Tuesday, May23, 2017 L-36.com


Marine Weather and Tides
Half Moon Bay, CA

Version 3.4
What's New / NOTES
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.
3/12/2015 - Added section for Gulf current for users in the GMZ marine zones.
This was requested by a user. If you have requests, please let me know.

Sunrise 5:52AMSunset 8:20PM Monday May 22, 2017 10:07 PM PDT (05:07 UTC) Moonrise 3:01AMMoonset 3:50PM Illumination 7% Phase: Waning Crescent; Moon at 27 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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PZZ545 Point Reyes To Pigeon Point To 10 Nm- 944 Pm Pdt Mon May 22 2017
Tonight..SW winds 10 kt. Wind waves 3 ft late in the evening... Becoming 2 ft or less. NW swell 3 ft at 9 seconds. Patchy fog after midnight.
Tue..SW winds 10 kt. Wind waves 2 ft or less. NW swell 3 ft at 9 seconds. Patchy fog in the morning.
Tue night..SW winds 10 kt. Wind waves 3 ft in the evening... Becoming 2 ft or less. NW swell 3 ft at 8 seconds. Patchy fog after midnight.
Wed..S winds 5 to 15 kt. Wind waves 1 to 3 ft. NW swell 3 to 4 ft at 11 seconds. Patchy fog in the morning.
Wed night..S winds 10 to 20 kt. Wind waves 2 to 4 ft. NW swell 3 to 5 ft at 11 seconds.
Thu..S winds 10 to 20 kt. Wind waves 2 to 4 ft...becoming 2 ft or less. NW swell 3 to 5 ft.
Fri..W winds 10 kt. Wind waves 2 ft or less. NW swell 3 to 5 ft.
Sat..W winds 5 to 15 kt. Wind waves 1 to 3 ft. NW swell 3 to 4 ft. Patchy fog.
...san francisco bar/fourfathom bank forecast..... In the deep water channel...combined seas 2 to 3 ft with a period of 15 seconds. Across the bar...combined seas 3 to 5 ft with a period of 15 seconds. Maximum ebb current of 1.7 knots at 01:30 am Tuesday and 1.1 knots at 01:54 pm Tuesday.
PZZ500 944 Pm Pdt Mon May 22 2017
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Surface high pressure over the eastern pacific will strengthen from tonight into Wednesday morning keeping northwesterly winds going over the outer waters. A surface ridge of high pressure over the central coast will cause winds over the inner coastal waters to be primarily light southwesterly through Tuesday. Except for the Monterey bay onshore winds will be gusty over the bays each afternoon and evening at least through mid-week.

7 Day Forecast for Marine Location Near Half Moon Bay, CA
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location: 37.47, -122.48     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 230400
afdmtr
area forecast discussion
national weather service san francisco bay area
900 pm pdt Mon may 22 2017

Synopsis Look for cooler conditions through most of the week as
a onshore flow combines with the marine layer. Minor warming is
then expected during the upcoming weekend especially for inland
locations.

Discussion As of 9:00 pm pdt Monday... No forecast updates
planned for this evening with about a 1500 foot marine layer in
place along the immediate coast. Low clouds making their way
through the golden gate and into the berkeley hill as well as
spreading inland around the monterey bay region. Inland areas that
reached the 90s today will see more significant cooling for
Tuesday as onshore flow continues to increase with a deepening
marine layer in response to upper troughing aloft.

All available MOS data suggests continued cooling trend through
midweek for inland areas with robust onshore winds in place and
likely persistent stratus around the coast and bays. The trend
will be for near or below normal temperatures for much of the rest
of the work week.

Looking ahead to the long holiday weekend, long range models
suggest a seasonable weather pattern with dry and near normal
temps.

Prev discussion As of 1:15 pm pdt Monday... As expected temperatures
are running cooler for all locations away from the coast today
with many spots 5 to 12 degrees less than values from Sunday.

Current readings show a wide range from 50s and 60s to parts of
the coast with 70s and 80s inland. Still a few hours of heating,
so would expect the warmest inland spots to again get into the
90s, however the number of locations should be less than
yesterday. Satellite shows widespread clouds along the water and
with the minor onshore flow expected to continue, likely that many
of the local beaches will see little to no sunshine today.

Tonight will be a near repeat of last night with patchy fog along
the coast and to some inland spots. Lows will mostly be in the 50s
with 60s above 1500 feet.

Synoptically the ridge of high pressure in charge will begin to
flatten out through the week as a system dives down from canada
and works into the northern rockies. 500 mb heights will drop from
587 dm today to 573 dm by Thursday. Inland locations that have
been in the 90s the past few days will drop back into the upper
60s to the lower 70s. Closer to the coast widespread mid 50s to
mid 60s can be expected. With the onshore flow in place, much of
the week could by quite grey at the coast.

Longer range guidance shows the ridge trying to rebuild by the
weekend although heights will be less than the past few days. By
Sunday inland spots will be back in the mid 70s to mid 80s away
from the coast with 60s to mid 70s near the water.

Aviation As of 5:34 pm pdt Monday... The marine layer depth
varies from 700 feet over the bay area to 1200 feet over the north
central coast late this afternoon. The smx-sfo gradient is 2.3
mb; at present as well as tonight into Tuesday the NAM forecasts a
neutral gradient, applying a 2 mb correction a southerly component
to the coastal winds is likely to continue into Tuesday. The sfo-
sac gradient is 2 mb which is line with the nam, which predicts
stronger onshore gradient/wind developing Tuesday afternoon and
evening with sfo-sac gradient near 4 mb, similarly a moderate to
strong gradient and wind develops again Wednesday.

00z tafs for the bay area indicateVFR except southerly flow will
likely bring lifr/vlifr CIGS and vsbys to ksts late tonight and
Tuesday morning. Also, for monterey bay area ifr/lifr is likely
to develop this evening. Moderate to high forecast confidence.

Vicinity of ksfo...VFR. W-nw winds with occasional gusts to 20-25
knots til 05z this evening. Gusty w-nw winds resume Tuesday afternoon
and evening.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals...VFR then tempo ifr/lifr 02z-07z then ifr/lifr
prevailing tonight into late Tuesday morning.VFR returns late Tuesday
morning and afternoon, onshore winds will likely bring stratus and
fog back Tuesday evening.

Marine As of 08:51 pm pdt Monday... Northerly flow will persist
with light to moderate winds and small seas. High pressure will
strengthen north of the region increasing winds midweek. Winds
will be strongest north of point reyes, especially the outer
waters.

Mtr watches/warnings/advisories
Tngt Sca... Sf bay until 9 pm
public forecast: rww
aviation: canepa
marine: canepa
visit us at

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 14 mi49 min NNW 13 G 15 58°F 70°F1013.8 hPa
FTPC1 - 9414290 - San Francisco, CA 23 mi49 min WSW 2.9 G 8.9 52°F 53°F1014.9 hPa
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 23 mi77 min WSW 3.9 G 3.9 53°F 56°F4 ft1014.7 hPa (+0.0)
PXOC1 - 9414311 - San Francisco (Pier 1), CA 23 mi49 min W 2.9 G 8 54°F 1013.5 hPa
AAMC1 - 9414750 - Alameda, CA 23 mi49 min WNW 4.1 G 8 56°F 65°F1014.9 hPa
PXSC1 23 mi49 min 54°F 53°F
46237 - San Francisco Bar, CA (142) 23 mi67 min 56°F3 ft
OBXC1 24 mi49 min 55°F 53°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 24 mi49 min WNW 7 G 8.9
OKXC1 - 9414776 - Oakland (Berth 34), CA 25 mi49 min WNW 8 G 9.9 55°F 1014.6 hPa
LNDC1 25 mi61 min NNW 4.1 G 5.1 58°F 1014.4 hPa
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 27 mi77 min WSW 3.9 G 5.8 51°F 55°F4 ft1015.2 hPa (-0.0)
TIBC1 - Tiburon Pier, San Francisco Bay, CA 29 mi50 min Calm 57°F 1014 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 31 mi49 min SW 5.1 G 6 58°F 1014.5 hPa
RCMC1 - 9414863 - Richmond, CA 32 mi49 min WSW 5.1 G 8 57°F 61°F1014 hPa
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 42 mi49 min W 8 G 11 61°F 1013.4 hPa
MZXC1 - 9415102 - Martinez-Amorco CA 43 mi49 min WNW 13 G 15 66°F 66°F1013.3 hPa60°F
UPBC1 44 mi49 min NW 12 G 17
PRYC1 - 9415020 - Point Reyes, CA 45 mi49 min ESE 5.1 G 7 53°F 55°F1014.9 hPa
46042 - MONTEREY - 27NM West of Monterey Bay, CA 47 mi77 min 54°F 55°F4 ft1015.1 hPa
PCOC1 - 9415144 - Port Chicago, CA 47 mi49 min W 19 G 23 68°F 67°F1012.4 hPa

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Half Moon Bay Airport, CA3 mi72 minN 05.00 miFog/Mist54°F51°F94%1015.6 hPa
San Francisco, San Francisco International Airport, CA12 mi71 minWNW 1410.00 miA Few Clouds56°F51°F84%1013.9 hPa
San Carlos Airport, CA13 mi80 minWNW 810.00 miA Few Clouds68°F50°F53%1013.5 hPa
Palo Alto Airport, CA19 mi80 minNW 910.00 miClear61°F57°F88%1013.9 hPa
Oakland, Metro Oakland International Airport, CA21 mi74 minNW 910.00 miPartly Cloudy58°F54°F87%1014.3 hPa
Mountain View, Moffett Field, CA23 mi71 minNW 610.00 miFair63°F57°F81%1014.4 hPa
Hayward, Hayward Air Terminal, CA23 mi73 minNW 710.00 miFair61°F50°F67%1014.9 hPa

Wind History from SFO (wind in knots)
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Last 24hrNW13W13W11NW9NW9W7W10NW8NW6NW7NW7NE6NE4NW9NW13NW14NW17NW18W19
G25
W21W20NW18W14NW11
1 day agoW11W9W7W8W11W8W9W7W6NW6CalmN5N5NW8NW10NW15W18W17W20W18W17NW17NW17W15
2 days agoW10W7W8W7W7W9W8W7W7NW3NE3NE3N5NE4N6N8NW12NW16W17W15W16NW14NW10W12

Tide / Current Tables for Half Moon Bay, California
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Half Moon Bay
Click for Map
Tue -- 03:24 AM PDT     -0.13 feet Low Tide
Tue -- 04:39 AM PDT     Moonrise
Tue -- 05:54 AM PDT     Sunrise
Tue -- 09:45 AM PDT     4.29 feet High Tide
Tue -- 03:09 PM PDT     1.19 feet Low Tide
Tue -- 05:59 PM PDT     Moonset
Tue -- 08:19 PM PDT     Sunset
Tue -- 09:24 PM PDT     6.00 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.91.50.4-0.1-00.61.52.53.54.14.33.93.22.31.51.21.42.23.34.45.45.95.95.2

Tide / Current Tables for San Mateo Bridge, South San Francisco Bay, California Current
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San Mateo Bridge
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Tue -- 03:06 AM PDT     -1.90 knots Max Ebb
Tue -- 04:38 AM PDT     Moonrise
Tue -- 05:53 AM PDT     Sunrise
Tue -- 06:25 AM PDT     0.01 knots Slack
Tue -- 09:10 AM PDT     1.92 knots Max Flood
Tue -- 12:39 PM PDT     -0.01 knots Slack
Tue -- 03:31 PM PDT     -1.39 knots Max Ebb
Tue -- 05:58 PM PDT     Moonset
Tue -- 06:22 PM PDT     0.01 knots Slack
Tue -- 08:18 PM PDT     Sunset
Tue -- 09:08 PM PDT     1.84 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-0.2-1-1.6-1.9-1.7-1.1-0.40.61.51.91.81.40.6-0.3-1-1.3-1.3-0.9-0.30.61.41.81.71.2

Weather Map and Satellite Images
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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 (1,6,7,8)
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Ground Weather Radar Station San Francisco Bay Area, CA
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weather_mapweather_map weather_map

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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.