ZCZC PWMWRKPWM DEF TTAA00 KPWM DDHHMM MEZ007>009-012>014-018>022-023>028-NHZ001>010-013-014-061200 PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE GRAY ME 700 AM EDT THU MAY 05 2011 The National Weather Service has declared the week of May 2nd through May 6th, SEVERE WEATHER AWARENESS WEEK in New England. This is the fourth in a series of five Public Information State- ments on various topics related to severe weather awareness. Tragically, last week's tornadoes in the southeastern United States have highlighted the deadly threat caused by nature's most violent storms. The National Weather Service encourages the public to become more aware of those threats so they can act appropriately when severe storms threaten. ...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 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 possibility that a tornado may be forming or has formed. The scale used to measure tornado damage is the Enhanced Fujita scale (named after Theodore Fujita, a famous tornado damage expert). This scale is commonly referred to as the E-F scale. Based on scientific studies of tornado damage, the original Fujita scale was modified and the new "Enhanced Fujita Scale" was officially implemented in 2007. EF-0 - Light damage (winds 65 to 85 mph) EF-1 - Moderate damage (winds 86 to 110 mph) EF-2 - Considerable damage (winds 111 to 135 mph) EF-3 - Severe damage (winds 136 to 165 mph) EF-4 - Devastating damage (winds 166 to 200 mph) EF-5 - Incredible damage (winds over 200 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. During 2010, there were five tornadoes recorded in Maine (four of which were EF-1) and one tornado in New Hampshire. July 21st was the most active day with three EF-1 tornadoes in York/Cumberland County area. The six tornadoes in 2010 followed a very active 2009 which recorded 7 tornadoes in the two-state area. Here are some of the tornadoes reported in Maine and New Hampshire since 1995. EF2/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 May 21 2006 Hampton Falls, New Hampshire Jul 24 2008 Deerfield to Freedom, New Hampshire (50 mile path length) EF1/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 northwest 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 Sep 29 2006 North Berwick, Maine May 24 2009 Eagle Lake, Maine May 31 2009 Westfield, Maine May 31 2009 Easton, Maine Aug 21 2009 Norway to Hartford, Maine (up to 700 yards wide) Jun 5 2010 South Paris, Oxford, Hebron, Maine Jul 21 2010 Newfield to Limerick, Maine Jul 21 2010 Buxton to Gorham, Maine Jul 21 2010 Shapleigh to Alfred, Maine EF0/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 Sanbornton/Meredith, New Hampshire Aug 01 2005 North Twin Lake, Maine Nov 24 2005 Brunswick, Maine Sep 29 2006 Effingham, New Hampshire Jul 15 2007 Long Lake in Aroostook County, Maine May 31 2009 Oxbow, Maine Jun 26 2009 Stockholm, Maine Jul 18 2009 East Bethel, Maine Jun 2 2010 Shin Pond, Maine Jun 5 2010 Gorham, New Hampshire 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 usual short life-span of tornadoes in northern New England, there is often little, if any, advance warning. Tornadoes in New England generally 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 or mobile homes, they offer little protection. Seek shelter in a substantial building. * 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