How strong are storm force winds in San Francisco?
Although rare, storm force winds of 48 knots or greater can occur with the strongest of these winter storms. A few notable storm force wind events over the greater San Francisco Bay region waters occurred on December 12, 1995 and January 4, 2008.
What is the National Weather Service in San Francisco Bay Area?
The National Weather Service Forecast office for the San Francisco Bay Area (located in Monterey) is responsible for issuing forecasts and warnings for the coastal waters outside the Golden Gate (out to 60 nautical miles offshore), and also for San Francisco Bay, San Pablo Bay, Suisun Bay and the west Delta.
What is the wind like in San Francisco in spring?
Wind speeds with the stronger springtime wind events sometimes reach gale force over the coastal waters outside the Golden Gate, and approach Gale Force locally in northern San Francisco Bay. West to northwest winds during the spring months decrease farther inland and are generally lighter in the Central Valley compared to the Bay and Delta.
Where are the strongest seabreezes in the San Francisco Bay?
In fact, some of the strongest summer seabreezes occur on the west side of the Bay from Hunters Point south through the area around SFO, and small craft conditions are common here as well. Elsewhere in the Bay, summer seabreezes generally do not exceed 20 knots.
Why is dredging important in San Francisco?
Where are the currents not kind?
Are there currents in a bay?
Current is the FLOW of water in and out of the bay. Tides are vertical, currents are horizontal. As sea-level drops or rises with the tide, water flows in and out of the bay.
How deep is the San Francisco Bay?
about 12-15 feet deepThe bay is actually only as deep as a swimming pool. The average depth of the bay is about 12-15 feet deep. Heck, between Hayward and San Mateo to San Jose it averages 12 to 36 inches. So much for that bridge!
How cold is the SF Bay water?
The ocean off San Francisco is at its warmest from mid August to late September when the temperature averages 60 degrees Fahrenheit (15.5 degrees Celsius). The coolest months are January and February, when the sea temperature is typically at 53 °F (11.7 ° C).
Why is it so windy in the Bay Area?
Because the ocean is cold and inland areas are hot and air always travels from high pressure (cold air) to low pressure (hot air). Also, air always wants to travel along the easiest path possible, which is to say around the mountains and through the city.
Can you swim in San Francisco Bay?
Our beloved bay isn't known as a swimmer's destination. But if you know where to look, you can find all kinds of sheltered coves, sandy beaches and picturesque parks right on the water and perfect for dipping a toe.
How deep does the BART go under the bay?
135 feetConstructed in 57 sections, and reposing on the bay floor as deep as 135 feet beneath the surface, the remarkable $180 million structure took six years of toil and seismic studies to design, and less than three years to contract.
How deep is the Golden Gate Bridge under water?
377-Feet Deep And Full Of Mystery At around 377 feet at its deepest point, the waters underneath the Golden Gate Bridge are bound to hold more than one ghostly tale from the past. And the National Oceanic and Atmospheric Administration has made it their mission to bring the eerie tales to the surface.
How long can you survive in 60 degree water?
1 - 6 hoursAt a water temperature of 50 - 60 degrees, death may occur in 1 - 6 hours. At a water temperature of 60 - 70 degrees, death may occur in 2 - 40 hours.
How cold is the water under the Golden Gate Bridge?
Golden Gate Bridge located in the northern hemisphere, at latitude 37 degrees. The water in this location never warms up to comfortable values. Average annual water temperature on the coast in Golden Gate Bridge is 54°F, by the seasons: in winter 53°F, in spring 53°F, in summer 54°F, in autumn 56°F.
Is San Francisco more windy than Chicago?
The windiest city in the United States is not the one nicknamed the "Windy City". Among large cities, Chicago ranks twelfth for fastest average wind speed....Windiest Cities in the United States.CityMPHKPHKansas City, Missouri10.617.1San Francisco, California10.617.1Cleveland, Ohio10.516.910 more rows
Why is San Francisco Bay water so cold?
The water along the coast of California is cold for a couple of reasons. First, the California Current brings cold water from Alaska southward along the coast. And second, cold water from the deep ocean comes up to the surface through a process called upwelling.
How strong is the wind in San Francisco?
Winds SW at 10 to 15 mph.
How deep is the water between Alcatraz and San Francisco?
It's just 4 or 5 meters deep. But in the center, it is about 20 or 30 meters deep. Every time when the tide is going in or out there's one big valley of water flowing in and out.
How deep is the water under Golden Gate?
377-Feet Deep And Full Of Mystery At around 377 feet at its deepest point, the waters underneath the Golden Gate Bridge are bound to hold more than one ghostly tale from the past. And the National Oceanic and Atmospheric Administration has made it their mission to bring the eerie tales to the surface.
How long can you survive in San Francisco Bay?
When the water first hits you, it's cold but not paralyzing. If you're wearing a PFD and you survive the first few minutes in the water, there's a good chance of surviving for up to four hours.
Are there great white sharks in San Francisco Bay?
Fisherman spots great white shark in San Francisco bay A fisherman spotted a great white shark in the San Francisco bay near the Golden Gate Bridge. SAN FRANCISCO - A fisherman got video of a great white shark swimming in the waters of the San Francisco bay.
What are the most famous tides in San Francisco?
Several places in San Francisco Bay are known for their tidal races (sometimes referred to as "tide rips"). The most prominent are Yellow Bluff on an ebb (shown in photo), Raccoon Strait off Pt. Stuart (mostly on an ebb, sometimes on a flood), and around Alcatraz Island.
How strong are the currents in San Francisco Bay?
The currents in San Francisco Bay are generated by the tides. At several locations in the Bay, currents can be as strong as six knots. As a recreational paddler, you paddle about three knots—four if racing or terrified.
Where do the strongest currents occur?
The strongest currents occur where the water masses streaming in and out of the bay are funneled through a constriction, like under the Golden Gate Bridge and through Raccoon Strait on the north side of Angel Island.
How far inland does fog go?
If the marine layer is shallow (i.e., less than about 1000 feet), low clouds will spread only locally inland around San Francisco Bay, but seldom reach as far inland as the Delta, and never to the Central Valley. A shallow marine layer typically results in more fog and reduced visibilities, especially over the coastal waters and locally over San Francisco Bay near the Golden Gate. Overall, the foggiest waters in summer are the ocean approaches to the Golden Gate, and locally inside the Gate to about Alcatraz.
What direction does the wind blow in San Francisco?
Wind direction is generally west-to-east, although there is a great deal of variation on a local scale due to the complex topography. The most prominent gap in the coastal ranges is the Golden Gate and it is here the onshore winds funnel inland with the least amount of resistance. Once the airflow moves through the Golden Gate, it fans out across San Francisco Bay, to the southeast toward the southern part of the Bay and the warm Santa Clara Valley, to the northeast toward the Carquinez Strait, Delta and the heat of the Central Valley beyond, and to the north into the Petaluma and Napa Valleys of the North Bay. The strongest afternoon and evening summer seabreezes usually occur along a path from the Golden Gate to the Central Valley that goes past Alcatraz and the southern end of Angel Island (Point Blunt), east to Berkeley, north past Pinole Point, northeast to the Carquinez Strait and finally east into the Delta and Central Valley. By the time the airflow reaches the Central Valley, it spreads out and diminishes. During the summer months, afternoon and evening wind speeds frequently reach 20 to 25 knots (meeting small craft advisory criteria) in the northern San Francisco Bay from mid-afternoon through mid-evening. In fact, small craft advisory conditions occur nearly every day in summer through the central and northern San Francisco Bay and eastward through the Carquinez Strait. Wind speeds sometimes locally reach 30 knots in these areas. Gales are rare in summer, but can occur during an unusually intense onshore push. Marine air also spills inland through other gaps in the coastal ranges, including the San Bruno gap just to the west-northwest of San Francisco Airport (SFO). In fact, some of the strongest summer seabreezes occur on the west side of the Bay from Hunters Point south through the area around SFO, and small craft conditions are common here as well. Elsewhere in the Bay, summer seabreezes generally do not exceed 20 knots. Wind speeds throughout the Bay Area gradually taper off after sunset and reach a low point from the late-night hours through late morning. On many days, winds can be variable at less than 10 knots during this time period. But once surface heating increases in the interior around midday, the daily cycle begins again and onshore winds start to increase.
How long does fog last in San Francisco?
Fog and low clouds can remain entrenched along the coast for days, sometimes weeks, at a time. During the late afternoon or early evening hours of a typical summer day, low clouds and fog over the ocean begin to spread into San Francisco Bay through the Golden Gate, and inland through gaps in the coastal mountains.
Why is fog less common in the spring?
Because the atmosphere in early spring is more unstable than in the late spring and summer months , fog and low clouds are then less frequent. Also, when a marine layer does develop in the spring, it typically is not as shallow as the summer season marine layer, and so dense fog episodes occur more rarely. Dense fog is most common in San Francisco Bay, and especially in the Delta and Central Valley, during the winter months.
How does the sea breeze work?
Summer winds across the Bay and Delta nearly always flow from high pressure offshore toward the lower pressure of the inland thermal trough. This type of wind flow is referred to as onshore flow or a seabreeze. The magnitude of the onshore flow is regulated by the daily cycle of differential heating between land and sea. Because ocean temperatures remain nearly constant from day to night, the most important factor in driving the daily wind cycle is inland heating. Daytime heating over land causes surface air pressure to diminish during the afternoon hours, increasing onshore pressure gradients. Onshore winds begin to increase by early afternoon and reach a peak by late afternoon into the early evening hours. Winds then gradually subside during the evening as surface heating over land decreases. Wind speeds reach their lowest point late at night and remain relatively light through mid-morning before the cycle starts over again.
What is the maximum wind speed in San Francisco?
Wind speeds generally range from 5 to 15 knots during the night and morning hours, increasing to 10 to 20 knots or even 15 to 25 knots in the afternoon and early evening hours.
What is dense fog?
Dense fog is defined by the National Weather Service as fog that reduces visibility to one-half mile or less on the San Francisco Bay or to one mile or less over the coastal waters. Spring and summer fog is not usually dense over the bays and into the Delta and Central Valley.
Why is dredging important in San Francisco?
Dredging created channels for vessels to bring goods directly into the San Francisco area and has also changed the geography of the area. In the WeatherOps GIS image below, you can see the regional currents of the bay. Because of the tides, the water flows in and out of the area multiple times a day. This motion is a boon for recreation allowing ...
Where are the currents not kind?
One area where the currents have not been kind is Alcatraz Island. While no longer a federal prison, in the past it held some of the most notorious criminals of the day. No prisoners successfully escaped, but many tried and failed. In 1962, three of them tried to flee on a raft made of raincoats. Due to the current, it is believed they were either pulled out to sea or drowned in the cold waters of the bay while trying to reach the mainland.