A look at the climate for 2018 so far for Minnesota

A look at the climate of 2018 so far for Minnesota:

On a statewide basis we just concluded the 12 warmest June-August period in state history. In addition it was the 24th wettest summer back to 1895, but with great disparity, notably surplus rainfall in the south and deficit rainfall in the northwest.

Also on a statewide basis the first 8 months of the year averaged only about 1°F above normal, but it was the 4th year in a row, and 15 out of the last 20 years that the first 8 months of the year have produced an above average statewide temperature. In addition the first 8 months of 2018 brought a statewide average precipitation about two-thirds of an inch above normal, the 9th consecutive year this has happened.

So, when we talk about Minnesota getting warmer and wetter with each passing decade, it appears that the year 2018 will follow that trend line.

Gusty winds:

The month of September is not known as one of Minnesota’s windiest months, but the last three days have brought a good deal of wind around the state. Not so much damaging wind, but consistently high wind speeds. Many climate stations have reported wind gusts over 30 mph on Tuesday, Wednesday, and Thursday. Combined with the warm temperatures such winds are helping to dry-down the corn and soybean crops around the state as they near maturation.

Weekly Weather Potpourri:

Hurricane Florence was slowly moving over the North Carolina coastline late on Thursday night, bringing wind gusts over 70 mph, and very heavy rainfall rates, up to 3 inches per hour. It is expected to impact the weather in the Carolinas throughout the weekend and may produce some rainfall totals over 30 inches in places. I find it odd that a number of years ago the NC government chose not to factor climate change into any of their planning to protect natural resources and infrastructure from severe weather elements.

Meanwhile in the Western Pacific Ocean Super Typhoon Mangkhut was heading for the Philippines, and expected to cross the northern part of that nation over Friday and Saturday. The storm is bringing heavy rains, winds over 160 mph, with gusts over 180 mph, and sea waves near 60 feet. Many evacuations were ordered in preparation.

MPR listener question:

I have lived in the Upper Midwest (Wisconsin and Minnesota) much of my life and I have noticed that it seems when there are horrible hurricanes south of us we have glorious weather. Is this a real correlation or just that the peak hurricane season happens to be the same time of year that we have these lovely days with blue sky and low humidity?

Answer:

It is mostly coincidence rather than cause and effect. September and October are famous for bringing some of the most comfortable and sunny weather of the year to Minnesota. However, there have been a few historical episodes when strong hurricanes along the SE coast of the USA have caused a buckle in the northern jet stream and Minnesota is visited by very cool and dry Canadian air masses, sometimes bringing early frosts. Such was the case with the famous September 17, 1928 hurricane that struck Florida.

Twin Cities Almanac for September 14th:

The average MSP high temperature for this date is 73 degrees F (plus or minus 9 degrees F standard deviation), while the average low is 53 degrees F (plus or minus 8 degrees F standard deviation).

MSP Local Records for September 14th:

MSP records for this date include: highest daily maximum temperature of 98 degrees F in 1939; lowest daily maximum temperature of 48 degree F in 1903; lowest daily minimum temperature of -3 degrees F in 1923; highest daily minimum temperature of 74 degrees F in 1939; record precipitation of 1.60 inches in 1994. Record snowfall on this date is 2.4 inches in 1934.

Average dew point for September 14th is 47°F; the maximum dew point on this date is 73°F in 1994; and the minimum dew point on this date is 25°F in 2011.

All-time state records for September 14th:

The all-time state high temperature for today's date is 103 degrees F at Redwood Falls (Redwood County) in 1939; the all-time state low for today's date is 18 degrees F at Cook (St Louis County) in 1964. The all-time state record precipitation for this date is 4.60 inches at Red Wing (Goodhue County) in 1994. Record snowfall is 0.3 inches at International Falls (Koochiching County) in 1964.

Past Weather Features:

On September 12, 1923 many northern Minnesota locations reported snow, mostly trace amounts. This was one of the earliest dates in history for snowfall. On September 15, 1916 the Twin Cities reported a trace of snow as well, the earliest date in the official records.

September 14, 1923 also brought many record-setting cold temperatures, as over 20 climate stations saw morning lows drop into the 20s F, ending the growing season.

Far and away the hottest September 14th in state history came along in 1939 bringing daytime high temperatures of 90 degrees F or higher to over 50 communities. In parts of Redwood, Chippewa, Lyon, and Nicollet Counties the temperature reached the century mark.

Slow moving thunderstorms drenched the southern Minnesota counties with rainfall over September 14-15, 2004. Many areas reported 6 to 13 inches of rainfall. Flash flood warnings were issued for 13 counties and many roads had to be closed. More details from this event can be found at the Minnesota State Climatology Office web site.

Outlook:

Very warm weekend coming up with daytime highs in the 80s F. Increasing cloudiness on Monday with a chance for showers and thunderstorms later in the day and on Tuesday. Tuesday and Wednesday will be unsettled with cooler than normal temperatures, then a warm-up again towards the end of next week.