Preliminary May Climate Summary

Preliminary May Climate Summary

With about an equal number of warmer than normal and cooler than normal days during the month, most climate stations reported a mean monthly temperature for May that was very close to normal. Extremes ranged from 95°F at Granite Falls (Yellow Medicine County) on the 1st to just 16°F at Brimson (St Louis County) on the 11th. Some daily maximum and minimum records were set with the erratic temperature behavior during the month. Thirty climate stations reported setting new daily high maximum temperatures (mostly in the 80s and 90s F). Rochester reported its highest May 1st temperature in history (128 years) with a reading of 91°F. Conversely over 60 climate stations reported setting new daily record cold minimum temperature readings during the month, including 22°F at International Falls on the 6th, 25°F at Zumbrota on the 11th, and 19°F at Cotton on the 28th. The majority of the record minimum temperatures were set on May 28th (see below).

Total rainfall for May was somewhat mixed with many western and northern communities reported less than normal values, and several southern and eastern communities reporting above normal values. While some parts of northwestern and north-central Minnesota reported less than 1 inch of rainfall for the month, many areas of eastern and southern Minnesota reported 3 to 4 inches. Among the wettest were Theilman (Wabasha County) with 5.76 inches, their 11th wettest May in history, and Minnesota City (Winona County) with 5.38 inches, their 18th wettest May. Some climate stations reported setting new daily rainfall records during the month, including 2.01” at La Crescent (Houston County) on the 3rd, 1.10” at Dawson (Lac Qui Parle County) on the 15th, and 2.22” at Theilman (Wabasha County) on the 24th. Despite the abundant recent rains (over an inch in many places this week), over 70 Minnesota counties report drier than normal conditions as we end the month, with another 18 counties reporting moderate drought.

Although there were several days with wind gusts over 30 mph, even a few days with 40 mph wind gusts, May did not bring the very high frequency of strong winds that March and April did. The surprising weather event was the outbreak of brief and weak tornadoes in southern Minnesota (Steele, Rice, and Scott Counties) on the evening of May 19th. Fortunately, little damage was done.

Record Setting Low Temperatures on May 28th

Following the rains on Thursday, May 27th, clearing skies overnight produced some record low temperatures across many northern areas of the state. Some of these cause damage to emerged corn fields but because the growing point was still below the soil surface agronomists think that many of the corn fields will brown off, but then recover with new growth. Some of the record lows reported on May 28th among long term climate stations included:
19°F at Cotton
20°F at Embarrass
21°F at Babbitt, Tower, Aitkin, and Hibbing
23°F at Ely and Winton
24°F at Bemidji, International Falls, and Floodwood
25°F at Grand Rapids, Cook, Park Rapids, Crane Lake, and Bigfork
26°F at Baudette
27°F at Waskish, Cass Lake, and Wright
29°F at Winnibigoshish Dam
30°F at Isle and New York Mills
32°F at Browns Valley and Brainerd
34°F at Kimball

This appears to be the last widespread threat of frost for many areas of the state, as a projected long term warm up is seen after this weekend.

Weekly Weather Potpourri:

The BBC reported this week that Tropical Cyclone Yaas brought high winds, storm surge, and heavy rains to portions of northeast India. Some areas received over 15 inches of rain with widespread flooding. The storm was expected to continue moving north and bring heavy rain to Nepal this weekend.

Death Valley and the desert southwest are heating up this week. A strong warming trend will push temperatures over the next week to highs well above 100° F in many areas. Death Valley is supposed to see afternoon maximum temperatures rise from 109°F this weekend to about 119°F by next Wednesday. Nighttime temperatures are expected to cool off into the mid 80s F. You can read more from the National Weather Service.

MPR listener question:

With the erratic temperature behavior this Spring my wife Cindy wanted me to check how often the daily temperature has actually hit the normal value (30 yr historical average), which we have not seen yet this month in the Twin Cities.

Answer:

Actually, the highly variable climate we live in does not permit us to hit “normal” very often. The daily temperature may land on “normal” about 5 percent of the time.

Here are the number of days that the daily mean temperature (ave of Max and Min) has landed on a “normal” (30 yr average) so far this year (148 days) at selected cities around the state.
International Falls 4 days
Duluth 3 days
Rochester 7 days
St Cloud 5 days
MSP Airport 5 days

It is far more frequent that the daily mean temperature ends up being several degrees above or below normal, as was the case when International Falls was 20°F above normal on both May 17th and May 21st, or when Rochester was 33°F colder than normal back on Valentine’s Day (February 14).

Twin Cities Almanac for May 28th:

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 28th:

MSP records for this date include: highest daily maximum temperature of 100 degrees F in 2018; lowest daily maximum temperature of 46 degrees F in 1947; lowest daily minimum temperature of 36 degrees F in 1965; highest daily minimum temperature of 75 degrees F in 2006; record precipitation of 2.08 inches in 1899. Record snowfall is a Trace in 1963.

Average dew point for May 28th is 50°F; the maximum dew point on this date is 70°F in 1943; and the minimum dew point on this date is 22 degrees F in 1965.

All-time state records for May 28th:

The state record high temperature for this date is 106 degrees F at Beardsley (Big Stone County) in 1934. The state record low temperature for this date is 17 degrees F at Pokegama Dam (Itasca County) in 1889. The state record precipitation for this date is 6.15 inches at Wabasha (Wabasha County) in 1970. Record snowfall is 4.0 inches at Orr (St Louis County) in 1947.

Past Weather Features:

By far the warmest May 28th in state history was in 1934. Most parts of the state saw afternoon high temperatures in the 90s F, and 17 climate stations surpassed the 100°F mark. Beardsley in Big Stone County reported 5 days of 100°F plus readings that May.

May 28, 1947 brought a return to winter. Many northern areas of the state reported morning low temperatures in the 20s F, and frost was observed as far south as Fairmont and Windom. In addition, snow flurries were reported in a number of communities, including Rochester and Albert Lea. Up to 4 inches of snow fell in northern St Louis County at Orr.

Constant rains blanketed the southern portions of Minnesota over May 27-29, 1970. Many areas reported 2-4 inches of rainfall. Portions of Wabasha County saw 5-6 inches which flooded the Zumbro River and many nearby farm fields.

Outlook: 

Cooler than normal temperatures this Memorial Weekend with a chance for showers Sunday later on Sunday and early on Monday. Warmer Tuesday through Thursday, with temperatures returning to near normal values. Chance for showers late Wednesday and Thursday. Warmer yet towards next weekend as temperatures climb to warmer than normal values during the first week of June.