Thursday, October21, 2021
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Marine Weather and Tides
Santa Clara, 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 7:20AMSunset 6:23PM Thursday October 21, 2021 1:53 PM PDT (20:53 UTC) Moonrise 6:11PMMoonset 7:18AM 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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PZZ531 San Francisco Bay South Of The Bay Bridge- 310 Am Pdt Thu Oct 21 2021
Today..SE winds 5 to 10 kt, becoming sw 10 to 15 kt with gusts up to 25 kt this afternoon. Rain likely, mainly this morning.
Tonight..S winds 15 to 20 kt with gusts up to 25 kt. Rain.
Fri..W winds 10 to 15 kt with gusts up to 25 kt. Rain.
Fri night..W winds around 5 kt.
Sat..S winds 5 to 10 kt. Rain likely.
Sat night..SE winds 10 to 20 kt with gusts up to 25 kt. Rain.
Sun..S winds 10 to 20 kt with gusts up to 30 kt. Rain.
Mon..SW winds 10 to 15 kt. Rain.
PZZ500 310 Am Pdt Thu Oct 21 2021
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Gusty winds continuing in the northernmost outer waters today and tonight. Moderate rainfall returns as a secondary weaker boundary moves over the waters late tonight into Friday morning. Winds are forecast to turn to the west and weaken in the wake of the front Friday. More impactful marine weather arrives with a strong atmospheric river late in the weekend into early next week. Gale force southerly winds, very steep waves, and large swell are possible Sunday into Monday.


7 Day Forecast for Marine Location Near Santa Clara, CA
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location: 37.38, -121.9     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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FXUS66 KMTR 211757 AFDMTR

Area Forecast Discussion National Weather Service San Francisco Bay Area 1057 AM PDT Thu Oct 21 2021

SYNOPSIS.

Light rainfall will diminish over much of the region by early afternoon while shifting northward over the North Bay. Another frontal system will sweep through the region late tonight into Friday with drying conditions Friday night into Saturday morning. An atmospheric river will then take aim on the region Sunday into Monday bringing gusty winds and potentially significant rainfall.

DISCUSSION. as of 09:24 AM PDT Thursday .

A potent low pressure system was located over the northeast Pacific with an associated frontal zone extending to the south-southwest. Southwesterly winds aloft are resulting in focused warm/moist advection and onshore flow into the area this morning. This is evident via the blended total precipitable water (PW) product with PW values of ~1.5" indicated along the Central Coast. Light rain showers were occurring in this regime with orographic ascent boosting rain rates along the coastal ranges while rain shadowing kept the interior valley areas drier. Amounts over the past 6 hours ranged from ~0.15"- 0.3" across the North Bay to a trace/few hundredths around Monterey Bay and for areas farther southeast. Showers should gradually diminish in coverage this morning with the best chances for measurable amounts remaining across the northern Bay area.

By this afternoon a consensus of the forecast models suggest that the better moisture flux may shift a bit farther north. This should keep the better shower chances across the northern Bay area, although that's not to say that we won't see a few showers and/or drizzle elsewhere. A consensus of the high resolution short-term model guidance suggests that the best chances for seeing an additional 0.05"+ through this afternoon is generally across the North Bay.

High temperatures today should remain in the 60s for the North Bay where showers may persist, with 60s to 70s expected elsewhere across the region. Shower chances increase tonight as the aforementioned front advances towards our area. See the previous discussion below for more details on this, and on the more impactful event expected on Sunday into Monday.

PREV DISCUSSION. as of 03:12 AM PDT Thursday . Moist onshore flow continues to advect inland across central California this morning with light rainfall occuring over much of the region. Generally speaking, rain rates are just a few hundredths of an inch per hour. Meanwhile, interior valley locations are being rain shadowed while orographic lift is resulting in slightly higher rates along the coastal ranges. Short-range guidance suggests this activity should diminish and shift northward through the morning with drying conditions returning to the Central Coast this afternoon. That said, light rain will be possible at times over the northern portion of the Bay Area throughout much of the day. This pattern should allow for 60s and 70s across the Central Coast, South Bay and interior East Bay this afternoon while 60s will be more common across the North Bay where rainfall may linger.

A more organized frontal system is then forecast to move into the North Bay late tonight and sweep southward across the Bay Area and Central Coast through Friday morning. Given better mid/upper level dynamics associated with this system, look for brief moderate rainfall along the frontal boundary along with a slight chance of thunderstorms across the North Bay. Expecting to see an additional 1.00"-3.00" rainfall amounts through Friday across the North Bay Mountains, with amounts tapering down to around 0.75" in the region's valleys. Meanwhile, 0.10"-0.50" is expected elsewhere across the region with locally higher amounts to around 1.00" in the Santa Cruz Mountains. Breezy to gusty onshore winds to around 30-40 mph will also be possible ahead of and along the frontal passage.

Brief drying is forecast to occur during the day Friday in wake of the frontal passage, yet cannot rule out an isolated shower or two into the afternoon. Mostly dry conditions are expected to persist into Friday Night as well ahead of the onset of our next, even stronger storm system.

As a deeper plume of moisture begins to advect inland on Saturday, look for warm frontal light rain to develop by late in the day. This will most likely impact the North Bay and then potentially as far south as the Santa Cruz Mountains by Saturday night into early Sunday morning. Rainfall will then begin to increase over the northern portion of the Bay Area during the day Sunday deeper moisture advects inland. IVT values are forecast to reach or exceed 750 kg m-1 s-1 associated with the first atmospheric river of the season. Albeit it early in the season, this would be at least a moderate strength atmospheric river bringing widespread moderate to locally heavy rainfall to much of the region as it slides southward down the central California coast. The main push southward of this deep moisture plume will be a mid/upper level low forecast to develop and drop out of the Gulf of Alaska and then into the Pacific Northwest and/or British Columbia late Sunday into Monday. The latest forecast models have been more progressive with this system and therefore move the band of heavier precipitation more quickly through the Bay Area and Central Coast during the aforementioned time frame. This is where the details remain a bit difficult to nail down at this point as any slowing or stalling of this moisture-laden plume could produce even greater rainfall totals somewhere along the coastline. Regardless, looking for 3.00"-5.00" rainfall amounts along the coastal ranges with 1.00"-3.00" totals elsewhere. As always with these types of systems, some rain shadowing will be likely, particularly in the Santa Clara and Salinas valleys. Strong and gusty southerly winds are also likely to accompany the system and it sweeps from north to south across the region Sunday into Monday morning.

Broad troughing looks to persist across the region into much of next week as well with the potential for light precipitation to occur off and on at times, especially across the North Bay and northern California. With the main atmospheric river event still 4 to 5 days out, still plenty of time for details to come into better focus. Stay tuned as we continue to update the forecast and monitor potential impacts associated with this early season atmospheric river.

AVIATION. as of 10:55 AM PDT Thursday . For the 18z TAFs. An active, unsettled pattern will bring suboptimal aviation weather through the TAF period and through at least Monday, however, there should be a couple of fair VFR conditions between the weather systems.

The first of these will occur through the remainder of the daylight hours today, primarily from the Golden Gate southward. The second of these will occur in the wake of tonight's cold frontal passage, so through day tomorrow and into early Saturday. In the near term, IFR-MVFR conditions will prevail across the North Bay as a pair of boundaries merge there over the next 12 to 18 hours. VFR conditions are expected elsewhere from roughly midday through this evening, before deteriorating conditions due to an approaching cold front lowers cigs/visbys overnight and into Friday morning. Moderate to heavy rain is possible with the next frontal passage (eyeing 09Z FRI in North Bay to 14-16Z FRI in South Bay/Central Coast) along with a wind shift towards the SW-W in the wake of the front. Winds generally south/southeast and light to locally breezy, becoming light west later tomorrow. LLWS of 40 KTS at 2000 feet is also concern ahead and along the front overnight in the North Bay (see TAF). A period of VFR conditions is expected at the tail end of the TAF period, however, a strong atmospheric river will bring very poor aviation weather from Sunday into Monday.

Vicinity of KSFO . SE/S winds to 11 KTS today, increasing slightly and becoming gusty overnight, then becoming SW to W through mid to late tomorrow morning. Light rain possible through the day, but mostly finished with precipitation until tonight's cold front passes through between 09-15Z FRI. With this front, expect briefly moderate rain, lowering visibility, wet runways, IFR/MVFR cigs, and a wind shift towards the SW in the wake of the front. VFR conditions in the wake of late tonight to tomorrow morning's frontal passage before the next (and strongest) system begins to impact the area Sunday into Monday.

KSFO Bridge Approach . Similar to KSFO.

Monterey Bay . VFR currently but MVFR CIGs to return ahead of incoming cold front this evening. VCSH early Friday morning with rain coming in ahead of cold front, then light rain proceeding it later in the morning. Brief IFR conditions possible Friday morning with the environment being moist which can lower visibilities with mist and light rain. Moderate winds through TAF period but could be gustier before and during frontal passage.

MARINE. as of 10:43 AM PDT Thursday . Gusty southerly winds continue in the northernmost outer waters today and tonight. Moderate rainfall returns as a secondary weaker boundary moves over the waters late tonight into Friday morning. Winds are forecast to turn to the west and weaken in the wake of the front Friday. More impactful marine weather arrives with a strong atmospheric river late in the weekend into early next week. Gale force southerly winds, very steep waves, and large swell are possible Sunday into Monday.

MTR WATCHES/WARNINGS/ADVISORIES. Tday. SCA . Pt Arena to Pigeon Pt 10-60 nm SCA . Pt Arena to Pt Reyes 0-10 nm from 3 PM



PUBLIC FORECAST: SPM/RGass AVIATION: DRP/SMM MARINE: DRP/Canepa

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 19 mi65 min S 8G11 71°F 1019.4 hPa
46269 32 mi53 min 58°F 58°F6 ft
AAMC1 - 9414750 - Alameda, CA 34 mi65 min SSW 5.1G6 65°F 61°F1019.3 hPa
LNDC1 35 mi65 min S 7G9.9 69°F 1018.8 hPa
OBXC1 37 mi65 min 64°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 37 mi65 min SSE 8G11
OKXC1 - 9414776 - Oakland (Berth 34), CA 38 mi65 min SSE 7G8.9 66°F 1018.9 hPa
PXOC1 - 9414311 - San Francisco (Pier 1), CA 39 mi65 min SE 6G9.9 66°F 1017.8 hPa
PXSC1 39 mi65 min 66°F 66°F
ELXC1 - Elkhorn Slough Reserve, CA 40 mi68 min WNW 7 65°F 1022 hPa60°F
MLSC1 - Moss Landing, South Harbor, CA 40 mi43 min 0 62°F 59°F
FTPC1 - 9414290 - San Francisco, CA 42 mi71 min SW 2.9G9.9 65°F 68°F1019.3 hPa
46092 - MBM1 44 mi98 min SSE 3.9 58°F 57°F1020.1 hPa (+0.0)
PPXC1 - 9414847 - Richmond (Point Potrero), CA 44 mi65 min W 6G8 64°F 1019.5 hPa
RCMC1 - 9414863 - Richmond, CA 46 mi65 min SSW 1G2.9 63°F 60°F1019.3 hPa
TIBC1 - Tiburon Pier, San Francisco Bay, CA 46 mi66 min 0 63°F 1019 hPa
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 46 mi65 min N 2.9G2.9 63°F 1018.8 hPa
PCOC1 - 9415144 - Port Chicago, CA 47 mi65 min NE 4.1G5.1 62°F 62°F1019 hPa
MZXC1 - 9415102 - Martinez-Amorco CA 47 mi65 min NNE 1.9G4.1 62°F 62°F1019.1 hPa
46237 - San Francisco Bar, CA (142) 48 mi53 min 58°F 55°F7 ft
46042 - MONTEREY - 27NM West of Monterey Bay, CA 49 mi33 min S 12G14 59°F 58°F1019.6 hPa

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, CA2 mi60 minSSW 910.00 miMostly Cloudy75°F60°F60%1018.4 hPa
San Jose / Reid / Hillv, CA5 mi66 minSSE 10 G 1710.00 miMostly Cloudy79°F61°F54%1018.6 hPa
Mountain View, Moffett Field, CA9 mi63 minSSE 8 G 1510.00 miFair73°F59°F61%1018.6 hPa
Palo Alto Airport, CA14 mi66 minSE 1210.00 miMostly Cloudy73°F61°F65%1018.6 hPa
San Carlos Airport, CA21 mi66 minSSE 1010.00 miMostly Cloudy72°F63°F73%1019 hPa
Hayward, Hayward Air Terminal, CA23 mi59 minS 810.00 miPartly Cloudy72°F61°F68%1019.4 hPa
Livermore, Livermore Municipal Airport, CA23 mi60 minNNE 310.00 miMostly Cloudy73°F62°F69%1018.2 hPa

Link to 5 minute data for KSJC

Wind History from SJC (wind in knots)
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Last 24hrSW7SW8S50S10S5SE10SE10SE10SE7SE6SE9SE6SE10S7SE5S3SE4SE7S5SE90SE7SW9
1 day agoS8SW9SW10SW11SW15S6SE11
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2 days ago6N7N7N9NW10N10N8NW6NW5SW3S300SE4SE3SE5S4000SE5SE9SE5SW7

Tide / Current Tables for Gold Street Bridge, Alviso Slough, San Francisco Bay, California
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Gold Street Bridge
Click for Map
Thu -- 02:03 AM PDT     8.21 feet High Tide
Thu -- 07:22 AM PDT     Sunrise
Thu -- 08:18 AM PDT     Moonset
Thu -- 08:35 AM PDT     1.89 feet Low Tide
Thu -- 01:34 PM PDT     9.61 feet High Tide
Thu -- 06:22 PM PDT     Sunset
Thu -- 07:10 PM PDT     Moonrise
Thu -- 09:18 PM PDT     0.16 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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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 -- 02:18 AM PDT     -0.00 knots Slack
Thu -- 06:16 AM PDT     -0.88 knots Max Ebb
Thu -- 07:22 AM PDT     Sunrise
Thu -- 08:19 AM PDT     Moonset
Thu -- 08:33 AM PDT     0.01 knots Slack
Thu -- 11:02 AM PDT     1.12 knots Max Flood
Thu -- 01:56 PM PDT     -0.00 knots Slack
Thu -- 06:22 PM PDT     Sunset
Thu -- 06:26 PM PDT     -1.27 knots Max Ebb
Thu -- 07:11 PM PDT     Moonrise
Thu -- 09:04 PM PDT     0.00 knots Slack
Thu -- 11:46 PM PDT     1.37 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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