Hurricanes: The Evil Wind Anthony R. Lupo Department of Soil, Environmental, and Atmospheric Science 302 E ABNR Building University of Missouri – Columbia Columbia, MO 65211

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Hurricanes are a tropical system, which have a unique structure, and, sometimes, unique behavior. Hurricanes are a tropical system, which have a unique structure, and, sometimes, unique behavior. “Hurricane” is a Spanish/French/Indian word literally meaning “evil wind” “Hurricane” is a Spanish/French/Indian word literally meaning “evil wind” In the Atlantic, there are typically 6 hurricanes and 10 named storms. They typically last for days. In the Atlantic, there are typically 6 hurricanes and 10 named storms. They typically last for days.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Hurricanes have a special structure, one that is quite different from mid-latitude storms. Hurricanes have a special structure, one that is quite different from mid-latitude storms. There is no frontal structure in tropical systems and they are “warm core”. That is, they are warmer in the center than in the surroundings. There is no frontal structure in tropical systems and they are “warm core”. That is, they are warmer in the center than in the surroundings.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind

They also need an atmosphere with very little wind shear (in the vertical) to exist. Otherwise, the circulation can be disrupted. They also need an atmosphere with very little wind shear (in the vertical) to exist. Otherwise, the circulation can be disrupted. Hurricanes are sustained by the release on heat due to condensation. They are a convective engine. Hurricanes are sustained by the release on heat due to condensation. They are a convective engine. They are “spun down” over land by frictional forces. They are “spun down” over land by frictional forces.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind In summary, they need: In summary, they need: –A pre-existing area of low pressure. –An atmosphere with little shear –Waters of 80 o F (26 o C) or more.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Hurricane movement is generally east to west in the tropics, but in the vicinity of North America are influenced heavily by mid-latitude circulations. Hurricane movement is generally east to west in the tropics, but in the vicinity of North America are influenced heavily by mid-latitude circulations. Winds in a deep layer (850 hPa – 200 hPa), 1 mile – 6 miles up, influence their movement. Winds in a deep layer (850 hPa – 200 hPa), 1 mile – 6 miles up, influence their movement. Models now doing a good job with their movement. Models now doing a good job with their movement.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Terminology: Terminology: Tropical “wave” – is an area of low pressure and thunderstorms with strong gusty winds, and no “closed” center. Tropical “wave” – is an area of low pressure and thunderstorms with strong gusty winds, and no “closed” center. Tropical depression – has sustained winds of up to 35 kts (39 mph), and a closed “cold” center of low pressure. Tropical depression – has sustained winds of up to 35 kts (39 mph), and a closed “cold” center of low pressure.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Tropical storm – storm acquires a name, and winds are sustained from 35 – 65 kts (39 – 74 mph). At this point, they are warm core storms. Tropical storm – storm acquires a name, and winds are sustained from 35 – 65 kts (39 – 74 mph). At this point, they are warm core storms. Hurricane – acquires an eye and sustained winds over 65 kts (74 mph). Hurricane – acquires an eye and sustained winds over 65 kts (74 mph).

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Tropical Entities passing within 250 miles of Norfolk, VA since Tropical Entities passing within 250 miles of Norfolk, VA since FMAMJJASONDTot Subtrop.1214 Depres Trop. S Cat Cat Cat Cat 4123 Cat 5 Total

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Tropical Entities passing within 250 miles of Birmingham, AL since Tropical Entities passing within 250 miles of Birmingham, AL since FMAMJJASONDTot Subtrop.0 Depres Trop. S Cat Cat 211 Cat 311 Cat 4 Cat 5 Total

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Since 1938, was the longest “threat free” period, and the 1960’s the quietest decade with 2 storms. The 1980s were not far behind with only 3 events. Since 1938, was the longest “threat free” period, and the 1960’s the quietest decade with 2 storms. The 1980s were not far behind with only 3 events. The year of 2005 was the worst, 5 storms pass within 250 miles of Birmingham. (August 2004, 2 storms!) The year of 2005 was the worst, 5 storms pass within 250 miles of Birmingham. (August 2004, 2 storms!)

Hurricanes: The Evil Wind Hurricanes: The Evil Wind During the 1960s through 1990s, there were only 15 events (mean 4 storms per decade). During the “oughts” (2000s), there were 15 storms. During the 1960s through 1990s, there were only 15 events (mean 4 storms per decade). During the “oughts” (2000s), there were 15 storms. Tropical storm threat is greatest in September. Season gears up in June and winds down by mid-October. Tropical storm threat is greatest in September. Season gears up in June and winds down by mid-October.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Ivan (2003) – In AL, none dead and $2.0 B in damage. Ivan (2003) – In AL, none dead and $2.0 B in damage.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Frederic (1979) – costliest hurricane in US history up to Frederic (1979) – costliest hurricane in US history up to 1989.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Eloise (Sept 1975) remained a Category 3 well inland, brought torrential rains and much flooding along the east coast. Eloise (Sept 1975) remained a Category 3 well inland, brought torrential rains and much flooding along the east coast.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind "Preparation through education is less costly than learning through tragedy.“ - MAX MAYFIELD, DIRECTOR NATIONAL HURRICANE CENTER "Preparation through education is less costly than learning through tragedy.“ - MAX MAYFIELD, DIRECTOR NATIONAL HURRICANE CENTER Hurricane Watch – hurricane conditions could happen at your location in 36 hours. Hurricane Watch – hurricane conditions could happen at your location in 36 hours. Hurricane Warning – hurricane conditions are expected within 24 hours. Hurricane Warning – hurricane conditions are expected within 24 hours. Source: ( National Hurricane Center Source: ( National Hurricane Centerhttp://

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Storm surge and heavy rains are the biggest killers in a hurricane, not winds, lightning, or tornadoes. Storm surge and heavy rains are the biggest killers in a hurricane, not winds, lightning, or tornadoes. People should be aware that they should take any tropical system seriously. Some of the biggest killers have not been hurricane intensity. People should be aware that they should take any tropical system seriously. Some of the biggest killers have not been hurricane intensity.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Hurricane numbers during a season are impacted by El Nino. El Nino can influence the atmospheric ingredients mentioned earlier. Hurricane numbers during a season are impacted by El Nino. El Nino can influence the atmospheric ingredients mentioned earlier. There tend to be fewer / less intense hurricanes in an El Nino year. This is mainly because of the inactive Gulf and Caribbean. There tend to be fewer / less intense hurricanes in an El Nino year. This is mainly because of the inactive Gulf and Caribbean.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Upper tropospheric trough! Upper tropospheric trough!

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Hurricane numbers also fluctuate on the decadal time-scale, especially since the El Nino in influenced in this manner. Hurricane numbers also fluctuate on the decadal time-scale, especially since the El Nino in influenced in this manner. There is little long term trend in Atlantic or Pacific hurricane numbers. There is little long term trend in Atlantic or Pacific hurricane numbers.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Are there more severe hurricanes? Are there more severe hurricanes? Long term, the ratio of Cat 3 – 5 storms to all storms is 42% Long term, the ratio of Cat 3 – 5 storms to all storms is 42% In 2000 – 2009, this ratio was 49%, a bit higher. In 2000 – 2009, this ratio was 49%, a bit higher.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind All things being equal, warmer waters will cause more and stronger hurricanes, but remember, these storms need a cooperative ocean and atmosphere. All things being equal, warmer waters will cause more and stronger hurricanes, but remember, these storms need a cooperative ocean and atmosphere. There is no evidence climate change is leading to more hurricanes. There is no evidence climate change is leading to more hurricanes.

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Check this out……… Check this out……… 2005 (27) versus 1933 (21) 2005 (27) versus 1933 (21)

Hurricanes: The Evil Wind Hurricanes: The Evil Wind Questions? Questions? Comments? Comments? Criticisms? Criticisms?

Hurricanes: The Evil Wind Hurricanes: The Evil Wind