Storm of the Century (1993)

Infobox winter storm|name=Storm of the Century (1993)
image location=Storm of the century satellite.gif

NASA of the superstorm on March 13, 1993, at 10:01 UTC.
stormtype=Cyclonic blizzard, Nor'easter
date formed=March 11, 1993
date dissipated=March 15, 1993
maximum amount=60 inches (152.4 cm) - Mt. Le Conte, TN
pressure=960 mbar (hPa)
total damages (USD)=$6-10 billion (2005 USD) cite web | url = http://www.intellicast.com/Almanac/Northeast/March/ | title = MARCH IN THE NORTHEAST | author = Intellicast.com | accessdate = 2007-03-03]
total fatalities=300 total
areas affected=Most of eastern and southern North America

The Storm of the Century, also known as the ’93 Superstorm, No-Name Hurricane, the White Hurricane, or the (Great) Blizzard of 1993, was a large cyclonic storm that occurred on March 12–March 15, 1993, on the East Coast of North America. It is unique for its intensity, massive size and wide-reaching effect. At its height the storm stretched from Canada to Central America, but its main impact was on the Eastern United States and Cuba. Areas as far south as central Alabama and Georgia received 6 to convert|8|in|cm of snow and areas such as Birmingham, Alabama, received up to convert|12|in|cm with isolated reports of convert|16|in|cm. Even the Florida Panhandle reported up to convert|2|in|cm, with hurricane-force wind gusts and record low barometric pressures. Between Florida and Cuba, hurricane-force winds produced extreme storm surges in the Gulf of Mexico, which along with scattered tornadoes killed dozens of people.

Formation

A "disorganized area of low pressure" that formed in the Gulf of Mexico joined an arctic high pressure system in the Midwestern Great Plains, brought into the mid-latitudes by an unusually steep southward jet stream. These factors combined to produce unusually low temperatures across the eastern half of the United States.

Forecasting

The 1993 Storm of the Century marked a milestone in U.S. weather forecasting. By March 8 (and by some accounts even earlier), several operational numerical weather prediction models and medium-range forecasters at the US National Weather Service recognized the threat of a significant snowstorm. By the 12th, many had reviewed the data and were convinced that a serious threat loomed overhead. This marked the first time that National Weather Service meteorologists were able to accurately predict a system's severity five days in advance. Official blizzard warnings were issued two days before the storm arrived, as shorter-range models began to confirm the predictions. Forecasters were finally confident enough in the computer-forecast models to support decisions by several Northeastern U.S. states to declare a State of Emergency before the snow even started to fall.cite web | title = Forecasting the "Storm of the Century" | url = http://celebrating200years.noaa.gov/events/storm/welcome.html#firsts | accessdate = 2007-03-14 ]
In the South, however, temperatures in the days prior to the storm were typical for early March. Although large fluctuations in temperature are not unusual in the deep south, many residents doubted that freezing temperatures could return so rapidly; nor that snow was likely due to the rarity of significant snowfall later than February. Many local TV news stations were reluctant to even broadcast the forecast models, due to the extreme numbers being predicted by the computers, but the models turned out to be right.

The storm

During Friday March 12, temperatures over much of the eastern United States began to fall quickly. The area of low pressure rapidly intensified during the day on Friday and moved into northwest Florida by early Saturday morning. As this happened snow began to spread over the eastern United States, and a large squall line moved from over the Gulf of Mexico into Florida and Cuba. The low tracked up the east coast during the day on Saturday and into Canada by early Monday morning.

The blizzard

saw daily maximum temperatures as low as 14°F (-10°C). Record low temperatures for March were recorded in much of the Southern U.S. Farther to the South, numerous supercells developed over the state of Florida, spawning eleven tornadoes and killing seven people.

This storm complex was massive, affecting at least 26 U.S. states and much of eastern Canada. Bringing cold air along with heavy precipitation and hurricane force winds, it caused a blizzard over much of the area it affected. The storm brought snow as far south as northern Florida, with and unofficial total of 8" at Jay in the NW Panhandle region, thundersnow from Texas to Pennsylvania, and whiteout conditions. Some affected areas saw more than 3.5 feet (1.1 m) of snow, and snowdrifts were as high as 35 feet (10.7 m). Central and Southern Florida saw no snow, but tornadoes and severe thunderstorms, resultant from the storm, occurred there and in Cuba. Responsible for 300 deaths and the loss of electric power to over 10 million, it is purported to have been directly experienced by over 130 million people in the United States, about half the country's population at that time. Every airport from Halifax, Nova Scotia to Atlanta, Georgia was closed for some time because of the storm. The volume of the storm's total snowfall was later computed to be 12.91 mi³ (53.96 km³), an amount which would weigh (depending on the variable density of snow) between 5.4 and 27 billion tonnes.
Barometric pressures recorded during the storm were also unusually low: readings of 28.35 inHg (960 mb or hPa) were observed in New England. Usually, such low readings are observed only in hurricanes (generally of Category 2 or 3 intensity on the Saffir-Simpson hurricane scale), which peak at almost the exact opposite time of year, or in other cyclonic storms far out to sea. It also pushed a storm surge ashore on the Florida panhandle, drowning a few people taken by surprise at the storm's ferocity. (This incident is featured occasionally on reruns of "Storm Stories".)

As one of the most powerful storms in recent history, the storm has been described as the "Storm of the Century" by many of the areas affected. The last blizzard to have such an effect on the Southeast was the Great Blizzard of 1899.

ubtropical derecho

Besides producing record low barometric pressure across a swath of the Southeast and Mid-Atlantic states, and one of the nation's biggest snowstorms, the low produced a potent squall line ahead of its cold front. The squall line produced a serial derecho as it moved into Florida and Cuba around midnight on March 13. Straight-line winds gusted above 100 mph/85 kts (160 km/h) at many locations in Florida as the squall line moved through.

A substantial storm surge was also generated along the gulf coast from Appalachee Bay in the Florida panhandle all the way around to Southwest Florida. Especially hard hit was Hernando County north of Tampa, where the coast faces northwest; right into the teeth of the approaching squall (see map).

Storm surges there reached up to convert|12|ft|m; higher than many hurricanes. With little advanced warning of incoming severe conditions, some coastal residents were awakened in the early morning of March 13th to find the waters of the Gulf of Mexico rushing into their homes. [ [http://www2.sptimes.com/weather/SW.3.3.html Losing a home, then losing a life ] ] Overall, the storm's surge, winds, and tornadoes damaged or destroyed 18,000 homes and killed at least 26 people in Florida. [ [http://www2.sptimes.com/weather/SW.3.html A storm with no name ] ]

killed three people when it struck a home which later collapsed, pinning the occupants under a fallen wall.

In Cuba, wind gusts reached 100 mph (160 km/h) in the Havana area. A survey conducted by a research team from the Institute of Meteorology of Cuba suggests that the maximum winds could have been as high as 130 mph (210 km/h). It is the most damaging squall line ever recorded in Cuba.

There was widespread and significant damage in Cuba, with damages estimated as intense as F2. [cite web | author = American Meteorological Society | title = The 13 March 1993 Severe Squall Line over Western Cuba | url = http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0434%281996%29011%3C0089%3ATMSSLO%3E2.0.CO%3B2 | accessdate = 2007-04-25] The squall line finally moved out of Cuba near sunrise, leaving 10 deaths and US$1 billion in damage on the island.

In the image above, measured gusts in mph are plotted (blue numbers). "+" symbols indicate the locations of wind damage or estimated wind gusts above severe limits (58 mph or greater). Red dots and paths indicate tornado events. Small red numbers indicate tornado intensities in F-scale. The approximate location of the squall line "gust front" is shown in two hour increments (curved purple lines).

Tornado table

Confirmed tornadoes

Impact

.

."

Overall, the Blizzard of 1993 caused a total of $6.6 billion of damage.

Across the Northeastern states and eastern Canadian provinces, the storm put down an average of 15 inches (40 cm) of snow, which, though most certainly heavy, is not exceptional by most local standards, but still somewhat unusual for mid-March, especially for the southernmost parts of the region such as the Baltimore-Washington area. New England residents tend to point to the Blizzard of 1978 as their "storm of the century," due largely to its unrelenting snowfall, which temporarily dislocated the weather-hardened region, while Mid-Atlantic residents tend to point to the Blizzard of 1996 for similar reasons. Based on widespread effects, barometric pressures, wind speeds and satellite images, however, there is little doubt that the storm of 1993 was the most remarkable.

torm amounts

ee also

*List of derecho events

References

External links

* [http://www.nws.noaa.gov/om/assessments/superstorm/superstorm.pdf NWS Service Assessment]
* [ftp://ftp.ncdc.noaa.gov/pub/data/techrpts/tr9301/tr9301.pdf The Big One! A Review of the March 12-14, 1993 "Storm of the Century" (PDF)]
* [http://www.spc.noaa.gov/misc/AbtDerechos/casepages/mar12-131993page.htm Summary of the Subtropical Derecho (NOAA)]