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: May 4, 2017
What happened in April 2017:
- April monthly precipitation totals varied from near normal in the northwest to one to two inches above normal in the eastern half of the state. A few locations in east central, south central and southeast Minnesota reported precipitation totals that were more than three inches above historical averages.
[see: April 2017 Precipitation Total Map | April 2017 Precipitation Departure Map | April 2017 Climate Summary Table | April 2017 Percent of Normal Precipitation Map]
- Average monthly temperatures for April were about one to two degrees above historical averages at most Minnesota reporting stations. The majority of the month was above normal. A sharp cool down for the last five days of the month tugged down the temperature departure a bit. Extremes for April ranged from a high of 83 degrees F near Milan on the 8th, to a low of 12 degrees F at Embarrass on the 11th and 12th.
[see: April 2017 Climate Summary Table | 2017 April Departure from Normal Temperature Map]
Where we stand now:
- The U. S. Drought Monitor map released on May 2 shows no area in Minnesota in a dryness category. The last time there was any drought indicator category was on August 30, 2016. 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 or near historical medians in central and southern Minnesota. Above normal to much above normal streamflows are present in southern and east central Minnesota. Elsewhere in Minnesota, stream flow values are near to above historical medians for the date.
[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 April. On May 3 Minnetonka was at 929.38 with 150 cfs flowing through Grays Bay Dam. White Bear Lake was at 923.22 feet on May 2, a rise of 1.12 feet from one year ago and a rise of 4.38 feet from the record low of 918.84 measured January 10, 2013. This is the highest level for White Bear Lake since July 25, 2006. Rainy and Lake of the Woods are in the median range for April. Lake Superior was at 601.94 feet on April 28, eight inches higher than the monthly average for April.
[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 reported on May 1, that topsoil moisture across Minnesota is 0 percent Very Short, 1 percent Short, 70 percent Adequate, and 29 percent Surplus. Soil moisture readings are above the historic average on April 15 at the Southwest Research and Outreach Center - Lamberton, MN and are the similar to the same date in 2016.
[see: Agricultural Statistics Service Crop Progress and Condition | U. of M. Southwest Research & Outreach Center (Lamberton)]
- The potential for wildfires on May 4, rated by DNR Forestry as ranging from Moderate across western Minnesota to Low in southeast and northeast Minnesota and High in Carlton, southern St. Louis and south of Lake of the Woods. Cool and damp weather lessened the fire danger a bit in late April. Warmer and drier conditions have returned in early May.
[see: Fire Danger Rating Map]
- Nearly all of Minnesota's lakes are free of ice. Ice out 2017 was a memorable season. It began with the rapid deterioration of the ice over southern Minnesota with dozens of lakes losing their ice at a record pace for the first week of March. Then cold weather settled in and refroze many of those lakes, a rare occurrence. The first ice out was for Zumbro Lake in Olmstead County on February 22, but this lake may have partially refroze with the cooler temps that settled in for the second week of March. ice out progresses northward throughout March and April and was running about one to two weeks ahead of the median at most locations. By May 3, there were still a few lakes still iced in the extreme northeast tip of Cook County including Greenwood Lake.
[see: 2017 Lake Ice-Out Dates | DNR Conservation Officer Reports]
- The May precipitation outlook leans towards normal precipitation across central and northern Minnesota. Southern Minnesota has a tendency for slightly below-average precipitation. May precipitation normals range from just over two inches in northwest Minnesota to just less than four inches in southeastern counties. The historical probability of measurable precipitation for any given day in May ranges from 25 percent in the northwest to near 40 percent in the southeast.
[see: Climate Prediction Center 30-day Outlook | May Precipitation Normal Map]
- The May temperature outlook tilts towards equal chances for above, below and normal conditions throughout Minnesota, with the southeast having a slight tendency for below normal temperatures. Normal May high temperatures are in the low to mid-60s early in the month, rising to the low to mid-70s at month's end. Normal May low temperatures are in the mid-30s to near 40 to start the month and climb to the mid-40s to low 50s as the month ends.
[see: Climate Prediction Center 30-day Outlook | May Temperature Normal Map]
- The 90-day precipitation outlook for May through July indicates equal chances of below-normal, near-normal, or above-normal conditions in the western thirds of Minnesota, and a tilt towards below-normal conditions in central and eastern counties. The May through July temperature projection favors 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:
- Planting fell behind at the end of April due to poor weather conditions. Soil temperatures were also quite cold, causing a delay in seed gemination. A warming trend after a cold start to may began to warm the soil and the sunshine was welcome by many in the state. [see: Minnesota Department Of Agriculture - 6 Inch Soil Temperature Network]
Upcoming dates of note:
- May 18: National Weather Service releases 30/90 day temperature and precipitation outlooks
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Pete Boulay, DNR Climatologist