Tuesday, September29, 2020
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Marine Weather and Tides
La Honda, CA

Version 3.4
NOTICE
8/26/2020 The 7 day forecast is taking about 5 seconds to load but it will eventually load. NOAA is still working on it.
8/18/2020 NOAA continues to have trouble. Wind guest will occasionally be left off graphs. I am working with NOAA to resolve the issue.
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
10/9/2019 Updated the Marine Zones.
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.

Sunrise 7:00AMSunset 6:56PM Monday September 28, 2020 9:11 PM PDT (04:11 UTC) Moonrise 4:55PMMoonset 2:51AM Illumination 90% Phase: Waxing Gibbous; Moon at 12 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- 819 Pm Pdt Mon Sep 28 2020
Tonight..NW winds 5 to 15 kt, becoming north around 5 kt after midnight. Hazy.
Tue..NW winds up to 10 kt. Hazy.
Tue night..NW winds up to 10 kt.
Wed..NW winds 5 to 15 kt.
Wed night..W winds up to 10 kt.
Thu..W winds up to 10 kt.
Thu night..SW winds 5 to 10 kt.
Fri..W winds 5 to 15 kt.
Sat..W winds 5 to 15 kt.
PZZ500 819 Pm Pdt Mon Sep 28 2020
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Stratus clouds stretch from point reyes southward along the coast past big sur. Areas of dense fog are possible overnight and into Tuesday morning over the waters. Winds are expected to be generally light and southerly Monday night before turning westerly on Tuesday. Northwest winds will redevelop by mid-week. Seas will be a mix of moderate northwest swell and a longer period, light southerly swell.


7 Day Forecast for Marine Location Near La Honda, CA
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location: 37.3, -122.29     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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FXUS66 KMTR 290400 AFDMTR

Area Forecast Discussion National Weather Service San Francisco Bay Area 900 PM PDT Mon Sep 28 2020

SYNOPSIS. A cooling trend along the coast and around the Bays on Tuesday but with very warm to hot weather continuing across inland areas through much of the work week. Cooling is expected to develop inland over the upcoming weekend.

DISCUSSION. as of 9:00 PM PDT Monday . Heat Advisory was allowed to expire at 7 pm this evening and Red Flag Warning will be allowed to expire at 9 pm. We had five record high temps today across the district including 96 at SFO, 101 San Jose and 103 for King City.

A shallow southerly surge worked northward today and is currently passing Pt Reyes. It brought cooling, only to the immediate coast for places like Santa Cruz and Half Moon Bay. The marine layer is very shallow with dense fog reports over the ocean and along the coast. The marine inversion is showing signs of deepening in excess of 1000 feet around Monterey Bay but likely remains only a few hundred feet around San Francisco so expect more dense fog near the Golden Gate overnight where a steady west of wind of 20 mph is bringing some cooling relief into the Bay.

All attention on the Glass Fire which continues to burn hot on satellite. Latest satellite trends suggest its most active in the hills roughly between Calistoga and Angwin. The return of the shallow marine layer is a hopeful sign, especially for places like Santa Rosa which should at least benefit from some higher humidity. As noted the Red Flag will expire at 9 pm tonight as the period of strongest offshore winds has ended. The SFO-WMC offshore gradient is still a healthy 12 mb after peaking around 15.7 mb 24 hours ago. The surface gradient appears to have verified much stronger than models had portended days ago when a 8-10 mb gradient was suggested. Looking ahead, the areas of northern Napa county will continue to be very warm and dry. Winds will be lighter overnight into Tuesday but with switching directions. General flow may turn southerly for a time on Tuesday and then eventually west to northwest later Tuesday evening. Again wind speeds look light but switching winds will test containment lines and potentially push the fire in new directions. In addition, winds will likely be so light with changing directions that smoke will swirl around and may not move much Tuesday adversely impacting air quality and fire fighting air operations. The only benefit of smoke is North Bay temps may be slightly cooler than forecast due to thick smoke. Today Santa Rosa ran about 15 degrees cooler than Napa just due to smoke cover.

In terms of temps we do expect cooling on Tuesday, especially near the coast and bays but inland cooling will be nominal. The strong and abnormal West Coast ridge looks to restrengthen midweek with further warming suggesting more widespread 90s inland.

PREV DISCUSSION. as of 01:55 PM PDT Monday . The Glass/Shady/Boysen fires have merged and are now referred soley as the Glass Fire. It has continued moving towards the southwest with the help of offshore flow, although those winds have been steadily decreasing over the last few hours. Elevated smoke from the fires has engulfed most of central and northern Sonoma County and approached the northern portions of Marin County. Weakening of the offshore winds has been observed since dawn as well, which has allowed for more of that smoke to travel more towards the west. In terms of intensities, gusts around Santa Rosa have still remained around the 25-30mph range. Expecting these winds to let up sometime later this afternoon/evening.

In terms of temperatures for today across the region, portions of southeastern and downtown SF made it up to 91-93 F, with 90s F currently observed over much of the Bay Shoreline. Of interesting note, the western half of the SF Peninsula is already showing the effects of the southerly surge that is being observed along the coast, resulting in temps along the western side of the city plummeting from 88 to 71 F in the span of an hour this afternoon. Interior East Bay locations will not be spared as easily, as they are currently in the low-90s this afternoon, with Livermore currently at 95 F, and are expected to get into the 97-102 F mark this afternoon. Expecting temps to peak around the Bay Shoreline and the East side of the City proper early this afternoon before quickly tumbling down as the southerly surge brings in marine stratus and fog past the Golden Gate. For now,the Heat Advisory for the San Francisco Bay Shoreline, SF shoreline, and the city proper is valid through 7PM tonight.

Temps are actually substantially cooler today across much of Central and Northern Sonoma county (including Santa Rosa), with several stations reporting 10-15 F temperature difference between now and 24 hours ago. Unfortunately this sharp drop-off has all to do with the smoke canopy associated with the active fires which has largely limited incident solar radiation across the area underneath it. By contrast, surrounding locations just outside the smoke plume are notably in the mid-to-upper 90s (e.g. Petaluma and Vallejo). Temps are expected to get up into the triple digits this afternoon in the ridges of the North Bay not under the smoke canopy and the East Bay. Red Flag Warning is valid through 9PM tonight, while the Heat Advisory for the San Francisco Bay Shoreline, SF shoreline, and the city proper is valid through 7PM tonight.

For the latest on active wildfires and firefighting efforts, please refer to CALFIRE and your local Sheriffs Office.

Ashfall has been reported in several locations across Sonoma County this afternoon as elevated smoke has permeated most of the central and northern portions of the county. Haze is also visible across much of the North Bay that is downstream from the incident site. As such, HRRRx smoke run for the afternoon expects most of this smoke to remain in the North Bay, with some particulates making it down into the SF Peninsula and East Bay. However, southerly surge should help to keep most of the Glass Fire smoke canopy away from the center of the Bay Area. It should be noted, however, that elevated smoke from the active wildfires in the Sierra has now made it into the skies of the South Bay and San Benito counties. Expecting more of this elevated smoke to move over the CWA this evening as it is advected by southerly winds into the core of the Bay Area.

For the latest on air quality concentrations in your area, please refer to either the Bay Area Air Quality District or AirNow.

Short and Mid-range guidance in agreement that this southerly surge will help keep temperatures along the coast predominantly in the 70s-to mid-80s F range tomorrow, with max temps in the Bay Area Shoreline dropping down to the upper-70s F to low 80s F. Max temps for SF tomorrow expected to be around 15 F cooler than today in places like Downtown and Twin Peaks, while Oakland and the coastal South Bay will experience similar drop-offs. The same cannot entirely be said for near-coastal locations like San Jose, where max temps are still expected to be around 90F, albeit 6 degrees F cooler than today. The primary focus is still on the North Bay, where interior Sonoma and Napa counties are only expecting little in the way of temperature recoveries. The good news is that winds are expected to weaken through tonight and into tomorrow all across the North Bay as the offshore flow gradually comes to a halt and is replaced by onshore SW winds. Unfortunately, these will be short-lived and will not bring in much needed moisture into the area. As such, overnight humidity recoveries are still expected to be poor over the next few days, with min RH values struggling to get over the 20th percentile through Wednesday.

Looking into the second half of this week, not expecting much of a change in extended forecast given that both the GEFS and ECMWF ensembles have the upper-level ridge locked in over the northern portions of the Great Basin through Friday. As such, the interior will not be seeing much in the way of temperature recoveries through the workweek. Do expect the ridge to finally break down sometime by this weekend, which will allow for the interior to finally some relief as well.

AVIATION. as of 04:42 PM PDT Monday . For the 00z TAFs. Mostly VFR with KSTS lower due to smoke visibility concerns. Winds are mostly light and variable, but breezier conditions are around the San Francisco Bay. Winds will ease overnight. Wildfire in the North Bay keeps smoke around terminals in the region makes for slant range visibility issues today upon approach. Marine layer continues to build, but impacts are expected only along the immediate coastline and along the Monterey Peninsula. Smoke impacts linger Tuesday, but mostly VFR around the region with an afternoon seabreeze.

Vicinity of KSFO . VFR. Winds are onshore and breezy, with a few gusts just under 20 kts. Good vis at the terminal currently, but smoke may drift near and around the terminal for slant range visibility issues upon approach. The marine layer slowly rebuilding over the ocean, but impacts are not expected at the terminal this evening. Winds ease overnight, increasing Tuesday afternoon with the seabreeze with VFR conditions and lingering smoke in the region.

SFO Bridge Approach . Possible slant-range vis issues with smoke and haze. Otherwise, similar to KSFO.

Monterey Bay Terminals . Stratus over the Bay is slowly starting to creep into the Salinas Valley. Currently VFR conditions at terminals, but are cigs are expected to lower this evening. Winds are onshore, breezy for the next 2 hours, then ease through the evening. Growing confidence in reduced cigs tonight and into Tuesday morning, with LIFR and fog possible. VFR expected Tuesday with onshore breezy winds in the afternoon.

CLIMATE. Here are record high temperatures for Monday .

. MONDAY SANTA ROSA . 104 in 2010 KENTFIELD . 102 in 1921 NAPA . 102 in 1966 RICHMOND . 97 in 2010 LIVERMORE . 105 in 2010 SAN FRANCISCO . 95 in 1966 SF AIRPORT . 95 in 2010 REDWOOD CITY . 98 in 2010 HALF MOON BAY . 91 in 1958 OAKLAND DOWNTOWN . 92 in 2010 SAN JOSE . 99 in 2010 GILROY . 101 in 1963 SANTA CRUZ . 100 in 1917 SALINAS . 99 in 1970 KING CITY . 102 in 1973

MARINE. as of 08:26 PM PDT Monday . Stratus clouds stretch from Point Reyes southward along the coast past Big Sur. Areas of dense fog are possible overnight and into Tuesday morning over the waters. Winds are expected to be generally light and southerly Monday night before turning westerly on Tuesday. Northwest winds will redevelop by mid-week. Seas will be a mix of moderate northwest swell and a longer period, light southerly swell.

MTR WATCHES/WARNINGS/ADVISORIES.

PUBLIC FORECAST: RWW 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 15 mi53 min NNW 7 G 8 68°F 75°F1013.1 hPa
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 32 mi41 min SSE 3.9 G 5.8 59°F 1014.1 hPa58°F
AAMC1 - 9414750 - Alameda, CA 33 mi53 min 70°F
LNDC1 34 mi53 min N 6 G 8 64°F 1012.5 hPa
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 35 mi53 min WNW 4.1 G 5.1
PXSC1 35 mi53 min 64°F
PXOC1 - 9414311 - San Francisco (Pier 1), CA 35 mi53 min WSW 1.9 G 4.1 64°F 1011.6 hPa
OBXC1 35 mi53 min 63°F 61°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 35 mi53 min WNW 8.9 G 11 61°F 1012.5 hPa
46042 - MONTEREY - 27NM West of Monterey Bay, CA 36 mi41 min SSE 3.9 G 5.8 59°F 61°F1014 hPa59°F
FTPC1 - 9414290 - San Francisco, CA 36 mi53 min 63°F
46237 - San Francisco Bar, CA (142) 38 mi41 min 59°F4 ft
46092 - MBM1 40 mi62 min SW 3.9 57°F 56°F1013.7 hPa (+0.3)
TIBC1 - Tiburon Pier, San Francisco Bay, CA 42 mi36 min Calm 67°F 1013 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 42 mi53 min S 5.1 G 8 66°F 1013 hPa
46114 - West Monterey Bay, CA 42 mi45 min 59°F5 ft
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 43 mi41 min S 5.8 G 7.8 57°F1013.9 hPa
MLSC1 - Moss Landing, South Harbor, CA 43 mi42 min WNW 4.1 G 9.9 57°F 1009.3 hPa57°F
ELXC1 - Elkhorn Slough Reserve, CA 44 mi86 min NW 2.9 58°F 58°F
RCMC1 - 9414863 - Richmond, CA 44 mi59 min ENE 1 G 4.1 67°F 66°F1012.3 hPa

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Palo Alto Airport, CA15 mi2.4 hrsNNW 810.00 miSmoke73°F60°F65%1011.2 hPa
San Carlos Airport, CA16 mi75 minNNW 410.00 miClear70°F59°F69%1012.2 hPa
Half Moon Bay Airport, CA18 mi16 minSSE 50.25 miFog55°F55°F100%1014.6 hPa
San Jose, San Jose International Airport, CA20 mi18 minNW 810.00 miMostly Cloudy73°F57°F57%1012.5 hPa
San Francisco, San Francisco International Airport, CA22 mi15 minWNW 1310.00 miA Few Clouds67°F55°F66%1012.3 hPa

Link to 5 minute data for KPAO

Wind History from PAO (wind in knots)
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Last 24hr------------------------------------34N9----NW8
1 day ago--------------------------Calm444N6N7NW9N9------
2 days ago----------------------------4N6N7NW10
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Tide / Current Tables for Ano Nuevo Island, California
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Ano Nuevo Island
Click for Map
Tue -- 03:34 AM PDT     0.20 feet Low Tide
Tue -- 04:51 AM PDT     Moonset
Tue -- 07:03 AM PDT     Sunrise
Tue -- 10:07 AM PDT     4.70 feet High Tide
Tue -- 03:54 PM PDT     1.63 feet Low Tide
Tue -- 06:23 PM PDT     Moonrise
Tue -- 06:54 PM PDT     Sunset
Tue -- 09:40 PM PDT     4.91 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.81.70.80.30.20.71.52.53.54.34.74.53.93.12.31.81.61.92.63.44.24.84.94.5

Tide / Current Tables for Dumbarton Bridge, San Francisco Bay, California Current
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Dumbarton Bridge
Click for Map
Tue -- 12:34 AM PDT     -0.00 knots Slack
Tue -- 03:37 AM PDT     -1.34 knots Max Ebb
Tue -- 04:50 AM PDT     Moonset
Tue -- 06:42 AM PDT     0.00 knots Slack
Tue -- 07:02 AM PDT     Sunrise
Tue -- 10:11 AM PDT     1.69 knots Max Flood
Tue -- 01:34 PM PDT     -0.00 knots Slack
Tue -- 04:13 PM PDT     -0.94 knots Max Ebb
Tue -- 06:22 PM PDT     Moonrise
Tue -- 06:52 PM PDT     0.00 knots Slack
Tue -- 06:53 PM PDT     Sunset
Tue -- 10:07 PM PDT     1.47 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.4-0.3-1-1.3-1.3-1.1-0.60.211.51.71.61.20.4-0.3-0.8-0.9-0.9-0.50.10.81.31.51.4

Weather Map
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wmap_P
GEOS 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.
Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East
Ground Weather Radar Station San Francisco Bay Area, CA
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