By: Mike Vuotto and Jake Mulholland Tropical Meteorology By: Mike Vuotto and Jake Mulholland

First: Where does tropical weather happen? - Tropics -Occur in the southern most region of the United States (i.e. the Caribbean, Atlantic Pacific and Indian Oceans) -Most tropical events occur down in the ITCZ ( Inter- tropical Convergence Zone)- located in the Eastern Pacific off of the South America and Mexico coastlines. -Occur from the 2 3 ½ ˚ latitude north line down to the equator to the 23 ½ ˚ latitude line south of the equator.

Inter-tropical Convergence Zone

First stage- Tropical Wave -Tropical waves (weak trough of low pressure) are migratory wavelike disturbances in the tropical easterlies. These can intensify into tropical cyclones and Hurricanes. -First to start to develop a circulation center and then produce heavy rains and thunderstorms in a more confined and organized manner. -These storms generally move anywhere between 10 and 20 knots- and the next phase is called a Tropical Depression

Picture of a tropical wave

Second Stage- Tropical Depression -A tropical depression is a mass of thunderstorms and clouds generally with a cyclonic wind circulation on the order of 25- 39 mph or (20-34 knots). - When a tropical disturbance gets to this point then a projected path (or cone of uncertainty) will be issued to track the system especially if it shows signs of more organization. - If a storm continues to get better organized and the circulation center gets even tighter- you then have a tropical storm which then warrants a name.

Third Stage- Tropical Storm -When a storm reaches this intensity the winds are anywhere from 39 mph- 74 mph or (35-64 knots). A tropical storm has organized thunderstorms with a cyclonic circulation to it but is more defined than a depression. Pressure in a tropical storm is usually around 980 to 1000mb. Key point- As pressure drops the winds in the system intensify and get stronger. -Trade wind inversion- sinking air around 20˚N which causes air to warm creating an inversion. - Hurricane

Tropical storm Chantal -Storm lifetime period- July 8-10 -Formed in the Atlantic -Peak intensity of 65 mph winds -1005 mb

Tropical storm Dorian -Formed in the Atlantic -July 24- August 3 -Peak intensity- 60 mph -999 mb

Last Stage: Hurricane -A Hurricane is a tropical cyclone having winds anywhere in excess of 74 mph which can create major destruction and hazards if one were to make landfall. A tropical storm is called a hurricane when the winds reach 75mph or (64 knots). -In order for a mass of unorganized storms to develop into a hurricane; surface winds must converge. -Trade wind inversion- sinking air around 20˚N which causes air to warm creating an inversion. -Form where the winds are light, humidity is high in a very deep layer of the troposphere which is the air we live and breathe in. -These storms develop over very warm Atlantic or Pacific waters of temperatures 80˚F or warmer. -Have very low wind shear in the upper level environment - There are many factors that describe the anatomy of a hurricane.

Typical Sounding of a Hurricane

Hurricane Katrina Hurricane Katrina as a Category 5

Video of a hurricane developing from a tropical wave http://www.youtube.com/watch?v=IYNgD5qguLY

Anatomy of a Hurricane - Eye Wall- area of the hurricane with extremely strong winds and rainfall; usually located in the right-front quadrant of the storm. This area produces usually the most damage inside a hurricane as well as the most storm surge. Eye- normally forms with hurricanes of intense strength with winds over 100mph.

Hurricane Charley- (2004)

Hurricane Structure

Structure (cont.)

Hurricane Michael- September 8, 2012 Eye Wall- area of strongest winds . Eye Lungs to breathe- outflow channels

Differences between a Mid-Latitude Cyclone and a Hurricane Hurricanes Mid- Latitude Cyclones -Warm Cored -Weakens with height -Upper-level high over storm -Contours eye with sinking air -No FRONTS!!!! -cold-cored -strengthens with height -upper-level low or trough above the storm -center has rising air -has fronts

Saffir-Simpson Scale -It has five categories: -Category 1 – the weakest a hurricane can be dropping back to tropical storm status. Must have winds in excess of 74mph and no greater than 95 mph. -Category 2- next stage above cat 1- must have winds in excess of 96 mph and less than 110 mph. -Category 3-MAJOR- must have winds in excess of 111 mph and less than 131 mph. -Category 4- MAJOR- must have winds in excess of 132 mph and than 135 mph. Category 5- MAJOR- the strongest a hurricane can become and the most devastating a hurricane can be- must have winds in excess of 155 mph.

Quiz time!!!!  The area off of the Mexico coast is called this?? Where do most tropical systems occur? What is a tropical wave called coming off Africa when the thunderstorms begin to become better organized or organize into a row of thunderstorms?? What is the first stage for tropical development, 2nd stage, 3rd stage and 4th stage?? When a tropical entity declared a hurricane? In other words what are the winds?? What are the characteristics for these storms to develop, form or thrive?? (Hint: there are 4 of them) What is the center of a hurricane called??? What is the area with the strongest winds called in a hurricane that revolve around the center?? What are the five categories of the Saffir-Simpson scale with the winds for each category??