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Extension > Mark Seeley's WeatherTalk > Wet August for Some

Friday, August 22, 2014

Wet August for Some

In this edition of Minnesota WeatherTalk

  • Wet August for only a few
  • New Seasonal Climate Outlook
  • State Fair
  • Weekly Weather potpourri
  • MPR listener question
  • Almanac for August 22nd
  • Past weather
  • Outlook



Wet August for some

Though most of the state has remained drier than normal for August, a few observers have reported above normal rainfall for the month thanks to some fairly isolated, but intense heavy thunderstorms. In the northern counties Backus, Duluth, and Brimson have received over 3.50 inches of rain so far this month, and Wadena and Little Falls report over 4 inches. In the west Glenwood, Hancock, Alexandria, Montevideo, and New York Mills have received over 3.50 inches, and Ortonville, Rothsay, Artichoke Lake, Madison, and Morris have reported over 4 inches. Dawson is the wet spot in the west with over 6 inches so far this month. In the southeastern counties Mantorville and Theilman have reported over 3.50 inches, while Zumbrota, Winona, Cannon Falls, and Minnesota City have reported over 4 inches.

Further, over August 20-21 this week fast-moving intense thunderstorms brought 2-4 inch rainfalls to some parts of the state. Some observers reported daily record rainfalls, including:

  • 4.00 inches at St James
  • 2.70 inches at Starbuck
  • 2.64 inches at Morris
  • 2.35 inches at Kimball
  • 2.34 inches at Artichoke Lake
  • 2.05 inches at Ottertail
  • 2.04 inches at Glenwood
  • 1.92 inches at Springfield
  • 1.89 inches at North Mankato


As opposed to the widespread wetter than normal pattern that prevailed across the state during the first half of summer, August rainfall has been very spotty. The US Drought Monitor expanded the geographic designation for an abnormally dry landscape in Minnesota. Last week the designated area was Freeborn and Faribault Counties and this week the Drought Monitor designation for abnormally dry includes portions of Winona, Fillmore, Mower, Blue Earth, Waseca, and Le Sueur Counties. Heavier than normal rainfall for much of Minnesota is in the outlook for the remainder of August, so most areas should see some significant rainfall amounts before the end of the month.


New Seasonal Climate Outlook

The NOAA Climate Prediction Center issued new seasonal climate outlooks on Thursday this week. They call for equal chances of above or below normal temperatures and precipitation for September across Minnesota. For later in autumn and early winter, the outlook clearly favors warmer than normal temperatures for the western Great Lakes Region for October through February. This is predominately based on the formation of an El Nino episode this fall which is correlated mild winters in our region.

State Fair Coming Up

This year our State Fair runs from August 21st to September 1st. I will be appearing on TPT's Almanac Program at noon on August 22nd at the MPR stage (corner of Judson and Nelson Streets) at the State Fair this year, and again at the MPR stage on Wednesday, August 27th at noon broadcasting the "Annual Minnesota Weather Quiz" with Stephen John . Please drop by if you are at the State Fair.

Some State Fair Weather History: All the climate data for the State Fair history has been compiled by Pete Boulay of the MN State State Climatology Office.  The hottest day in the history of the Minnesota State Fair was on September 10, 1931 with 104 degrees. Note that the Minnesota State fair in 1931 ran eight days from September 5-12. The coldest maximum temperature for the fair is 52 degrees on September 7, 1911 and the coldest minimum temperature is 33 degrees on September 13, 1890. The coolest fair morning in modern history was a chilly 36 degrees on September 1, 1974.

The Minnesota State Fair has been held at its current site since 1885. Beginning in 1975, the fair has a 12 day run each year ending with Labor Day. Thus since 1975, the fair begins on a Thursday in August. Before 1975 the fair was held for shorter durations. On average it rains about 3 to 4 days during the fair's 12 day run. The wettest fair of the modern era (12-day runs) was in 1977 with 9.48 inches, and the driest fair was 2003 with only .02 inch of rain. The largest rain event in the State Fair's history was August 30, 1977. At 8:20 pm heavy rains hit the State Fair. The U of M St. Paul Campus climate observatory ½ mile north of the fairgrounds saw 4.06 inches of rain. This caused some of the worst street flooding seen at the fairgrounds. The grandstand show was cancelled.


Weekly Weather potpourri:

Environment Canada reported that two tornadoes touched down in Ontario on Tuesday (Aug 19) evening this week, one near South Windsor and the other near Harrow. These storms caused some damage to farm buildings but no fatalities.

The USGS and Army Corps of Engineers along with NOAA have released a new online training module called "Preparing Hydro-climate inputs for Climate Change in Water Resources Planning." This science-based self-taught course is supported by a variety of other online data and resources. For those interested in managing water resources by incorporating what we know about climate change, I encourage you to take a look at this.

MPR listener question:

"Which State Fairs have seen the greatest and least frequencies of daily rainfall?"

Answer: Since 1885 the only State Fair to see no rainfall at all was in 1906, over a six day run from September 3 to September 8th. Probably the highest frequency of rainfall during the Fair dates to 1940 when it rained on the first 7 consecutive days. Fortunately the last three days of the State Fair that year were dry, boosting attendance. The 1940 State Fair was plagued by weather even before it started as a strong thunderstorm dislodged and collapsed the Machinery Hill Big Top Tent before the fair even opened. It had to be repaired and resurrected in time for the start of the State Fair.

Twin Cities Almanac for August 22nd:

The average MSP high temperature for this date is 79 degrees F (plus or minus 8 degrees F standard deviation), while the average low is 60 degrees F (plus or minus 6 degrees F standard deviation).

MSP Local Records for August 22nd

MSP weather records for this date include: highest daily maximum temperature of 97 degrees F in 1971; lowest daily maximum temperature of 60 degrees F in 1891; lowest daily minimum temperature is 43 degrees F in 1890; highest daily minimum temperature of 80 F in 1968; record precipitation of 3.32 inches in 1914; and there has been no snow on this date.

Average dew point for August 15th is 58 degrees F, with a maximum of 75 degrees F in 1968 and a minimum of 38 degrees F in 1934.

Past Weather Features

Slow moving thunderstorms brought heavy rains to many parts of the state over August 22-24, 1959. In southern counties rainfall amounts from 2 to 4 inches were quite common. Some communities experienced widespread flooding with heavier amounts of rainfall including 5.23 inches at Zumbrota, 5.94 inches at Austin, 6.01 inches at Blue Earth, and 7.53 inches at Bricelyn.

The coldest August 22nd in state history occurred in 1967 as many northern counties reported overnight lows in the 30s F and there were several reports of frosts. At Cook, Cotton, and Bigfork temperatures dropped into the upper 20s F, ending the gardening season for residence of those communities.
August 22, 1971 was probably the hottest in history across the southern half of the state as most observers reported afternoon highs in the 90s F and six cities in western Minnesota topped the 100 degrees F mark. Fortunately it just last one day, as a Canadian cold front dropped temperatures back into the 70s F the next day.


Outlook

Still humid through the weekend and early next week with high dewpoints. Air temperatures will generally be warmer than normal, especially on Sunday. There will be chances for showers and thunderstorms each day. Cooler than normal temperatures will settle in for Tuesday through Thursday, but there will still be chances for showers.

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