Monday, September20, 2021
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Marine Weather and Tides
San Leandro, CA

Version 3.4
NOTICE
3/30/2021 -- ANZ330 has been split into ANZ331 and ANZ332. Click EDIT in Marine Forecast and select your new zone.
1/26/2021 -- The West Coast Satellite images havd been updated. They now use GEOS-17.
1/1/2021 -- The 7 day forecast are now working well. Thank you NOAA for your support.

Sunrise 6:52AMSunset 7:11PM Sunday September 19, 2021 10:35 PM PDT (05:35 UTC) Moonrise 6:01PMMoonset 4:22AM Illumination 98% Phase: Waxing Gibbous; Moon at 13 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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PZZ531 San Francisco Bay South Of The Bay Bridge- 800 Pm Pdt Sun Sep 19 2021
Tonight..NW winds 15 to 20 kt with gusts up to 25 kt, becoming W 5 to 10 kt after midnight.
Mon..W winds 10 to 15 kt.
Mon night..W winds 10 to 15 kt.
Tue..NW winds 5 to 10 kt.
Tue night..N winds 5 to 10 kt.
Wed..NW winds 10 to 15 kt with gusts up to 25 kt.
Wed night..W winds 5 to 10 kt.
Thu..W winds 10 to 15 kt.
Fri..W winds 10 to 15 kt.
PZZ500 800 Pm Pdt Sun Sep 19 2021
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Gusty northwest winds will persist into Monday morning with hazardous seas conditions for much of the waters, particularly for smaller vessels. Winds will diminish Monday afternoon and evening. Light to locally moderate winds will then persist into mid week before increasing over the outer water by late week. Mixed seas continue with a short period northwest swell and a weak longer period southerly swell. An additional longer period northwest swell will arrive around mid week.


7 Day Forecast for Marine Location Near San Leandro, CA
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location: 37.68, -122.17     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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FXUS66 KMTR 200448 AFDMTR

Area Forecast Discussion National Weather Service San Francisco Bay Area 948 PM PDT Sun Sep 19 2021

SYNOPSIS. A burst of northerly winds brings rapidly drying conditions overnight. Red Flag Warnings go into effect at 11 pm for the North and East Bay hills as well as the East Bay interior valleys through 8 pm Monday for drying offshore winds. Otherwise sunny and warmer Monday and Tuesday regionwide under fall offshore wind pattern. Slight cooling trend by Wednesday but continued dry and seasonable through the work week.

DISCUSSION. as of 09:48 PM PDT Sunday . Night satellite imagery shows a stark contrast to 24 hours ago. Predominantly clear skies, with marine stratus struggling to materialize over the coastal waters. The marine layer has been fractured in the wake of last night's low pressure system, with drier air filtering in and a ridge building offshore. The benefits of last night's rain event are already apparent throughout NorCal. Minimal smoke or fire signals are emanating from the Trinity/Siskiyou wildfires. ERC's around the Central Coast and Bay Area have fallen below or to near normal levels. Air quality is predominantly green(healthy) in the northern half of the state. Unfortunately, lots of smoke and moderate/poor air quality remains in SoCal from the Sequoia fires, which haven't seen any rain. HRRR smoke model actually shows some of this smoke drifting northward into the Bay Area tomorrow night.

Otherwise, all attention turns toward the warming/drying trend beginning overnight with a burst of gusty winds funneling down the Sac Valley. Red Flag Warning goes into effect at 11 p.m. for the North Bay Mountains and East Bay hills and valleys due to the incoming gusty winds and rapidly lowering RH's. Winds are pretty tame at this hour, but have been seeing some strong gusts at the higher peaks in the last hour (35+ mph at Mt St Helena and 30+ mph at Mt Diablo). Could easily see 50+ mph gusts tonight at these and other peaks. Main question is how long it will take RH's to drop to critical levels while winds are still gusting. Still quite moist in Sonoma County due to the recent rain, but dry in Napa County which saw little to no precip. Seeing RH's in the 30%-40% in Napa at this hour, so already entering critically dry levels once the winds pick up. Drying trend will continue through tomorrow, so RFW goes through 8 P.M. Monday. Also will see a notable warming trend through Tuesday as the offshore ridge moves over the coast and light offshore winds continue. Ensembles have been trending warmer for Tuesday, warranting more attention to heat impacts all the way to the coast. Not unusual for the second half of September with a moderate offshore flow event. See below discussion for more on the weekly outlook.

PREV DISCUSSION. as of 2:03 PM PDT Sunday . Skies have cleared out behind last nights frontal passage with just some lingering clouds over the ocean and a few instability clouds over the hills this afternoon with mild temps warming into the upper 70s and lower 80s inland. All focus will shift to developing offshore winds and associated Red Flag Warning as well as a noted warming and drying trend for Monday and Tuesday.

Todays forecast focus has been on the Red Flag Warning that covers the North/East Bay hills and East Bay valleys from 11 pm tonight through 8 pm Monday. As expected any rainfall of note was confined to northwest Sonoma county down to coastal Marin. Interior North Bay and the heart of the Bay Area generally saw trace amounts or less than a tenth which is not considered a wetting rain or enough to have an appreciable impact on the fine fuels let alone the heavier drought impacted fuels. So the areas of most concern will be the Napa hills across the North Bay as well as the East Bay hills/valleys where stronger winds, low humidity values and dry fuels are most likely to line up.

For tonight northerly winds will develop over the Napa hills before midnight and then spread over the rest of the Bay Area hills overnight into Monday morning. Initially most of the strong winds will be confined to the higher ridges above 2000 feet before slowly mixing down closer to the 1000 foot elevation. We can expect to see some gusts to around 50 mph for Mt Saint Helena and Diablo but more significant rainfall was observed around those higher peaks last night. The initial burst of winds will arrive with humidity readings quite moist, thus the period of strongest winds will not line up with the lowest humidity but rather the initial energy of the winds will be spent drying the fine fuels out. Without getting too esoteric its also worth noting the 10 hour fuel stick values are remaining fairly high, even for those locations that didn't see rainfall so fuel conditions are not too extreme going into the event which is supported by the latest ERC fuel chart readings as well. Nonetheless the synoptic weather pattern features a fairly typical mid-September offshore wind event. From sunrise through about 10 am winds should be peaking in strength regionwide and riding on-top of the nighttime inversion layer right around 1000 to 1500 feet in elevation. As the morning inversion breaks some of those winds will mix down to the lower elevations of the North/East Bay as well as the coastline. As this occurs we should see rapid spike in temperatures before noon on Monday as readings quickly approach 80 degrees, even near the coast and bays. Persistent but fairly light offshore flow to continue through Monday afternoon but the main impact will become hotter temps regionwide with widespread upper 80s to mid 90s as humidity values lower into the teens.

Offshore flow to continue Monday night but as the sun goes down we dont expect any strong wind speeds. Thus for now and in coordination with neighboring offices will plan to let the Red Flag expire at 8 pm Monday evening. That being said we expect little or no humidity recovery Monday night into Tuesday morning, especially in the hills with readings staying from 18-30% overnight keeping conditions near critical.

The offshore flow should ease by Tuesday morning but the stage will be set for another hot day with widespread readings in the upper 80s and 90s. Were at the time of year when things become more isothermal and the hottest temps can actually be closer to the coast under offshore/downslope flow. No expectation of any heat products as the dry airmass will allow good radiational cooling under the longer Sept nights.

Will be watching a midweek shortwave that will turn the wind pattern back to onshore by Weds morning and induce a modest cooling trend. This feature will get rid of the inland 90s but still expect comfortable temps in the 70s and 80s for Weds.

Models then take the midweek shortwave and drop it towards the Central Valley before potentially it turns into a weak cut-off low by late in the week. Nearly all the models are now indicating this potential with the likely result of little appreciable impact of note for the Bay Area though some solutions indicate an outside chance of some showers for the Central Coast though that remains doubtful. The North Bay and greater Bay Area will likely be on the dry northeast side of the upper low with fair and nice wx.

Longer range solutions suggest as that feature finally kicks out towards Nevada dry high pressure will build later next weekend with continued dry and seasonable weather.

AVIATION. as of 04:29 PM PDT Sunday . For the 00z TAFs. Satellite imagery shows stratus remains along the coast from Sonoma County down through the Monterey Bay as well as some scattered cumulus and a line of passing high clouds. VFR conditions are expected to prevail as dry offshore flow sets up tonight and persists through the forecast period. As northerly winds strengthen overnight, there is a possibility of LLWS (mainly in the North and East Bay) late tonight into early tomorrow morning. Breezy northwest winds this afternoon in the wake of a cold front with most sites around 10 to 20 kt into this evening before surface winds diminish tonight. Occasional higher gusts overnight may mix down to the surface from the offshore flow aloft, but no widespread consistent stronger winds are anticipated.

The latest HRRR smoke model is showing an increase in total smoke beginning just at the end of this taf package from south to north. Expect reduced slant range visibility starting late tomorrow afternoon.

Vicinity of KSFO . VFR. Breezy W/NW winds this afternoon at 15 to 25 kt diminishing this evening. Increasing offshore winds aloft overnight may lead to some LLWS on and off into early Monday morning.

KSFO Bridge Approach . Similar to KSFO.

Monterey Bay . VFR prevailing, though satellite does show some stratus moving into the Monterey Bay. There is the chance of SCT to BKN cigs developing over the terminals early this evening. Should this occur, expecting clearing to occur by early Monday morning. Breezy onshore winds this afternoon around 10-15 kt diminishing overnight. As mentioned above, HRRR smoke model shows increasing smoke beginning late tomorrow afternoon.

MARINE. as of 08:27 PM PDT Sunday . Gusty northwest winds will persist into Monday morning with hazardous seas conditions for much of the waters, particularly for smaller vessels. Winds will diminish Monday afternoon and evening. Light to locally moderate winds will then persist into mid week before increasing over the outer water by late week. Mixed seas continue with a short period northwest swell and a weak longer period southerly swell. An additional longer period northwest swell will arrive around mid week.

MTR WATCHES/WARNINGS/ADVISORIES. Tngt. Red Flag Warning . CAZ507-510-511 SCA . Mry Bay until 9 PM SCA . Pigeon Pt to Pt Pinos 0-10 nm until 9 PM SCA . Pt Arena to Pigeon Pt 10-60 nm from 9 PM SCA . Pt Pinos to Pt Piedras Blancas 0-10 nm SCA . Pigeon Pt to Pt Piedras Blancas 10-60 nm from 9 PM SCA . Pt Arena to Pt Reyes 0-10 nm until 3 AM



PUBLIC FORECAST: Lorber/RWW AVIATION: AS MARINE: AS

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
AAMC1 - 9414750 - Alameda, CA 9 mi48 min W 4.1 G 6 62°F 67°F1017.5 hPa
LNDC1 10 mi48 min WSW 4.1 G 4.1 63°F 1017.1 hPa
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 12 mi48 min WSW 6 G 8
RTYC1 - 9414523 - Redwood City, CA 12 mi48 min WSW 2.9 G 2.9 63°F 1018 hPa
OBXC1 12 mi48 min 63°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 13 mi48 min W 1 G 2.9 63°F 1017.1 hPa
PXOC1 - 9414311 - San Francisco (Pier 1), CA 14 mi48 min SW 2.9 G 4.1 62°F 1016.1 hPa
PXSC1 15 mi48 min 63°F 63°F
FTPC1 - 9414290 - San Francisco, CA 18 mi54 min SSW 5.1 G 8 60°F 65°F1017.1 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 19 mi48 min SW 4.1 G 5.1 64°F 1017.5 hPa
RCMC1 - 9414863 - Richmond, CA 21 mi54 min Calm G 1 65°F 64°F1017.2 hPa
MZXC1 - 9415102 - Martinez-Amorco CA 25 mi48 min WNW 8 G 9.9 65°F 68°F1016.9 hPa
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 26 mi48 min W 4.1 G 6 66°F 1016.7 hPa
46237 - San Francisco Bar, CA (142) 26 mi36 min 60°F 59°F6 ft
PCOC1 - 9415144 - Port Chicago, CA 27 mi48 min SW 8 G 9.9 64°F 68°F1016.6 hPa
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 29 mi48 min WNW 7 G 11 69°F 1015.9 hPa
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 36 mi26 min NNW 9.7 G 14 57°F1017.5 hPa
SFXC1 - San Francisco Bay Reserve, CA 37 mi51 min NW 4.1 60°F 1017 hPa53°F
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 44 mi26 min NNW 16 G 23 59°F 1017.6 hPa55°F
PRYC1 - 9415020 - Point Reyes, CA 48 mi48 min 62°F1017.7 hPa

Wind History for Alameda, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hayward, Hayward Air Terminal, CA3 mi42 minN 010.00 miFair62°F56°F80%1017.8 hPa
Oakland, Metro Oakland International Airport, CA3 mi43 minWNW 510.00 miFair63°F55°F76%1017 hPa
San Carlos Airport, CA11 mi41 minN 010.00 miFair63°F52°F68%1017.6 hPa
San Francisco, San Francisco International Airport, CA11 mi40 minWNW 1010.00 miFair61°F54°F78%1016.7 hPa
Palo Alto Airport, CA14 mi1.8 hrsNW 610.00 miClear61°F52°F72%1015.9 hPa
Livermore, Livermore Municipal Airport, CA19 mi43 minN 010.00 miFair63°F56°F78%1016.5 hPa
Half Moon Bay Airport, CA21 mi41 minSE 58.00 miFair57°F54°F88%1017.6 hPa
Concord, Buchanan Field, CA22 mi43 minSW 310.00 miFair66°F51°F59%1015.3 hPa

Link to 5 minute data for KOAK

Wind History from OAK (wind in knots)
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1 day agoW9W5W7W5W4N3CalmSE8S7S11S10S8S6S3S44W13W13W12W13W12W10SW5S6
2 days agoNW3W6W9W7W8SW7W4SW5SW5S3S73W3W6NW8NW10W10NW13W11W15W15W12W9W9

Tide / Current Tables for Roberts Landing, 1.3 miles west of, San Francisco Bay, California
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Roberts Landing
Click for Map
Mon -- 12:16 AM PDT     7.47 feet High Tide
Mon -- 06:27 AM PDT     Moonset
Mon -- 06:55 AM PDT     Sunrise
Mon -- 07:05 AM PDT     0.20 feet Low Tide
Mon -- 01:17 PM PDT     6.99 feet High Tide
Mon -- 04:54 PM PDT     Full Moon
Mon -- 07:08 PM PDT     Sunset
Mon -- 07:23 PM PDT     1.53 feet Low Tide
Mon -- 07:27 PM PDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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7.47.36.44.93.21.70.60.20.61.73.24.86.26.96.864.73.32.11.61.72.645.5

Tide / Current Tables for Oakland Airport SW, South San Francisco Bay, California Current
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Oakland Airport SW
Click for Map
Mon -- 12:12 AM PDT     -0.01 knots Slack
Mon -- 03:10 AM PDT     -0.88 knots Max Ebb
Mon -- 06:27 AM PDT     Moonset
Mon -- 06:41 AM PDT     0.00 knots Slack
Mon -- 06:55 AM PDT     Sunrise
Mon -- 09:58 AM PDT     0.76 knots Max Flood
Mon -- 01:01 PM PDT     -0.00 knots Slack
Mon -- 03:37 PM PDT     -0.69 knots Max Ebb
Mon -- 04:54 PM PDT     Full Moon
Mon -- 06:52 PM PDT     0.01 knots Slack
Mon -- 07:08 PM PDT     Sunset
Mon -- 07:27 PM PDT     Moonrise
Mon -- 10:03 PM PDT     0.69 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.1-0.4-0.7-0.9-0.8-0.6-0.30.10.50.70.80.70.40-0.4-0.7-0.7-0.6-0.300.40.60.70.6

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