Active 2011 hurricane season breaks "Hurricane Amnesia"

[CrazyC83]

Active 2011 hurricane season breaks 'Hurricane Amnesia'

Irene the first hurricane to hit U.S. in three years; Northeast reminded it’s also vulnerable
November 28, 2011

The 2011 Atlantic hurricane season officially ends Wednesday, having produced a total of 19 tropical storms of which seven became hurricanes, including three major hurricanes. This level of activity matched NOAA’s predictions and continues the trend of active hurricane seasons that began in 1995.

The 19 tropical storms represent the third-highest total (tied with 1887, 1995, and 2010) since records began in 1851 and is well above the average of 11. However, the number of hurricanes and major hurricanes is only slightly above the average of six and two, respectively. This year’s totals include a post-storm upgrade of Tropical Storm Nate to hurricane status, and the addition of a short-lived, unnamed tropical storm that formed in early September between Bermuda and Nova Scotia. This unnamed storm, along with several other weak, short-lived named storms, could have gone undetected without modern satellite technology.

Irene was the lone hurricane to hit the United States in 2011, and the first one to do so since Ike struck southeast Texas in 2008. Irene was also the most significant tropical cyclone to strike the Northeast since Hurricane Bob in 1991.

“Irene broke the ‘hurricane amnesia’ that can develop when so much time lapses between landfalling storms,” said Jack Hayes, Ph.D., director of NOAA’s National Weather Service. “This season is a reminder that storms can hit any part of our coast and that all regions need to be prepared each and every season.”

As far as landfalling major hurricanes (Category 3, 4 or 5 with top winds of 111mph and greater) are concerned, the lull continues. 2011 marks a record six straight years without one hitting the United States. The last one to do so was Wilma in 2005. Nonetheless, wind is not the only threat with tropical systems as proven by Irene and Lee, which caused deadly and destructive flooding. On average, more than half of the fatalities related to tropical systems are due to flooding.

Hurricane Irene is an example of increasing accuracy in forecasting storm track. Its landfall in eastern North Carolina and path northward were accurately predicted more than four days in advance by NOAA’s National Hurricane Center using information from weather satellites, hurricane models, aircraft observations, and other data. NOAA’s delivery of critical environmental forecasts provided essential advance information that allowed emergency officials to plan necessary evacuations and sparked individuals to take safety precautions. But a weaker-than-anticipated Irene at landfall also highlighted the challenges that remain in forecasting storm intensity.

“Improving intensity forecasts is a focus of ongoing research and is part of NOAA’s Hurricane Forecast Improvement Project,” said Frank Marks, Ph.D., director of NOAA’s Hurricane Research Division. HFIP bridges research and operational components to better anticipate rapid changes in storm intensity and its goal to extend track forecasts from the current five days to seven days.

“Although the 2011 hurricane season has ended, our need to prepare for disasters hasn't,” said Craig Fugate, administrator of the Federal Emergency Management Agency. “Being prepared for all kinds of hazards, from hurricanes to blizzards to tornadoes, is a year-round activity. We encourage all members of the team, especially the public, to continue to prepare for emergencies by staying informed of forecasted weather events, making an emergency plan, and building your emergency preparedness kit. Visit Ready.gov to learn more.”

NOAA will issue its initial outlook for the 2012 hurricane season in May just prior to the official start of the season on June 1.

NOAA's National Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories. NOAA’s National Weather Service operates the most advanced weather and flood warning and forecast system in the world, helping to save lives and livelihoods and enhance the national economy. Working with partners, NOAA’s National Weather Service is building a Weather-Ready Nation to support community resilience in the face of increasing vulnerability to extreme weather. Visit us online at weather.gov and join us on Facebook, Twitter and our other social media channels.

NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Facebook, Twitter and our other social media channels.

[bg1]

Good to know the 2011 season did something worthwhile... uh... wait, we had a season?... What are we talking about again?

[CrazyC83]

Tell that to the millions of people hit hard by Irene...

[bg1]

I meant it increased hurricane awareness, even if it did have to cause billions of dollars in damage. At least maybe the next time a hurricane threatens, more people will be prepared. Sorry.

[Hurricanehink]

The article also confirmed that unnamed storm in September.

[CrazyC83]

The article also confirmed that unnamed storm in September.

Yep we just need pressure and wind and phase estimates, we can only use 94L estimates right now.

[Hurricaneman]

People should know of the dangers even if its been decades since the last one, because you never know when one is going to hit, and in this case its the first hurricane in 20 years to hit that region

[Ptarmigan]

Tell that to the millions of people hit hard by Irene...

Irene was quite a nasty storm for the East Coast. Likely worse than Floyd in 1999.

[CrazyC83]

Tell that to the millions of people hit hard by Irene...

Irene was quite a nasty storm for the East Coast. Likely worse than Floyd in 1999.

In terms of number of people affected, it couldn't be much worse. In terms of intensity, it could have been, but it would have been a much smaller storm (think Carol).

[Crostorm]

[youtube]http://www.youtube.com/watch?v=fX7Q-0QuID4[/youtube]

[DIwestender]

That is a great video! Thanks for posting it.

[islandgirl45]

Kinda surprised the article doesn't mention the subtropical storm or whatever it was that formed off the coast of Florida in October and came ashore in Central Florida. You can see it on the animation, though.

[brunota2003]

The system that hit Florida in October is not being upgraded per the NHC Facebook Page:

NOAA NWS National Hurricane Center - That was a fascinating system for a variety of reasons. It had a number of characteristics of named storms, and we considered adding that one also, but decided in the end that it didn't meet the technical criteria to qualify either as a tropical or subtropical cyclone. So that one is not going to be added to the list.

NOAA NWS National Hurricane Center - Here are NHC's working definitions that were applied:

Tropical Cyclone - A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere. In this they differ from extratropical cyclones, which derive their energy from horizontal temperature contrasts in the atmosphere (baroclinic effects).

Subtropical Cyclone - A non-frontal low-pressure system that has characteristics of both tropical and extratropical cyclones. Like tropical cyclones, they are non-frontal, synoptic-scale cyclones that originate over tropical or subtropical waters, and have a closed surface wind circulation about a well-defined center. In addition, they have organized moderate to deep convection, but lack a central dense overcast. Unlike tropical cyclones, subtropical cyclones derive a significant proportion of their energy from baroclinic sources, and are generally cold-core in the upper troposphere, often being associated with an upper-level low or trough. In comparison to tropical cyclones, these systems generally have a radius of maximum winds occurring relatively far from the center (usually greater than 60 n mi), and generally have a less symmetric wind field and distribution of convection.

The October cyclone was difficult to classify, consisting of a small area of very strong (~50 kt sustained) winds embedded within a much broader environment of low pressure that was itself producing gale/tropical-storm-force winds, at least early on. The inner system possessed some of the essential characteristics of a tropical storm: it had sustained winds in excess of 34 kt, it had a well-defined center of circulation, it had a warm core, at least in the lower troposphere, and the low center itself did not lie along any frontal boundaries, at least at the time the center moved onshore. In particular, the strength, distribution, and impacts of the winds near the center of this system were indistinguishable from many other small tropical storms.

Other attributes of the system, however, argued against its classification as a tropical storm. The system's convection near the core was intermittent and of short duration, and was considered too transient to satisfy the definition's organized deep convection requirement. The transient nature of the strong inner core circulation itself also cast doubt as to whether it could be considered of synoptic scale. The vertical extent of the cyclonic circulation was limited to below about 12,000 ft, very uncharacteristic of a tropical cyclone of this strength.

We also considered whether the system should be classified as a subtropical cyclone. There were clearly mixed characteristics of extratropical and tropical cyclones present, including the presence nearby of an upper-level cold low, and the large-scale distribution of winds and convection. However, there was enough air mass contrast associated with the system to raise doubts as to whether it was truly non-frontal. The very small radius of maximum winds and occasional convection very near the center also made the system difficult to classify as a subtropical cyclone.

Nature does not always cooperate with the classification systems designed by man. There is a continuum of cyclone types in the real atmosphere, and it is often difficult to place these systems into the small number of bins that meteorologists have created for them. The 9-10 October Florida system is certainly one of these difficult cyclones. NHC’s historical record, however, requires its members to belong to either the “tropical” or “subtropical” bins, and our view in this case is that neither applies. It is simply “something else”.
November 24 at 11:20am · Like · 8

[tolakram]

Great explanation, especially

Nature does not always cooperate with the classification systems designed by man.

[islandgirl45]

The system that hit Florida in October is not being upgraded per the NHC Facebook Page:

NOAA NWS National Hurricane Center - That was a fascinating system for a variety of reasons. It had a number of characteristics of named storms, and we considered adding that one also, but decided in the end that it didn't meet the technical criteria to qualify either as a tropical or subtropical cyclone. So that one is not going to be added to the list.

NOAA NWS National Hurricane Center - Here are NHC's working definitions that were applied:

Tropical Cyclone - A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere. In this they differ from extratropical cyclones, which derive their energy from horizontal temperature contrasts in the atmosphere (baroclinic effects).

Subtropical Cyclone - A non-frontal low-pressure system that has characteristics of both tropical and extratropical cyclones. Like tropical cyclones, they are non-frontal, synoptic-scale cyclones that originate over tropical or subtropical waters, and have a closed surface wind circulation about a well-defined center. In addition, they have organized moderate to deep convection, but lack a central dense overcast. Unlike tropical cyclones, subtropical cyclones derive a significant proportion of their energy from baroclinic sources, and are generally cold-core in the upper troposphere, often being associated with an upper-level low or trough. In comparison to tropical cyclones, these systems generally have a radius of maximum winds occurring relatively far from the center (usually greater than 60 n mi), and generally have a less symmetric wind field and distribution of convection.

The October cyclone was difficult to classify, consisting of a small area of very strong (~50 kt sustained) winds embedded within a much broader environment of low pressure that was itself producing gale/tropical-storm-force winds, at least early on. The inner system possessed some of the essential characteristics of a tropical storm: it had sustained winds in excess of 34 kt, it had a well-defined center of circulation, it had a warm core, at least in the lower troposphere, and the low center itself did not lie along any frontal boundaries, at least at the time the center moved onshore. In particular, the strength, distribution, and impacts of the winds near the center of this system were indistinguishable from many other small tropical storms.

Other attributes of the system, however, argued against its classification as a tropical storm. The system's convection near the core was intermittent and of short duration, and was considered too transient to satisfy the definition's organized deep convection requirement. The transient nature of the strong inner core circulation itself also cast doubt as to whether it could be considered of synoptic scale. The vertical extent of the cyclonic circulation was limited to below about 12,000 ft, very uncharacteristic of a tropical cyclone of this strength.

We also considered whether the system should be classified as a subtropical cyclone. There were clearly mixed characteristics of extratropical and tropical cyclones present, including the presence nearby of an upper-level cold low, and the large-scale distribution of winds and convection. However, there was enough air mass contrast associated with the system to raise doubts as to whether it was truly non-frontal. The very small radius of maximum winds and occasional convection very near the center also made the system difficult to classify as a subtropical cyclone.

Nature does not always cooperate with the classification systems designed by man. There is a continuum of cyclone types in the real atmosphere, and it is often difficult to place these systems into the small number of bins that meteorologists have created for them. The 9-10 October Florida system is certainly one of these difficult cyclones. NHC’s historical record, however, requires its members to belong to either the “tropical” or “subtropical” bins, and our view in this case is that neither applies. It is simply “something else”.
November 24 at 11:20am · Like · 8

Thanks for posting that info. So, it was an Unidentified Spinning Object storm!

[hurricanetrack]

A "something else" watch. We can add this to the list of stuff we keep up with next season....

[CrazyC83]

When do the first 2012 forecasts come out?

I have a hunch that El Nino might be brewing in the next year...

[Hurricane Jed]

When do the first 2012 forecasts come out?

I have a hunch that El Nino might be brewing in the next year...

I feel the same way. Plus I read somewhere that strong El Nino's occur every 10-15 years and its been about that time frame since the last strong one in 97-98. So maybe we could see a strong El Nino in 2012 or 2013?