Thursday, March23, 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 7:04AMSunset 7:26PM Thursday March 23, 2017 3:08 PM PDT (22:08 UTC) Moonrise 3:25AMMoonset 2:02PM Illumination 14% Phase: Waning Crescent; Moon at 26 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- 220 Pm Pdt Thu Mar 23 2017
.small craft advisory in effect from 9 pm pdt this evening through Friday afternoon...
Tonight..S winds 5 to 15 kt...increasing to 15 to 25 kt after midnight. Wind waves 3 to 5 ft. W swell 4 to 6 ft at 13 seconds. Slight chance of rain in the evening, then rain after midnight.
Fri..S winds 20 to 30 kt. Wind waves 5 to 7 ft. W swell 8 to 10 ft at 14 seconds. Rain.
Fri night..NW winds 5 to 15 kt. Wind waves 1 to 3 ft... Becoming 3 ft after midnight. W swell 6 to 8 ft at 12 seconds. Rain likely in the evening, then slight chance of showers after midnight.
Sat..NW winds 5 to 15 kt. Wind waves 1 to 3 ft. W swell 6 to 8 ft at 15 seconds.
Sat night..NW winds 5 to 15 kt. Wind waves 1 to 3 ft. W swell 7 to 9 ft at 14 seconds.
Sun..SW winds 15 to 25 kt. Wind waves 3 to 5 ft. W swell 5 to 7 ft. Chance of showers, then showers likely.
Mon..NW winds 15 to 25 kt. Wind waves 3 to 5 ft. W swell 8 to 10 ft. Slight chance of showers.
Tue..NW winds 15 to 25 kt. Wind waves 3 to 5 ft. W swell 10 to 13 ft.
...san francisco bar/fourfathom bank forecast..... In the deep water channel...combined seas 7 to 9 ft with a dominant swell period of 13 seconds. Across the bar...combined seas 8 to 10 ft with a period of 13 seconds. Maximum ebb current of 0.8 knots at 01:24 am Friday and 1.5 knots at 12:54 pm Friday.
PZZ500 220 Pm Pdt Thu Mar 23 2017
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... A storm system is currently approaching the waters from the west. This will cause winds to increase and turn southerly late this afternoon. Occasional gale force gusts are possible late tonight and into tomorrow...especially for the northern coastal waters. Rough seas possible just ahead of and behind the frontal passage, but should begin to decrease by Saturday. Expect northwest winds to return by Saturday as well before briefly becoming southerly on Sunday as another weak system moves over the waters.

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 232038
afdmtr
area forecast discussion
national weather service san francisco bay area
138 pm pdt Thu mar 23 2017

Rain and gusty southerly winds return on Friday...

Synopsis Rain and moderately south winds return to the north
bay area late tonight as a frontal system approaches. Rain and
winds will spread southward Friday as the front moves across the
region. A break in the rain is expected Saturday with showers
anticipated to return Sunday night into Monday as a low pressure
system moves through the region.

Discussion As of 1:40 pm pdt Thursday... After an active
weather day yesterday, today -- as expected -- has been tranquil
with just scattered clouds. Temperatures have been running close
to values from Tuesday with most spots in the upper 50s to the
lower 60s. Hard to believe in less than 24 hours we will be
dealing with another round of active weather.

Synoptically a cold front associated with a 988 mb low heading
toward british columbia will move through our region on Friday.

Models have shown very little variation from previous runs, so the
forecast was changed very little during the shift. Rain will move
north-to-south starting overnight in the north bay then down to
the sf bay area early in the morning and to monterey bay region
close to noon. Rain rates will pick up with the approaching front
and could be moderate to heavy at times. Current timing brings the
main band through sf bay late in the morning or early in the
afternoon. In fact, if the current NAM verifies the bulk of the
rain will fall after morning rush and before the afternoon
commute. Along with the rain southerly winds will increase with
many spots forecast to see gusts of 25 to 35 mph. Winds for higher
elevation locations will be stronger -- gusts over 45 mph are
likely.

Rainfall totals still look like 1.5" to 3" for the north bay with
2/3" to 1.5" around sf bay with generally less than 2/3" for
points to the south. All of the coastal ranges are expected to be
in the 2-4" range with a few local spots possibly seeing slightly
higher amounts.

Rain will switch to showers behind the front with light
precipitation possible through Friday night. However, by mid-day
Saturday all of the rain should be well to our south and east.

Similar to today's time period, that break will be short as
another system moves across on Sunday. This one should be quite a
bit weaker and will have less moisture to utilize. In general
amounts will be around half of what we get out of the first round.

Rain will switch over to showers going into Monday.

A ridge of high pressure will build back to our region starting
next Tuesday, although a system will dive down from the north late
Wednesday/early Thursday possibly bringing a few light showers.

However, after it departs a more pronounced pattern change will
take place as a stronger ridge of high pressure returns to our
region. This should give us dry conditions with warmer
temperatures toward the end of next week possibly through the
following week.

Aviation As of 10:35 am pdt Thursday... For 18z tafs. Patchy
MVFR CIGS possible through late this morning. OtherwiseVFR
conditions prevail through this evening. Expecting winds to
increase this afternoon to 10-15 kt. Showers expected to move
in from north to south beginning with ksts at around 04z Friday.

Steady rain expected across all terminals by tomorrow morning.

MVFR CIGS possible early Friday morning for bay area terminals.

Low confidence on timing of rain.

Vicinity of ksfo... MainlyVFR with periods of MVFR cigs. Se/sw
winds 10-15 kt beginning late this afternoon. Rain and lower cigs
return early Friday morning.

Sfo bridge approach... Same as ksfo.

Monterey bay terminals... Patchy MVFR possible this morning with
vfr prevailing. W/wsw winds 10-12 kt this afternoon. Rain not
likely until after 12z Friday, but a shower or two before is still
possible.

Marine As of 08:25 am pdt Thursday... Winds will become
southerly and increase this afternoon ahead of another storm
system. Wind gusts may reach gale force at times late tonight and
into Friday... Especially for the northern coastal waters. Seas
may be rough ahead of and just behind the storm system on
Friday... But should decrease by Saturday morning. Winds will
switch back to the northwest by Saturday morning. Another weak
storm system is expected Sunday and may briefly switch winds out
of the south. However... Winds will quickly turn back to the
northwest by Monday morning.

Mtr watches/warnings/advisories
Tngt Sca... Pigeon pt to pt pinos 0-10 nm from 5 am
sca... Pt pinos to pt piedras blancas 0-10 nm from 5 am
sca... Pt arena to pigeon pt 10-60 nm
sca... Pt reyes to pigeon pt 0-10 nm from 9 pm
sca... Pigeon pt to pt piedras blancas 10-60 nm from 9 pm
sca... Pt arena to pt reyes 0-10 nm from 8 pm
sca... Sf bay from 5 am
public forecast: bell
aviation: as
marine: as
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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 14 mi50 min N 6 G 8.9 58°F 59°F1022.7 hPa
FTPC1 - 9414290 - San Francisco, CA 23 mi56 min WSW 5.1 G 13 55°F 58°F1023.9 hPa
AAMC1 - 9414750 - Alameda, CA 23 mi50 min WSW 6 G 8 57°F 60°F1024 hPa
46237 - San Francisco Bar, CA (142) 23 mi68 min 57°F7 ft
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 23 mi78 min SW 3.9 G 5.8 54°F 56°F7 ft1024 hPa (+0.0)
PXSC1 23 mi50 min 57°F 42°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 24 mi50 min SW 8 G 9.9
OBXC1 24 mi50 min 56°F 44°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 25 mi50 min WSW 7 G 8.9 58°F 1023.5 hPa
LNDC1 25 mi68 min WSW 8 G 11 55°F 1023.6 hPa (+0.0)
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 27 mi78 min WSW 5.8 G 7.8 53°F 56°F8 ft1024.2 hPa (+0.0)
PPXC1 - 9414847 - Richmond (Point Potrero), CA 31 mi50 min SSW 12 G 18 56°F 1023.4 hPa
RCMC1 - 9414863 - Richmond, CA 32 mi56 min S 8 G 11 56°F 56°F1023.1 hPa
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 42 mi50 min WSW 7 G 8.9 58°F 1022.8 hPa
MZXC1 - 9415102 - Martinez-Amorco CA 43 mi50 min WSW 7 G 8.9 58°F 58°F1023.2 hPa42°F
UPBC1 44 mi50 min W 9.9 G 12
PRYC1 - 9415020 - Point Reyes, CA 45 mi50 min SE 2.9 G 6 55°F 55°F1023.2 hPa
46042 - MONTEREY - 27NM West of Monterey Bay, CA 47 mi78 min 1.9 G 7.8 54°F 56°F7 ft1024.3 hPa (+0.0)
PCOC1 - 9415144 - Port Chicago, CA 47 mi50 min W 12 G 15 58°F 58°F1022.6 hPa

Wind History for Redwood City, CA
(wind in knots)    EDIT      (on/off)   Help
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W14
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1 day
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SW10
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G14
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SE8
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W12
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G14

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Half Moon Bay Airport, CA3 mi73 minSW 49.00 miFair55°F44°F67%1024.4 hPa
San Francisco, San Francisco International Airport, CA12 mi72 minW 1010.00 miA Few Clouds59°F42°F54%1023.6 hPa
San Carlos Airport, CA13 mi81 minWSW 1010.00 miA Few Clouds59°F42°F55%1023.7 hPa
Palo Alto Airport, CA19 mi81 minN 1010.00 miPartly Cloudy61°F48°F63%1023.7 hPa
Oakland, Metro Oakland International Airport, CA21 mi75 minW 910.00 miA Few Clouds60°F45°F58%1023.8 hPa
Mountain View, Moffett Field, CA23 mi72 minN 910.00 miFair61°F46°F60%1024.1 hPa
Hayward, Hayward Air Terminal, CA23 mi74 minWNW 1010.00 miFair60°F41°F50%1024.6 hPa

Wind History from HAF (wind in knots)
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Last 24hrNW13
G19
NW14NW13NW14
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NW13
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NW12NW16
G22
N14
G20
NW14
G23
NW15
G23
NW14NW13NW11NW10
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NW6NW10NW6NW6NW5SW4SW6
1 day agoS12
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E4CalmNW3NW5W5N5NW7NW9N10NW11NW10NW12NW12
2 days agoS15
G22
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G25
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S10SE5SE6SE6SE11
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G21
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G18
SW7SW7S7S9S11S11
G15

Tide / Current Tables for Half Moon Bay, California
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Half Moon Bay
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Thu -- 02:01 AM PDT     2.65 feet Low Tide
Thu -- 04:24 AM PDT     Moonrise
Thu -- 07:08 AM PDT     Sunrise
Thu -- 07:30 AM PDT     4.82 feet High Tide
Thu -- 02:27 PM PDT     0.29 feet Low Tide
Thu -- 03:01 PM PDT     Moonset
Thu -- 07:24 PM PDT     Sunset
Thu -- 09:20 PM PDT     4.38 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
3.12.82.72.83.23.84.44.84.84.43.62.51.50.70.30.40.81.52.43.344.44.33.9

Tide / Current Tables for San Mateo Bridge, South San Francisco Bay, California Current
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San Mateo Bridge
Click for Map
Thu -- 01:53 AM PDT     -0.80 knots Max Ebb
Thu -- 04:23 AM PDT     Moonrise
Thu -- 05:00 AM PDT     0.00 knots Slack
Thu -- 07:07 AM PDT     Sunrise
Thu -- 07:33 AM PDT     1.07 knots Max Flood
Thu -- 10:38 AM PDT     -0.00 knots Slack
Thu -- 02:04 PM PDT     -1.50 knots Max Ebb
Thu -- 03:00 PM PDT     Moonset
Thu -- 05:36 PM PDT     0.00 knots Slack
Thu -- 07:24 PM PDT     Sunset
Thu -- 08:30 PM PDT     1.59 knots Max Flood
Thu -- 11:55 PM PDT     -0.01 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-0.4-0.7-0.8-0.7-0.5-00.6110.80.4-0.2-0.8-1.3-1.5-1.4-1-0.50.41.11.51.61.30.7

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 (18,4,5,8)
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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.