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 3, 2015
What happened in August 2015:
- August monthly precipitation totals were highly variable across Minnesota. Above-average rainfall was reported in a number of counties, especially in southwest and east central Minnesota. Below-average monthly rainfall totals were observed in northwest and southeast sections of the state.
[see: August 2015 Precipitation Departure Map | August 2015 Climate Summary Table | August 2015 Percent of Normal Precipitation Map]
- Heavy rainfall events, associated with severe storms, occurred during the first two weeks of August.
[see: Heavy Rain and Tornadoes: August 6 | Large Hail in NW MN: August 12 | Heavy Rain: August 16-17]
- Average monthly temperatures for August were very near, to slightly below, historical averages across Minnesota. Extremes for August ranged from a high of 95 degrees F at a number of locations on the 14th, to a low of 33 degrees F in low-lying areas of northeast Minnesota on the 26th.
[see: August 2015 Climate Summary Table | August 2015 Departure from Normal Temperature Map]
Where we stand now:
- Seasonal precipitation totals (April through August) rank near or above the historical median in most Minnesota counties. A few locations in northwest and northeast Minnesota report below-median seasonal precipitation totals.
[see: Seasonal Precipitation Ranking Map]
- The U. S. Drought Monitor map released on September 3 depicts a portion of northeast Minnesota (roughly 3% of Minnesota's landscape) 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 and the Minnesota DNR report that stream discharge values are near, to somewhat above, historical medians for the date on most Minnesota rivers. A few gauging locations in northern Minnesota report below-median streamflow for this time of year.
[see: USGS Stream Flow Conditions | MNDNR Weekly Stream Flow Maps and Tables]
- Water levels on most Minnesota lakes are near the middle of the historical data distribution for this time of year. Some northeast Minnesota lakes are below historical averages for the date.
[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]
- In their August 31 report, the Agricultural Statistics Service reported that topsoil moisture across Minnesota was 1 percent Very Short, 8 percent Short, 87 percent Adequate, and 4 percent Surplus.
[see: Agricultural Statistics Service Crop Progress and Condition | U. of M. Southwest Research & Outreach Center (Lamberton) | U. of M. Southern Research & Outreach Center (Waseca)]
- The potential for wildfires is currently rated by DNR Forestry as Moderate in west central, northwest, and north central Minnesota. Elsewhere, the fire danger rating is Low.
[see: Fire Danger Rating Map]
- The September precipitation outlook tilts towards above-normal conditions for all Minnesota counties. September precipitation normals range from near two inches in far western Minnesota to around three and one-half inches in eastern sections of the state.
[see: Climate Prediction Center 30-day Outlook | September Precipitation Normal Map]
- The September temperature outlook favors above-normal conditions across Minnesota. Normal September high temperatures are in the mid-70s to start the month, dropping to the low to mid-60s by month's end. Normal lows are in the mid-50s early in the month, falling to around 40 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. The odds tilt towards above-normal precipitation in far southwest Minnesota. The September through November temperature projection offers equal probabilities of below-normal, near-normal, or 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:
- For most Minnesota locales, the summertime weather was close to ideal. The state did not suffer a major heat wave or consistently unbearable humidity levels. With the exception of some northeast Minnesota communities, growing season rainfall totals have been adequate to abundant. The excellent growing season weather conditions are apparent when reviewing the latest USDA survey of two of Minnesota's major commodities, corn and soybeans. In a late-August report, corn condition was rated 88 percent good to excellent. Soybean condition was rated 79 percent good to excellent.
[see: 2015 Summer Glory Index]
Upcoming dates of note:
- September 17: National Weather Service releases 30/90 day temperature and precipitation outlooks
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Greg Spoden, DNR Climatologist