Monday, May20, 2019 L-36.com


Marine Weather and Tides
Half Moon Bay, CA

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 5:55AMSunset 8:16PM Sunday May 19, 2019 11:58 PM PDT (06:58 UTC) Moonrise 8:21PMMoonset 5:47AM Illumination 99% Phase: Waning Gibbous; Moon at 16 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 Coastal Waters From Point Reyes To Pigeon Point California Out To 10 Nm- 900 Pm Pdt Sun May 19 2019
.small craft advisory for rough bar in effect through Monday morning...
.small craft advisory in effect through Tuesday afternoon...
Tonight..NW winds 10 to 15 kt...becoming 5 to 15 kt after midnight. Wind waves 2 ft or less. W swell 11 to 13 ft at 13 seconds...subsiding to 9 to 11 ft at 13 seconds after midnight. A slight chance of rain.
Mon..NW winds 10 to 20 kt. Wind waves 3 to 4 ft. W swell 8 to 10 ft at 13 seconds.
Mon night..W winds 10 to 20 kt with gusts up to 25 kt. Wind waves 3 to 4 ft. W swell 6 to 8 ft at 12 seconds. Rain likely.
Tue..NW winds 20 to 30 kt. Wind waves 5 to 6 ft. W swell 7 to 9 ft at 11 seconds and sw around 3 ft at 18 seconds. A chance of rain.
Tue night..NW winds 20 to 30 kt. Wind waves 6 to 7 ft. W swell 11 to 13 ft at 14 seconds and sw around 3 ft at 18 seconds. A slight chance of rain.
Wed..NW winds 15 to 25 kt with gusts up to 30 kt. Wind waves 4 to 5 ft. W swell 9 to 11 ft at 13 seconds.
Wed night..NW winds 10 to 20 kt with gusts up to 25 kt. Wind waves 4 to 5 ft. W swell 9 to 11 ft at 12 seconds.
Thu..NW winds 5 to 15 kt. Wind waves 2 ft or less. W swell 7 to 9 ft.
Fri..W winds up to 10 kt. Wind waves 2 ft or less. NW swell 4 to 6 ft.
...san francisco bar/fourfathom bank forecast..... In the deep water channel...combined seas 9 to 11 ft with a dominant period of 13 seconds decreasing to 7 to 9 ft Monday. Across the bar...combined seas 10 to 12 ft with a dominant period of 13 seconds decreasing to 8 to 10 ft Monday. Maximum ebb current of 4.1 kt at 05:43 am Monday and 1.6 kt at 07:01 pm Monday.
PZZ500 900 Pm Pdt Sun May 19 2019
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... High pressure is about 1000 miles west of Monterey. A low pressure will move into the oregon coast Monday night and Tuesday. The high will build towards the coast after the low passes. Winds will remain light west to northwest through Monday night then increase on Tuesday and Wednesday. Large swells generated by the last strorm system will create hazardous conditions particularly for smaller vessels.


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 200529
afdmtr
area forecast discussion
national weather service san francisco bay area
1029 pm pdt Sun may 19 2019

Synopsis Scattered showers dissipating through the evening
hours then dry weather returns late tonight and into Monday. A
cold system dropping in from the north will bring renewed shower
chances from Monday night through Tuesday evening. Drier weather
is forecast later in the week, but temperatures will remain cooler
than normal.

Discussion As of 8:35 pm pdt Sunday... Scattered showers will
slowly diminish through the evening with the loss of daytime
surface heating. The cold core upper level low responsible for
instability will reach the four corners by Monday evening.

High temperatures today were more fit for winter season weather
especially in the north bay with highs mostly topping out only in
the upper 50s. Both 850 mb and 500 mb temperatures are within a
couple degrees celsius of equaling the all time recorded minimums
for late may on all oakland upper air soundings for the period of
record 1948-2014 per spc's sounding climatology page. Any snow on
the high peaks of the central coast is noteworthy for late may,
less so for the sierra nevada crest. Essentially we're seeing an
extension of an active to very active 2018-2019 cool season northern
hemispheric long wave pattern and the outlook in the 8 to 10 day 500
mb mean height forecasts indicates a similar scenario continues.

Prev discussion As of 01:38 pm pdt Sunday... Afternoon kmux radar
imagery pretty much says it all - widely scattered showers and
thunderstorms across the bay area. The showers thunderstorms are
thanks to an unstable atmosphere associated with a cold core upper
low. Cold upper low is also keeping temperatures below normal
this afternoon. In fact, many locations are currently running
10-20 degrees below normal for late may. Snow in the sierra is not
that uncommon in may or june for that matter. Snow in may for the
central coast is definitely noteworthy. No official confirmation
yet, but observations show temps in the mid 30s (5k ft) and the pt
sur profiler puts snow levels around 4,900 feet. Precip that
passes over the higher peaks above big sur could fall as snow or
rain snow mix this afternoon.

For the rest of the day - scattered showers thunderstorms will
continue this afternoon through early tonight as the upper low
slowly drifts southeast across the state. It will be a chilly
night across the bay area with lows in the 40s to lower 50s -
upper 30s higher peaks. Given the ample low level moisture
wouldn't be surprised to see some patchy fog tomorrow morning.

A break in the action early Monday before another system will
bring precip chances back to the bay area Monday evening through
Tuesday. The tail end of a cold front will drop south across the
region bringing rain initially to the north bay Monday evening
before moving south overnight and into Tuesday. Rainfall amounts
will be much less than the Sunday system - a few hundredths to a
quarter of an inch. Scattered showers will then linger Tuesday
into early Wednesday as the associated low pressure system move
southward. Not much in the way of QPF with the low pressure
either.

For the most part drier weather late Wednesday into early Friday
as the upper low moves farther inland toward the desert
southwest. A broad upper trough does remain over the region
keeping cooler below normal weather in place. Precip chances
return again late in the week next weekend as weak disturbance
rounds the base of the retrograding trough. Simply put, low
confidence, but precip chances will linger in the extended with
below normal temperatures.

Aviation As of 10:30 pm pdt Sunday... Shower activity is winding
down in the sfo bay area while residual showers will continue in
the mry bay area through 10-12z. Plenty of low level moisture
remains so we could see some areas of MVFR CIGS early Monday
morning as well as patchy fog in the north bay valleys. An upper
level low will bring increasing clouds and west winds to the area
Monday night.

Vicinity of ksfo... In the short term CIGS remaining 4000-5000
feet. A lower level inversion layer will develop late tonight
which could bring CIGS down to 1500-2500 feet after 12z.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals... Scattered showers through 10-12z.VFR MVFR
cigs with bases between 2500-4000 feet through Monday midmorning.

Marine As of 10:23 pm pdt Sunday... High pressure is about 1000
miles west of monterey. A low pressure will move into the oregon
coast Monday night and Tuesday. The high will build towards the
coast after the low passes. Winds will remain light west to
northwest through Monday night then increase on Tuesday and
Wednesday. Large swells generated by the last strorm system will
create hazardous conditions particularly for smaller vessels.

Mtr watches warnings advisories
Tngt 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... Pt arena to pigeon pt 10-60 nm
sca... Pigeon pt to pt piedras blancas 10-60 nm
sca... Rough bar advisory for sf bar
sca... Mry bay until 3 am
public forecast: canepa mm
aviation: W pi
marine: W pi
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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 mi59 min W 4.1 G 5.1 55°F 63°F1012.7 hPa (+1.4)
46237 - San Francisco Bar, CA (142) 23 mi59 min 57°F9 ft
AAMC1 - 9414750 - Alameda, CA 23 mi65 min W 1 G 2.9 54°F 61°F1012.3 hPa
FTPC1 - 9414290 - San Francisco, CA 23 mi65 min W 2.9 G 4.1 53°F 58°F1012.1 hPa
PXSC1 23 mi59 min 55°F 51°F
PXOC1 - 9414311 - San Francisco (Pier 1), CA 23 mi59 min NW 2.9 G 5.1 53°F 1011 hPa (+1.5)
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 24 mi65 min SW 1 G 1.9
OBXC1 24 mi59 min 54°F 53°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 25 mi59 min WSW 1.9 G 2.9 54°F 1012 hPa (+1.5)
LNDC1 25 mi59 min S 1 G 1.9 54°F 1011.9 hPa (+1.4)
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 27 mi39 min W 3.9 G 5.8 54°F 56°F1012.2 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 31 mi59 min S 4.1 G 5.1 55°F 1012.2 hPa (+1.5)
RCMC1 - 9414863 - Richmond, CA 32 mi65 min S 1.9 G 2.9 55°F 59°F1011.7 hPa
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 42 mi59 min SSW 4.1 G 5.1 54°F 1011.7 hPa (+1.5)
MZXC1 - 9415102 - Martinez-Amorco CA 43 mi65 min SSW 2.9 G 4.1 54°F 62°F1011.9 hPa54°F
UPBC1 44 mi59 min SW 4.1 G 5.1
PRYC1 - 9415020 - Point Reyes, CA 45 mi65 min 57°F1011.7 hPa
PCOC1 - 9415144 - Port Chicago, CA 47 mi65 min SW 4.1 G 5.1 54°F 62°F1012 hPa
46042 - MONTEREY - 27NM West of Monterey Bay, CA 48 mi69 min WNW 12 G 16 56°F 57°F11 ft1011.6 hPa (+1.1)

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Half Moon Bay Airport, CA3 mi64 minE 310.00 miOvercast52°F50°F94%1012.2 hPa
San Francisco, San Francisco International Airport, CA12 mi2 hrsSW 610.00 miMostly Cloudy54°F48°F83%1011.5 hPa
San Carlos Airport, CA13 mi3.1 hrsWSW 410.00 miMostly Cloudy54°F48°F82%1011.8 hPa
Palo Alto Airport, CA19 mi3.2 hrsW 510.00 miLight Rain55°F46°F72%1011.8 hPa
Oakland, Metro Oakland International Airport, CA21 mi66 minW 510.00 miMostly Cloudy56°F48°F75%1012.2 hPa
Hayward, Hayward Air Terminal, CA23 mi65 minW 410.00 miMostly Cloudy54°F48°F83%1013 hPa
Mountain View, Moffett Field, CA23 mi2 hrsN 010.00 miMostly Cloudy54°F48°F83%1012.3 hPa

Wind History from SFO (wind in knots)
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1 day agoW9W5S5S4SW4SE4SE6S4SE8S9S7S8S9SE11SE12SE9SE8SE20
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Tide / Current Tables for Half Moon Bay, California
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Half Moon Bay
Click for Map
Mon -- 05:56 AM PDT     Sunrise
Mon -- 06:29 AM PDT     -1.20 feet Low Tide
Mon -- 07:29 AM PDT     Moonset
Mon -- 01:28 PM PDT     4.35 feet High Tide
Mon -- 06:20 PM PDT     2.50 feet Low Tide
Mon -- 08:16 PM PDT     Sunset
Mon -- 10:21 PM PDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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5.85.23.92.40.8-0.5-1.1-1.1-0.50.51.62.83.84.34.33.93.32.82.52.63.13.84.65.3

Tide / Current Tables for San Mateo Bridge, South San Francisco Bay, California Current
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San Mateo Bridge
Click for Map
Mon -- 02:25 AM PDT     -0.00 knots Slack
Mon -- 05:55 AM PDT     Sunrise
Mon -- 06:02 AM PDT     -2.10 knots Max Ebb
Mon -- 07:28 AM PDT     Moonset
Mon -- 09:29 AM PDT     0.00 knots Slack
Mon -- 12:22 PM PDT     2.05 knots Max Flood
Mon -- 04:04 PM PDT     -0.00 knots Slack
Mon -- 06:38 PM PDT     -1.00 knots Max Ebb
Mon -- 08:15 PM PDT     Sunset
Mon -- 09:24 PM PDT     0.00 knots Slack
Mon -- 10:20 PM PDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.410.4-0.4-1.2-1.9-2.1-1.9-1.3-0.50.61.6221.610.1-0.6-0.9-1-0.7-0.20.41.1

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.