Hurricane Fran, also referred initially as Subtropical Storm Bravo, was a long-tracked

Category 1 hurricane Category, plural categories, may refer to: Philosophy and general uses *Categorization, categories in cognitive science, information science and generally *Category of being * ''Categories'' (Aristotle) *Category (Kant) *Categories (Peirce) *C ...

that caused little damage during its existence in early October 1973. Originating from a

tropical wave A tropical wave (also called easterly wave, tropical easterly wave, and African easterly wave), in and around the Atlantic Ocean, is a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which ...

that developed off the coast of

Hispaniola Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and th ...

on October 1, the precursor to Fran slowly developing during the first week of October. By October 4, a surface low formed within the system and convective activity increased. The system was eventually classified as a

subtropical depression A subtropical cyclone is a weather system that has some characteristics of both tropical and an extratropical cyclone. As early as the 1950s, meteorologists were uncertain whether they should be characterized as tropical or extratropical cyclon ...

on October 8 and was upgraded to Subtropical Storm Bravo shortly thereafter. Bravo became increasingly tropical throughout the day as it intensified. Following a

reconnaissance mission In military operations, reconnaissance or scouting is the exploration of an area by military forces to obtain information about enemy forces, terrain, and other activities. Examples of reconnaissance include patrolling by troops (skirmishers, ...

into the storm on October 10, it was deemed fully tropical and upgraded to a hurricane, at which time it was renamed Fran. Hurricane Fran rapidly tracked towards the northeast in response to an area of low pressure within the

westerlies The westerlies, anti-trades, or prevailing westerlies, are prevailing winds from the west toward the east in the middle latitudes between 30 and 60 degrees latitude. They originate from the high-pressure areas in the horse latitudes and trend to ...

. By October 11, the hurricane attained its peak winds of and its lowest

barometric pressure Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, 7 ...

of 978 mbar (hPa; ) after bypassing the

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islands. Situated over exceedingly cold waters, Fran transitioned into an

extratropical cyclone 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 ...

late on October 12 as it neared the French coastline. Shortly before reaching land, the system was absorbed by a

cold front A cold front is the leading edge of a cooler mass of air at ground level that replaces a warmer mass of air and lies within a pronounced surface trough of low pressure. It often forms behind an extratropical cyclone (to the west in the Norther ...

. Throughout its existence, Fran had little effect on land.

Meteorological history

Hurricane Fran originated from a

associated with an area of convection north of

on October 1. The system tracked westward at but gained little strength and the

National Hurricane Center The National Hurricane Center (NHC) is the division of the United States' NOAA/National Weather Service responsible for tracking and predicting tropical weather systems between the Prime Meridian and the 140th meridian west poleward to the 3 ...

(NHC) did not anticipate development of the storm. By October 4, the system interacted with a mid-tropospheric trough near the southeast United States, resulting in the formation of a surface low. Tracking eastward, showers and thunderstorms began to develop around the circulation; however, the structure of the system was not fully tropical. On October 7, ships in the vicinity of the low reported decreasing

s, indicating a strengthening system. Satellites monitoring the system depicted a disorganized storm with mainly subtropical characteristics. Late on October 8, the cyclone had become sufficiently organized to be classified a subtropical depression. Cold air from the remnants of a

became entrained within the circulation; however, the cold air gradually warmed. On October 9, winds increased to gale-force and the depression was upgraded to a subtropical storm, at which time it was given the name Bravo. By October 10, Bravo had intensified substantially, as hurricane hunters recorded hurricane-force winds roughly from the center of the storm. Following this finding, the National Hurricane Center reclassified the system as a tropical system and renamed it Fran, dropping its previous designation of Bravo. Upon becoming tropical, Fran developed a strong

outflow Outflow may refer to: *Capital outflow, the capital leaving a particular economy *Bipolar outflow, in astronomy, two continuous flows of gas from the poles of a star *Outflow (hydrology), the discharge of a lake or other reservoir system * Outflow ...

and several convective feeder bands. Additionally, the storm had developed a wide

eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...

. Steered generally eastward by a deep surface low in the

, Fran accelerated towards the Azores Islands. The storm traveled at a rapid pace of but continued to organize. By October 11, the hurricane began to undergo an

extratropical transition 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 p ...

as it continued to move unusually fast towards the northeast. Around this time, Fran attained its peak winds of . Shortly after bypassing the Azores islands on October 12, the system moved over an area with

sea surface temperature Sea surface temperature (SST), or ocean surface temperature, is the ocean temperature close to the surface. The exact meaning of ''surface'' varies according to the measurement method used, but it is between and below the sea surface. Air mass ...

s around , well below what is required for tropical cyclone development. Later that day, the central pressure of Fran decreased to 978 mbar (hPa; ), the lowest recorded in relation to the hurricane. Shortly after reaching this intensity, the hurricane transitioned into an extratropical cyclone and quickly merged with a cold front off the coast of France.

Preparations and impact

Although Fran passed near the Azores as a hurricane, winds on the islands only reached and no damage was recorded. On October 12, a French ship encountered the storm, recording sustained winds of and an air pressure of 981 mbar (hPa; ). Ships near the English and French coastlines recorded winds up to as the extratropical remnants of Fran passed through the region.

References

External links

The National Hurricane Center's Preliminary Report on Hurricane FranMonthly Weather Review
{{DEFAULTSORT:Fran (1973) 1973 Atlantic hurricane season Category 1 Atlantic hurricanes Hurricanes in the Azores

Meteorological history

Preparations and impact

See also

References

External links