Friday, August23, 2019 L-36.com


Marine Weather and Tides
Portola Valley, CA

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Sunrise 6:29AMSunset 7:53PM Thursday August 22, 2019 11:27 PM PDT (06:27 UTC) Moonrise 10:54PMMoonset 12:04PM Illumination 48% Phase: Third Quarter Moon; Moon at 22 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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PZZ560 Coastal Waters From Pigeon Point To Point Pinos California Out To 10 Nm- 917 Pm Pdt Thu Aug 22 2019
Tonight..NW winds 15 to 25 kt with gusts up to 30 kt, diminishing to 10 to 15 kt after midnight. NW swell 7 to 9 ft at 9 seconds, becoming W 6 to 7 ft at 9 seconds after midnight. SWell sw around 2 ft.
Fri..SW winds 10 to 15 kt. NW swell 5 to 7 ft at 9 seconds and sw around 2 ft at 18 seconds.
Fri night..S winds 5 to 10 kt. NW swell 4 to 6 ft at 10 seconds and sw around 2 ft at 16 seconds.
Sat..SW winds 5 to 10 kt. Mixed swell nw 2 to 4 ft at 10 seconds and sw around 2 ft at 16 seconds.
Sat night..NW winds around 5 kt. Wind waves 2 to 3 ft. W swell 2 to 3 ft at 13 seconds and sw around 2 ft at 15 seconds.
Sun..W winds 10 to 15 kt. Wind waves 2 to 3 ft. W swell 2 to 3 ft at 13 seconds and sw around 2 ft at 15 seconds.
Sun night..NW winds 5 to 10 kt. Wind waves 1 to 2 ft. NW swell 3 to 5 ft at 12 seconds and sw around 2 ft at 15 seconds.
Mon..W winds 5 to 10 kt. Wind waves 3 to 4 ft. NW swell 3 to 5 ft and sw around 2 ft.
Tue..SW winds 5 to 10 kt. Wind waves around 2 ft. NW swell 3 to 4 ft and sw around 2 ft.
PZZ500 917 Pm Pdt Thu Aug 22 2019
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Northwest winds across the waters will generate a steep northwest swell hazardous to small craft vessels at 8 to 10 second periods tonight into Friday. A coastally trapped southerly wind reversal will also develop turning winds to a southwesterly direction along the coast late tonight through Friday. A decreasing northerly pressure gradient and winds Friday will ease aforementioned wind generated seas. Small, longer period swells will move through the coastal waters next week.


7 Day Forecast for Marine Location Near Portola Valley, CA
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location: 37.36, -122.23     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 230440
afdmtr
area forecast discussion
national weather service san francisco bay area
940 pm pdt Thu aug 22 2019

Synopsis The warm temperatures today cool slightly on Friday
across the bay area. However, high dew point temperatures
tomorrow will keep inland areas feeling warmer. Temperatures will
increase this weekend as high pressure builds over california
lasting through the early work week. By midweek, moisture
increases as the remnants of ivo traverses northward in the
pacific ocean just off the california coast allowing muggy
conditions to return.

Discussion As of 9:40 pm pdt Thursday... Higher humidity values
today, especially this morning, resulted in much warmer minimum
temperatures, especially in higher terrain areas. This morning's
lows ranged from the upper 50s to the lower 70s, which were as
many as 10 to 15 degrees above yesterday's mins in some cases.

High temperatures today were a mixed bag, with some warmer and
some slightly cooler than yesterday's values. Today's highs ranged
from the 60s to lower 70s at the immediate coast to the 80s and
90s most other locations. The warmest locations reached 100
degrees, bookending our cwa, at pope valley in northern napa
county, as well as bradley in southern monterey county. Current
observations indicate that dew point temperatures are cooler than
last night at this time, thus, expect cooler minimum temperatures
tonight. Latest satellite imagery shows scant stratus formation
thus far, limited to along the coast from san mateo county south
as well as through the monterey bay and starting to extend down
the salinas valley. The marine layer depth is a little higher per
the fort ord profiler, and onshore flow persists with 2.5 mb
between sfo and sac, so expect the area of low clouds to expand
farther inland overnight. Did a minor update to the temperature
forecast for tomorrow, mainly to cool some temperatures somewhat
to reflect a slightly stronger seabreeze by tomorrow afternoon.

Previous discussion There are higher dewpoint temperatures
today around the bay area, ranging from 61 in salinas to 69 in san
jose giving a muggy feel to the day. The marine layer has been
pseudo- constant around 1500 feet the last few hours and will
remain fairly shallow overnight, though patchy fog may be possible
in the early morning hours along the coast. Onshore flow
strengthens slightly tomorrow, providing slightly cooler
temperatures on Friday. Lingering higher dew point temperatures
inland will keep temperatures feeling warmer for interior
locations.

High pressure builds over california this weekend which will drive a
warming trend for temperatures. Temperatures will MAX out on Sunday
in the mid to upper 90s, with isolated locations in southern san
benito and monterey counties reaching the low 100s. However, those
values are based on current models having the ridge axis of high
pressure north of the bay area. If the ridge retrogrades slightly,
temperatures around our area could increase even higher, thus will
be monitored as the next round of models are produced.

The warming trend looks to continue through the early part of the
work week. By Wednesday, the remnants of the tropical system ivo
will have moved northward in the pacific just west of the bay area.

Ivo will bring an increase in moisture giving a better chance for
clouds cover across the area and an overall muggy feeling. No
precipitation or thunderstorms are currently forecast, though it
will be something that will be closely monitored as the time
interval draws closer.

Aviation As of 6:22 pm pdt Thursday... An influx of drier air,
an air flow with origins having more mid-latitude influence, has
spread in on northwest coastal winds. Ifr ceilings due to coastal
stratus and fog are presently limited to the san mateo coast and
the southern half of the monterey bay area and the northern
salinas valley south along the coast to point sur. Elsewhere it's
vfr, and land based surface weather observations still show
elevated dew point temperatures, a measure of water vapor, in the
upper 50s to mid 60s. At present the latest WRF model boundary
layer relative humidity is over-forecasting areal coverage of
coastal stratus and fog. The marine layer remains compressed to
700 to 800 feet with inversion temperatures from 24c to 26c still
plenty warm to keep the inversions intact through the period
despite some near surface based cool air advection tonight and
Friday.

For this evening's volume, it's a moderate to high confidenceVFR
forecast for the bay area terminals. Ifr will be confined to
aforementioned locations for the evening, and still expecting ifr to
spread inland tonight, however it'll be delayed somewhat until
nighttime cooling and still favorable thermodynamics combine to
produce increasing areal coverage of coastal stratus and fog. On
Friday there should be sufficient diurnal mixing to lift ceilings to
vfr at most, mainly inland, terminals, however in terms of areal
coverage of stratus and fog it's a very low confidence forecast
Friday into Saturday morning; a temporarily ramped up (4 mb) smx-sfo
pressure gradient and wind juxtaposed to a diminishing (3 mb or
less) acv-sfo pressure gradient and wind could cause any combination
of coverage.

Vicinity of ksfo...VFR, west wind 20 knots with occasional gusts
to 30 knots until 04z this evening. The combination of a compressed
marine layer and absence of stratus and fog upstream to the
northwest supports a moderate to high confidenceVFR forecast for
the evening. After this however it's a lowering confidence ifr
ceiling forecast for tonight. The terminal and approach may just
hold on toVFR for the overnight and Friday if the aforementioned
smx-sfo pressure gradient develops (usually the NAM is slow with
this forecast) under a compressed marine layer. Will monitor as we
approach the 06z TAF issuance, a reduction in ifr forecast
duration for Friday morning is possible.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals... A solid coverage of stratus and fog exists
over the southern monterey bay area and northern salinas valley.

Lifr-ifr conditions forecast tonight with northwest winds ushering
in some surface based cooling, a brief uptick in cooling and marine
layer depth is most recently seen on the fort ord profiler, cooling
then extends up to the 925 mb level Friday. Lifr-ifr Friday morning
lifts toVFR by late morning.

Marine As of 09:17 pm pdt Thursday... Northwest winds across
the waters will generate a steep northwest swell hazardous to
small craft vessels at 8 to 10 second periods tonight into Friday.

A coastally trapped southerly wind reversal will also develop
turning winds to a southwesterly direction along the coast late
tonight through Friday. A decreasing northerly pressure gradient
and winds Friday will ease aforementioned wind generated seas.

Small, longer period swells will move through the coastal waters
next week.

Mtr watches warnings advisories
Tngt Sca... Pt arena to pigeon pt 10-60 nm
sca... Pt reyes to pigeon pt 0-10 nm until 3 am
sca... Pt pinos to pt piedras blancas 0-10 nm until 3 am
sca... Pigeon pt to pt piedras blancas 10-60 nm until 3 am
sca... Pt arena to pt reyes 0-10 nm
public forecast: sims
aviation: canepa
marine: canepa
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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 10 mi58 min NW 6 G 8.9 64°F 75°F1008.1 hPa
AAMC1 - 9414750 - Alameda, CA 29 mi64 min W 8 G 8.9 63°F 73°F1008 hPa
LNDC1 30 mi58 min SW 4.1 G 5.1 63°F 1007.4 hPa
OBXC1 31 mi58 min 64°F 60°F
PXOC1 - 9414311 - San Francisco (Pier 1), CA 31 mi58 min WSW 6 G 8 62°F 1006.4 hPa
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 31 mi58 min SSW 2.9 G 7
OKXC1 - 9414776 - Oakland (Berth 34), CA 32 mi58 min SW 4.1 G 5.1 64°F 1007.5 hPa
PXSC1 32 mi58 min 62°F 58°F
FTPC1 - 9414290 - San Francisco, CA 33 mi58 min SSW 2.9 G 6 60°F 62°F1007.7 hPa
46237 - San Francisco Bar, CA (142) 36 mi58 min 62°F6 ft
PPXC1 - 9414847 - Richmond (Point Potrero), CA 38 mi58 min SSW 12 G 16 62°F 1007.4 hPa
TIBC1 - Tiburon Pier, San Francisco Bay, CA 39 mi77 min S 4.1 62°F 1007 hPa
RCMC1 - 9414863 - Richmond, CA 40 mi58 min 65°F
46042 - MONTEREY - 27NM West of Monterey Bay, CA 41 mi38 min 14 G 18 59°F 58°F8 ft1007.4 hPa (+0.6)
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 42 mi28 min NW 9.7 G 12 59°F 60°F1008 hPa (+0.0)
46092 - MBM1 43 mi78 min NW 14 58°F 57°F1007.5 hPa (+0.9)
46114 - West Monterey Bay, CA 44 mi28 min 58°F7 ft
MLSC1 - Moss Landing, South Harbor, CA 45 mi39 min SE 5.1 G 15 60°F 1008 hPa (+0.0)58°F
ELXC1 - Elkhorn Slough Reserve, CA 46 mi103 min S 6 59°F 1007 hPa58°F
MZXC1 - 9415102 - Martinez-Amorco CA 47 mi58 min WNW 8.9 G 9.9 71°F 71°F1006.2 hPa
UPBC1 47 mi58 min WNW 7 G 9.9
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 48 mi58 min WSW 6 G 8.9 67°F 1006.1 hPa
PCOC1 - 9415144 - Port Chicago, CA 49 mi58 min W 11 G 12 73°F 74°F1006.1 hPa

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Palo Alto Airport, CA10 mi2.7 hrsNW 710.00 miClear66°F60°F83%1007.1 hPa
Mountain View, Moffett Field, CA11 mi3.5 hrsNNW 810.00 miFair69°F61°F76%1007.2 hPa
San Carlos Airport, CA12 mi4.7 hrsWNW 1610.00 miClear75°F57°F54%1006.4 hPa
San Jose, San Jose International Airport, CA16 mi95 minNNW 810.00 miFair67°F60°F79%1007.2 hPa
Half Moon Bay Airport, CA18 mi93 minNW 33.00 miFog/Mist59°F57°F94%1008.8 hPa
San Francisco, San Francisco International Airport, CA19 mi3.5 hrsWNW 1610.00 miA Few Clouds66°F55°F68%1006.6 hPa
Hayward, Hayward Air Terminal, CA22 mi94 minNNW 610.00 miFair64°F57°F78%1008.3 hPa
San Jose / Reid / Hillv, CA22 mi93 minWNW 610.00 miClear70°F59°F69%1007.4 hPa
Oakland, Metro Oakland International Airport, CA23 mi95 minWNW 99.00 miA Few Clouds64°F57°F78%1007.6 hPa

Link to 5 minute data for KPAO

Wind History from PAO (wind in knots)
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Last 24hr------------------------------NW8N12NW12NW14----NW15N9NW7
1 day ago------------------Calm33NE544N10N12N15
G19
N12----------
2 days ago------------------CalmCalm--5N6--NW12
G21
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G20
NW14NW10W7

Tide / Current Tables for Granite Rock, Redwood Creek, San Francisco Bay, California
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Granite Rock
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Fri -- 01:13 AM PDT     1.51 feet Low Tide
Fri -- 06:31 AM PDT     Sunrise
Fri -- 07:17 AM PDT     5.44 feet High Tide
Fri -- 07:58 AM PDT     Last Quarter
Fri -- 12:42 PM PDT     2.73 feet Low Tide
Fri -- 02:05 PM PDT     Moonset
Fri -- 06:45 PM PDT     7.94 feet High Tide
Fri -- 07:50 PM PDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.91.51.72.43.34.355.45.34.84.13.42.92.83.24.25.56.87.77.97.56.55.23.8

Tide / Current Tables for Dumbarton Hwy Bridge, South San Francisco Bay, California Current
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Dumbarton Hwy Bridge
Click for Map
Fri -- 01:45 AM PDT     0.00 knots Slack
Fri -- 04:43 AM PDT     1.00 knots Max Flood
Fri -- 06:31 AM PDT     Sunrise
Fri -- 07:54 AM PDT     -0.00 knots Slack
Fri -- 07:58 AM PDT     Last Quarter
Fri -- 10:43 AM PDT     -0.56 knots Max Ebb
Fri -- 01:09 PM PDT     0.00 knots Slack
Fri -- 02:04 PM PDT     Moonset
Fri -- 04:39 PM PDT     0.95 knots Max Flood
Fri -- 07:23 PM PDT     -0.00 knots Slack
Fri -- 07:50 PM PDT     Sunset
Fri -- 11:14 PM PDT     -1.02 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-0.6-0.20.10.60.910.80.4-0-0.3-0.5-0.5-0.3-00.30.60.90.90.70.2-0.2-0.5-0.8-1

Weather Map and Satellite Images
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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 (2,6,7,8)
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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.