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The February 13, 1979 windstorm is a natural phenomenon that took place on February 13, 1979 in Pacific Canada and the United States. During the early morning of February 13, 1979, an intense wave cyclone moved across southern Vancouver Island, British Columbia. South of the low center, a strong atmospheric pressure gradient was carried across Washington, with associated high winds. With a cold airflow moving toward the northeast interacting with the high terrain of the Olympic Mountains, a lee low developed east of the Olympics. The mesoscale low caused a particularly intense pressure gradient to develop across the Kitsap Peninsula region.
In meteorology, a cyclone is a large scale air mass that rotates around a strong center of low atmospheric pressure. Cyclones are characterized by inward spiraling winds that rotate about a zone of low pressure. The largest low-pressure systems are polar vortices and extratropical cyclones of the largest scale. Warm-core cyclones such as tropical cyclones and subtropical cyclones also lie within the synoptic scale. Mesocyclones, tornadoes and dust devils lie within smaller mesoscale. Upper level cyclones can exist without the presence of a surface low, and can pinch off from the base of the tropical upper tropospheric trough during the summer months in the Northern Hemisphere. Cyclones have also been seen on extraterrestrial planets, such as Mars and Neptune. Cyclogenesis is the process of cyclone formation and intensification. Extratropical cyclones begin as waves in large regions of enhanced mid-latitude temperature contrasts called baroclinic zones. These zones contract and form weather fronts as the cyclonic circulation closes and intensifies. Later in their life cycle, extratropical cyclones occlude as cold air masses undercut the warmer air and become cold core systems. A cyclone's track is guided over the course of its 2 to 6 day life cycle by the steering flow of the subtropical jet stream.
Vancouver Island is in the northeastern Pacific Ocean. It is part of the Canadian province of British Columbia. The island is 460 kilometres (290 mi) in length, 100 kilometres (62 mi) in width at its widest point, and 32,134 km2 (12,407 sq mi) in area. It is the largest island on the West Coast of the Americas.
British Columbia is the westernmost province of Canada, located between the Pacific Ocean and the Rocky Mountains. With an estimated population of 5.016 million as of 2018, it is Canada's third-most populous province.
At 6 mbar over 8 miles, the geostrophic wind potential easily exceeded 200 knots (which roughly translates to about 100 knots in ageostrophic flow over the Earth's rough surface, or 115 mph). As reported by the crew of the Hood Canal Bridge, average winds reached at least 80 mph out of the south, with gusts into the triple digits. These wind velocities were cross-checked on two different anemometers at the bridge control tower.
The Hood Canal Bridge is a floating bridge in the northwest United States, located in western Washington. It carries State Route 104 across Hood Canal of Puget Sound and connects the Olympic and Kitsap Peninsulas. At 7,869 feet in length, it is the longest floating bridge in the world located in a saltwater tidal basin, and the third longest floating bridge overall. First opened 57 years ago in 1961, it was the second concrete floating bridge constructed in Washington. Since that time, it has become a vital link for local residents, freight haulers, commuters, and recreational travelers. The convenience it provides has had a major impact on economic development, especially in eastern Jefferson County.
Extensive damage to trees on surrounding private timberland also corroborate the extreme intensity of this tempest. The pressure of wind and wave on the Hood Canal Bridge stressed the structure enough to cause catastrophic failure. It is suspected that a severe list in the bridge exposed pontoon access hatches to the waves, which subsequently tore the covers loose and allowed water to enter the flotation devices, causing sections to sink. It took nearly three years and over $140 million U.S. to rebuild the lost bridge.
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Surface weather analysis is a special type of weather map that provides a view of weather elements over a geographical area at a specified time based on information from ground-based weather stations.
Wind speed, or wind flow velocity, is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature. Note that wind direction is usually almost parallel to isobars, due to Earth's rotation.
Wind shear, sometimes referred to as wind gradient, is a difference in wind speed or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal wind shear. Vertical wind shear is a change in wind speed or direction with change in altitude. Horizontal wind shear is a change in wind speed with change in lateral position for a given altitude.
A squall line or quasi-linear convective system (QLCS) is a line of thunderstorms forming along or ahead of a cold front. In the early 20th century, the term was used as a synonym for cold front. It contains heavy precipitation, hail, frequent lightning, strong straight-line winds, and possibly tornadoes and waterspouts. Strong straight-line winds can occur where the squall line is in the shape of a bow echo. Tornadoes can occur along waves within a line echo wave pattern (LEWP), where mesoscale low-pressure areas are present. Some bow echoes which develop within the summer season are known as derechos, and they move quite fast through large sections of territory. On the back edge of the rainband associated with mature squall lines, a wake low can be present, sometimes associated with a heat burst.
A low-pressure area, low, depression or cyclone is a region on the topographic map where the atmospheric pressure is lower than that of surrounding locations. Low-pressure systems form under areas of wind divergence that occur in the upper levels of the troposphere. The formation process of a low-pressure area is known as cyclogenesis. Within the field of meteorology, atmospheric divergence aloft occurs in two areas. The first area is on the east side of upper troughs, which form half of a Rossby wave within the Westerlies. A second area of wind divergence aloft occurs ahead of embedded shortwave troughs, which are of smaller wavelength. Diverging winds aloft ahead of these troughs cause atmospheric lift within the troposphere below, which lowers surface pressures as upward motion partially counteracts the force of gravity.
Tropical waves, easterly waves, or tropical easterly waves, also known as African easterly waves in the Atlantic region, are a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which moves from east to west across the tropics, causing areas of cloudiness and thunderstorms. West-moving waves can also form from the tail end of frontal zones in the subtropics and tropics, and may be referred to as easterly waves, but these waves are not properly called tropical waves; they are a form of inverted trough sharing many characteristics with fully tropical waves. All tropical waves form in the easterly flow along the equatorward side of the subtropical ridge or belt of high pressure which lies north and south of the Intertropical Convergence Zone (ITCZ). Tropical waves are generally carried westward by the prevailing easterly winds along the tropics and subtropics near the equator. They can lead to the formation of tropical cyclones in the north Atlantic and northeastern Pacific basins. A tropical wave study is aided by Hovmöller diagrams, a graph of meteorological data.
Cyclogenesis is the development or strengthening of cyclonic circulation in the atmosphere. Cyclogenesis is an umbrella term for at least three different processes, all of which result in the development of some sort of cyclone, and at any size from the microscale to the synoptic scale.
A mesoscale convective system (MCS) is a complex of thunderstorms that becomes organized on a scale larger than the individual thunderstorms but smaller than extratropical cyclones, and normally persists for several hours or more. A mesoscale convective system's overall cloud and precipitation pattern may be round or linear in shape, and include weather systems such as tropical cyclones, squall lines, lake-effect snow events, polar lows, and Mesoscale Convective Complexes (MCCs), and generally form near weather fronts. The type that forms during the warm season over land has been noted across North America, Europe, and Asia, with a maximum in activity noted during the late afternoon and evening hours.
The 2008 Atlantic hurricane season was the most disastrous Atlantic hurricane season since 2005, causing over 1,000 deaths and nearly $50 billion in damages. It was an above-average season, featuring sixteen named storms, eight of which became hurricanes, and five which further became major hurricanes, the highest number since the record-breaking 2005 season. It officially started on June 1 and ended on November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. However, the formation of Tropical Storm Arthur caused the season to start one day early. This season is the fifth most costly on record, behind only the 2004, 2005, 2012 and 2017 seasons, with over $49.5 billion in damage. It was the only year on record in which a major hurricane existed in every month from July through November in the North Atlantic.Bertha became the longest-lived July tropical cyclone on record for the basin, the first of several long-lived systems during 2008.
Typhoon Bess, known in the Philippines as Typhoon Susang, was responsible for the disappearance of a United States Air Force weather reconnaissance aircraft. Developing out of a poorly organized system on October 8 to the east of the Philippines, Bess featured two centers of circulation. Initially the southern low was monitored; however, a low to the north soon became the dominant center. Tracking generally west-northwestward, the storm gradually intensified before striking northern Luzon as a minimal typhoon on October 11. Temporary weakening took place due to interaction with land. After moving back over water the following morning, Bess regained typhoon intensity. This was short-lived though, as conditions surrounding the cyclone soon caused it to weaken. Now moving due west, the weakening storm eventually struck Hainan Island as a tropical storm on October 12 before diminishing to a tropical depression. The depression briefly moved back over water before dissipating in northern Vietnam on October 14.
Rapid intensification is a meteorological condition that occurs when a tropical cyclone intensifies dramatically in a short period of time. The United States National Hurricane Center (NHC) defines rapid intensification as an increase in the maximum 1-min sustained winds of a tropical cyclone of at least 30 knots in a 24-hour period.
The African easterly jet is a region of the lower troposphere over West Africa where the seasonal mean wind speed is at a maximum and the wind is easterly. The temperature contrast between the Sahara Desert and the Gulf of Guinea causes the jet to form to the north of the monsoon trough. The jet's maximum wind speeds are at a height of 3 kilometres (1.9 mi). The jet moves northward from its south-most location in January, reaching its most northerly latitude in August. Its strongest winds are in September while it begins shifting back towards the equator. Within the easterly jet, tropical waves form. Convective complexes associated with these waves can form tropical cyclones. If the jet is south of its normal location during August and September, tropical cyclogenesis is suppressed. If desertification continues across Sub-Saharan Africa, the strength of the jet could increase, although tropical wave generation probably would decrease, which would decrease the number of tropical cyclones in the Atlantic basin.
The November 2006 nor'easter was a powerful extratropical cyclone that formed offshore of the Southeastern United States on November 20, bringing heavy rains, high winds, beach erosion, and coastal flooding to the Carolinas and southern New England. In addition, the earliest snowfall ever noted in both Charleston, South Carolina and Savannah, Georgia occurred on the southwest side of this cyclone. Over 10,000 were without power during the storm. No longer a nor'easter, the extratropical cyclone accelerated rapidly across the North Atlantic while rapidly strengthening, becoming a cyclonic storm again by November 25, but this time with hurricane-force sustained winds. The intense low made a cyclonic loop west of Iceland, before being absorbed by another strengthening extratropical cyclone to the west of Great Britain, late on December 1.
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low-pressure areas which, along with the anticyclones of high-pressure areas, drive the weather over much of the Earth. Extratropical cyclones are capable of producing anything from cloudiness and mild showers to heavy gales, thunderstorms, blizzards, and tornadoes. These types of cyclones are defined as large scale (synoptic) low pressure weather systems that occur in the middle latitudes of the Earth. In contrast with tropical cyclones, extratropical cyclones produce rapid changes in temperature and dew point along broad lines, called weather fronts, about the center of the cyclone.
Hurricane Jeanne was a moderate hurricane that formed and dissipated in the Gulf of Mexico without making landfall. The tenth tropical cyclone and eighth hurricane of the 1980 Atlantic hurricane season, Jeanne developed over the southern Caribbean on November 7. It moved swiftly northward, and it intensified to a tropical storm on November 9. It entered the southern Gulf of Mexico on November 10. Jeanne turned to the west on November 11, and it rapidly intensified to its peak intensity of 100 mph (155 km/h). It weakened on November 12, and its forward motion slowed; the cyclone weakened further to a tropical storm because of dry air intrusion, and it executed a clockwise loop on November 15. It dissipated on November 16.
Cyclone Justin was a tropical cyclone of the 1996–97 Australian region cyclone season that caused seven deaths and had a major economic impact in northern Queensland, Australia. It had a long 3½-week life from 6 March to 24 March 1997. Peaking as a Category 3 cyclone and making landfall as a Category 2, it caused significant damage in the Cairns region, which it approached on two occasions. Houses were undermined by huge waves, a marina and boats were severely damaged, roads and bridges suffered from flood and landslide damage and huge losses were inflicted on sugar cane, fruit and vegetable crops. The death toll in Queensland was seven including five on a yacht which sank. There were 26 who died in Papua New Guinea, which was also severely affected. Total estimated costs from damages in Australia were $190 million.
The Braer Storm of January 1993 was the most intense extratropical cyclone ever recorded over the northern Atlantic Ocean. Developing as a weak frontal wave on 8 January 1993, the system moved rapidly northeast. The combination of the absorption of a second low-pressure area to its southeast, a stronger than normal sea surface temperature differential along its path, and the presence of a strong jet stream aloft led to a rapid strengthening of the storm, with its central pressure falling to an estimated 914 hPa on 10 January. Its strength was well predicted by forecasters in the United Kingdom, and warnings were issued before the low initially developed.
Cyclone Friedhelm, also referred to unofficially as Hurricane Bawbag, was an intense extratropical cyclone which brought hurricane-force winds to Scotland at the beginning of December 2011. The storm also brought prolonged gales and rough seas to the rest of the British Isles, as well as parts of Scandinavia. On 8 December, winds reached up to 165 mph (265 km/h) at elevated areas, with sustained wind speeds of up to 80 mph (135 km/h) reported across populous areas. The winds uprooted trees and resulted in the closure of many roads, bridges, schools and businesses. Overall, the storm was the worst to affect Scotland in 10 years, though a stronger storm occurred less than a month afterwards, on 3 January 2012. Although the follow-up storm was more intense, the winter of 2011/12 is usually remembered for Bawbag among Scots.
Pacific Northwest windstorms, sometimes colloquially known as Big Blows, are extratropical cyclones which form in the Pacific basin, and affect land areas in the Pacific Northwest of the United States and British Columbia, Canada. They form as cyclonic windstorms associated with areas of low atmospheric pressure that track across the North Pacific Ocean towards western North America. Deep low pressure areas are relatively common over the North Pacific. They are most common in the winter months. On average, the month when most windstorms form is December.