Mtr watches warnings advisories
Tngt Heat advisory... Caz506>508-510>513-516>518
sca... Pt arena to pigeon pt 10-60 nm
sca... Pt arena to pt reyes 0-10 nm until 3 am
sca... Pt pinos to pt piedras blancas 0-10 nm from 9 pm
sca... Pt reyes to pigeon pt 0-10 nm until 9 pm
sca... Pigeon pt to pt piedras blancas 10-60 nm until 9 pm
sca... Pt reyes to pigeon pt 0-10 nm from 5 am
sca... Sf bay from 5 am
public forecast: drp
aviation: canepa
marine: as
visit us at

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
FTPC1 - 9414290 - San Francisco, CA 1 mi41 min SW 12 G 17 59°F 58°F1006.7 hPa
PXSC1 2 mi41 min 70°F 52°F
PXOC1 - 9414311 - San Francisco (Pier 1), CA 3 mi41 min E 6 G 9.9 68°F 1005.4 hPa
OBXC1 5 mi41 min 69°F 53°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 6 mi41 min W 2.9 G 4.1
OKXC1 - 9414776 - Oakland (Berth 34), CA 6 mi41 min NW 6 G 8 65°F 1006.4 hPa
LNDC1 8 mi41 min NNE 7 G 8.9 68°F 1006.4 hPa
RCMC1 - 9414863 - Richmond, CA 8 mi41 min SE 1.9 G 5.1 69°F 65°F1006 hPa
AAMC1 - 9414750 - Alameda, CA 8 mi41 min W 6 G 8 70°F 71°F1006.7 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 8 mi41 min SSW 4.1 G 8 66°F 1006.6 hPa
46237 - San Francisco Bar, CA (142) 10 mi41 min 58°F4 ft
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 19 mi41 min WSW 7 G 8.9 81°F 1005.3 hPa
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 21 mi31 min NW 9.7 G 14 55°F 53°F1007.5 hPa55°F
MZXC1 - 9415102 - Martinez-Amorco CA 23 mi41 min WNW 12 G 12 83°F 73°F1005.2 hPa58°F
RTYC1 - 9414523 - Redwood City, CA 24 mi41 min N 12 G 14 72°F 74°F1006.3 hPa
PCOC1 - 9415144 - Port Chicago, CA 27 mi41 min W 12 G 14 85°F 71°F1004.9 hPa
PRYC1 - 9415020 - Point Reyes, CA 31 mi41 min WNW 19 G 24 54°F1006.5 hPa
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 33 mi41 min WNW 8 G 9.9 83°F 1004.7 hPa
SFXC1 - San Francisco Bay Reserve, CA 35 mi86 min WNW 7 93°F 1005 hPa56°F
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 39 mi81 min NW 12 G 14 58°F 56°F7 ft1008.6 hPa (-1.0)

Wind History for San Francisco, CA
(wind in knots)    EDIT      (on/off)   Help
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1 day
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SW9
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G16
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G27
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G26

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
San Francisco, San Francisco International Airport, CA14 mi15 minWNW 1510.00 miFair68°F51°F55%1006 hPa
Oakland, Metro Oakland International Airport, CA14 mi18 minWNW 1010.00 miFair68°F55°F63%1006.2 hPa
Hayward, Hayward Air Terminal, CA20 mi17 minW 710.00 miFair76°F57°F54%1006.8 hPa
Half Moon Bay Airport, CA21 mi16 minSSE 64.00 miFog/Mist57°F53°F88%1008.5 hPa
San Carlos Airport, CA22 mi81 minWNW 1210.00 miClear90°F46°F22%1005.4 hPa
Novato / Gnoss Field, CA24 mi16 minVar 410.00 miFair88°F48°F25%1005.4 hPa
Concord, Buchanan Field, CA24 mi18 minWNW 1010.00 miFair94°F46°F20%1003.8 hPa

Wind History from SFO (wind in knots)
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Last 24hrNW14NW12W12W9W8W9W7NW6CalmW6W4W3CalmN4NE4NE4W12W13NW15W17W15W18W20W12
1 day agoW15W16W17W16W14W12W9W9NW7W9W7W7NW5NW10NW8NE6NE5NW12NW15NW17W20
G29
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2 days agoW17
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W8W12NW15W17W17NW17W22W23W25
G31
W23W21

Tide / Current Tables for San Francisco, California
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San Francisco
Click for Map
Sat -- 03:03 AM PDT     Moonset
Sat -- 03:14 AM PDT     0.44 feet Low Tide
Sat -- 05:48 AM PDT     Sunrise
Sat -- 09:42 AM PDT     4.07 feet High Tide
Sat -- 02:37 PM PDT     1.75 feet Low Tide
Sat -- 04:34 PM PDT     Moonrise
Sat -- 08:35 PM PDT     Sunset
Sat -- 09:18 PM PDT     6.14 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
31.70.80.50.61.11.82.73.4443.732.31.81.82.22.93.94.85.76.165.2

Tide / Current Tables for Alcatraz Island S, San Francisco Bay, California Current
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Alcatraz Island S
Click for Map
Sat -- 01:06 AM PDT     -2.25 knots Max Ebb
Sat -- 03:03 AM PDT     Moonset
Sat -- 04:53 AM PDT     0.01 knots Slack
Sat -- 05:48 AM PDT     Sunrise
Sat -- 08:13 AM PDT     1.50 knots Max Flood
Sat -- 10:51 AM PDT     -0.01 knots Slack
Sat -- 01:29 PM PDT     -1.33 knots Max Ebb
Sat -- 04:34 PM PDT     Moonrise
Sat -- 04:41 PM PDT     0.00 knots Slack
Sat -- 07:59 PM PDT     1.44 knots Max Flood
Sat -- 08:35 PM PDT     Sunset
Sat -- 10:35 PM PDT     -0.01 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-2-2.3-2.2-1.8-0.90.10.81.31.51.40.8-0.2-1-1.3-1.3-1.1-0.60.20.91.31.41.20.6-0.5

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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Wind Forecast for San Francisco/Monterey Bay Area, CA (23,6,7,8)
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Ground Weather Radar Station San Francisco Bay Area, 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.