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: July 2, 2020
What happened in June 2020:
- June 2020 showed a wide variation in precipitation across the state. In general rainfall totals were below normal in the north east and central and well above normal in the northwest and southeast. The preliminary statewide average precipitation total was 4.47 inches or .15 inches above normal. Southeast Minnesota saw excessive rains and that really tugged at the statewide average. Mabel in far southeastern Fillmore County had 8.05 inches for one of the wetter locations in the state. One of the driest locations in the state was the Duluth International Airport that had only .69 inches of rain or 3.54 inches below normal.
[see: June 2020 Precipitation Total Map | June 2020 Precipitation Departure Map | June 2020 Climate Summary Table | June 2020 Percent of Normal Precipitation Map]
- Despite the fact that not all parts of the state saw heavy rains in June, it was an active month for storms. The first truly summer-like air mass over Minnesota gave way to the first widespread severe weather event of the year, as thunderstorms with hail, strong winds, heavy rain, and isolated tornadoes pelted central and especially southern Minnesota on Tuesday June 2, 2020.
[see: Hot weather and severe storms, June 2, 2020]
- An unusually potent low-pressure system moved straight north out of Montana, into southern Canada on Saturday June 6. Another system formed in its wake, passing from the Black Hills into north-central North Dakota on Sunday June 7th. These two systems produced back-to-back nights of extraordinary thunderstorms in the region, with some of those storms affecting northwestern and northern Minnesota.
[see: Heat and Storms Strike Again, June 7,2020]
- Intense thunderstorms pounded the parts of the north for the third day in a row. The storms on June 8 produced hail the size of golf balls and slightly larger as they drifted over the Kittson, Roseau, and Lake of the Woods Counties, with a brief tornado reported in Marshall County. The National Weather Service in Grand Forks confirmed an EF-1 tornado at Norris Camp, in Lake of the Woods County, which also reported large hail at 850 PM.
[see: Hot South, Stormy North (Again), June 8, 2020]
- Minnesota's first known direct encounter with a tropical cyclone produced heavy rains and flooding in southeastern Minnesota on June 9, 2020. Fillmore and Winona Counties received the most rain, with CoCoRaHS observers near Lewiston, Stockton, and Minnesota City reporting 4.19 to 4.62 inches, and the automated DNR gauge at Lanesboro reporting 4.54 inches. The area southeast of a line from Albert Lea to Red Wing generally received 1 to 3 inches of rain, including a total of 1.83 inches at the Rochester International Airport.
[see: Tropical Depression Cristobal Drenches Southeast Minnesota, June 9, 2020]
- Over 18 hours of thunderstorm activity led to widespread heavy rains and scattered flash-flooding across southern Minnesota. One broad swath of heavy rain fell from southern Brown and northern Watonwan Counties, northeastward through Mankato, Northfield, Cannon Falls, Red Wing, and the southeastern half of the Twin Cities area. Here, precipitation totals of 2-4 inches were common, with isolated areas receiving 5-8 inches of rain. An automated tipping bucket rain gauge on the Minnesota River at Judson (just northwest of Mankato) reported 8.46 inches. Rain gauge volunteers reported totals on Monday morning (as rain was still falling) of 4.55 inches in St. Peter, 5.40 inches near Burnsville, 4.80 inches in Woodbury, 5.54 inches near Cannon Falls, and 6.13 inches between Hastings and Miesville. Law enforcement reported water and mudslides covering roads in valleys south of the Twin Cities.
[see: Intense Rains, June 28-29, 2020]
- A nearly stationary band of strong thunderstorms in the afternoon and evening over central Minnesota produced very high rainfall totals and flash flooding in and around Little Falls. The heaviest rains and flash-flooding were centered on Little Falls area, where stream gauges and automated weather stations reported 7-8 inches of rain. Observers in the CoCoRaHS network measured 8.76 inches in Little Falls itself, 5.01 inches near Swanville, 4.58 inches in Pierz, and 3.27 inches near Longville. Spikes of relatively high totals, generally 3-4 inches, radiated away from this area up into northwestern Todd County, and then eastward towards Ogilvie and Braham. The National Weather Service cooperative observer in Brainerd reported 2.93 inches.
[see: Central Minnesota Extreme Rainfall, June 29-30, 2020]
- June was a warm month. The preliminary statewide average temperature for June 2020 was 68.2 degrees or three degrees above normal. June 2019 was 65.4 degrees or .2 degrees below normal. The warmest temperature reported in Minnesota was 102 degrees at Granite Falls on June 7 and the coldest temperature reported for the month was 29 degrees seven miles northwest of Two Harbors on June 13.
[see: June 2020 Climate Summary Table | 2020 June Departure from Normal Temperature Map]
Where we stand now:
- Seasonal precipitation so far (April 1 through June 30) shows a pattern of the state split by the very damp northwest and southeast, to quite dry in a swath from west central to northeast Minnesota. Northeast Minnesota in particular has been missing the storms this summer with precipitation ranking below the 5th percentile. One the other side of the coin, parts of Kittson, Roseau and Dakota Counties are in the 90th percentile for the wettest season so far.
[see: Seasonal Precipitation Maps]
- The U. S. Drought Monitor map released on July 2 depicts 19% of the state in Moderate Drought conditions and 45% of the state in Abnormally Dry conditions. 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 levels to be much above normal to normal over southeast Minnesota, normal across the central, and below normal to low across the north central and northeast. Northwest Minnesota has much above normal streamflow.
[see: Cooperative Stream Gauging | USGS Stream Flow Conditions]
- Water levels on Minnesota lakes vary depending on lake and location in the state. On July 1, Minnetonka was at 929.22 feet with 25 cfs flowing through Gray's Bay Dam. Last year at this time there was 250 cfs flowing out the lake. White Bear Lake was at 925.2 and was nearly the same as a month ago. Rainy Lake was at the low end of the normal band and Lake of the Woods was below the median range for early July. Lake Superior was at 62.82 feet on June 26, eleven inches above the June average and four inches below the record June level set in 2019.
[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 July 8 reported that topsoil moisture across Minnesota is 1 percent Very Short, 11 percent Short, 71 percent Adequate, and 17 percent Surplus. Soil moisture levels at Lamberton on June 15 were slightly below historical averages. Most of the deficit was in the top twelve inches of soil.
[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 southern and west central and east central Minnesota. Fire danger was Moderate over central and northwest Minnesota. Fire danger was high in the far north central and all of the Arrowhead. Historically, 80 percent of all wildfires in Minnesota occur during April and May.
[see: Fire Danger Rating Map]
- The July precipitation outlook has a tilt for above normal precipitation over much of the state, except the northeast and southeast. July precipitation normals range from just under three inches in northwest Minnesota to about five inches in southeastern counties.
[see: Climate Prediction Center 30-day Outlook | July Precipitation Normal Map]
- The July temperature outlook looks to be heavily tilted to above normal, with the greatest chance in the southeast. Normal July high temperatures are in the 80s in the south and the upper 70s in the north. Normal July low temperatures are in the 50s in the north, and in the 60s in the south.
[see: Climate Prediction Center 30-day Outlook ]
- he 90-day precipitation and temperature outlook for July through September indicates above normal precipitation in the far south and equal chances everywhere else. It looks like there is a continued tendency for above normal temperature conditions. Looking ahead to the winter of 2020-21, there are equal chances of below, normal and above normal temperatures with a tendency for above normal precipitation.
[see: Climate Prediction Center 90-day Outlook | Dec-Jan_Feb 2020-21]
From the author:
- The pan evaporation for the St. Paul Campus in June 2020 was 8.18 inches. This was the highest June evaporation total since 8.81 inches in June 2007. The normal June pan evaporation is 6.56.
Upcoming dates of note:
- July 16: National Weather Service releases 30/90 day temperature and precipitation outlooks
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