HydroClim Minnesota for Early September 2016

A monthly electronic newsletter summarizing Minnesota's climate conditions and the resulting impact on water resources. Distributed on the first Thursday of the month.

State Climatology Office - DNR Division of Ecological and Water Resources, St. Paul
distributed: September 1, 2016

What happened in August 2016:

  • August 2016 gave July 2016 competition for the wettest month of the summer and managed to succeed in some places. St. Cloud had its 2nd wettest August on record and the Twin Cities saw its 6th wettest August on record. The preliminary statewide departure from normal was +2.29 inches, roughly the same departure from normal in July. A large swath of the state from Big Stone County in the west to Wabasha County in the east, saw twice the amount of normal August precipitation. Parts of central and north central areas of the state also saw a surplus of moisture. The few areas in the state that wound up falling a bit short were in the northeast and southwest Minnesota.
    [see: August 2016 Precipitation Total Map  | August 2016 Precipitation Departure Map  | August 2016 Climate Summary Table
    August 2016 was no stranger to heavy rain events with the largest event occurring on August 10-11 affecting central Minnesota. Some notable events of the month include:
  • August 10-11 saw the second "mega rain" event of the year for Minnesota. A large area of two to three inches of rain fell from Lac Qui Parle County eastward through Kandiyohi County to the Twin Cities and southeastward to Wabasha County. There were two areas seeing six inches of rain or more, centered around the Willmar-Olivia area and also in Wabasha County near the Mississippi River. The highest precipitation total found so far was 9.74 inches at a Kandiyohi Soil and Water Conservation District rain gauge site just east of Willmar. There were many reports of basement flooding in Willmar. One basement caved in. The arena and track at the Kandiyohi County Fairgrounds flooded, postponing the demolition derby on the 11th. Residents in Willmar were being asked to limit water use due to the impact on the city's wastewater treatment plant. The highest total found in Wabasha County was 7.75 inches in Theilman, with the most damage reported just across the border in Wisconsin in Buffalo County.
    [see: Flooding Rains: August 10-11, 2016]
  • Heavy rains just clipped southeast Minnesota on during the evening of August 23, with the brunt of the heaviest rain staying just south of the Minnesota border, hitting Decorah Iowa the hardest. The highest rainfall total found in southeast Minnesota with this event was 3.50 inches at Harmony in Fillmore County.
    [see: Heavy Rains in Southeast Minnesota: August 23-24 2016]
  • Next to see heavy rain was northwest Minnesota with two events happening over a 48 hour period. The first was a severe storm and heavy rain event on August 27, that saw 3.49 inches fall at Ada in Norman County. Quarter-sized hail was reported in Moorhead and golf ball-sized hail in Wilkin County causing damage to crops in the vicinity of Everdell.
    [see: Severe Storms: August 27, 2016]
  • The next day, August 28, was stormy again and had more widespread rain. Two tornadoes were reported in northwest Minnesota at dusk, the larger of the two was on the ground for over an hour and moved very slowly. It touched down near the Polk/Norman County line and moved to the southeast and lifted just to the northwest of Gary in Norman County. Hundreds of trees were uprooted or damaged in the track and one barn was destroyed. A location three miles west-southwest of Fertile in Polk County saw 5.85 inches of rain.
    [see: Severe Storms: August 28, 2016]
  • During the evening of August 29, clusters of very slow-moving thunderstorms developed over east central Minnesota and sagged to the south with some storms drifting to the southwest. The storms dropped torrential rains in a hopscotch pattern with one location seeing several inches of rain, with other nearby places seeing very little. Case in point was St. Cloud. Officially at the St. Cloud Airport, located five miles to the southeast of downtown St. Cloud, saw 4.03 inches of rain (2.05 inches in an hour) but downtown St. Cloud saw only about .75 (3/4) of an inch. Other locations that that saw heavy rain were in Benton and southern Mille Lacs County with a volunteer observer east of Milaca seeing 4.7 inches. Street flooding was reported in Foley in Benton County.
    [see: Heavy Rain: August 29, 2016]
  • August average temperatures wound up being above normal across Minnesota for the month of August. The average statewide August temperature was 1.2 degrees above normal. The highest temperature found for the state was 96 degrees in Marshall in Lyon County on August 10. The coldest temperature for the month was 37 degrees at Brimson in St. Louis County on August 31.
    [see: August 2016 Climate Summary Table  |  2016 August Departure from Normal Temperature Map]

Where we stand now:

  • Seasonal precipitation totals(April 1 through August 30) ranked above the historical median over much of Minnesota, with a few pockets in north central and west central Minnesota near to below normal.
    [see: Seasonal Precipitation Ranking Map]
  • The U. S. Drought Monitor map released on September 1, depicts a very small area of southwest Minnesota as Abnormally Dry. The map shows no other areas in Minnesota in a dryness category. The U.S. Drought Monitor index is a blend of science and subjectivity where drought categories (Moderate, Severe, etc.) are based on several indicators.
    [see: Drought Conditions Overview]
  • The U.S. Geological Survey reports that stream discharge values are above to much above normal across large sections of western, central and southern Minnesota, with some stream flow values the highest for the time of year in Lake of the Woods, Norman, Clay, Morrison and Hennepin Counties. Normal flows are in the northeast and southwest.
    [see: USGS Stream Flow Conditions]
  • Water levels on most Minnesota lakes vary depending on lake and location in the state. Mille Lacs was above the median lake level for August. On September 1, Minnetonka was at 929.55 with 250 cfs flowing through Grays Bay Dam. White Bear Lake was at 922.39 feet on September 1, a rise of 1.03 feet from one year ago and a rise of 3.55 feet from the record low of 918.84 measured January 10, 2013. Rainy and Lake of the Woods are in the median range for August. Lake Superior was at 602.66 feet on August 26, six inches higher than the monthly average for August.
    [see: Mille Lacs Lake Water Level  |  Lake Minnetonka Water Level  |  White Bear Lake Water Level  |  Lake of the Woods Control Board Basin Data  |  Corps of Engineers Great Lakes Water Levels]
  • The Agricultural Statistics Service on August 29 reports that topsoil moisture across Minnesota is 0 percent Very Short, 2 percent Short, 76 percent Adequate, and 22 percent Surplus. Soil moisture levels at Lamberton is above the historical median.
    [see: Agricultural Statistics Service Crop Progress and Condition  |  U. of M. Southwest Research & Outreach Center (Lamberton)]
  • The potential for wildfires is currently rated by DNR Forestry as Low across Minnesota, except for northwest, northeast and parts of north central sections where the fire danger is Moderate. Historically, 80 percent of all wildfires in Minnesota occur during April and May.
    [see: Fire Danger Rating Map]

Future prospects:

  • The September precipitation outlook leans towards above normal precipitation across the entire state with the best chances in central and southern Minnesota. September precipitation normals range from about one-and-a-half inches in northwest Minnesota to about four inches in northeast and southeastern counties.
    [see: Climate Prediction Center 30-day Outlook  |  September Precipitation Normal Map]
  • The September temperature outlook leans towards equal chances for below, above normal temperatures throughout Minnesota. Normal September high temperatures are in the middle to upper 70's degrees to start the month, dropping to the low to mid 60's by month's end. Normal lows are in the 50's early in the month, falling to the middle 30's to mid-40s by late September.
    [see: Climate Prediction Center 30-day Outlook  | September Temperature Normal Map]
  • The 90-day precipitation outlook for September through November indicates equal chances of below-normal, near-normal, or above-normal conditions across most of Minnesota, with the The September through November temperature projection also offers a fairly strong tendency for above-normal conditions statewide.
    [see: Climate Prediction Center 90-day Outlook]
  • The National Weather Service produces long-range probabilistic river stage and discharge outlooks for the Red River, Minnesota River, and Mississippi River basins. These products address both high flow and low flow probabilities.
    [see: National Weather Service - North Central River Forecast Center]

From the author:

Upcoming dates of note:

  • September 15: National Weather Service releases 30/90 day temperature and precipitation outlooks


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Pete Boulay, DNR Climatologist

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