Main development region

File:Atlantic hurricane tracks.jpg tracks from 1851 to 2019]]

Tropical cyclone formation requires several factors, including: high humidity, low wind shear, and sufficiently warm sea surface temperatures. Regions of Earth's oceans with the required conditions are generally found between the latitudes of 8° and 20° from the Equator.{{cite web|url=http://earthobservatory.nasa.gov/Features/Hurricanes/|title=Hurricanes: The Greatest Storms on Earth|author1=Steve Graham|author2=Holli Riebeek|date=1 November 2006|publisher=NASA|access-date=29 July 2013}} An ocean temperature of at least {{cvt|26.5|C|F}} is normally considered the minimum to maintain a tropical cyclone. If water temperatures are lower, a system will most likely weaken. Conversely, higher water temperatures can enable a system to undergo rapid intensification.{{cite web|url = http://earthobservatory.nasa.gov/Features/HurricaneHeart/heart_2.php|title = Seeing into the Heart of a Hurricane| date=12 October 2000 |publisher = Earth Observatory}}

In the Atlantic, the area between 10°N and 20°N spawns the most hurricanes in a given season because of the warmer temperatures. Hurricanes do not form outside this range because nearer to the equator the Coriolis effect is not strong enough to create the tight circulation needed, and farther north the temperatures are too cool.{{cite web|url = http://www.srh.noaa.gov/srh/jetstream/tropics/tc.htm|title = NWS JetStream - Tropical Cyclone Introduction|publisher = National Weather Service}} The waters are only at the necessary temperatures from July until mid-October. In the Atlantic this is the height of the season.

Since hurricanes rely on sea surface temperature, sometimes an initially active season becomes quiet later. This is because the hurricanes are so strong that they churn the waters and bring colder waters up from the deep. This creates an area of the sea the size of the hurricane, which has cooler waters, which can be {{convert|5|-|10|C-change}} lower than before the hurricane. When a new hurricane moves over the cooler waters they have no fuel to continue to thrive, so they weaken or dissipate.{{cite web|url = http://earthobservatory.nasa.gov/Features/HurricaneHeart/heart_5.php|title = Seeing into the Heart of a Hurricane| date=12 October 2000 |publisher = Earth Observatory}}

According to an Azores High hypothesis of geographer Kam-biu Liu, an anti-phase pattern is expected to exist between the Gulf of Mexico coast and the North American Atlantic coast. During the quiescent periods (3000–1400 BC, and 1000 AD to present), a more northeasterly position of the Azores High would result in more hurricanes being steered towards the Atlantic coast. During the hyperactive period (1400 BC to 1000 AD), more hurricanes were steered towards the Gulf coast as the Azores High was shifted to a more southwesterly position near the Caribbean.{{cite conference |first=Kam-biu |last=Liu |title=Millennial-scale variability in catastrophic hurricane landfalls along the Gulf of Mexico coast |conference=23d Conf. on Hurricanes and Tropical Meteorology |publisher=Amer. Meteor. Soc. |date=1999 |location=Dallas, TX |pages=374–377 }}{{cite journal |last=Liu |first=Kam-biu |author2=Fearn, Miriam L. |year=2000 |title=Reconstruction of Prehistoric Landfall Frequencies of Catastrophic Hurricanes in Northwestern Florida from Lake Sediment Records |journal=Quaternary Research |volume=54 |issue=2 |pages=238–245 |doi=10.1006/qres.2000.2166 |bibcode=2000QuRes..54..238L|s2cid=140723229 }} Such a displacement of the Azores High is consistent with paleoclimatic evidence that shows an abrupt onset of a drier climate in Haiti around 3200 years ago,{{cite journal |last=Higuera-Gundy |first=Antonia |year=1999 |title=A 10,300 ¹⁴C yr Record of Climate and Vegetation Change from Haiti |journal=Quaternary Research |volume=52 |issue=2 |pages=159–170 |doi=10.1006/qres.1999.2062 |bibcode=1999QuRes..52..159H|s2cid=129650957 |display-authors=etal}} and a change towards more humid conditions in the Great Plains during the late-Holocene as more moisture was pumped up the Mississippi Valley through the Gulf coast. Preliminary data from the northern Atlantic coast seem to support the Azores High hypothesis. A 3,000-year proxy record from a coastal lake in Cape Cod suggests that hurricane activity has increased significantly during the past 500–1,000 years, just as the Gulf coast was amid a quiescent period of the last millennium.{{cite web|url=https://www.geo.umass.edu/climate/hadley/abstracts/liu.pdf|title=Millennial-scale Variability in Atlantic Hurricane Activities: Possible Links to the Hadley Circulation|author=Kam-biu Liu|publisher=University of Louisiana}}

{{Portal|Tropical cyclones}}

• Bermuda Triangle
• Hailstorm Alley
• Typhoon Alley
• Tornado Alley

{{Reflist}}

• [http://www.nhc.noaa.gov/climo/ Tropical Cyclone Climatology]
• [http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MYD28M Sea Surface Temperature]

Category:Atlantic hurricanes

Category:Tropical meteorology

Category:Tropical Atlantic

fr:Principale région de développement