Tuesday, August20, 2019 L-36.com


Marine Weather and Tides
Colma, CA

Version 3.4
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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 6:28AMSunset 7:57PM Tuesday August 20, 2019 9:17 AM PDT (16:17 UTC) Moonrise 9:53PMMoonset 10:08AM Illumination 75% Phase: Waning Gibbous; Moon at 20 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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PZZ530 San Pablo Bay, Suisun Bay, The West Delta And The San Francisco Bay North Of The Bay Bridge- 813 Am Pdt Tue Aug 20 2019
.small craft advisory in effect from noon pdt today through this evening...
.small craft advisory in effect from Wednesday afternoon through Wednesday evening...
Today..SW winds 10 to 15 kt, increasing to 15 to 25 kt with gusts up to 30 kt this afternoon.
Tonight..SW winds 10 to 15 kt.
Wed..SW winds 10 to 15 kt, increasing to 15 to 25 kt with gusts up to 30 kt in the afternoon.
Wed night..SW winds 10 to 15 kt.
Thu..SW winds 10 to 15 kt.
Thu night..SW winds 15 to 20 kt with gusts up to 25 kt.
Fri..SW winds 15 to 20 kt.
Sat..SW winds 10 to 15 kt.
PZZ500 813 Am Pdt Tue Aug 20 2019
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Generally light to moderate northwesterly winds will continue over the coastal waters through mid-week as high pressure sits over the eastern pacific. Locally gusty coastal jets are expected south of point arena, pigeon point, and point sur that will create hazardous seas conditions for smaller vessels. Breezy afternoon and evening winds are also forecast over the san francisco bay around the golden gate and through the delta as well as over the Monterey bay. Mixed seas will continue with shorter period northwest waves at around 8 to 10 seconds, a light longer period west swell, and a light southerly swell.


7 Day Forecast for Marine Location Near Colma, CA
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location: 37.68, -122.42     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 201444 cca
afdmtr
area forecast discussion
national weather service san francisco bay area
740 am pdt Tue aug 20 2019

Synopsis A warming trend is forecast through Thursday as high
pressure builds over central and southern california. Inland areas
will see less in the way of night and morning low clouds as the
marine layer compresses. Seasonable temperatures are forecast
through the upcoming weekend, along with continued dry
conditions.

Discussion As of 07:40 am pdt Tuesday... The base of an
advancing 546dm 500mb low pressure trough offshore of the pacific
northwest has temporarily lowered heights aloft and allowed the
marine layer to deepen slightly versus yesterday morning (2600 ft
vs 2200 ft on 12z koak sounding). The fort ord profiler shows
less of a day over day change as it is farther southward from the
trough. As a result, the marine layer is inundating most inland
areas approx 2500 ft and below. Above the marine layer, a
warm dry air mass looms in response to a retrograding ridge
backing westward over the southern half of california. This high
pressure ridge will become the dominate synoptic scale feature
midweek and result in tomorrow (Wednesday) being the warmest day
of the next few. Temperatures tomorrow will range from near normal
along the shorelines to up to 10 degrees above normal for the
inland areas. Afternoon highs of 60s to low 70s are forecast along
the coast, upper 70s to upper 80s for areas in some proximity to a
coast shoreline, and into the low to mid 90s for the extreme
inland areas far from the coast.

A few reports of coastal drizzle came in this morning, but
otherwise, the current (overnight) forecast looks on track and no
updates are planned until the afternoon package. The main forecast
challenges today are determining if how much onshore flow will cool
temperatures Thursday and what impacts, if any, the remnants of a
tropical system may have across our area early next week. See
previous discussion for more information on the current forecast.

Previous discussion As of 3:35 am pdt Tuesday... Our weather
during the past few days was primarily influenced by a deep marine
layer, resulting in widespread night and morning low clouds,
local drizzle, and cooler than normal inland temperatures. The
first sign that the pattern is changing is evident early this
morning with the fort ord profiler indicating a decrease in the
depth of the marine layer as an upper ridge over the southern
plains and desert southwest begins to build to the west and across
southern california. In addition, light southerly low level flow
over the weekend is changing to a more typical west and northwest
direction. The building ridge and more typical wind patterns will
result in a warming trend across our region through Thursday.

Satellite currently shows an upper trough offshore along 140w.

The models track this trough inland across the pacific northwest
on Wednesday, but the trough is expected to remain too far north
of our area to have an impact on our weather. In fact, the models
agree that the biggest increase in temperatures during the
upcoming warming trend will occur on Wednesday. Temperatures are
forecast to warm slightly above normal by Wednesday when low to
mid 90s will be common in the inland valleys. Persistent light
onshore flow will keep coastal temperatures seasonably mild.

As the marine layer compresses over the next few days, expect
decreasing night and morning low clouds across inland areas, while
patchy fog is likely to develop near the ocean.

Models forecast a continued gradual increase in h5 heights late
in the week and through the weekend as the upper ridge continues
to build over california. However, both the GFS and ECMWF indicate
the warming trend will stall on Friday, and even reverse in some
areas with slight cooling forecast from Friday into the weekend.

The likely reason for this counterintuitive temperature trend
during the extended forecast period is the development of a weak
surface trough off the california coast which will turn surface
winds to a southerly direction by Friday. This southerly flow
will more readily transport marine air inland, especially in
places like the north bay valleys and santa cruz county. Forecast
temperatures from Friday through Sunday have been reduced below
the nbm values and brought more in line with the GFS and ECMWF mos
guidance.

One wildcard late in the extended period is the possibility of
tropical moisture reaching our area during the first half of next
week. Longer range models track a weak tropical system near the
west coast of mexico to the northwest and to a position off the
coast of the baja peninsula by the upcoming weekend. Moisture
from this system could then be drawn north and across california
sometime early next week. In fact, the 00z GFS develops
precipitation over our area by next Tuesday night. There is still
a great deal of uncertainty as to how this scenario will play out
and any potential impacts in our area are currently at the end of,
or just beyond, our extended forecast period. But this is
something that will need to be monitored closely over the next few
days.

Aviation As of 4:39 am pdt Tuesday... For 12z tafs. Widespread
stratus under a 3000 ft marine layer has brought MVFR to localized
lifr CIGS to area terminals this morning. Low clouds are forecast
to scatter out between 17z-22z today depending on location. See
tafs for more details. Light onshore flow around 5 to 10 kt will
persist through the morning hours becoming moderate and gusty
around 10 to 15 kt in the afternoon. Gusts to 25 kt possible over
ksfo.

Vicinity of ksfo... MVFR CIGS will prevail through the morning
hours with clearing anticipated around 18z-22z today. West winds
of around 10 kt will prevail overnight becoming moderate and
gusty around 10 to 15 kt in the afternoon with gusts to 25 kt
possible over ksfo.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals... MVFR to ifr CIGS will persist through
the morning with clearing is anticipated around 18z-20z today.

West winds of around 5 kt will prevail through the morning then
increasing to 10 to 15 kt in the afternoon.

Marine As of 3:00 am pdt Tuesday... High pressure over the
eastern pacific will maintain generally light to moderate
northwesterly winds over the coastal waters through mid-week.

Locally gusty coastal jets south of point arena, pigeon point and
point sur will create hazardous conditions for small vessels.

Breezy winds are also forecast for san francisco bay around the
golden gate and through the delta, and over the monterey bay.

Mixed seas will continue with shorter period northwest waves at
around 8 to 10 seconds, a light longer period west swell, and a
light southerly swell.

Mtr watches warnings advisories
Tday Sca... Sf bay from 12 pm
sca... Mry bay from 12 pm
sca... Pt arena to pt reyes 0-10 nm from 12 pm
sca... Pigeon pt to pt pinos 0-10 nm from 12 pm
sca... Pt pinos to pt piedras blancas 0-10 nm
public forecast: drp dykema
aviation: cw
marine: cw
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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
PXOC1 - 9414311 - San Francisco (Pier 1), CA 8 mi47 min W 5.1 G 7 61°F 1015.6 hPa
PXSC1 9 mi47 min 62°F 59°F
AAMC1 - 9414750 - Alameda, CA 9 mi47 min WNW 4.1 G 6 1017.1 hPa
FTPC1 - 9414290 - San Francisco, CA 9 mi47 min W 4.1 G 12 60°F 61°F1017 hPa
OBXC1 10 mi47 min 61°F 60°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 10 mi47 min WNW 5.1 G 8.9 61°F 1016.6 hPa
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 10 mi47 min WSW 4.1 G 7
LNDC1 11 mi47 min WSW 5.1 G 7 62°F 1016.6 hPa
46237 - San Francisco Bar, CA (142) 14 mi47 min 60°F3 ft
TIBC1 - Tiburon Pier, San Francisco Bay, CA 15 mi30 min Calm 62°F 1017 hPa (+2.0)
PPXC1 - 9414847 - Richmond (Point Potrero), CA 16 mi47 min WSW 1.9 G 4.1 63°F 1016.9 hPa
RTYC1 - 9414523 - Redwood City, CA 16 mi47 min W 6 G 7 63°F 75°F1017.7 hPa
RCMC1 - 9414863 - Richmond, CA 17 mi47 min W 4.1 G 7 62°F 64°F1016.4 hPa
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 23 mi37 min W 5.8 G 7.8 59°F 1017.7 hPa
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 27 mi47 min WSW 6 G 8.9 62°F 1016 hPa
UPBC1 29 mi47 min W 12 G 15
MZXC1 - 9415102 - Martinez-Amorco CA 29 mi47 min W 9.9 G 13 62°F 71°F1016.3 hPa
PCOC1 - 9415144 - Port Chicago, CA 33 mi47 min SW 14 G 18 62°F 72°F1016.1 hPa
PRYC1 - 9415020 - Point Reyes, CA 37 mi47 min 58°F1016.8 hPa
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 38 mi47 min WNW 16 G 21 64°F 1015.2 hPa
SFXC1 - San Francisco Bay Reserve, CA 42 mi92 min WNW 9.9 60°F 1016 hPa59°F

Wind History for Alameda, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
San Francisco, San Francisco International Airport, CA5 mi81 minW 810.00 miOvercast65°F55°F70%1016.6 hPa
Oakland, Metro Oakland International Airport, CA11 mi84 minW 910.00 miOvercast64°F55°F73%1016.7 hPa
Half Moon Bay Airport, CA12 mi82 minNW 410.00 miOvercast61°F57°F88%1017.3 hPa
San Carlos Airport, CA14 mi84 minWSW 510.00 miOvercast63°F55°F77%1017.3 hPa
Hayward, Hayward Air Terminal, CA16 mi83 minW 910.00 miOvercast62°F55°F78%1017.5 hPa
Palo Alto Airport, CA21 mi90 minN 010.00 miOvercast63°F53°F73%1017.3 hPa

Link to 5 minute data for KSFO

Wind History from SFO (wind in knots)
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Last 24hrSW8SW9SW12--SW10W18W16W16
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W10--------W11--W11--W9W7W11W11W8W10
1 day agoNE6NE6E6S12
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S4--------SW6----SW4SW7W7--W6--SW5
2 days agoNE6S8S11S12S14SW11SW13
G20
W7S9S12S6S9S10S9S7--S12S6S6S8--S6S9E4

Tide / Current Tables for South San Francisco, San Francisco Bay, California
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South San Francisco
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Tue -- 03:32 AM PDT     5.98 feet High Tide
Tue -- 06:29 AM PDT     Sunrise
Tue -- 09:53 AM PDT     1.26 feet Low Tide
Tue -- 11:07 AM PDT     Moonset
Tue -- 04:22 PM PDT     6.47 feet High Tide
Tue -- 07:55 PM PDT     Sunset
Tue -- 10:37 PM PDT     1.95 feet Low Tide
Tue -- 10:52 PM PDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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3.44.45.35.95.95.44.53.32.21.51.31.62.53.74.95.96.46.35.74.73.52.622

Tide / Current Tables for Sierra Point 1.3 mi ENE, South San Francisco Bay, California Current
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Sierra Point 1.3 mi ENE
Click for Map
Tue -- 01:06 AM PDT     0.73 knots Max Flood
Tue -- 04:08 AM PDT     -0.00 knots Slack
Tue -- 06:29 AM PDT     Sunrise
Tue -- 07:23 AM PDT     -0.98 knots Max Ebb
Tue -- 10:14 AM PDT     0.00 knots Slack
Tue -- 11:07 AM PDT     Moonset
Tue -- 01:28 PM PDT     0.81 knots Max Flood
Tue -- 04:41 PM PDT     -0.00 knots Slack
Tue -- 07:51 PM PDT     -0.96 knots Max Ebb
Tue -- 07:55 PM PDT     Sunset
Tue -- 10:52 PM PDT     Moonrise
Tue -- 10:54 PM PDT     0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.60.70.60.40.1-0.3-0.7-1-0.9-0.5-0.10.30.60.80.80.60.3-0.1-0.5-0.9-1-0.7-0.30

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 (12,3,4,5)
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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.