Preliminary climate summary for August 2012The mean monthly temperature for August was very close to normal for most observers in Minnesota, often plus or minus 1 degrees F from the historical average. Extremes temperatures for the month ranged from 99 degrees F at several southern locations on August 30th to just 33 degrees F at Embarrass on the 17th. Minnesota reported the coldest temperature in the 48 contiguous states on August 10th with a reading of 38 degrees F at International Falls.
August continued with a drier than normal weather pattern as most observers reported below normal rainfall amounts for the month. There were a few exceptions as Morris (3.26 inches), Grand Marais (3.39 inches), Winsted (nearly 6 inches), and Grand Portage (3.78 inches) received above normal monthly amounts.
Crop maturation advanced very rapidly during August and by the end of the month some corn fields were nearly ready for harvest, and soybeans were yellowing and dropping leaves.
Invitation to the State Fair on Sept 2ndNewscaster and radio host Phil Picardi and I will be at the Minnesota Public Radio Booth on the State Fair Grounds (corner of Judson and Nelson) at noon this Sunday, September 2nd to talk weather. It won't be a program to broadcast on FM91.1, but we will enjoy chatting with a live audience. We'll discuss the big weather happenings of this year and take questions from the audience. If you are in the area or plan to come to the State Fair anyway, please drop by at noon. I'd love to see you there.
Warm Wednesday and ThursdayA bubble of warm air brought some record-setting temperatures to the Dakotas and parts of Minnesota on Wednesday (Aug 29) and Thursday (Aug 30) this week. In the Dakotas Chamberlain, SD reported 112 degrees F, Pierre, SD had 111 degrees F, and Sioux Falls, SD reached a high of 100 degrees F, then hit a record 104 degrees F on Thursday, August 30th. The airport at Grand Forks, ND reported 97 degrees F, while Rochester, MN reached 92 degrees F tying the record for August 29th from 1945. Eau Claire, WI tied a record high with 97 degrees F on Thursday (Aug 30th), while La Crosse, WI set a new record with an identical reading of 97 degrees F. So many western communities reported daytime highs in the 90s F that several schools dismissed students early as their non-air conditioned classrooms heated up. Fortunately a cool front brought relief with lower temperatures and dewpoints by Thursday night.
August 23 tornado in Carver County confirmedTodd Krause of the National Weather Service in Chanhassen confirmed this week that an EF-0 (winds 65-85 mph) tornado northeast of Plato in Carver County on August 23rd, damaging corn fields and trees, and destroying a barn. It was on the ground for 3.2 miles. The same relatively small but intense thunderstorm system brought 5.40 inches of rain to Winsted (McLeod County), 3.26 inches to Montrose (Wright County), 2.85 inches to Watertown (Carver County), and 1.76 inches to Jordan (Scott County). August is the fifth month this year to bring a tornado to Minnesota. There were also tornado reports in March, April, May, and June.
Crop condition holding steady and soil moisture reserves way downThe Weekly Weather and Crop Report for Minnesota showed just 17 percent of the state's corn acreage was in very poor to poor condition, and 12 percent of the state's soybean acreage was in similar conditions. That means that the balance of Minnesota's 15 plus million acres of corn and soybeans is in fair to excellent condition as the harvest season approaches. This is far better off than most states which were more adversely affected by drought this year.
With the lack of abundant rainfall in August, soil moisture conditions are extremely depleted. The University of Minnesota Southwest Research and Outreach Center (SWROC) at Lamberton reports less than 2 inches of stored moisture in the top 5 feet of soil, while the Southern Minnesota ROC at Waseca reports just a little over 3 inches stored in their soil profile. Further north at the Northwestern ROC at Crookston, the stored soil moisture values are less than 1 inch in the top 5 feet. Obviously larger than normal amounts of rainfall are desperately needed to recharge soils this fall before winter freeze-up. Fortunately it looks like September may start out wetter than normal.
New AMS statement on climate changeGiven the building body of scientific evidence about the Earth climate system and how it is changing, the American Meteorological Society earlier this month issued a new statement on climate change and a new statement on climate services. These are carefully crafted statements to reflect scientific assessment, value of the data, and implications for our future. If you are interested in reading these statements I encourage you to view their web site.
Weekly Weather potpourriEarlier this week the NOAA National Ice Center reported the lowest amount of Arctic Sea Ice observed since satellite observations began in 1979. The report on August 26th showed 1.58 million square miles of ice cover in the Arctic Sea, breaking the record low from 2007 of 1.61 million square miles. You can read more about this at these links.
Additionally in western and central sections of Lake Superior this week surface water temperatures were ranging as high as 73-74 degrees F, not bad for swimming in some places. Even around Isle Royal National Park water temperatures were ranging from 65 to 68 degrees F.
Following a path taken by Typhoon Bolaven last weekend, Tropical Storm Tembin was headed for South Korea this week with heavy rains, high seas, and winds over 50 mph. This long-lived storm which tormented Taiwan earlier was expected to dissipate by the weekend. Tropical Storm Ileana was spinning off the southwest coast of Baja California, but it was not a threat to land. Tropical Storm Kirk was in the middle of the North Atlantic Ocean and posing no threat either, while another tropical storm was expected to develop over the weekend in the central North Atlantic Ocean as well.
The BBC Weather Center in London reports that the United Kingdom is recording one of its wettest summers in history, with a country-wide mean total rainfall of over 12 inches since June 1st. Despite this near historical wetness the weather abated during most of the Olympic Games and did not cause as much disruption as once anticipated.
MPR listener question
I heard that the all-time high temperature record for the Minnesota State Fair was changed this week, due to the variable historical dates that the State Fair has been hosted at the Fairgrounds. What is the new temperature record?
Answer: Yes, that is correct. When I studied the history of State Fair weather earlier and published this my book Minnesota Weather Almanac I thought the record high temperature was 97 degrees F on September 1, 1913, and tied on August 24, 2003. Recent research by the Minnesota State Climatology Office shows that in 1931 (warmest year in Minnesota history) the State Fair was held from September 5-12 (an 8 day run). On September 10th the daytime high was 104 degrees F, which is now the record high for the State Fair, and also the record highest September temperature ever measured in the Twin Cities. You can read more about State Fair weather records here.
MPR listener questionWhat positive purpose does nature have in mind for hurricanes to form?
Answer: Hurricanes are one of nature's mechanism for balancing out disparities in moisture and heat within the Earth climate system. They help redistribute the excess heat and moisture that accumulate in tropical latitudes and disperse this to higher latitude positions. Additionally they are the major supplier of moisture (rainfall) to many landscapes such as Mexico and Japan which receives over half of its annual rainfall from typhoons. Hurricanes sculpt the landscape in terms of reshaping dunes and inland waterways, and they periodically rearrange coral reefs. They have also been the savior of certain civilizations as on more than one occasion historically China attempted to invade Japan only to lose most of their fleet of ships to a typhoon.
Twin Cities Almanac for August 31stThe 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 31stMSP 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; highest daily minimum temperature of 75 F in 1898 and 1961; and record precipitation of 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 24thThe state record high temperature for this date is 100 degrees F at Beardsley (Big Stone County) and 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 at Duluth on this date in 1949, earliest ever.
Past Weather Features:Probably the hottest August 31st in state history was in 1898 when over three dozen Minnesota communities reported daytime highs of 90 degrees F or higher. Actually August 31st that year was the middle of a five-day Heat Wave that plagued much of the state. Relief finally came with five consecutive days of rain in early September.
August 31, 1906 brought frost to many parts of northern Minnesota as areas from International Falls to Ely saw overnight lows drop to 27 to 31 degrees F. A similar and even more widespread cold snap occurred on August 31, 1970 when temperatures across the north ranged from 23 to 31 degrees F.
August 31, 1947 brought a F-3 tornado (winds 158-206 mph) to Le Sueur County. Between 8:00 and 8:30 pm the tornado moved 17 miles across the landscape south of Le Center, destroying rural homes and barns. One person was killed and eight were injured by this storm.
About 2:30 pm on August 31, 1975 an enormous F-2 tornado (winds 113-157 mph) moved 6 miles across Clay County northeast of Moorhead. At times this funnel was nearly one mile wide. Fortunately it traveled primarily over agricultural fields and destroyed only one barn.
August 31, 1989 brought severe thunderstorms and widespread large hail to many parts of the state. Hail as large as baseballs was observed in parts of McLeod and Wright Counties. Further north heavy rainfall amounts set records as well. Georgetown reported 5.57 inches of rain, Park Rapids 4.38 inches, and Deep Portage 4.29 inches. Record amounts of rainfall were also reported from Moose Lake (4.42 inches), Sandy Lake (4.23 inches), and Wright (3.80 inches).