Marine Weather and Tides
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 6:18AM||Sunset 9:07PM||Sunday June 24, 2018 12:29 AM CDT (05:29 UTC)||Moonrise 5:01PM||Moonset 3:06AM||Illumination 82%|
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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 South San Francisco, CAHourly EDIT Help
Area Discussion for - San Francisco/Monterey Bay Area, CA  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxus66 kmtr 240413|
area forecast discussion
national weather service san francisco bay area
913 pm pdt Sat jun 23 2018
Synopsis Noted cooling trend overnight into Sunday as onshore
flow returns to the region. Red flag warnings remain in effect
for the north and east bay hills into Sunday. Pattern returns to
more seasonable set up Monday through most of next work week with
a return of the marine layer and more seasonable temperatures.
Discussion As of 9:13 pm pdt Saturday... It was a hot day
inland today with widespread readings in the upper 90s and lower
100s. No official records appear to have been broken at long term
climate sites. Things are already showing signs of significant
change in terms of cooler temperatures. A southerly surge was hung
up near pt sur for much of today but made a quick advancement
northward around 00z into monterey bay. Often times the rapid
northward advance occurs several hours after the daytime heating
has been maximized but alas mother nature beats to its own drum.
Rapid cooling has occurred around monterey bay with watsonville
and monterey already down to 57 degrees with stratus rapidly
forming as the marine layer has locally deepened to nearly 2000
feet. The northerly gradient down the coast is still an impressive
8 mb while we have 4 mb coming up the coast the other way, so
quite a battle going on as cool dense air is poised to spread
through the golden gate overnight or towards dawn. We already have
west winds showing up from the golden gate and out into the west
delta as onshore sfo-sac is 2mb. Given all this, with the signs
towards cooling the heat advisory was allowed to expire at 8 pm.
The trend for Sunday could be as much as 20 degrees of cooling for
places like concord and livermore or at least 15 degrees of
cooling back closer to seasonal norms with onshore winds blowing.
For details on red flag warning please see update fire weather
By Sunday evening all areas will notice much cooler temps with all
signs pointing to a strong marine push of air Sunday night into
Monday with a deep inland intrusion of stratus by Monday morning.
A trough well to our north will keep onshore flow in place this
week with a seasonable weather pattern forecast of daytime highs
in the 60s coast, 70s bayside and 80s inland with night and
morning intrusions of stratus.
Prev 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
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
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
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
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
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 9:13 pm pdt Saturday... Red flag warning
will remain in place at least through the overnight hours. Low
humidity and warm temps are in place. Models do bring another
burst of moderate northeast winds, mainly over napa and portions
of sonoma county tonight, roughly between 10 pm and sunrise,
strongest in the hills above 2000 feet or so. Given ongoing fire
activity in the state (lake county) as well as initial attack
activity over the east bay valleys this afternoon feel its prudent
to leave warning in place even though by the book overall
conditions are marginal.
However across norcal today the lion fire south of yosemite in the
high country appeared to get active with several significant new
starts around redding and another currently burning hot in lake
county. Some small brush fires in eastern contra costa are
apparently contained as well.
Cooling trend is already underway near the coast but the
transition day (Sunday) can be troublesome across our hot interior
valleys as the strong winds will precede the high humidity. Upshot
is warning will be left in place for now and will re-examine data
Marine As of 8:29 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 Sca... Pt arena to pigeon pt 10-60 nm
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 arena to pt reyes 0-10 nm until 3 am
sca... Pt reyes to pigeon pt 0-10 nm from 5 am
sca... Sf bay from 5 am
public forecast: rww
fire weather: rww
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Weather Reporting StationsEDIT (on/off)  Help NOTE: Click on distance to see the station location on a map
|Stations||Dist||Age||Wind||Air Temp||Water Temp||Waves||Pressure||DewPt|
|RTYC1 - 9414523 - Redwood City, CA||1178 mi||42 min||NW 2.9 G 5.1||69°F||73°F||1008.1 hPa|
|AAMC1 - 9414750 - Alameda, CA||1180 mi||48 min||Calm G 4.1||65°F||67°F||1007.8 hPa|
|OMHC1 - 9414769 - Oakland Middle Harbor Met, CA||1181 mi||48 min||W 8.9 G 11|
Wind History for Alameda, CA(wind in knots) EDIT (on/off)  Help
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports
|Dodge City, Dodge City Regional Airport, KS||23 mi||38 min||NNW 22 G 38||8.00 mi||Thunderstorm Light Rain and Breezy||62°F||57°F||86%||1012.3 hPa|
Wind History from SFO (wind in knots)
|1 day ago||W||W||W||W||W||NW||W||W||W||NW||NW||NW||NE||NE||NW||NW||NW||W|
|2 days ago||W|
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of Data
|Point San Bruno |
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Sun -- 03:36 AM PDT Moonset
Sun -- 05:13 AM PDT 0.10 feet Low Tide
Sun -- 05:49 AM PDT Sunrise
Sun -- 11:26 AM PDT 5.31 feet High Tide
Sun -- 04:37 PM PDT 2.22 feet Low Tide
Sun -- 05:32 PM PDT Moonrise
Sun -- 08:34 PM PDT Sunset
Sun -- 10:35 PM PDT 7.27 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
EDIT (on/off)  Help One Week of Data
|Oyster Point 2.8 mi E |
Click for Map
Sun -- 02:16 AM PDT -1.64 knots Max Ebb
Sun -- 03:36 AM PDT Moonset
Sun -- 05:28 AM PDT 0.01 knots Slack
Sun -- 05:48 AM PDT Sunrise
Sun -- 08:43 AM PDT 1.01 knots Max Flood
Sun -- 11:40 AM PDT -0.01 knots Slack
Sun -- 02:50 PM PDT -0.87 knots Max Ebb
Sun -- 05:16 PM PDT 0.01 knots Slack
Sun -- 05:32 PM PDT Moonrise
Sun -- 08:20 PM PDT 0.84 knots Max Flood
Sun -- 08:34 PM PDT Sunset
Sun -- 11:07 PM PDT -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Weather Map and Satellite Images(on/off)  HelpWeather Map
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 (1,6,7,8)(on/off)  Help
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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 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.