To: MPR's Morning Edition From: Mark Seeley, Univ. of Minnesota Extension, Dept of Soil, Water, and Climate Subject: Minnesota WeatherTalk for Friday, August 31, 2007 HEADLINES: -MPR's Jet Streaming Podcast this week -State Fair Weather Quiz Online -Preliminary August Climate Summary -Weather Potpourri -Question on lightning -Almanac for August 31st -Labor Day Extremes -Definition of Drizzle Radar -Outlook Topic: On this week's "Jet Streaming" podcast This week's podcast, available at the MPR web site, includes conversations from the 2007 Minnesota State Fair where a favorite topic is the weather. Paul Huttner and Mark Seeley share their perceptions and memories of weather during past State Fairs. In addition Paul and Cathy Wurzer visit with some of the weather professionals attending the Fair. You can find more at.... http://minnesota.publicradio.org/radio/programs/morning_edition/ or http://minnesota.publicradio.org/radio/podcasts/jet_streaming/ Topic: Take the 11th Annual Minnesota Weather Quiz online during the State Fair On Thursday, August 23rd the 11th Annual Minnesota Weather Quiz was broadcast on Minnesota Public Radio's Midday program during the 11:00 to noon time slot. The quiz is composed of 20 questions, equally divided between this year's weather headlines and Minnesota weather history. Test your knowledge by taking the quiz online at the following web address.... http://minnesota.publicradio.org/features/2007/08/23_newsroom_weatherquiz/ This web site will automatically score your quiz. Topic: Preliminary Climate Summary for August 2007 Average monthly temperatures around Minnesota were near normal, ranging from 1 to 2 degrees F warmer than average to 1 to 2 degrees F cooler than average. Extremes for the month were a high of 100 degrees F at Wild River State Park on August 10th, and a low of 28 degrees F at Embarrass on the 30th, a new record low there for the date. International Falls also recorded a record low of 35 degrees F on the 20th. The 28 F reading on the 30th and another reading of 33 degrees F on the 26th at Embarrass were the lowest in the 48 contiguous states, the only two times that Minnesota showed the coldest temperature in national weather headlines during the month. Minnesota usually does better than this! Precipitation for August was extreme in both directions, very dry in northern areas, and exceptionally wet in the south. Several northern observers reported less than two inches. Alexandria reported their 2nd driest August in history with just 0.22 inches, while Hibbing reported its driest August ever with only 0.17 inches. Conversely, numerous record-setting rains fell across southern counties. In the Twin Cities MSP International Airport reported the wettest August ever with 9.32 inches, while Worthington (Nobles County) reported its wettest August as well with 13.23 inches. The most impressive records were from southeastern observers, many of whom reported the wettest month ever in their climate records, including the following: Hokah 20.15" La Crescent 18.13" Lanesboro 16.35" Preston 14.88" Rochester 14.07" Spring Grove 17.56" Theilman 15.84" Zumbro Falls 16.71" Three notable events in August: Drought Disaster, Flash Floods, and Wind Storms During the first week of August the drought situation in parts of SW, central, and NE Minnesota was acknowledged as severe to extreme, with associated economic consequences for agricultural producers. As a result Governor Pawlenty petitioned for a federal disaster declaration in 25 counties. This was granted by Secretary of Agriculture Mike Johanns in an announcement at Farm Fest on August 7th with a provision that 32 additional adjacent counties might be considered for relief as well. Since that time some counties have seen relief in the form of abundant precipitation (southern counties), while the drought has worsened in other areas (central and northeastern counties). The storms of August 17-19 produced a new state 24-hour rainfall record at Hokah (Houston County) with 15.10 inches. The resulting flash floods (nearly 30 reports in all) from this storm affected many SE Minnesota watersheds, including the Root River at Houston where a new record flood crest was established with a gage reading of 19.33 feet, and the Whitewater River in Whitewater State Park which reported a new record flood crest of 19.24 feet. Winona, Fillmore, Houston, Steele, Wabasha, and Olmsted Counties were declared federal disaster areas as a result of these floods and all were eligible for federal assistance. Total loss and damages were estimated at over $60 million. The wind storms (straight-line winds) of August 10-11 and August 13-14 were very destructive along pathways from west-central Minnesota into SW Wisconsin. Wind speeds from 60 to 80 mph cut a wide and spotty damage swath across the region, shearing off the tops of trees, uprooting trees, and damaging buildings. The storm of August 10-11 was a likely derecho (large bow echo on radar) as it developed in the eastern Dakotas and hung together all the way to northern Illinois. Many hail reports were also associated with these storms. In all August produced over 100 reports of hail, over 80 reports of damaging winds, over 30 reports of flash flooding, and three tornado reports (Polk and Marshall Counties in NW Minnesota) across the state. All of these challenging and destructive weather events ensued following the I35 bridge collapse in Minneapolis on August 1st. It was indeed a dramatic and traumatic month for Minnesotans! Topic: Weekly Weather Potpourri..... NASA-Goddard scientists reported this week in the Journal of Climate that their study of tropical ocean rainfall over the past three decades reveals an upward trend, with the rainiest year in 2005. Research on climate change has suggested that rainfall might be increasing in these areas as a result of higher evaporation brought about by warming temperatures. The researchers suggest that rainfall in the tropical oceans has increased by as much as 5 percent. Very high temperatures in California pushed electricity use to a new record level on Tuesday through Thursday this week. Many central valley locations surpassed 100 degrees F, while Palm Springs reported 116 degrees F. Energy conservation measures were being emphasized by state government officials who were asking customers to use air conditioning settings of 78 degrees F. The prolonged heat wave in Southeastern states during this month has claimed at least 50 lives. Parts of Alabama have recorded 15 days with daytime highs of 100 degrees F or higher during August, one of their hottest months ever. It is also likely that both Naples and Ft Lauderdale, FL will reported their warmest month of August in history with monthly mean temperature values near 86 degrees F. Parts of Japan have been suffering through an August heat wave as well. Osaka is close to reporting an average temperature for the month of 86 degrees F, mostly due to very warm nights, but some hot days as well. Even Tokyo has averaged close to 85 degrees F for the month so far, a record value. An August heat wave combined with a lack of rainfall has produced devastating wildfires in Greece. An estimated 6.5 million acres of farmland has burned, and in addition areas of pine forests and olive groves. At least 64 deaths have been blamed on the fires, the worst to hit Greece in decades. The smoke plumes have been detectable on weather satellite imagery for most of this week. A new record size hail stone was reported from South Dakota last week. The stone that fell in Dante (NW of Yankton) on Tuesday night (August 21) was confirmed by State Climatologist Dennis Todey as a state record. Todey measured the stone, which is 6 7/8 inches in diameter, weighs 1 pound and has a circumference of 18 inches. This hail stone bests the previous record of 6 inches set in Custer County on June 22, 1968. The stone falls just short of the national record of 7 inches and 18 3/4 inches circumference in Aurora, Neb., in June 2003. The Department of Energy's Oak Ridge National Laboratory announced this week that research with new roofing materials may lead to significant improvements in energy efficiency of homes. New thermal barriers are being developed in combination with infrared reflective materials that will help prevent home attics from reaching extremely high temperatures. The net effect of these materials is to help conserve moderate temperatures indoors and reduce energy use. More can be found at.... http://www.sciencedaily.com/releases/2007/08/070828163444.htm MPR listener question: We have had many storms happening recently in the middle of the night, and they are full of lightning. How safe is a person inside his or her house? Answer: Because lightning can behave in different forms and patterns very erratically, no place is perfectly safe. However, being indoors is certainly one of the safest environments. The National Weather Service has estimated there are 60-80 deaths in the USA per year due to lightning and close to 90 percent of these take place outdoors. Of those that happen indoors, some are attributed to lightning caused house fires and not the lightning itself. In most circumstances houses are not the tallest objects in the landscape, so the lightning favors other targets. In addition most lightning is cloud to cloud and not cloud to ground. We hear both types and if you count following the flash until you hear the thunder, then divide your count by five, that is the distance in miles from the lightning itself. There are several standard safety precautions even for those who are indoors. Stay away from water and plumbing fixtures, windows, appliances, and metal furniture or objects. Don't use the telephone and certainly don't step outside to watch the display. Twin Cities Almanac for August 31st: The average MSP high temperature for this date is 78 degrees F (plus or minus 9 degrees F standard deviation), while the average low is 58 degrees F (plus or minus 8 degrees F standard deviation). MSP Local Records for August 31st: MSP weather records for this date include: highest daily maximum temperature of 94 degrees F in 1898 and 1907; lowest daily maximum temperature of 56 degrees F in 1944; lowest daily minimum temperature of 40 F in 1974 (just 32 degrees F in 1832 of the Pioneer Era); highest daily minimum temperature of 75 F in 1898 and 1961. Record rainfall for this date is 1.50 inches in 1914. Average dew point for August 31st is 57 degrees F, with a maximum of 75 degrees F in 1960 and a minimum of 34 degrees F in 1949. All-time state records for August 31st: The state record high temperature for this date is 100 degrees F at Beardsley (Big Stone County) and at New London (Kandiyohi County) in 1898. The state record low temperature for this date is 23 degrees F at Cotton (St Louis County) in 1970; state record precipitation for this date is 5.85 inches at Crookston (Polk County) in 1908. And there was a trace of snowfall reported at Duluth on this date in 1949, the only known instance. From "Minnesota Weather Almanac":(from bookstores or write the author) The first Monday of September has been traditionally celebrated as Labor Day since 1894. Noted by many as the end of summer, there are many vivid weather memories of this holiday. Probably the coldest Labor Day occurred on September 2, 1935 when frost was reported by many northern weather observers. Sawbill Camp (Cook County) reported a state record of just 22 degrees F, while Alborn reported 29 degrees F, Grand Rapids reported 31 degrees F, and Baudette reported 32 degrees F. Though not quite as cold, frost was reported again on Labor Day (September 2nd) in 1974, with some observers as far south as Austin reporting ground frost. The wettest Labor Day occurred on September 2, 1957 when Halstad (Norman County) received 5.91 inches of rainfall, causing long delays in the crop harvest. Similarly, the wettest Labor Day at Duluth was September 7, 1964 when over 4 inches of rain produced local flash flooding and damaged over 60 basements and a local elementary school. September 4, 1922 arguably brought the hottest Labor Day to the state with a daytime high of 103 degrees F at Beardsley (Big Stone County) and highs of 100 F or greater at four other locations (Montevideo, New London, Tracy, and Fergus Falls). It was obviously not a good afternoon for a Labor Day picnic. Words of the Week: Drizzle Radar This week TU-Delft, a research university in the Netherlands unveiled a new highly sensitive radar system capable of detecting even the smallest of droplets in the atmosphere. It is called the "Drizzle Radar" and it can be used to study the interactions of dust, clouds and rain. This instrument may lead to a better understanding of cloud condensation nuclei, as well as cloud formation and dissipation. Outlook: Generally dry and warm over the weekend with a chance for scattered showers in the north Sunday and Monday. Temperatures will continue a trend of above normal next week and it will be mostly dry, with chances for widely scattered showers again on Thursday.