April Climate Summary

April Climate Summary:

April was roughly an equal mixture of warmer than normal and colder than normal days, with the greatest departures on the cool side. A number of days tied or set records for cold daytime maximum temperature values with readings only in the twenties and low 30s F. Overall most climate stations in the state reported a mean monthly temperature that ranged from 3 to 5 degrees F colder than normal. Minnesota reported the coldest temperature in the nation only once during the month. Extremes for the month ranged from -10°F at Goodridge (Marshall County) on the 4th to 83°F at Sherburn (Martin County) on the 22nd.

April was a drier than normal month, with about 90 percent of the climate stations reporting less than average precipitation. The largest amounts were reported from western counties. Ottertail reported 3.03 inches. Many other areas reported less than 1 inch. In fact April of 2020 will rank among the 20 driest historically with a statewide average precipitation total of only 1.36 inches.

Portions of Kittson and Polk Counties in northwestern Minnesota reported the most snowfall for the month with 12 inches.

Over half of the days in the month brought wind gusts over 30 mph. Several areas reported a few days with wind gusts over 40 mph and on the 20th a number of climate stations reported wind gusts over 50 mph.

Most of the states thousands of lakes lost their ice cover during the month, and the last week of the month brought the best opportunities for farmers to get started on field work and planting. By the 26th of the month 40 percent of the corn crop was planted and nearly third of the sugarbeet crop was in the ground as well.

Weekly Weather Potpourri:

This week NOAA features an interview with their chief climate monitoring scientists Deke Arndt. It is well worth reading. I met Deke years ago in Asheville, NC where he works. He is absolutely dedicated to his profession. The Climate Monitoring Branch of NOAA is in good hands.

Also, this week the NOAA blog at Climate.gov features an interesting article about how human activity influences tropical storms in the Atlantic and Gulf of Mexico. There is pretty clear evidence for effects from greenhouse gas emissions, but there are also countering effects from various atmospheric aerosols.

NOAA outlook models continue to favor a cooler and drier than normal first half of May. This may help farmers catch up on field work, and those workers deployed for the repair and maintenance of Minnesota roads and highways will benefit from this outlook as well. You can see more at the Climate Prediction Center.

MPR listener question:

Is it my imagination, or is the sky actually bluer in the Metro Area since before the pandemic? Can air pollution change the weather?

Answer:

Certainly the decline in airline traffic (40 percent worldwide, and even greater in some countries), as well as motor vehicle traffic during the pandemic has improved air quality. Overall emissions into the atmosphere are down. In addition, much of the agricultural field working season is just ramping up, so the countryside has been relatively quiet for most of April as well. This means that soil and dust particles have been relatively absent too.

Where solar radiation is measured (the total amount of sun’s energy reaching the Earth) the numbers have been higher than normal on days without clouds. This means that atmospheric transmissivity has been exceptionally high. In other winds, a cleaner atmosphere has allowed more energy to reach the Earth’s surface minus any cloud cover.

Bottom line is, that on clear days our view of the beautiful blue sky is less obstructed or distorted, and the clarity of the blue hue in the sky is indeed more vivid.

Twin Cities Almanac for May 1st:

The average MSP high temperature for this date is 65 degrees F (plus or minus 13 degrees F standard deviation), while the average low is 44 degrees F (plus or minus 9 degrees F standard deviation).

MSP Local Records for May 1st:

MSP records for this date include: highest daily maximum temperature of 91 degrees F in 1959; lowest daily maximum temperature of 33 degrees F in 1909; lowest daily minimum temperature of 24 degrees F in 1909; highest daily minimum temperature of 64 degrees F in 1934; record precipitation of 1.26 inches in 1983. Record snowfall is 3.0 inches also in 1935.

Average dew point for May 1st is 36°F; the maximum dew point on this date is 66°F in 2001; and the minimum dew point on this date is 8°F in 1958.

All-time state records for May 1st:

The state record high temperature for this date is 100 degrees F at Beardsley (Big Stone County) in 1959. The state record low temperature for this date is 4 degrees F at Pine River (Cass County) in 1909. The state record precipitation for this date is 3.83 inches at Winona (Winona County) in 1936. Record snowfall for this date is 8.0 inches at Hinckley (Pine County) in 1909.

Past Weather Features:

The warmest May 1st was in 1959 when most communities saw the afternoon high climate into the mid 80s to mid 90s F. Beardsley reached 100°F. The nighttime minimum temperatures only cooled off into the 50s and 60s F.

One of the coldest ever May 1st came in 1966. Arctic high pressure brought single digit lows to portions of northeastern Minnesota, while much of the rest of the state saw morning lows in the teens and twenties F. Luverne measured a minimum temperature of 19°F and Hallock reached a daily high of only 30°F.

May started off winter-like back in 2013 with cold temperatures, as well as rain and snow over the first three days of the month. Many southeastern Minnesota communities measured from 8 to 15 inches of snowfall.

Outlook:

Sunny with pleasant temperatures over the weekend. Increasing cloudiness on Monday and Tuesday with cooler temperatures (below normal) and a chance for showers. Continued cooler than normal temperatures for the second half of next week as well.