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Preliminary climate summary for September

Preliminary climate summary for September:

Like most months of 2016 September was warmer than normal. Most observers report a mean monthly temperature that is 2 to 4 degrees F warmer than normal. On a statewide basis September of 2016 will be among the 15 percent warmest in history back to 1895. This follows a trend towards warm Septembers, as last year produced the warmest September in state history, while 2004, 2005, 2009, and 2013 were among the warmest ten Septembers in history as well. Extreme values of temperature for the month were 94 degrees F at Amboy (Blue Earth County) on the 21st and just 29 degrees F at several locations in northern Minnesota on the 14th.

The month of September was moderately wetter than normal in the north and very much wetter than normal in southern Minnesota, where some observers reported rainfall that was 4X or 5X times normal. Most observers reported rainfall on at least half of the days of the month. Some of the rains came in heavy thunderstorms which produced well over 100 daily rainfall records in the Minnesota observation network during the month, including 7.64 inches at Waseca on the 22nd which was a new statewide record for the date.

Some observers reported their wettest September in history. Among these locations were:

Albert Lea 10.31 inches
Lanesboro 12.75 inches
Caledonia 13.13 inches
Spring Valley 10.44 inches
Hokah 11.54 inches
La Crescent 10.33 inches
Waseca 14.80 inches
Spring Grove 13.89 inches
Chatfield 12.55 inches

Overall on a statewide basis it was the 10th wettest September in history back to 1895. The heaviest rains over September 21-22 caused flash flooding in many areas, and an EF-1 tornado struck Camp Ripley on September 7th causing some damages to structures and cars (a somewhat rare event).
Climate Adaptation: Transforming Awareness Into Action:

Climate Adaptation Discussion:

I will be offering a one-night program on this topic through the University of Minnesota College of Continuing Education's LearningLife Program on October 5th at at 630 pm on the St Paul Campus. If you are interested about enrollment you can find out more at the LearningLife web site.

Weekly Weather Potpourri:

This week NOAA scientists offer an interesting look at the climatology of first seasonal snowfalls. Naturally the higher elevations in the western states are likely to have seen some this month, but many areas of the Northern Plains and Northern Great Lakes can see first snowfalls during the month of October.

The United Kingdom Met Office reported this week that September of 2016 will likely be the 2nd or 3rd warmest since countrywide record keeping began in 1910. The warmest day of the year occurred there (at Gravesend in Kent) when 94 degrees F was reported on September 13th.

Tropical Storm Chaba was churning in the Western Pacific Ocean and was expected to develop into a typhoon over the weekend. It will strengthen and heat for southern Japan next week, perhaps bringing high winds, large waves, and intense rainfall by the middle of next week.

MPR listener question:

You mentioned last week that Waseca is on a pace to set a new annual precipitation record for Minnesota. What other locations might set a new annual precipitation record during this extraordinary wet year of 2016?


Using the year-to-date precipitation totals for 2016 so far, there are several communities that are within 6 inches of setting a new record for wettest year in history. Some of these are listed below with their year-to-date total precipitation in parenthesis:

Aitkin (35.79")
Brainerd (33.65")
Redwood Falls (38.06")
Faribault (39.57")
New Ulm (37.75")
St James (44.28")
St Peter (38.64")
Waseca (49.11")
Austin (37.79")
Harmony (43.22")
Preston (41.31")
Rochester (37.37")
Winona (38.51")
Zumbrota (38.92")

With three months left in 2016, climate statistics show that average precipitation for those months totals in the range of 4-6 inches for most locations in the state. With normal precipitation, most of these communities will set new annual precipitation records this year, and Waseca could be the first stations ever to report over 54 inches for a year.

Twin Cities Almanac for September 30th:

The average MSP high temperature for this date is 65 degrees F (plus or minus 10 degrees F standard deviation), while the average low is 46 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for September 30th:

MSP weather records for this date include: highest daily maximum temperature of 87 degrees F in 1897; lowest daily maximum temperature of 44 degrees F in 1985; lowest daily minimum temperature is 26 degrees F in 1939; highest daily minimum temperature of 68 degrees F in 1878; record precipitation of 1.06 inches in 2007; and a record 0.1 inches of snow fell on this date in 1961.

Average dew point for September 30th is 43 degrees F, with a maximum of 66 degrees F in 1971 and a minimum of 18 degrees F in 1974.

All-time state records for September 30th:

The state record high temperature for this date is 93 degrees F at Montevideo (Chippewa County) in 1897. The state record low temperature for this date is 10 degrees F at Big Falls (Koochiching County) in 1930. State record precipitation for this date is 5.00 inches at Cook (St Louis County) in 1995; and record snowfall is 3.0 inches at Isabella (Lake County) in 1985.

Past Weather Features:

The end of September and beginning of October brought a mini Heat Wave to Minnesota in 1897. Most communities saw daytime temperatures climb into the 80s F, while 20 climate stations set new temperature records with highs in the 90s F.

Thunderstorms brought heavy rains and flash flooding over September 29-30, 1925. Many areas reported 2 to 4 inches of rain. Harvest delays lasted over a week.

Widespread frost was reported on September 30, 1930. Many observers reported morning lows in the 20s F, while sections of northern Minnesota fell into the teens F.

North-central and northeastern Minnesota communities recorded their first snowfall of the season over September 30 to October 1 of 1985. Observers there reported 2-8 inches of slushy snow. Thankfully it did not last for more than a day or two.


Mostly sunny with above normal temperatures over the weekend and into next week. A chance for showers by Wednesday, then a drop in temperatures and showery the rest of the week.

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