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: November 6, 2020
What happened in October 2020:
- October 2020 was the second month in a row to finish with below normal precipitation statewide, albeit at not the same deficit that September 2020 had. The preliminary statewide average precipitation was 1.90 inches or .55 inches below normal. Last year, October 2019 had the 9th wettest October on record and 2018 was the 12th wettest on record, so one major difference in fall 2020 is that the state is not going into the winter with an autumn precipitation surplus in general. In October 2020, There were a few monthly totals exceeding three inches in the southeast and the northeast parts of the state, with Cloquet finishing at 3.39 inches or .27 inches above normal. The location with the least amount of precipitation in October was in the Grand Forks area where the International Airport there had only .37 inches or 1.60 inches short of normal. A good portion of the precipitation in October 2020 fell as snow.
[see: October 2020 Precipitation Total Map | October 2020 Precipitation Departure Map | October 2020 Climate Summary Table ]
Some notable events include: - A swath of heavy snow spread over southern and central Minnesota on Tuesday October 20, 2020, leading to widespread accumulations of 6 to 9 inches, and breaking numerous early-season snowfall records in the process.
[see: Record-Setting Heavy Snows, October 20, 2020] - Following on the heels of a historic early-season snowstorm just two days earlier, a low-pressure system moved from northeastern Kansas into southeastern Wisconsin on Thursday October 22, 2020. With temperatures in the 20s and 30s throughout Minnesota and deep moisture streaming into the region, the atmosphere was primed once again for significant accumulating snowfall.
[see: Winter Storm, October 22, 2020] - With these two snow events, it was the snowiest October on record for places such as the Twin Cities and St. Cloud.
[see: Snowy and Cold October, 2020] - October 2020 was the third October in a row that finished with below normal statewide temperatures and was the coldest of the three. The preliminary statewide average for October 2020 was 40.3 degrees or 5.9 degrees below normal. October 2020 ranked in the top ten coldest for many locations in the state, but was generally not as cold as October 2002 or 2009. The Twin Cities saw its eighth coldest October on record. The cold month was tempered a bit, due to a warm spell during the first half of the month. Many places in Minnesota saw maximum temperatures in the upper 70s to low 80s. The highest temperature for the month was 88 degrees at Marshall on the 10th and the coldest reading found was 2 degrees at Brimson in St. Louis County on the 27th.
[see: October 2020 Climate Summary Table ]
Where we stand now:
- 2020 is trending to be the driest year since 2009. Looking at the seasonal precipitation totals (April 1-November 3), much of the state is in the 20th to the 70th percentile. There are pockets of south central, west central and northwest Minnesota that are in the 70th to 90th percentile, with the wettest areas in the 99th percentile, or nearly the wettest growing season on record, in Sibley and Nicollet Counties. Large areas of northeast and along the South Dakota border are in the 5th to 20th percentile or much below normal.
[see: Precipitation Maps for November 5, 2020] - Most of the snow that fell in October melted by the end of the month and no snow has fallen in early November.
[see: NWS Snow Depth Estimation Map | Midwest Regional Climate Center Snow Depth Map] - The U. S. Drought Monitor map released on November 5, depicts nearly half of Minnesota with some level of drought designation. Last year at this time the state was free of any drought. On November 5, 2020 about 50% of the state was Abnormally Dry, and 11% of the state was Moderate Drought conditions. A small area in Rock County in southwest Minnesota had Severe Drought 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 values are mostly near normal across the state, with the exception of below normal to much below normal stream flow conditions across the far north, and especially in the northeast.
[see: USGS Stream Flow Conditions] - Water levels on most Minnesota lakes vary depending on lake and location in the state. Mille Lacs was close to the median lake level for early November and has fallen about one foot over the course of 2020. On November 6, Minnetonka was at 928.48 feet, falling about a foot since May 2020. The Gray’s Bay Dam closed on October 19. White Bear Lake was at 924.15 feet on November 4, a fall of .91 foot from one year ago. Rainy Lake is in the median range and Lake of the Woods is well below the median range for November. Lake Superior was forecasted to be at 602.79 feet on October 30, eight inches higher than the monthly average for October and six inches lower than the same time last year.
[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 November 2 reports that topsoil moisture across Minnesota is 2 percent Very Short, 8 percent Short, 84 percent Adequate, and 6 percent Surplus. Soil moisture levels at Lamberton are near historic averages and Waseca’s fall readings are close to what they were in the spring.
[see: Agricultural Statistics Service Crop Progress and Condition | U. of M. Southwest Research and Outreach Center (Lamberton) | U. of M. Southern Research and Outreach Center (Waseca)] - The potential for wildfires on November 6, 2020 is currently rated by DNR Forestry as Moderate across much of central and northern Minnesota, Very High in east central Minnesota, and Extreme in southwest and south central Minnesota. Historically, 80 percent of all wildfires in Minnesota occur during April and May.
[see: Fire Danger Rating Map]
Future prospects:
- The November precipitation outlook leans towards equal chances of above, normal and below normal precipitation. November precipitation normals range from about three-quarters of an inch in northwest Minnesota to about two-and-a-half inches in Cook County. Southern and central Minnesota range by about one-and-a-quarter of an inch in the southwest to about two-inches and a quarter in south central Minnesota.
[see: Climate Prediction Center 30-day Outlook | November Precipitation Normal Map] - The November temperature outlook has a tendency for above normal temperatures, especially in central and south. Through November 5th, statewide average temperatures are about four to ten degrees above normal. Normal November high temperatures are in the 40s to start the month, dropping to the 30s by month's end. Normal lows are in the 30s to upper 20s early in the month, falling to the teens by late November.
[see: Climate Prediction Center 30-day Outlook | November Temperature Normal Map] - The 90-day temperature outlook for November through January has equal chances of above below and normal temperatures, with a tendency of above normal precipitation in the northwest half of the state.
[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:
- There were some windy days in October, 2020. At the Twin Cities International Airport, there were six days in a row with a wind gust of 40mph or higher from the 11th-16th. The grand finale was most likely one of the windiest Halloweens on record, with an average wind speed of 17.3 mph and a peak gust of 52mph at the Twin Cities International Airport. It was a blustery night for Trick or Treating. [see: Windy October]
- La Niña conditions are forecast to be present though the winter and into the spring. The Winter Outlook (December-February) from the Climate Prediction Center has equal chances for below above and normal temperatures over the east and a tilt to colder than normal temperatures over the west. The precipitation outlook is for a tendency for above normal precipitation over all but the far southwest. [see: Climate Prediction Center December-February Outlook]
Upcoming dates of note:
- November 19: National Weather Service releases 30/90 day temperature and precipitation outlooks
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Pete Boulay, DNR Climatologist