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: October 10, 2024
What happened in September 2024:
- September 2024 was a dry month across Minnesota with very few exceptions. The locations that saw the most precipitation was in the far northwest and north central and in the far southeast. Nearly the entire state finished with below normal precipitation as the drought reasserted itself. The preliminary average statewide precipitation was only .70 inches, or 2.58 inches short of normal. September 2024 will likely finish in the top five driest Septembers going back to 1895. One of the few locations that finished with above normal precipitation was at International Falls with 3.58 inches or .58 above normal. There were many locations that finished two inches short of normal. One of the driest locations was at the Twin Cities International Airport with only .06 inches (six hundredths of an inch) and 2.96 inches below normal and was the driest September on record back to 1873. Fargo, North Dakota also had its driest September on record with only .08 (eight hundredths) of an inch.
[see: September 2024 Precipitation Total Map | September 2024 Precipitation Departure Map | September 2024 Climate Summary Table | 2024 September Departure from Normal Precipitation Map - In a month where precipitation was scant, there was one severe episode of note.
- On September 19, a broken line of storms stretched from Kansas to northeast Minnesota and marched east. Some of these storms turned severe in eastern Minnesota and dropped hail the size of half dollars at near Miesville in Dakota County and Kenyon in Goodhue County. There was also a tornado reported near the towns of Canyon and Cotton of St. Louis County.
[see: September 19, 2024 Severe Weather and Cotton Tornado] - Preliminary temperature data for September shows that it could rank as the warmest September on record back to 1895 for Minnesota. The Preliminary average temperature was 65.6 degrees, or 6.1 degrees above normal. If this holds, it would break the old record of 63.7 degrees in 2015. Just last year in September 2023 it was the second warmest on record with 63.4 degrees. The warmest temperature found so far in the state was 93 degrees at Gaylord in Sibley County. The coldest temperature found so far was 28 degrees at both Brimson and Celina in northeast Minnesota on September 7. No widespread killing frost was reported in Minnesota during the month of September.
[see: September 2024 Climate Summary Table | 2024 September Departure from Normal Temperature Map]
Where we stand now:
- Minnesota is still seeing lingering echoes of the wet spring and early summer. Seasonal precipitation totals (April 1 through October 8) ranked above the historical median south of a line from Fargo to Duluth and over the Red River Valley. Pockets of below normal precipitation for the warm season are beginning to show up particularly in St. Louis and northern Cook and Lake Counties.
[see: Seasonal Precipitation Ranking Maps] - The U. S. Drought Monitor map released on October 10, depicts drought intensity that has increased over the last couple weeks. 29% of the state in the Abnormally Dry category, 49% is in the Moderate Drought category and 20% in the Severe Drought 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 levels have been on a downward trend. On October 10, stream flows are generally below to much below normal over central and northern Minnesota and near normal to below normal over the south. The Mississippi River at Brainerd was in the “Low” category.
[see: USGS Stream Flow Conditions | Weekly Stream Flow Maps and Tables] - Water levels fell on lakes in general during the lake summer and into autumn. Mille Lacs was about two-tenths of a foot below the median lake level for early October. On October 10, Minnetonka was at 928.58 about three tenths of a foot higher than this time a year ago. The Gray’s Bay Dam closed on October 4, after being open for 156 days. White Bear Lake was at 922.63 feet. While this is a rise of .38 tenths of a foot from a year ago, it is a fall of about six tenths of a foot from the peak during the summer of 2024. Lake of the Woods was at the low end of the normal band for early October, Rainy Lake as also at the lower end of the normal band. Lake Superior was at 601.10 on October 4, five inches below the early October average. Superior is forecasted to fall two inches by the beginning of November.
[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 October 1 reports that topsoil moisture across Minnesota is 17 percent Very Short, 40 percent Short, 42 percent Adequate, and 1 percent Surplus. 82% of the corn crop was mature, slightly ahead of the five year average. About 15% was harvested for grain. 68% of soybeans were harvested, one week ahead of the five year average. Soil moisture levels at Lamberton on September 15 are about .36 inches short of the historic average. There is very little moisture in the top two feet of the profile.
[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 as of October 5 rated by DNR Forestry as High in a line from International Falls southward to St. Cloud and west of the Twin Cities to southeast Minnesota, and Very High across the rest of the state. Historically, 80 percent of all wildfires in Minnesota occur during April and May.
[see: Fire Danger Rating Map]
Future prospects:
- The Climate Prediction Center's outlook paints a picture of a generally warm and dry October. There is a tilt for below normal precipitation in the south, with equal chances for below, normal, and above normal precipitation in the north. October precipitation normals range from about one-and-a-half inches in northwest Minnesota to about three-and-a-half inches in Cook County. Southern and central Minnesota range by about one-and-three-quarters of an inch in the southwest to about two-and-a-half inches in east central Minnesota.
[see: Climate Prediction Center 30-day Outlook | October Precipitation Normal Map] - The October temperature outlook has a strong tendency for above normal temperatures throughout Minnesota for October, and much of the country west of the Mississippi River. In Minnesota, normal October high temperatures are in the 60s to start the month, dropping to the low 50s to upper 40s by month's end. Normal lows are in the 40s early in the month, falling to the 30s by late October.
[see: Climate Prediction Center 30-day Outlook | October Temperature Normal Map] - The 90-day temperature outlook for October through December has a three-sided coin of equal chances of above, normal and below normal temperatures. The 90-day precipitation outlook for October through December indicates equal chances of below-normal, near-normal, or above-normal conditions across most of Minnesota, except the northeast where there is a slight tilt to above normal precipitation. .
[see: Climate Prediction Center 90-day Outlook] - According to the October El Niño-Southern Oscillation (ENSO) Outlook, there is a 71% chance of La Niña from September-November 2024, and is expected to persist though January-March 2025. The Outlook for December 2024-February 2024 has equal chances of below normal and above normal temperatures and a slight tilt for above normal precipitation. Will this mean more snow? We will have to wait and see!
[see: Climate Prediction Center December-January 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:
- Even though the drought has returned in Minnesota, it was so wet during spring and early summer that many places in central and southern Minnesota will likely wind up above normal for precipitation for 2024. As of October 10, the Twin Cities has 31.60 inches of precipitation for the year so far, or 4.45 inches above normal for the year to date. If the Twin Cities gets .03 (three hundredths) of an inch of precipitation by December 31, the year will wind up with above normal precipitation (with normal being 31.62 inches). The last four years saw below normal precipitation.
Upcoming dates of note:
- October 17: National Weather Service releases 30/90 day temperature and precipitation outlooks
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Pete Boulay, DNR Climatologist