Preliminary Climate Summary for May 2020

Preliminary Climate Summary for May of 2020:

As the month of May winds down this weekend, we can summarize the character of its weather. It was a cooler than normal month (following the pattern of April) with most climate stations reporting a mean monthly temperature that was 1 to 3 degrees F below normal. There was roughly an equal distribution of warmer and cooler than normal days. The extremes for the month were 89°F at Granite Falls (Chippewa County) on the 1st and just 14°F at Brimson (St Louis County) on the 12th. No new high maximum temperatures were reported within the climate station network, but 46 climate stations reported tying or setting new low minimum temperature records. Many areas of the state reported multiple frosts during the month. The highest dew points (between 65 and 70 degrees F) were measured earlier this week.

May brought a mixture of precipitation. Many portions of northern Minnesota reported snowfall earlier in the month, some of which disrupted the Fishing Opener with up to 2 inches in portions of Becker, Cass, and Otter Tail Counties. Southern portions of the state saw above normal rainfall prevail with amounts that were typically 1-2 inches above normal. Portions of Winona, Wabasha, Mower, Goodhue, Washington, Dakota, and Olmsted Counties accumulated over 6 inches of rainfall. Across the southern part of the state within the climate station network over 25 climate stations reported at least one new daily rainfall record.

In central and northern counties most climate stations reported less than normal precipitation for the month. Some areas of the state received less than 1 inch, and many areas of central and northern Minnesota now show up as abnormally dry on the U.S. Drought Monitor Map.

May 26 brought severe weather to some parts of the state. Brief tornado touchdowns were reported from Freeborn and Dakota Counties, and strong winds that damaged trees were reported in Houston and Goodhue Counties.

Weekly Weather Potpourri:

Earlier this week Tropical Storm Bertha (the 2nd named storm of the Atlantic Hurricane Season) brought heavy rains to portions of South Carolina. Some areas reported 2-3 inches of rain. But the storm soon dissipated out to sea and inflicted only a glancing blow. The National Hurricane Center is expecting a more active than usual 2020 season.

The BBC Weather Centre offers a retrospective on how 80 years ago the weather actually helped the Allied Evacuation of Dunkirk along the coast of France. Thanks to cloud cover that obscured the beaches from German aircraft, over 300,000 soldiers were successfully evacuated by a mixture of military and civilian watercraft in an operation called Dynamo.

In addition, the BBC News Service reported this week that the United Kingdom looks to have one of the best strawberry crops in recent memory thanks to the sunniest spring of all time (at least back to 1929). Parts of England are also reporting the driest month of May in 124 years.

Reported this week from Science Daily was a new study from Imperial College in London that suggests that the asteroid which killed the dinosaurs struck Earth at an angle that maximized the disturbance to the atmosphere. The mathematical simulations of the impact show that the asteroid hit Earth at an angle of about 60 degrees, which maximized the amount of climate-changing gases thrust into the upper atmosphere.

MPR listener question:

As you are aware, we have yet to have our first 80F high here in the Twin Cities. This got me wondering as to what is the latest first 80F day that has occurred in the Spring/Summer season?

Answer:

For the Twin Cities climate record back to 1873, the only years when an 80 F temperature was not reached until June were:

1873
1878
1883
1888
1892
1893
1905
1924
1935
1983

Further the latest date in the year for a temperature reading of 80 degrees F or higher was June 16 in both 1878 (81°F on June 16th) and 1883 (88° F on June 16th).

This year the Twin Cities recorded the first reading of 80°F or higher on May 26th (with a maximum of 81°F). This is still much later than normal. Aside from the years listed above, the only other years when it has taken this long to see such a temperature are 1919, 1937, 1973, 1984, 1995, 1997, and 1999. It is not an indicator of a cooler than normal summer.

Twin Cities Almanac for May 29th:

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 May 29th:

MSP records for this date include: highest daily maximum temperature of 94 degrees F in 2018; lowest daily maximum temperature of 53 degrees F in 1947; lowest daily minimum temperature of 33 degrees F in 1965; highest daily minimum temperature of 74 degrees F in 2006; record precipitation of 2.49 inches in 1949. No snowfall has occurred on this date.

Average dew point for May 29th is 50°F; the maximum dew point on this date is 72°F in 1953; and the minimum dew point on this date is 25°F in 1947.

All-time state records for May 29th:

The state record high temperature for this date is 101 degrees F at Chaska (Carver County) in 1934. The state record low temperature for this date is 20 degrees F at Bigfork (Itasca County) in 1965. The state record precipitation for this date is 7.50 inches at Thief River Falls (Pennington County) in 1949. Record snowfall for this date is 2.6 inches at Spring Grove (Houston County) in 1947.

Past Weather Features:

By far the warmest May 29th in state history occurred in 1934. Well over half of the state landscape saw afternoon temperatures reach the 90s F. Portions of western Minnesota reached the century mark. This began a four-day Heat Wave.

A freak, and short-lived snowstorm brought a trace of snow to a few tenths across portions of Minnesota on May 29, 1947. Associated with this storm were some frosty temperatures as many climate stations in western and northern Minnesota reported temperatures in the 20s F which damaged the corn and wheat crops.

May 28-29, 1953 brought strong thunderstorms to the state. Many communities saw 2-4 inches of rainfall. Pelican Rapids reported over 4.5 inches with widespread flooding.

Outlook:

A pleasant weekend coming up with slightly cool than seasonable temperatures and sunshine. Cloudiness with a chance for rain returns on Monday and Tuesday. Temperatures begin climbing into the 80s F for the middle of next week with higher dew points. Indications are that the first half of June will run warmer than normal.