Thursday, September21, 2017 L-36.com


Marine Weather and Tides
Portola Valley, CA

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
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 6:55AMSunset 7:06PM Thursday September 21, 2017 12:42 PM PDT (19:42 UTC) Moonrise 7:20AMMoonset 7:19PM Illumination 1% Phase: Waxing Crescent; Moon at 1 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
    EDIT      (on/off)   Help
PZZ560 Pigeon Point To Point Pinos To 10 Nm- 850 Am Pdt Thu Sep 21 2017
.small craft advisory in effect through this evening...
Today..NW winds 15 to 25 kt. Wind waves 3 to 5 ft. NW swell 4 to 6 ft at 11 seconds.
Tonight..NW winds 15 to 25 kt. Wind waves 3 to 5 ft. NW swell 4 to 6 ft at 11 seconds.
Fri..NW winds 5 to 15 kt. Wind waves 1 to 3 ft. NW swell 4 to 6 ft at 10 seconds.
Fri night..NW winds 10 to 20 kt. Wind waves 2 to 4 ft. NW swell 4 to 5 ft at 10 seconds.
Sat..NW winds 10 to 20 kt. Wind waves 2 to 4 ft. NW swell 3 to 5 ft at 10 seconds.
Sun..NW winds 5 to 15 kt. Wind waves 1 to 3 ft. NW swell 3 to 4 ft.
Mon..NW winds 5 to 15 kt. Wind waves 1 to 3 ft. NW swell 3 to 4 ft.
PZZ500 850 Am Pdt Thu Sep 21 2017
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Increasing northwest winds today as a trough moves through the region. Winds subside slightly late tonight through the weekend. Northwest swell will continue to decrease through the coming days while steep wind waves continue through Friday.

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


Area Discussion for - San Francisco/Monterey Bay Area, CA
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
Fxus66 kmtr 211800
afdmtr
area forecast discussion
national weather service san francisco bay area
1100 am pdt Thu sep 21 2017

Synopsis A cool, upper level trough will dominate the western
portion of the country through the workweek maintaining cooler
than average temperatures and breezy conditions. Aside from the
potential for isolated showers offshore or near the coast Thursday,
dry weather conditions will prevail. A gradual warming trend is
then expected to begin this weekend and persist into early next
week.

Discussion As of 8:41 am pdt Thursday... Water vapor satellite
imagery shows a cold front passing through central california and
continuing into nevada and idaho. In its wake, temperatures across
the san francisco bay area and central california coast are
generally in the 50s with a few readings in the middle 40s for
parts of the north bay, such as santa rosa and napa. The 24 hour
temperature change varies depending on location. For the monterey
bay area temperatures are generally running at or slightly warmer
than this time yesterday, whereas the san francisco bay area
temperatures are running about 5 to 10 degrees cooler. Go farther
north and temperatures are running even cooler with a 15 degree
change at napa. Expect mostly clear, dry, and cool conditions
across the region with afternoon highs in the 60s along the coast
and 70s for interior areas. The exception to the dry weather would
be the higher elevations of monterey county where locally patchy
drizzle is possible through mid morning. The cool weather won't
last much longer as temperatures will begin to rebound tomorrow
with the warming trending continuing through the weekend and into
early next week. The short-term grids remains on track and don't
anticipate any major changes to the forecast. For additional
details beyond today, please refer to the previous discussion
section.

Prev discussion As of 2:45 am pdt Thursday... A cold front passed
through the bay area on Wednesday bringing some light showers,
breezy conditions and cooler temperatures. The cold front is now
south of the forecast area, but continues to produce precipitation
across the sierra. Behind the front and rather robust upper level
trough is currently swinging through norcal. Latest satellite
imagery and radar both indicate showers over the coastal waters.

These showers are tracking mostly north to south. Model guidance
has not changed too much from previous runs regarding the shower
activity. Showers will continue early today, but remain offshore
with no impact to the land areas of the bay area region.

Do expect some clearing of clouds today, but temperatures will
remain cool as the upper trough moves through. Latest model runs
still show a cool airmass with 850mb temps in the 4-5 deg c range.

As a result, daytime highs will be in the 60s and 70s or about 5
to 10 deg below normal for late september. Overnight lows will be
chilly as well with the hills dropping into the upper 30s.

Additionally, hi-res models show some breezy winds today and
Friday. Gusts 30 to 40 mph along the coast and higher terrain
seems plausible.

Another pattern shift is forecast to develop this weekend and then
persisting into next week. In the wake of the upper trough high
pressure will build over the region this weekend. A noticeable
warming trend is forecast to develop this weekend and peak next
week. Widespread 80s to possibly mid 90s will be possible by early
next week. Pattern recognition and climatology also suggest
periods of north to offshore winds will possible this weekend and
next week. The offshore flow will further enhance any warming and
drying. Fire weather concerns may increase due to offshore flow
with hot and dry conditions.

Aviation As of 010:55 am pdt Thursday for 18z tafs...

postfrontal environment bringing well mixed marine layer and
widespreadVFR CIGS this morning. Unstable postfrontal airmass is
firing some shallow convection over the higher terrain over the
south bay, east bay, santa lucia mountains and santa cruz
mountains. A few sprinkles possible today in these areas if
convection deepens, however this is unlikely. Otherwise, breezy
onshore winds forecast today, with sust winds 10-20 kt, with peak
gusts 20 to 30 kt. Some high clouds will arrive late today. Dirty
feed of sct-bkn AOA 2000-4000 ft agl will bring intermittent MVFR
cigs in a window from 10-18z fri, depending on location. High
confidence for today, low confidence on exact details for tomorrow
mornings dirty feed.

Vicinity of ksfo...VFR. Sustained onshore winds 15 to 20 kt, gusts
25 to 30 kt. MVFR CIGS possible Fri morning from 12-17z with dirty
onshore feed as trough shifts through.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals...VFR. Shallow convection distant south
and east with few-sct at 3000 to 5000 ft agl. Breezy onshore winds
10 to 15 kt with gusts up to 20kt possible, locally stronger along
the immediate coastline. Intermittent MVFR CIGS posbl 12 to 18z
fri W sct-bkn from 2000-4000 ft.

Marine As of 10:48 am pdt Thursday... Increasing northwest winds
today as a trough moves through the region. Winds subside slightly
late tonight through the weekend. Northwest swell will continue to
decrease through the coming days while steep wind waves continue
through Friday.

Mtr watches warnings advisories
Tday Sca... Mry bay
sca... Pt arena to pt reyes 0-10 nm
sca... Pt reyes to pigeon pt 0-10 nm
sca... Pigeon pt to pt pinos 0-10 nm
sca... Pt pinos to pt piedras blancas 0-10 nm
sca... Pigeon pt to pt piedras blancas 10-60 nm
sca... Pt arena to pigeon pt 10-60 nm
sca... Sf bay from 1 pm
public forecast: rowe mm
aviation: drp
marine: drp
visit us at

Weather Reporting Stations
   EDIT       (on/off)   Help   NOTE: Click on distance to see the station location on a map
Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 10 mi42 min WNW 14 G 17 61°F 69°F1012.5 hPa (+0.0)
AAMC1 - 9414750 - Alameda, CA 29 mi42 min NNW 2.9 G 5.1 64°F 67°F1013.1 hPa (+0.3)
LNDC1 30 mi42 min WNW 7 G 11 63°F 1012.5 hPa (+0.0)
PXOC1 - 9414311 - San Francisco (Pier 1), CA 31 mi42 min N 2.9 G 4.1 61°F 1011.6 hPa (+0.3)
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 31 mi42 min WNW 2.9 G 8
OBXC1 31 mi42 min 63°F 45°F
PXSC1 32 mi42 min 63°F 46°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 32 mi42 min WNW 1.9 G 4.1 62°F 1012.6 hPa (+0.4)
FTPC1 - 9414290 - San Francisco, CA 33 mi42 min W 8.9 G 14 61°F 63°F1012.8 hPa (+0.0)
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 35 mi52 min NW 18 G 21 60°F 62°F8 ft1013.2 hPa (+0.7)
46237 - San Francisco Bar, CA (142) 36 mi42 min 60°F5 ft
PPXC1 - 9414847 - Richmond (Point Potrero), CA 38 mi42 min NNW 4.1 G 8 68°F 1012.7 hPa (+0.0)
TIBC1 - Tiburon Pier, San Francisco Bay, CA 39 mi55 min Calm 63°F 1013 hPa
RCMC1 - 9414863 - Richmond, CA 40 mi42 min NW 5.1 G 7 63°F 66°F1012.2 hPa (+0.0)
46042 - MONTEREY - 27NM West of Monterey Bay, CA 41 mi52 min NW 16 G 19 61°F 62°F8 ft1013.9 hPa (+1.0)
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 42 mi52 min NW 18 G 21 57°F 56°F7 ft1013.1 hPa (+0.6)
46092 - MBM1 43 mi97 min WNW 14 60°F 58°F1013.6 hPa (+0.8)
46114 - West Monterey Bay, CA 44 mi42 min 62°F8 ft
ELXC1 - Elkhorn Slough Reserve, CA 46 mi57 min WNW 12 63°F 1012 hPa53°F
MZXC1 - 9415102 - Martinez-Amorco CA 47 mi42 min W 5.1 G 8 62°F 68°F1012.8 hPa (+0.4)45°F
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 48 mi42 min WSW 4.1 G 5.1 63°F 1012.1 hPa (+0.0)
PCOC1 - 9415144 - Port Chicago, CA 49 mi42 min W 7 G 8.9 62°F 68°F1012.3 hPa (+0.0)

Wind History for Redwood City, CA
(wind in knots)    EDIT      (on/off)   Help
1
PM
2
PM
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
9
AM
10
AM
11
AM
12
PM
Last
24hr
W9
SW11
G17
W12
W13
G16
SW14
W10
G15
W7
G11
W10
W11
W11
W12
G15
NW13
G16
W11
G17
W13
G16
W12
W14
G19
W13
G16
W13
G16
W10
W10
G13
NW14
G22
W15
G19
W17
NW14
G17
1 day
ago
NW7
G11
NW8
G12
NW10
G13
W12
G16
W14
G19
W17
G22
W15
W10
G14
W10
G13
NW9
SW4
SW1
SW2
S2
SE2
W7
W10
G16
NW6
G10
NW3
N1
SE4
N1
NE4
E4
2 days
ago
W12
SW16
SW8
G12
NW14
G17
NW11
G14
SW13
G16
W14
G17
W13
G16
W16
W12
G18
W16
G24
W10
G14
W14
W13
G18
W12
G16
NW13
W15
W12
G15
NW6
NW8
W8
NW5
G9
NW6
G11
NW5
G10

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Palo Alto Airport, CA10 mi55 minWNW 1610.00 miPartly Cloudy68°F48°F49%1012.9 hPa
Mountain View, Moffett Field, CA11 mi1.8 hrsWNW 10 G 1710.00 miFair65°F45°F49%1013.1 hPa
San Carlos Airport, CA12 mi55 minW 16 G 2110.00 miPartly Cloudy64°F44°F49%1013.2 hPa
San Jose, San Jose International Airport, CA16 mi49 minWNW 1010.00 miPartly Cloudy68°F46°F45%1012.8 hPa
Half Moon Bay Airport, CA18 mi47 minNW 16 G 2110.00 miFair63°F0°F%1012.5 hPa
San Francisco, San Francisco International Airport, CA19 mi46 minWNW 1610.00 miA Few Clouds65°F45°F49%1012.5 hPa
San Jose / Reid / Hillv, CA22 mi54 minN 610.00 miPartly Cloudy64°F46°F52%1013.5 hPa
Hayward, Hayward Air Terminal, CA22 mi48 minW 1210.00 miA Few Clouds65°F43°F45%1013.5 hPa
Oakland, Metro Oakland International Airport, CA23 mi49 minW 710.00 miPartly Cloudy65°F44°F47%1012.5 hPa

Wind History from PAO (wind in knots)
1
PM
2
PM
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
9
AM
10
AM
11
AM
12
PM
Last 24hrN8W11W13--NW13W13W13W13W11--------------------W10NW10NW12NW15NW16
1 day agoNW10N14NW9NW12NW12--------------------------NW5--Calm6--6
2 days agoNW11NW12W12W14NW10W10W12W6W7------------------NW8NW10NW11NW10NW11NW10

Tide / Current Tables for Granite Rock, Redwood Creek, San Francisco Bay, California
   EDIT   RT Ports Option   Weekend mode (on/off)   (on/off)   Help   One Week of Data
Granite Rock
Click for Map
Thu -- 01:40 AM PDT     8.26 feet High Tide
Thu -- 06:56 AM PDT     Sunrise
Thu -- 08:08 AM PDT     0.73 feet Low Tide
Thu -- 08:19 AM PDT     Moonrise
Thu -- 02:09 PM PDT     8.30 feet High Tide
Thu -- 07:06 PM PDT     Sunset
Thu -- 08:18 PM PDT     Moonset
Thu -- 08:34 PM PDT     0.80 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
6.888.27.56.14.32.51.20.71.12.44.267.58.386.95.23.31.80.90.91.83.4

Tide / Current Tables for Dumbarton Hwy Bridge, South San Francisco Bay, California Current
   EDIT      (on/off)   Help   One Week of Data
Dumbarton Hwy Bridge
Click for Map
Thu -- 02:28 AM PDT     -0.00 knots Slack
Thu -- 05:42 AM PDT     -1.23 knots Max Ebb
Thu -- 06:55 AM PDT     Sunrise
Thu -- 08:19 AM PDT     Moonrise
Thu -- 08:52 AM PDT     0.01 knots Slack
Thu -- 11:55 AM PDT     1.82 knots Max Flood
Thu -- 02:47 PM PDT     -0.00 knots Slack
Thu -- 06:02 PM PDT     -1.23 knots Max Ebb
Thu -- 07:06 PM PDT     Sunset
Thu -- 08:18 PM PDT     Moonset
Thu -- 09:13 PM PDT     0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.81.40.5-0.3-0.9-1.2-1.2-1-0.50.111.61.81.60.8-0.1-0.7-1.1-1.2-1.1-0.7-0.10.71.5

Weather Map and Satellite Images
       (on/off)   Help
Weather Map
wmap_P
IR Satellite Image from GEOS
west_satellite

GOES Local Image of CentralWestCoast    EDIT
Geos

Wind Forecast for San Francisco/Monterey Bay Area, CA (15,3,4,5)
      (on/off)   Help

Ground Weather Radar Station San Francisco Bay Area, CA
   (on/off)   Help
weather_mapweather_map weather_map

Ad by Google

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.