Friday, August23, 2019 L-36.com


Marine Weather and Tides
Half Moon Bay, CA

Version 3.4
NOTICE
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.
6/2/2019. Many thanks to a user for reporting an error on one of the Edit pages. The switch to PHP 7.2 caused many pages that previously worked to quit working. I fixed many but I still depend on users to report ones I missed. Please report errors HERE or send an email to me at L-36.com. Allen

Sunrise 6:30AMSunset 7:53PM Friday August 23, 2019 12:35 PM PDT (19:35 UTC) Moonrise 11:33PMMoonset 1:06PM Illumination 43% Phase: Third Quarter Moon; Moon at 23 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 Am Pdt Fri Aug 23 2019
Today..SW winds 5 to 10 kt, becoming S 10 to 15 kt this afternoon. W swell 6 to 8 ft at 9 seconds and sw around 2 ft at 17 seconds.
Tonight..S winds 10 to 15 kt. W swell 3 to 5 ft at 10 seconds and sw around 2 ft at 16 seconds.
Sat..S winds 5 to 10 kt. NW swell 3 to 5 ft at 10 seconds and sw around 2 ft at 16 seconds.
Sat night..W 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..SW winds 5 to 10 kt. Wind waves 1 to 2 ft. Mixed swell W 2 to 4 ft at 13 seconds and S 2 to 3 ft at 15 seconds. Patchy fog.
Sun night..W winds 5 to 10 kt. Mixed swell W 3 to 5 ft at 12 seconds and S 2 to 3 ft at 14 seconds. Patchy fog.
Mon..W winds 5 to 10 kt. Mixed swell nw 3 to 5 ft and S 2 to 3 ft. Patchy fog.
Tue..SW winds 5 to 10 kt. Mixed swell nw 2 to 4 ft and S 2 to 3 ft. Patchy fog.
...san francisco bar/fourfathom bank forecast..... In the deep water channel...seas 6 to 8 ft with a dominant period of 9 seconds. Across the bar...seas 7 to 9 ft with a dominant period of 9 seconds. Maximum ebb current of 1.0 kt at 11:13 am Friday and 2.3 kt at 10:43 pm Friday.
PZZ500 900 Am Pdt Fri Aug 23 2019
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Northwest winds will decrease across the area today but remain breezy over the northern outer waters. Steep northwesterly swell at 8 to 10 seconds will decrease today through the weekend with period becoming 7 to 8 seconds. Southwesterly winds are forecast over the near shore coastal waters this weekend. A moderate southerly swell will arrive on Sunday and persist through early next week with light northwesterly swell continuing through the period.


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 231817
afdmtr
area forecast discussion
national weather service san francisco bay area
1117 am pdt Fri aug 23 2019

Synopsis A shallow marine layer along the coast with onshore
winds will bring seasonable temperatures to the bay area today.

High pressure begins to strengthen and rebuild over the state this
weekend allowing for inland areas to warm back into the 90s.

Milder conditions will persist near the coast with a shallow
marine layer. The ridge will weaken slightly by Tuesday and
Wednesday as the remnants of tropical storm ivo pass west of the
golden gate. This may bring some increasing clouds and more
humidity to the region.

Discussion As of 9:03 am pdt Friday... Goes-west visible
imagery reveals a mix of clouds and Sun throughout the area as
marine stratus impacts parts of our coastline. With the marine
layer generally between 500 and 1,000 ft deep, the majority of the
san francisco bay area has managed to stay clear, including
locations such as oakland, san jose, all of the interior north
bay, as well as around the san francisco airport. The only
locations in the bay area with low clouds overhead at the present
include western and northern portions of the city of san
francisco, coastal marin county, as well as parts of berkeley and
richmond. The stratus is more widespread south in the monterey bay
area with overcast conditions spanning all the way along the bay
shoreline as well south into the salinas valley past king city.

Mostly clear skies should prevail by mid-morning and beyond for
most locations (with the exception of some lingering stratus into
the afternoon along the immediate pacific coast). Present short-
term forecast package remains on track with no planned morning
update. For additional forecast details, please refer to the
previous discussion section.

Prev discussion As of 3:38 am pdt Friday... 24 hour temps and
humidity trends are noteworthy this morning with dewpoints running
5-10 degrees drier than yesterday at this time with readings back
down into the 50s while temps hover in the lower 60s. The moist
airmass has been pushed south of our region per the latest tpw
satellite scans. A more typical summertime regime is returning to
the bay area and central coast. A shallow 500-1000 foot marine
layer is hugging the coast from the golden gate southward to big
sur. Cloud bases are shallow from 400-600 feet from half moon bay
to the monterey bay region. There is steady onshore pressure
gradients in place with about 2 mb sfo to sacramento allowing the
cooler marine air to ooze inland. The 850 mb temps are around 22
celsius this afternoon which should keep the warmest inland areas
in the lower 90s while 70s 80s persist around the bay with 60s for
the beaches.

A broad 594 dm ridge is forecast to build on Saturday, extending
from the eastern pacific, across california and all the way
towards arizona. This will bring some more inland warming with mid
and upper 90s returning to the inland valleys by Sunday and Monday
as 850 mb temps warm to around 25 celsius. The surface onshore
gradients will remain fairly light with the thermal trough trying
to hug the coastline night and morning hours. Given the strength
of the ridge dont expect the marine layer to deepen too much
through the weekend and into early next week. There will likely be
bouts of morning dense fog near the coast and coastal slopes that
the marine layer covers as it gets squashed by the warm upper
ridge. Locations in the hills above 1500 feet will likely see
little night time variation with warm and dry weather persisting
day and night right through early next week.

In general the pattern the next few days looks to be fairly
typical but inland highs look to be about 4-8 degrees warmer than
normal due to the strong ridge and expected lighter afternoon
seabreezes.

Perhaps the most interesting forecast item to watch will be as the
remnants of tropical storm ivo shift northward by early next week.

The models have been fairly consistent in bringing the remnant
upper level disturbance west of the golden gate by about next
weds. We should see some increasing high clouds as early as
Tuesday night and feel some higher dewpoint air getting ushered in
under a gentle southerly flow.

Conceptually the pattern screams watch out as the tropical
remnants push north and bump up against the previously mentioned
stout upper ridge. As this occurs a mid-latitude trough will be
crossing the east pac and approaching from the northwest. This
will induce a negatively tilted upper trough. For days now the
models have been consistent in not really showing much moisture or
instability over our region. This should be viewed with some
skepticism. At this time its clear that the areas from mendocino
northward up towards mt shasta and modoc as well as much of oregon
look to see much better chances for t-storms as diffluent flow
aloft will develop. The latest 06z GFS implies a large t-storm
outbreak later weds night up near the oregon border. Will need to
watch all these trends closely in the coming days.

Aviation As of 10:56 am pdt Friday... Low clouds are quickly
clearing to the coast as a southerly surge of stratus makes a run
northward. Anticipate a return of stratus this evening and tonight
to coastal terminals as the onshore gradient increases. Confidence
is low as to the extent of the stratus intrusion overnight as the
marine layer is expected to remain shallow. Therefore have limited
cigs to mainly coastal terminals. Light onshore winds will ramp
up this afternoon to around 10 to 15 kt.

Vicinity of ksfo...VFR conditions will prevail with ifr MVFR cigs
likely to return after midnight tonight. Low confidence. Light
winds this morning becoming westerly around 15kt after 21z.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals... Ifr CIGS over kmry will scatter out
between 19z and 20z this afternoon with an early return expected
between 03z-05z this evening. Light winds this morning becoming
westerly 5 to 10kt this afternoon.

Marine As of 9:00 am pdt Friday... Northwest winds will
decrease across the area today but remain breezy over the northern
outer waters. Steep northwesterly swell at 8 to 10 seconds will
decrease today through the weekend with period becoming 7 to 8
seconds. Southwesterly winds are forecast over the near shore
coastal waters this weekend. A moderate southerly swell will
arrive on Sunday and persist through early next week with light
northwesterly swell continuing through the period.

Mtr watches warnings advisories
Tday Sca... Pt arena to pigeon pt 10-60 nm
sca... Sf bay
public forecast: rowe rww
aviation: cw
marine: cw
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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 mi48 min WNW 9.9 G 13 69°F 75°F1010.5 hPa
PXOC1 - 9414311 - San Francisco (Pier 1), CA 23 mi54 min SW 4.1 G 12 67°F 1009.2 hPa
46237 - San Francisco Bar, CA (142) 23 mi66 min 60°F5 ft
AAMC1 - 9414750 - Alameda, CA 23 mi54 min NW 4.1 G 7 70°F 71°F1010.7 hPa
FTPC1 - 9414290 - San Francisco, CA 23 mi54 min WSW 11 G 20 62°F 64°F1010.8 hPa
PXSC1 23 mi48 min 67°F 60°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 24 mi54 min W 9.9 G 12
OBXC1 24 mi48 min 66°F 62°F
LNDC1 25 mi48 min N 6 G 8.9 68°F 1010.2 hPa
OKXC1 - 9414776 - Oakland (Berth 34), CA 25 mi48 min NW 11 G 13 65°F 1010.3 hPa
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 27 mi36 min S 14 G 16 59°F 59°F1011.6 hPa (+1.5)
TIBC1 - Tiburon Pier, San Francisco Bay, CA 29 mi37 min S 9.9 64°F 1010 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 31 mi54 min SW 12 G 16 63°F 1010.7 hPa
RCMC1 - 9414863 - Richmond, CA 32 mi48 min 67°F
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 42 mi48 min WSW 17 G 20 67°F 1009 hPa
MZXC1 - 9415102 - Martinez-Amorco CA 43 mi54 min NW 16 G 19 73°F 73°F1008.6 hPa
UPBC1 44 mi48 min NW 14 G 19
PRYC1 - 9415020 - Point Reyes, CA 45 mi54 min 52°F1010.8 hPa
PCOC1 - 9415144 - Port Chicago, CA 47 mi48 min W 15 G 16 74°F 72°F1008.7 hPa
46042 - MONTEREY - 27NM West of Monterey Bay, CA 48 mi46 min 14 G 18 59°F 59°F7 ft1010.8 hPa (+0.8)

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Half Moon Bay Airport, CA3 mi61 minS 11 G 186.00 miFog/Mist63°F57°F83%1011.8 hPa
San Francisco, San Francisco International Airport, CA12 mi1.7 hrsNE 510.00 miA Few Clouds71°F60°F68%1009.6 hPa
San Carlos Airport, CA13 mi49 minW 810.00 miClear73°F59°F61%1010.2 hPa
Palo Alto Airport, CA19 mi1.8 hrsN 710.00 miClear72°F62°F73%1009.8 hPa
Oakland, Metro Oakland International Airport, CA21 mi1.7 hrsW 710.00 miA Few Clouds72°F59°F64%1010 hPa
Hayward, Hayward Air Terminal, CA23 mi1.7 hrsW 610.00 miFair72°F61°F68%1010.5 hPa
Mountain View, Moffett Field, CA23 mi1.7 hrsN 410.00 miFair76°F62°F62%1009.8 hPa

Link to 5 minute data for KSFO

Wind History from SFO (wind in knots)
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Last 24hrNW18W22W19W21W20W20W20W16----W12NW8----W7W6W8--W8W3NE3N5NE5NE4
1 day agoNW15W19W22W20
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W16----W8--W10W9NW8NW7NW8N6NW10
2 days agoW13--W19
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--------W9--NW6W10W9----W8W3E4E3NW9NW11

Tide / Current Tables for Half Moon Bay, California
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Half Moon Bay
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Fri -- 05:16 AM PDT     3.51 feet High Tide
Fri -- 06:32 AM PDT     Sunrise
Fri -- 07:58 AM PDT     Last Quarter
Fri -- 10:21 AM PDT     2.63 feet Low Tide
Fri -- 02:06 PM PDT     Moonset
Fri -- 04:44 PM PDT     5.25 feet High Tide
Fri -- 07:51 PM PDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.622.533.33.53.53.332.82.62.733.54.14.75.15.24.94.33.42.51.71.2

Tide / Current Tables for San Mateo Bridge, South San Francisco Bay, California Current
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San Mateo Bridge
Click for Map
Fri -- 01:52 AM PDT     0.00 knots Slack
Fri -- 04:29 AM PDT     1.00 knots Max Flood
Fri -- 06:31 AM PDT     Sunrise
Fri -- 07:58 AM PDT     Last Quarter
Fri -- 08:07 AM PDT     -0.00 knots Slack
Fri -- 10:50 AM PDT     -0.75 knots Max Ebb
Fri -- 01:16 PM PDT     0.00 knots Slack
Fri -- 02:05 PM PDT     Moonset
Fri -- 04:25 PM PDT     0.95 knots Max Flood
Fri -- 07:36 PM PDT     -0.00 knots Slack
Fri -- 07:51 PM PDT     Sunset
Fri -- 11:21 PM PDT     -1.36 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-0.8-0.40.10.6110.80.50.1-0.3-0.7-0.7-0.5-0.10.30.60.90.90.70.3-0.2-0.6-1.1-1.3

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 (15,3,4,5)
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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.