NEWSLETTER June 2007  |
 issue of the WEATHERFUN Newsletter |
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| Welcome to the Weatherfun June issue of the Weatherfun Newsletter. First, I would like to thank Bill for filling in for me last month, while I had my family problems. We are very slowly getting back to normal at this end. Well, as you know June 1st has come and gone and two events just began. The first of course is the beginning of the 2007 hurricane season. Yes, the hurricane season opens June 1st and goes to the end of November. Already we have T. S Barry that is kicking up in the Florida area and giving them some much needed rain. It will then move up the coast and bring again some much needed rain to my area of the northeast. Just as long as the storms stay like this it would be a mild hurricane season, but as you all know that will not happen. They are expecting an average to above average hurricane season this year. They even have one named Jerry. Now that is one to watch out for. The next thing on June 1st is the beginning of summer. Yes, I know what the calendar says, but we are a weather group and meteorologically speaking summer begins on June 1st. So, I wish the best of summer and hope that the weather is just what you ordered. In my case that would be nice warm temps and clear days. The next big thing I would like to talk about is the 2007 Weatherfun Family Reunion. As I type this we are finalizing our plans for this year's reunion. You already have the important information about the motel, rates and location. This year looks like it very well could be the most attended reunion of all of our past reunions. Yes, we could very well have the most people attending this year's reunion from all parts of our great nations. As you know the dates are July 12th to the 15th. Some members will be coming up a little early to relax and enjoy some of the area of South Eastern New England. If you have not made your plans to attend why not do it now and beat the dead line of June 12th for your room reservations. A great weekend of weather stories, visiting special areas, family fun, games, Professor's Bill's famous weather quiz with real weather related prizes, good food but above all good friendship. As I have said in the past you really do not know what a great group we have here on Weatherfun until you attend a Weatherfun Family Reunion. Then you really know what a great group we have. Again this year we will be keeping those who will not be attending the reunion up to date on what is going on at the reunion. I will have my laptop with me as other members will, and we will be sending out daily reports and also pictures. But, please try to attend this year's reunion. Yes, we do guarantee you a great time. Remember folks, this is your newsletter and if you would like to see a weather related article in the next issue why not send it to Bill or me and we will see to it that it is included in the next issue. Until next month's newsletter, enjoy your summer, and I hope that the weather is a perfect Jerry 12 in your area of this great nation. See you all at the reunion. JERRY LAROCHE |
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Hyannis, Massachusetts |
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HURRICANE DEVELOPMENT There are six widely accepted conditions for hurricane development. The first condition is that ocean waters must be above 26 degrees Celsius (79 degrees Fahrenheit). Below this threshold temperature, hurricanes will not form or will weaken rapidly once they move over water below this threshold. Ocean temperatures in the tropical East Pacific and the tropical Atlantic routinely surpass this threshold. The second ingredient is distance from the equator. Without the spin of the earth and the resulting Corioles force, hurricanes would not form. Since the Corioles force is at a maximum at the poles and a minimum at the equator, hurricanes can not form within 5 degrees latitude of the equator. The Corioles force generates a counterclockwise spin to low pressure in the Northern Hemisphere and a clockwise spin to low pressure in the Southern Hemisphere. The third ingredient is that of a saturated lapse rate gradient near the center of rotation of the storm. A saturated lapse rate insures latent heat will be released at a maximum rate. Hurricanes are warm core storms. The heat hurricanes generate is from the condensation of water vapor as it convectively rises around the eye wall. The lapse rate must be unstable around the eyewall to insure rising parcels of air will continue to rise and condense water vapor. The fourth and one of the most important ingredients is that of a low vertical wind shear, especially in the upper level of the atmosphere. Wind shear is a change in wind speed with height. Strong upper level winds destroy the storms structure by displacing the warm temperatures above the eye and limiting the vertical accent of air parcels. Hurricanes will not form when the upper level winds are too strong. The fifth ingredient is high relative humidity values from the surface to the mid levels of the atmosphere. Dry air in the mid levels of the atmosphere impedes hurricane development in two ways. First, dry air causes evaporation of liquid water. Since evaporation is a cooling process, it reduces the warm core structure of the hurricane and limits vertical development of convection. Second, dry air in the mid levels can create what is known as a trade wind inversion. This inversion is similar to sinking air in a high pressure system. The trade wind inversion produces a layer of warm temperatures and dryness in the mid levels of the atmosphere due to the sinking and adiabatic warming of the mid level air. This inhibits deep convection and produces a stable lapse rate. The sixth ingredient is that of a tropical wave. Often hurricanes in the Atlantic begin as a thunderstorm complex that moves off the coast of Africa. It becomes what is known as a midtropospheric wave. If this wave encounters favorable conditions such as stated in the first five ingredients, it will amplify and evolve into a tropical storm or hurricane. Hurricanes in the East Pacific can develop by a midtropospheric wave or by what is known as a monsoonal trough. |
| We hope that you enjoyed this month's Newsletter. See you next month, and be sure to visit the WEATHERFUN Website but most of all have fun with your weather. |
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Jerry or Bill |
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