What is Hurricane: Definition and 69 Discussions

A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and/or squalls. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane (), typhoon (), tropical storm, cyclonic storm, tropical depression, or simply cyclone. A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean; in the south Pacific or Indian Ocean, comparable storms are referred to simply as "tropical cyclones" or "severe cyclonic storms".
"Tropical" refers to the geographical origin of these systems, which form almost exclusively over tropical seas. "Cyclone" refers to their winds moving in a circle, whirling round their central clear eye, with their winds blowing counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. The opposite direction of circulation is due to the Coriolis effect. Tropical cyclones typically form over large bodies of relatively warm water. They derive their energy through the evaporation of water from the ocean surface, which ultimately recondenses into clouds and rain when moist air rises and cools to saturation. This energy source differs from that of mid-latitude cyclonic storms, such as nor'easters and European windstorms, which are fueled primarily by horizontal temperature contrasts. Tropical cyclones are typically between 100 and 2,000 km (60 and 1,240 mi) in diameter. Every year tropical cyclones impact various regions of the globe including the Gulf Coast of North America, Australia, India and Bangladesh.
The strong rotating winds of a tropical cyclone are a result of the conservation of angular momentum imparted by the Earth's rotation as air flows inwards toward the axis of rotation. As a result, they rarely form within 5° of the equator. Tropical cyclones are almost unknown in the South Atlantic due to a consistently strong wind shear and a weak Intertropical Convergence Zone. Conversely, the African easterly jet and areas of atmospheric instability give rise to cyclones in the Atlantic Ocean and Caribbean Sea, while cyclones near Australia owe their genesis to the Asian monsoon and Western Pacific Warm Pool.
The primary energy source for these storms is warm ocean waters. These storms are therefore typically strongest when over or near water, and weaken quite rapidly over land. This causes coastal regions to be particularly vulnerable to tropical cyclones, compared to inland regions. Coastal damage may be caused by strong winds and rain, high waves (due to winds), storm surges (due to wind and severe pressure changes), and the potential of spawning tornadoes. Tropical cyclones draw in air from a large area and concentrate the water content of that air (from atmospheric moisture and moisture evaporated from water) into precipitation over a much smaller area. This replenishing of moisture-bearing air after rain may cause multi-hour or multi-day extremely heavy rain up to 40 kilometers (25 mi) from the coastline, far beyond the amount of water that the local atmosphere holds at any one time. This in turn can lead to river flooding, overland flooding, and a general overwhelming of local water control structures across a large area. Although their effects on human populations can be devastating, tropical cyclones may play a role in relieving drought conditions, though this claim is disputed. They also carry heat and energy away from the tropics and transport it towards temperate latitudes, which plays an important role in regulating global climate.

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  1. nsaspook

    CATEGORY 5 HURRICANE OTIS Acapulco, Mexico

    What happened to the forecasting on this one?
  2. nsaspook

    Get ready for Hurricane Hilary

    Tropical Update from the NHC in Miami, FL. (August 18, 2023)
  3. BWV

    Sailing drone video from inside cat 4 hurricane

    https://www.saildrone.com/press-release/ocean-drone-captures-video-inside-category-4-hurricane The Saildrone Explorer SD 1045 was directed into the midst of Hurricane Sam, which is currently on a path that fortunately will miss the US East Coast. SD 1045 is battling 50-foot waves and winds of...
  4. S

    Hurricane forces — Comparing the force from a 60 mph wind to a 120 mph wind

    The marker wrote that the answer is 4 and it's because m and v double. I don't understand how m doubles??
  5. .Scott

    The Peak Day of a Very Active Atlantic Hurricane Season

    I just took a peek at the NOAA Hurricane site: NOAA Atlantic Hurricane Site It's pretty crowded out there: 4 disturbances and 2 tropical storms. I have never seen so much activity. Here is a screen shot (from 9/11/2020): If there are more storms (and this is just the middle of the season)...
  6. G

    Change in Mass of Hurricane Harvey's Rain

    First I have to explain that this is not actually a homework problem. It is a problem I created to use in a sort of game. If I made a mistake, it tends to ball up the game. So I am looking for someone to double check my answer, and to point out any errors in my statement about physics. I prefer...
  7. X

    B NASA: Hurricane Anatomy - Understanding Angular Momentum & Air Motion

    Here is a NASA article on "Hurricane Anatomy" https://earthobservatory.nasa.gov/features/Hurricanes/hurricanes_2.php The first issue I have is the apparent reversal of the angular momentum when going from surface winds to the winds in the covering cloud cap. In the northern hemisphere, surface...
  8. CPW

    Hurricane Rotations: Physics Q&A on Cross-Equator Persistence

    Here's a question I want to ask a physicist: Is it possible for a hurricane in Earth's northern hemisphere to have sufficient linear momentum (directed South) to cross Earth's equator and still persist as a CCW-rotating hurricance but in the southern hemisphere? If so, for approximately how much...
  9. Spinnor

    Hurricane hunters spot 'stadium effect' inside Dorian's eye

    Hurricane hunters spot 'stadium effect' inside Dorian's eye amid 'extremely intense' storm, from, https://www.foxnews.com/us/hurricane-dorian-eye-hunters-stadium-effect-cyclone.amp?cmpid=prn_newsstand A collection of images and videos of the hurricane Dorian from...
  10. hagopbul

    Cloud chamber approach to stopping hurricanes

    mod note: positively no politics will be allowed Hello All: The current hot topic on the news is using nuclear weapons against hurricanes . But couldn't we use other approaches ,using some nuclear reactors mounted in a plane or balloon that emit calculated levels of radiation in the center of...
  11. Greg Bernhardt

    Hurricane Florence (and Michael) Reports

    Stay safe PFers in the area. We know there are many of you. Reports are the outer bands have just hit NC and there is already flooding. https://weather.com/
  12. Spinnor

    NASA’s new visualization of the 2017 hurricane season

    "How do you observe the invisible currents of the atmosphere? By studying the swirling, billowing loads of sand, sea salt and smoke that winds carry. A new simulation created by scientists at NASA’s Goddard Space Flight Center in Greenbelt, Md., reveals just how far around the globe such aerosol...
  13. A

    Why does bathwater in a plughole spin AT ALL

    I don't care whether it goes clockwise or anticlockwise so this is not the usual Coriolis conversation. Why doesn't it just go down straight?
  14. PhanthomJay

    News This Hurricane Jose is....?

    I find it interesting that most of the tropical forecast "Spaghetti" models put out by the NHC have Jose well out to sea as it tracks off the east coast of the US. But those models do not include the incredibly accurate ECMWF "European" model, which tracks the storm closer to the US east coast...
  15. S

    Online satellite views of hurricane Irma results?

    Is there a website that has online satellite views of locations recent enough to show results of hurricane Irma?
  16. MarkFL

    MHB Tracking Hurricane Irma: Potential US Impact in a Week

    From CNN: Powerful Hurricane Irma is rapidly intensifying in the open Atlantic and poses a major threat to the Caribbean and potentially to the United States next week. With the storm still five days away from the outermost Caribbean islands and at least a week away from any potential US...
  17. D

    News This hurricane Harvey/Irma is nuts

    This is a picture my buddy sent me. There is an interstate underneath all this water. Anyone in Texas, be safe!
  18. scottdave

    Science which goes into computing hurricane predictions

    With Hurricane Harvey hitting the Texas Gulf Coast, I came across this article, while trying to learn about these different computer models. I found the article in this PDF file an interesting read. I'm sure that there have been some advances in real-time prediction methods, since this article...
  19. MarkFL

    MHB Hurricane Harvey: Rapid Intensification, Expected to Make Landfall in 24 Hours

    Hurricane Harvey, rapidly intensifying in the Gulf of Mexico, is expected to make landfall in less than 24 hours near Corpus Christi, Texas. After hitting Corpus Christi, the storm is expected to stall over the state, forecasters say. The storm officially became a category 2 hurricane as of 1...
  20. jtbell

    News Hurricane Matthew evacuation

    It looks like Hurricane Matthew is going to run up the US east coast like a buzz-saw from Florida to South Carolina: http://www.bbc.com/news/world-us-canada-37571685 If you're curious about what a one-way expressway (motorway) looks like, check out the traffic cameras along route I-26 between...
  21. Feodalherren

    CFD LES: Simulating a Hurricane

    Hi, I'm doing research in CFD and I'm trying to do a LES of a hurricane. Problem is, I don't remember much about LES. I took a class in CFD about a year and a half ago and most of it is gone. I've read the wikipedia page on LES but I'd like to dive in deeper. Does anyone have any suggestions?
  22. A

    Hurricane reduction through ocean surface cooling

    Old article: http://edition.cnn.com/2009/TECH/science/08/28/hurricanes.gates.gray/ What do you guys think? Where do you see this project going? The official word is that it's not being publicly funded. But if there was even a 10% chance it would work, I see governments lining up at the...
  23. Astronuc

    Hurricane Patricia - October 22-24, 2015

    Why did Hurricane Patricia become a monster so quickly? http://news.yahoo.com/why-did-hurricane-patricia-become-monster-quickly-202419311.html [Broken] Patricia slams Mexico Pacific Coast as Category 5 hurricane...
  24. H

    Hurricane Pressure on a Roof: Exploring the Forces at Play

    Would the pressure on my skin, try to explode out, just like a hurricane and a roof, in which the high velocity over the roof causes low pressure ontop of the roof and high pressure beneath the roof?
  25. F

    Hurricane Fluid flow, torque, cross product

    Homework Statement In 1993 the radius of Hurricane Emily was about 350 km. The wind speed near the center ("eye") of the hurricane, whose radius was about 30 km, reached about 200 km/h. As air swirled in from the rim of the hurricane toward the eye, its angular momentum remained roughly...
  26. B

    Kinetic Energy of a Hurricane

    Homework Statement In a simple model of the wind speed associated with hurricane Emily, we assume there is calm eye 18.8 km in radius. The winds, which extend to a height of 4000 m, begin with a speed of 303.0 km/hr at the eye wall and decrease linearly with radial distance down to 0 km/hr at a...
  27. Mordred

    Saturn hurricane spotted by Cassini

    Current event Nasa satellite Cassini spotted a North pole locked hurricane 2000 km wide. http://theconversation.com/nasa-pics-reveal-huge-rose-hurricane-on-saturn-13823
  28. Newtons Apple

    After Hurricane Sandy A Question about Electricity

    Ok, I"m from New Jersey, and as you may have heard we've been hit pretty bad. ...After spending 3 days in the dark and cold... I've had some time to ponder. My question is a very basic one. I know that many phone lines and wires are put underground. That's why you see the Bell logo on many...
  29. V

    Protecting cruise ship in harbor against hurricane?

    Hi folks, Some people allegedly claim it is better to have a cruise ship out in the ocean rather than in harbor during a hurricane. I don't quite believe it however. I can imagine a cruise ship slamming against docks and getting damaged, but in the ocean it could easily overturn and sink...
  30. russ_watters

    Last Year a Snowstorm, This Year a Hurricane? Really?

    Last year, on the weekend before Halloween, we had about 8 inches of snow. Snow! On Halloween! This year, a hurricane (hurricane??!) is threatening to drive up the coast, hang a left through the barren wasteland and plow through southeastern Pennsylvania. Last year, I drove through the...
  31. C

    Better to stay outside the Hurricane or head inside the eye?

    Homework Statement Imagine the following. You and your best friend are at sea on your ship. Your ship is designed to withstand seas during 120 knot winds. You measure the winds outside your ship at 30 knots. From satellite images and Global Positioning System (GPS) data, you pinpoint your...
  32. C

    Hurricane Evacuation, how l long will it take to evacuate100 000 people?

    Homework Statement There is a single two ane road connecting the Keys with the mainland. The south- bound lane must remain open for emergency vehicles, so only one lane is available for evacuation. In summer, 100,000 residents live on the Keys. Past data taken on the bridge that connects...
  33. B

    My Personal Hurricane Barometer Watch: Anyone Want To Join?

    Observed at Providence, Rhode Island: 05:30 UTC 28 August 2011: 29.68"Hg 05:45 UTC 28 August 2011: 29.67"Hg 06:00 UTC 28 August 2011: 29.68"Hg 06:15 UTC 28 August 2011: 29.70"Hg 06:30 UTC 28 August 2011: 29.71"Hg 06:45 UTC 28 August 2011: 29.70"Hg 07:00 UTC 28 August 2011: 29.67"Hg 07:15...
  34. H

    Hurricane path projection and mathematics

    I imagine differential equations and statistics are used. What type of math is used to predict the path of hurricanes?
  35. B

    Could a hurricane or tornado have enough energy to create a worm hole

    Hello all, I am new here. I have a crazy question. Could a hurricane or tornado have enough energy to create a worm hole? Thanks Buster
  36. B

    Air pressure inside a hurricane

    Homework Statement Estimate the air pressure inside a category 5 hurricane, where the wind speed is 300 km/hr. Homework Equations P=F/A The Attempt at a Solution I converted km/hr to m/s. V=83.33m/s. That's all I can get. I don't know the area of a category 5 hurricane or the...
  37. K

    The force of a Hurricane on a person

    Homework Statement During a hurricane, winds can whip horizontally at speeds of 150 km/h. Given that the density of air is 1.20 kg/m3 and the wind after striking the person is brought to rest, calculate the force of the wind on the person. You may assume the person's area to be 1.50 m high...
  38. R

    Hurricane + Oil Spill = ?

    What would happen if a hurricane swept through the gulf over the area of the spill? How would the oil effect water temp., which contributes to hurricane strength? Would a hurricane pick-up and disperse the oil inland if it made land-fall?...or would a hurricane basically spread the oil out so...
  39. P

    Physics of Hurricane Balls

    Physics of "Hurricane Balls" Two ball bearings are welded together, placed on a mirror, and blown upon using a straw. The RPM's reportedly can reach 10,000 rpm's. There are numerous vid links, here's one: http://www.liveleak.com/view?i=d5c_1179564591 Anyway, I know this can also be done...
  40. X

    Hurricane wind blowing across a flat roof

    1.A hurricane wind blows across a 7.8 m x 12 m flat roof at a speed of 180 km/hr. What is the pressure difference? How much force is exerted on the roof? 2. Homework Equations P= p_atmos + pgd P=F/AThe Attempt at a Solution p = 101300Pa - (1.3)(9.8m/s^2)(93.6m^2) p = 100107.5Pa 100107.5Pa =...
  41. L

    Supersonic Jets Breaking Up Hurricanes: Possibilities

  42. H

    Hurricane size whirlpool on the Sun

    I wonder if the whirlpool that was recently discovered on the sun effects our weather on earth. http://space.newscientist.com/article/dn14878-hurricanesized-whirlpools-spotted-on-the-sun.html
  43. D

    Energy Released by Hurricane

    Is there a way the quantify the energy 'released' by a hurricane? Does the energy have a source so to speak?
  44. jtbell

    News Here comes Hurricane Gustav

    It's approaching the western end of Cuba as a category 4 hurricane already. It looks like it will hit the U.S. on Monday night or Tuesday morning. The mayor of New Orleans said today, "I am strongly, strongly encouraging everyone in this city to evacuate. Start the process now." From cnn.com...
  45. M

    Distance of Hurricane from Grand Bahama Island: 104 km

    Homework Statement The eye of a hurricane passes over Grand Bahama Island. It is moving in a direction 60.0° north of west with a speed of v1 = 37.0 km/h. Exactly three hours later, the course of the hurricane shifts due north, and its speed slows to v2 = 27.0 km/h, as shown in Figure 3-30...
  46. P

    Air pressure in hurricane

    Homework Statement Estimate the air pressure at the center of a hurricane with wind speed of 300 km/h at the center. Answer in Pa Homework Equations P + 1/2 (density)(velocity)^2 density of air 1.29 kg/m^3 The Attempt at a Solution P + 0.5 (1.29 kg/m^3)(90000) Pressure = 58050...
  47. Astronuc

    What is the chance of a major hurricane hitting the US Gulf Coast in 2007?

    Well, it doesn't officially start for another three weeks. But whereas the government moved up daylight savings time - Mother Nature got a jump on this year Atlantic storm season. The first named storm this year is - Andrea - which is only a subtropical storm at the moment. From the...
  48. N

    A Tree that a Hurricane Created

    Read more on how this "tree" was created here. Quite amazing!
  49. E

    How far is the hurricane from an island

    The eye of a hurricane passes over Grand Bahama Island. It is moving in a direction 60.0° north of west with a speed of 41.0km/h. Exactly 3 hours later, the course of the hurricane shifts due north, and its speed slows to 25.0km/h. How far from Grand Bahama is the hurricane 4.50 hours after it...
  50. R

    Will the 2006 North Atlantic Hurricane Season be as Active as Predicted?

    Since many of us have personal interest in tropical weather, including myself, I thought it might be helpful to have a thread to keep up with it before it happens. Especially since this season is forecasted to be "very active" (NOAA) in the N. Atlantic. :frown: I think my main objective with...