ZCZC PWMWRKPWM DEF TTAA00 KPWM DDHHMM MEZ007>009-012>014-018>022-023>028-NHZ001>010-013-014-051200 PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE GRAY ME 700 AM EDT THU MAY 04 2006 The National Weather Service has declared the week of May 1st through May 5th, SEVERE WEATHER AWARENESS WEEK in New England. This is the fourth in a series of five Public Information Statements on various topics related to severe weather awareness. ...SEVERE WEATHER AWARENESS - TORNADOES... Tornadoes are nature's most violent storm. By definition, a tornado is a violently rotating column of air that extends from the base of the thunderstorm cloud to the ground. In addition to the three basic ingredients needed for the formation of thunderstorms and severe thunderstorms (low-level moisture, an unstable atmosphere, and a source of lift), winds at various levels in the atmosphere also factor into the development of tornadoes. Usually, prior to the development of a tornado, a pre-tornadic thunderstorm develops a circulation, that is, it starts rotating (a meso-cyclone). As this rotation becomes stronger, the chance that a tornado may develop also increases. Although the National Weather Service's Doppler RADAR generally can not see the actual tornado, the RADAR does detect rotation of the thunderstorm cloud, and thereby gives some indication of the likelihood that a tornado is forming or has formed. The scale used to measure tornado damage is the Fujita scale (named after Theodore Fujita, a famous tornado damage expert). This scale is commonly referred to as the F scale. F0 - Light damage (winds 40 to 72 mph) F1 - Moderate damage (winds 73 to 112 mph) F2 - Considerable damage (winds 113 to 157 mph) F3 - Severe damage (winds 158 to 206 mph) F4 - Devastating damage (winds 207 to 260 mph) F5 - Incredible damage (winds 261 to 318 mph) Peak tornado activity in northern New England occurs between June and August, but tornadoes have occurred as early as May and as late as November (as was seen in 2005). Most tornadoes occur between 3 and 9 pm and have an average forward speed of about 30 mph. For the 40 year period between 1950 and 1990, 74 tornadoes occurred in Maine while 68 tornadoes occurred in New Hampshire. Based on these data, each state averages about two tornadoes per year. During this period, the average path length of the tornadoes was 1.08 miles for Maine and 1.64 miles for New Hampshire. The strongest tornado observed in Maine was an F2, while the strongest tornado observed in New Hampshire was an F3. Last year in Maine, a weak tornado (F0) touched down on North Twin lake in Penobscot County on August 1st, and two tornadoes/waterspouts touched down on Thanksgiving Day in (F0 in Brunswick and F1 in Phippsburg). In New Hampshire, there were no confirmed tornadoes during 2005. Here are some of ther tornadoes reported in Maine and New Hampshire since 1995. F2 Jul 08 1996 Cobbosseecontee Lake, Maine Jul 03 1997 Greenfield, New Hampshire May 31 1998 Antrim, New Hampshire Jul 06 1999 Pittsfield/Barnstead/Strafford, New Hampshire Aug 09 2000 Cornville, Maine F1 Jul 23 1995 New Hampton, New Hampshire Jun 21 1997 Rome, Maine Jul 03 1997 Swanzey, New Hampshire Oct 01 1998 South Paris, Maine Aug 13 1999 Sweden, Maine Aug 13 1999 Plainfield/Enfield, New Hampshire Jul 18 2000 Newry/Hanover, Maine Jun 17 2001 Newry/Hanover, Maine Jul 24 2001 Penobscot County (16 miles nortwest of Patten) Jul 24 2001 Oakfield, Maine May 31 2002 West Paris, Maine Jul 04 2002 Aroostook County (8 miles west of Littleton) Nov 24 2005 Phippsburg, Maine F0 Jul 28 1997 Ft. Kent, Maine Aug 27 1997 Charleston, Maine Jul 23 2002 Aroostook County (7 miles northwest of Knowles Corner) Aug 08 2004 Sebago Lake, Maine Aug 13 2004 Sanbornto/Meredith, New Hampshire Aug 01 2005 North Twin Lake, Maine Nov 24 2005 Brunswick, Maine To alert the public to the threat of tornadoes, the National Weather Service issues TORNADO WATCHES and WARNINGS. A TORNADO WATCH indicates that atmospheric conditions are favorable for the development of tornadoes. A TORNADO WARNING indicates that a tornado is imminent or is already occurring. If you hear that a TORNADO WARNING has been issued for your area, seek safe shelter immediately if you are in the path of the storm. Due to the short life-span of tornadoes in northern New England, there is often little, if any, advance warning. Tornadoes in New England touch down and then lift off the ground very quickly. Many of the tornadoes that have occurred in the past, have occurred while severe thunderstorm warnings have been in effect. If you hear that a severe thunderstorm warning is in effect for your area, be alert for the possibility of a tornado. A low rotating cloud, large hail, and/or a load roar are all signs that may precede the touchdown of a tornado. Here are some tornado facts and safety tips. * Flying debris causes most deaths and injuries in tornadoes * The safest place in your home during a tornado is your basement. * Stay away from windows. * Get out of vehicles and mobile homes, they offer little protection. Lie flat in a nearby ditch or depression. * Do NOT seek shelter under a bridge overpass. Bridge overpasses offer little, if any, protection from wind-driven debris. Here is a list of the remaining topics that will be covered in Public Information Statements issued by the National Weather Service this week. Friday......Flash Floods $$ Jensenius National Weather Service Gray, Maine NNNN