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version 4.11
June 1, 2018

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Table of Contents

INTRODUCTION

A : BASIC DEFINITIONS

• A1) What is a hurricane, typhoon, or tropical cyclone?


• A2) What is "Cape Verde" hurricane?


• A3) What is a super-typhoon? What is a major hurricane ? What is an intense hurricane ?


• A4) What is an easterly wave and what causes them?


• A5) What is a tropical disturbance, tropical depression, tropical storm?


• A6) What is a sub-tropical cyclone?


• A7) What is an extratropical cyclone ?


• A8) What is storm surge and how is it different from storm tide ?


• A9) What is a "CDO" ?


• A10) What is a TUTT ?


• A11) What is the "eye" ? How is it formed and maintained ? What is the "eyewall" ? What are "spiral bands" ?


• A12) What is a moat in a hurricane ?


• A13) What is UTC, GMT, Z, or Zulu Time ? How do I tell at what time a satellite picture was taken ?


• A14) How do I convert from mph to knots (or m/s), from inches of mercury to millibars (or hPa), or from degrees of latitude to miles (or kilometers) ?


• A15) How do tropical cyclones form ?


• A16) Why do tropical cyclones require at least 80°F ocean temperatures to form ?


• A17) What is the Saharan Air Layer (SAL) ? How does it affect tropical cyclones ?


• A18) What is a neutercane ?


• A19) What does ATCF stand for and how are tropical cyclones numbered?


• A20) What does AL90, AL91, or 92L refer to in the tropical discussions?


• A21) What is a "post-tropical cyclone", "remnant low", or "potential tropical cyclone"?Revised

B : TROPICAL CYCLONE NAMES

• B1) How and why are tropical cyclones named? Revised


• B2) What are the upcoming tropical cyclone names ? Revised


• B3) What storm names have been retired? Revised


• B4) What is the origin of the word 'hurricane' ?


• B5) What happens to the name of a tropical cyclone if it moves from the Atlantic regions to the Northeast Pacific, or vice versa?


• B6)What happens if they run out of names on the list ?


• B7)How can I nominate a new name for the list ?

C : TROPICAL CYCLONE MODIFICATION AND MYTHS

• C1) Doesn't the low pressure in the tropical cyclone center cause the storm surge?


• C2) Doesn't the friction over land kill tropical cyclones?


• C3) Aren't big tropical cyclones also intense tropical cyclones?


• C4) Has there ever been an attempt or experiment to reduce the strength of a hurricane ?


• C5) Why don't we try to destroy tropical cyclones by: (pick one or more)
  1. seeding them with silver iodide ?
     
  2. placing a substance on the ocean surface ?
     
  3. nuking them ?
     
  4. adding water absorbing substances ?
     
  5. cooling the surface waters with icebergs or deep ocean water?
     
  6. harnessing their energy ?
     
  7. altering their heat balance using high altitude particles ?
     
  8. seeding them with hygroscopic particles ?
     
  9. other means ?
     
• C6) During a hurricane are you supposed to have the windows and doors on the storm side closed and the windows and doors on the lee side open ?


• C7) Should I tape my windows when a hurricane threatens?


• C8) How will a hurricane be affected by an oil slick? How will an oil slick be affected by a hurricane?

D : TROPICAL CYCLONE WINDS AND ENERGY

• D1) How are Atlantic hurricanes ranked?


• D2) How are Australian tropical cyclones ranked?


• D3) Why do tropical cyclones' winds rotate counter-clockwise (clockwise) in the Northern (Southern) Hemisphere?


• D4) What does "maximum sustained wind" mean ? How does it relate to gusts in tropical cyclones ?


• D5) How does the damage that hurricanes cause increase as a function of wind speed?


• D6) Why are the strongest winds in a hurricane typically on the right side of the storm?


• D7) How much energy does a hurricane release?


• D8) What are "concentric eyewall cycles" (or "eyewall replacement cycles") and why do they cause a hurricane's maximum winds to weaken ?


• D9) What causes each hurricane to have a different maximum wind speed for that given minimum sea-level pressure?


• D10) Why do hurricane force winds start at 64 knots ?

E : TROPICAL CYCLONE RECORDS

• E1) Which is the most intense tropical cyclone on record?


• E2) Which tropical cyclone intensified the fastest?


• E3) Which tropical cyclone has produced the highest storm surge?


• E4) What are the largest rainfalls associated with tropical cyclones?


• E5) Which are the largest and smallest tropical cyclones on record?


• E6) Which tropical cyclone lasted the longest?


• E7) What is the farthest a tropical cyclone has traveled?


• E8) What tropical cyclones have been at Category Five the longest?


• E9) Which tropical cyclones have caused the most deaths and most damage?


• E10) What are the average, most, and least tropical cyclones occurring in each basin?


• E11) How many tropical cyclones have there been each year in the Atlantic basin? What years were the greatest and fewest seen? Revised


• E12) What have been the deadliest tropical cyclones in the United States?


• E13) What have been the costliest tropical cyclones in the United States?


• E14) What have been the most intense hurricanes to strike the United States?


• E15) What tropical storms and hurricanes have moved from the Atlantic to the Northeast Pacific or vice versa?


• E16) When did the earliest and latest hurricanes occur?


• E17) How many hurricanes have there been in each month?Revised


• E18) What was the largest number of hurricanes in the Atlantic Ocean at the same time?


• E19) How many direct hits by hurricanes of various categories have affected each state?Revised


• E20) When are major hurricanes likely to strike each state?


• E21) What is the total United States damage (before and after adjustment for inflation) and death toll for each year since 1900?


• E22) What tracks did the continental U.S. major hurricanes take by decade?


• E23) What is the complete list of continental U.S. landfalling hurricanes?Revised


• E24) How long has it been since a hurricane or a major hurricane hit a given community in the United States?Revised


• E25) Which countries have had the most tropical cyclones hits?


• E26) How vulnerable is my coast to storm surge?

F : TROPICAL CYCLONE FORECASTING

• F1) What regions around the globe have tropical cyclones and who is responsible for forecasting there?


• F2) What are those track and intensity models that the Atlantic forecasters are talking about in the hurricane and tropical storm Discussions?


• F3) What are the various forecasts that are being issued for seasonal tropical cyclone activity around the world ?


• F4) What is the official U.S. Government (NOAA) seasonal hurricane outlook for the Atlantic basin for this year and what are the predictive factors ?


• F5) How has the official U.S. Government (NOAA) seasonal hurricane outlook done in previous years ?


• F6) How accurate are the forecasts from the National Hurricane ?


• F7) How is storm surge forecast ?


• F8) How is storm surge observed and measured?

G : TROPICAL CYCLONE CLIMATOLOGY

• G1) When is hurricane season?


• G2) How does El Niño-Southern Oscillation affect tropical cyclone activity around the globe?


• G3) How might global warming change hurricane intensity, frequency, and rainfall?


• G4) Why do tropical cyclones occur primarily in the summer and autumn?


• G5) What determines the movement of tropical cyclones?


• G6) Why doesn't the South Atlantic Ocean experience tropical cyclones?


• G7) Does an active June and July mean the rest of the season will be busy too?


• G8) Why do hurricanes hit the East coast of the U.S., but never the West coast?


• G9) How much lightning occurs in tropical cyclones?


• G10) What is the 20th century hurricane record for each U.S. coastal county?


• G11) What is my chance of being struck by a tropical storm or hurricane?


• G12) What is my chance of having a tropical storm or hurricane strike by each month?


• G13) What is the average number of tropical storms and hurricanes to affect my town?


• G14)What is the peak number of tropical storms and hurricanes to affect my town?


• G15)I'm vacationing in the Caribbean/the Bahamas/Central America/Miami or elsewhere in the tropics during hurricane season. What's my chance of getting hit by a hurricane ?


• G16)What is the average forward speed of a hurricane ?

H : TROPICAL CYCLONE OBSERVATION

• H1) What is the Dvorak technique and how is it used?


• H2) Who are the "Hurricane Hunters" and what are they looking for?


• H3) What is it like to fly into a hurricane?


• H4) Can I get a seat on a hurricane flight?


• H5) What's it like to go through a hurricane on the ground ? What are the early warning signs of an approaching tropical cyclone ?


• H6) Are there hurricanes on other planets ?


• H7) How does the ocean respond to a hurricane and how does this feedback to the storm itself?

I : REAL TIME INFORMATION

• I1) Where can I get real-time advisories for tropical cyclones?


• I2) Where can I get real-time tropical weather analyses?Revised


• I3) Where can I get real-time ship and buoy data?


• I4) Where can I get real-time sea surface temperature data?


• I5) Where can I get real-time satellite pictures and satellite products?


• I6) Where can I get real-time radar data?


• I7) Where can I get real-time hurricane aircraft reconnaissance data?


• I8) Where can I get real-time forecasts of tropical cyclone motion?


• I9) What computer software is available for tracking tropical cyclones?


• I10) How can I get hurricane information when I'm not at my computer ?Revised

J : HISTORICAL INFORMATION

• J1) Where can I get historical data on tropical cyclones ?Revised


• J2) What journals have regular articles on tropical cyclones ?


• J3) What books have been written about tropical cyclones ?


• J4) What fictional books,plays, poems, and movies have been written involving tropical cyclones ?


• J5) What refereed articles were written in recent years on tropical cyclones ?


• J6) What are some important dates in the history of hurricanes and hurricane research ?

K : HURRICANE PREPARATION

• K1) What steps should I take when a hurricane watch/warning is posted?


• K2) What can I do to make my home/business more disaster resistant?


• K3) What kind of hurricane shutters are available ?

L : HURRICANES versus TORNADOES

• L1) How are tropical cyclones different from tornadoes?


• L2) Why do tropical cyclones spawn tornadoes?


• L3) What percentage of tropical cyclones spawn tornadoes?


• L4 What parts of a tropical cyclone are most favored for tornado formation?


• L5) How long after landfall are TC tornadoes a threat?


• L6) Are TC tornadoes weaker than midlatitude tornadoes?


• L7) What is the largest known outbreak of TC tornadoes?


• L8) What is the deadliest single TC-spawned tornado?


• L9) What is the most damaging single TC-spawned tornado?


• L10) Why are TC tornadoes especially difficult to deal with?


• L11) Which states are most vulnerable to TC tornadoes outbreaks?


• L12) What about Florida ? They get the most hurricane strikes; do they also get a lot of TC tornadoes ?


• L13) How does the damage from hurricanes compare to tornadoes ?

Introduction
This FAQ (Frequently Asked Questions) web site attempts to address various questions regarding hurricanes, typhoons and tropical cyclones that have been posed to us as hurricane researchers over the years. While it is not intended to be a technical guide, references are given throughout the FAQ for those that would like additional, detailed information. Also, there is no guarantee that all that is in here is completely accurate (we're human!). If you do see an item that needs correction, or if you have any additional questions that you think should be added to this FAQ, please contact us directly.

Hopefully, this FAQ site can help answer some of the questions that you may have about the characteristics of these catastrophic storms, how they are monitored and forecasted, and what are some of research topics that are being addressed today.

We'd like to thank various people for helping to put together this FAQ: Sim Aberson, Jack Beven, Gary Padgett, Tom Berg, Julian Heming, Gary Gray, Frank Woodcock, Stephen Caparotta, Steven Young, D. Walston, James Lewis Free, Jon Gill, Miles Lawrence, Robert A. Black, Bill McCaul, Bart Hagemeyer, Frank Marks, Joe Cione, Frank Lepore, and John Guiney, all provided substantial bits to this FAQ. Many thanks also to Jan Null for providing the first .html version of the FAQ.

For the Spanish language version:
The first version of the Spanish translation was written by Ada Monzon. The current version was provided by Todd Kimberlain, Gladys Rubio, and Felix Garcia of NHC, the Modern Language and Meteorology departments of FIU, and (for section A) personnel at the University of Puerto Rico. Thank you all.

Chris Landsea (NHC)

Neal Dorst webmaster
Erica Rule outreach coordinator and main contact

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