Thursday, September23, 2021
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Marine Weather and Tides
Cupertino, 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 6:56AMSunset 7:04PM Thursday September 23, 2021 11:16 AM PDT (18:16 UTC) Moonrise 7:43PMMoonset 8:29AM Illumination 94% Phase: Waning Gibbous; Moon at 17 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- 249 Am Pdt Thu Sep 23 2021
Today..NW winds around 5 kt, increasing to 10 to 15 kt with gusts up to 25 kt this afternoon.
Tonight..W winds 10 to 15 kt with gusts up to 25 kt.
Fri..NW winds 10 to 15 kt.
Fri night..NW winds 10 to 15 kt.
Sat..NW winds 10 to 15 kt with gusts up to 25 kt.
Sat night..NW winds 5 to 10 kt.
Sun..W winds 5 to 10 kt.
Mon..W winds 10 to 15 kt.
PZZ500 249 Am Pdt Thu Sep 23 2021
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Expect gusty northwest winds over the northern outer waters to decrease by late Thursday morning. Northwest winds over all coastal zones will be light Friday into the weekend. A longer period northwest swell mixing in with the weaker southerly swell. The next chance for new longer period swell is Sunday.


7 Day Forecast for Marine Location Near Cupertino, CA
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location: 37.31, -122.06     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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FXUS66 KMTR 231733 AFDMTR

Area Forecast Discussion National Weather Service San Francisco Bay Area 1033 AM PDT Thu Sep 23 2021

SYNOPSIS. Warming and drying trend Thursday as offshore flow continues to develops across the region. Marine layer will persist through the morning hours along the coast. Onshore winds return Friday afternoon and will bring slight cooling. A seasonable weather pattern this weekend with a shallow marine layer along the coast while clear and warm weather continues inland. Will be watching for a frontal passage by Tuesday that should bring cooler temperatures and perhaps some showers to the North Bay.

DISCUSSION. as of 08:40 AM PDT Thursday . While the marine layer along the coast has deepened to around 1,200 feet in depth, patchy dense fog has also be reported across many of the region's interior valleys. The greatest coverage is over the valleys of Sonoma County where 1/4 mile visibility is being reported at many ASOS/AWOS sites. That said, satellite imagery is showing a gradual clearing trend with respect to the stratus/fog especially across the South Bay. With offshore flow localized to the highest peaks in the interior North Bay Mountains, look for the warmer and drier air mass aloft to allow for another warm-up across much of the region this afternoon. For complete details, please see the previous forecast discussion below.

PREV DISCUSSION. as of 02:57 AM PDT Thursday . Short Term . Today and Tonight . Satellite shows a stratus deck snuggled up along the length of our coast line this morning. Patchy low clouds are sitting over most of the coastal valleys. The marine layer is around 1000ft, however patchy fog has been seen around the typical stratus hot spots tonight. The Fort Ord profiler shows off shore winds starting to organize around the 2000 to 3500ft range. A few observations in Napa county's higher peaks are seeing gusts from 20 to 35 mph. There is still a strong marine layer below 1000ft, as the Santa Rosa and Monterey Bay airports are seeing persistent patchy fog.

Off shore winds will gradually build and continue through the short term. Models have been consistent with keeping pressure gradients lower for these winds, which will in turn keep speeds lighter too. Maximum winds gusts at the highest peaks in Napa county could occasionally reach to 35 to 40 mph around noon today. This window for moderate gusts is smaller, with winds slowly diminishing after later this afternoon.

With the off shore winds, temperatures will warm back up today. Most areas along the coast should see temperatures around normal or 5 degrees above. Areas inland will see temperatures 5 to 15 degrees above normal, with warmest temperatures in the East Bay hills. There is high confidence in temperatures remaining below any product thresholds today.

The weaker off shore winds will battle with the stratus over the ocean this afternoon. The winds should have enough compressional heating to warm the air over the ocean and mix out the cloud cover. However, there is model agreement in the stratus building back Friday morning with a quasi-southerly surge.

.Long Term. Friday through Thursday . With lighter off shore winds forecasted, onshore winds should have little resistance when trying to reestablish themselves over the area Friday afternoon. The SNS-PRB gradient starts to reach negative values Friday morning, which could indicate a southerly surge. As cloud cover moves back over the waters, cooler air will be advected onto land when the winds switch back to onshore. Temperatures reflect this with cooling down a few degrees from Thursday. More cooling is on its way this weekend and into early next week.

With weak upper level high pressure over the area this weekend, temperatures will be mild and winds will remain onshore.

As we move into fall, more upper level troughs will begin to swing down to the central CA coast. Our next potential system looks to approach Nor Cal Monday morning. Models have slowly been trending down the moisture forecasted to accompany this system. GFS and ECM 06Z run show trace amounts of QPF over the North Bay and northern waters, with no QPF reaching south. There is a better chances of seeing some breezy to windy conditions as the front passes through. Another upper level trough is right behind this one, and will swing through at the end of the period. This one also looks dry, however with the back to back upper level troughs we could see some windy conditions. Especially as these systems advect colder and colder air.

AVIATION. as of 10:31 AM PDT Thursday . For the 18z TAFs. Low clouds are slowly peeling away from Bay Area terminals. While low stratus clouds will remain over the ocean, VFR is forecast for Thursday afternoon. Winds will remain onshore, with a weaker seabreeze Thursday afternoon. As high pressure over the ocean slowly grows, the marine layer will remain compressed. This means any cig development will be low at IFR/LIFR levels at coastal terminals with the chance for reduced vis and patchy fog possible as well. Low confidence in the exact timing, given the weakening of the wind field, but clouds will work there way back into area terminals.

Vicinity of KSFO . VFR. Skies are gradually clearing around the terminal. A seabreeze will develop this afternoon, accelerating through the San Bruno Gap, but will be weaker than previous day. Low clouds return to the Bay Area overnight for IFR/LIFR conditions surrounding the terminal, but expecting the clouds at KSFO to not reach the terminal at this time, but will be closely followed.

KSFO Bridge Approach . Similar to KSFO.

Monterey Bay . LIFR cigs give way to clear VFR skies Wednesday afternoon. A weak seabreeze is forecast to develop late in the afternoon. By Thursday evening, low clouds and a chance for patchy fog returns. There is a chance the cigs come in at IFR levels, but expect cigs to lower back to LIFR early Friday morning.

MARINE. as of 08:34 AM PDT Thursday . Winds out of the northwest will be light to moderate Friday into the weekend. There is a longer period northwest swell mixing in with the weaker southerly swell. The next chance for new longer period swell is Sunday.

MTR WATCHES/WARNINGS/ADVISORIES. Tday. None.

PUBLIC FORECAST: RGass/Dhuyvetter AVIATION: DK MARINE: DK

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 16 mi46 min WNW 1 G 1.9 63°F 1015.5 hPa
46269 26 mi46 min 56°F 61°F5 ft
AAMC1 - 9414750 - Alameda, CA 34 mi46 min WSW 1.9 G 2.9 60°F 67°F1015.3 hPa
LNDC1 36 mi46 min WSW 2.9 G 4.1 62°F 1014.9 hPa
OBXC1 37 mi46 min 59°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 37 mi46 min W 4.1 G 5.1
PXSC1 38 mi46 min 60°F 60°F
PXOC1 - 9414311 - San Francisco (Pier 1), CA 38 mi46 min N 1.9 G 2.9 59°F 1013.9 hPa
ELXC1 - Elkhorn Slough Reserve, CA 38 mi91 min E 1 57°F 1016 hPa57°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 38 mi46 min WNW 4.1 G 5.1 58°F 1015 hPa
MLSC1 - Moss Landing, South Harbor, CA 38 mi17 min 60°F
46092 - MBM1 39 mi62 min SSE 1.9 55°F 59°F1014.8 hPa (+0.5)
FTPC1 - 9414290 - San Francisco, CA 40 mi46 min NW 2.9 G 4.1 58°F 66°F1014.8 hPa
46042 - MONTEREY - 27NM West of Monterey Bay, CA 40 mi26 min NE 1.9 G 5.8 58°F 62°F7 ft1014.8 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 44 mi46 min WSW 1.9 G 5.1 59°F 1015.4 hPa
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 44 mi26 min ENE 3.9 G 7.8 57°F 8 ft1015.4 hPa55°F
46237 - San Francisco Bar, CA (142) 45 mi76 min 55°F 62°F5 ft
46114 - West Monterey Bay, CA 45 mi50 min 62°F7 ft
46240 - Cabrillo Point, Monterey Bay, CA (158) 48 mi20 min 62°F3 ft

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
San Jose, San Jose International Airport, CA8 mi23 minN 06.00 miMostly Cloudy with Haze71°F54°F55%1014.1 hPa
Palo Alto Airport, CA12 mi89 minVar 48.00 miA Few Clouds63°F57°F83%1014.9 hPa
San Jose / Reid / Hillv, CA13 mi29 minN 010.00 miClear68°F55°F64%1014.6 hPa
San Carlos Airport, CA18 mi29 minN 08.00 miA Few Clouds64°F57°F78%1014.9 hPa
Hayward, Hayward Air Terminal, CA24 mi22 minW 46.00 miFair with Haze66°F58°F75%1015.3 hPa

Link to 5 minute data for KNUQ

Wind History from NUQ (wind in knots)
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Last 24hr3E3SE43E53N7SE6
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NW6N9N10N12N13N14N14N12N11N6NE7N4CalmS6S4SE3
1 day agoCalmCalmCalmCalmCalmCalmN5N5N6N8NW9N10NW9
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NW8N8NW8NE6E3CalmN4E4SE5SE3SE4
2 days agoCalmCalmSE3SE4E3NW4N65NW5NW9
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Tide / Current Tables for Upper Guadalupe Slough, San Francisco Bay, California
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Upper Guadalupe Slough
Click for Map
Thu -- 02:54 AM PDT     8.61 feet High Tide
Thu -- 06:57 AM PDT     Sunrise
Thu -- 09:29 AM PDT     Moonset
Thu -- 09:31 AM PDT     1.58 feet Low Tide
Thu -- 02:58 PM PDT     9.28 feet High Tide
Thu -- 07:02 PM PDT     Sunset
Thu -- 08:42 PM PDT     Moonrise
Thu -- 10:07 PM PDT     0.96 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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4.56.58.18.68.27.15.53.82.41.71.72.94.978.69.38.97.86.14.32.61.411.4

Tide / Current Tables for Dumbarton Point 2.3 mi NE, South San Francisco Bay, California Current
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Dumbarton Point 2.3 mi NE
Click for Map
Thu -- 12:04 AM PDT     1.35 knots Max Flood
Thu -- 03:12 AM PDT     -0.01 knots Slack
Thu -- 06:57 AM PDT     Sunrise
Thu -- 07:19 AM PDT     -1.02 knots Max Ebb
Thu -- 09:29 AM PDT     Moonset
Thu -- 09:41 AM PDT     0.00 knots Slack
Thu -- 12:12 PM PDT     1.19 knots Max Flood
Thu -- 03:13 PM PDT     -0.00 knots Slack
Thu -- 07:03 PM PDT     Sunset
Thu -- 07:35 PM PDT     -1.18 knots Max Ebb
Thu -- 08:42 PM PDT     Moonrise
Thu -- 10:07 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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1.31.20.80.2-0.3-0.7-0.9-1-0.9-0.40.20.91.21.10.70.2-0.3-0.7-1-1.1-1.1-0.7-0.10.6

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NOTE: This section has been updated as of 1/26/2021. If the image you are expecting is not showing, please let me know. You may use the EDIT function to update your location.
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