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Preliminary Climate Summary for August 2021



Preliminary Climate Summary for August 2021:


Warmer than normal was the temperature signal across Minnesota during August of 2021. Most climate stations will report a mean monthly temperature that ranges from 1.5°F to 4.5°F above normal. This August when combined with the monthly temperatures for June and July of this year will give us a mean summer temperature across the state that ranks among the warmest 3 in state history and represents the warmest summer since that of 1988.

The largest temperature departures were in the northern portions of the state, where many new daily maximum temperature records were set during the month. The climate station at Cotton (St Louis County) reported 8 new daily maximum temperature records during August, including a new record high of 96°F on the 20th. Another northern Minnesota climate station, Thorhult (Beltrami County) reported setting 4 new daily maximum temperature records, including 96°F on the 18th. International Falls known as the nation’s icebox reported three new daily maximum temperatures during August including 92°F on the 17th. There were a number of days when the high temperature in the state was reported somewhere in northern Minnesota, a very unusual circumstance for August. The extreme temperatures for the month were 97°F at Red Lake Falls (August 4th) and at Roseau (August 18th), and a minimum of 33°F reported at Embarrass on the 14th.

Rainfall for August was mixed, but mostly (and thankfully) above normal, at least across the southern two-thirds of the state. Much of the northern third of Minnesota reported rainfall totals for August that were closer to normal and well below normal. Many climate stations will report between 4 and 7 inches of rainfall for the month, perhaps even higher with the additional rains expected on Friday and Saturday. Portions of southeastern Minnesota reported have over 7 inches for the month so far, while portions of north-central and northeastern Minnesota are likely to report less than 1 inch. Among the two dozen or more new daily rainfall records reported from the Minnesota climate station network, an amount of 5 inches at La Crescent on August 8th was the largest.

Some strong, damaging wind gusts were reported on August 23 and 26 and there were several Air Quality Alerts released by the MPCA, mostly due to wildfires in both northeastern Minnesota and southwestern Ontario.

Drought Implications from August:

Even with the surplus rainfall reported from many places across the state, the drought has persisted and even worsened in some northern areas of the state. The additional rainfalls expected over the coming weekend may benefit some areas and mitigate the areal extent of Severe, Extreme, and Exceptional Drought (currently standing at 88 percent of the state landscape). The climate for the months of September and October will be even more important in terms of their potential to mitigate the 2021 drought even further, as soil moisture recharge from each inch of rainfall is far more efficient during those months than the month of August. There are some signs in the NOAA-CPC model trends that September will start out wetter than normal, at least during the first half of the month.

25th Annual MPR Minnesota State Fair Weather Quiz:


Despite the fact that Minnesota Public Radio will not be broadcasting programs from the Minnesota State Fair this year, we will broadcast the 25th edition of the MPR Minnesota State Fair Weather Quiz from noon to 1pm on Friday, September 3rd (MPR Day at the Fair). Tom Crann will host from the St Paul radio studios and I will participate remotely. I always look forward to this program and will do my best to provide some interesting, entertaining, educational, and downright nerdy weather questions for you to consider. FM 91,1 in the Twin Cities and check your local FM radio listings for Greater Minnesota.

Weekly Weather Potpourri:


Earlier this week, August 20-22 brought record-setting rainfall to many portions of central TN. Areas of Dickson, Humphrey, and Hickman Counties reported rainfall of 11 to 17 inches. There was widespread flooding, power outages, and up to 22 people lost their lives. The NOAA-National Weather Service Office in Nashville provide a spatial analysis of the storm, and the BBC Weather Center also described the damages observed.

Meanwhile over roughly the same period of time (Aug 20-23), Tropical Storm Henri brought some record-setting rainfall amounts to portions of NY, NJ, RI, and MA. Many climate stations reported rainfalls of 6-10 inches and CNN reported on the damages from these storms.

Speaking of storms, the NOAA-National Hurricane Center is tracking Tropical Storm Ida and notes that it is expected to turn into a Hurricane as it moves through the Gulf of Mexico toward the coast of Louisiana. Storm surge, strong winds, and heavy rains (up to 10 inches) are expected to encompass the southeast coastal communities there by Sunday, perhaps in the area of New Orleans.

Scientists from the University of Southhampton have recently published a study that shows that “extensive chains of volcanoes have been responsible for both emitting and then removing atmospheric carbon dioxide over geological time.” The weathering aspects learned from Earth’s surface geology may provide some knowledge for designing pulverized rock system that through their chemical weathering can remove carbon dioxide from the atmosphere at accelerated rates. The authors caution that this is far from a silver lining story, and much more research is needed.

MPR listener question:


Chatting at the Bayside Bar and Grill in Walker, MN this week, after getting a 3-inch rainfall last weekend that flooded many streets. The question came up does flooding in the middle of a drought occur very often?

Answer:


It does occur periodically. During the historical drought of 1910 (arguably the worst in state history), portions of northern Minnesota saw flash flooding resulting from 3-inch rains on July 23rd. Also during the equally historic 1936 drought, 3-inch rains caused flash flooding in Goodhue and Nicollet Counties on August 28th. More recently, during the summer drought of 2012, June weather brought two significant flash floods: on the 14th, 6-8 inch rains fell across portions of Goodhue, Dakota, and Rice Counties leading to widespread flooding along the Cannon and Vermillion Rivers; then on June 19-20 rainfalls of 7-10 inches fell over Duluth and portions of Carlton County, leading to all-time flood crests on the St Louis River. That summer the federal government declared Drought Disasters and Flood Disasters simultaneously in some Minnesota Counties!

Twin Cities Almanac for August 27th:

The average MSP high temperature for this date is 79 degrees F (plus or minus 9 degrees F standard deviation), while the average low is 60 degrees F (plus or minus 7 degrees F standard deviation).

MSP Local Records for August 27th:

MSP records for this date: highest daily maximum temperature of 99 degrees F in 1926; lowest daily maximum temperature of 60 degrees F in 1914; lowest daily minimum temperature of 42 degrees F in 1887; highest daily minimum temperature of 79 degrees F in 2013; record precipitation of 2.80 inches in 1978. No snowfall has occurred on this date.

Average dew point for August 27th is 60°F; the maximum dew point on this date is 77°F in 2013; and the minimum dew point on this date is 33 degrees F in 1935.

All-time state records for August 27th:


The state record high temperature for this date is 103 degrees F at Tracy (Lyon County) in 1973. The state record low temperature for this date is 22 degrees F at Tower (St Louis County) in 1986. The state record precipitation for this date is 5.63 inches at Winsted (McLeod County) in 1978. No snowfall on this date.

Past Weather Features:


August 27, 1973 was probably the hottest in Minnesota history bringing 90 degrees F to most of the state, and 100°F to seven southwestern counties. The cool spot in the state was Duluth Harbor with an afternoon temperature of only 65°F.

Repeating waves of thunderstorms brought heavy rains across portions of the Twin Cities Metro Area over August 26-27, 1978. Many communities reported 3-5 inches of rainfall. It was part of a very wet August that brought 6 to 10 inches of rainfall to many areas.

A frosty morning greeted campers in northern Minnesota on August 27, 1986. Many portions of St Louis, Roseau, Beltrami, and Marshall Counties reported temperatures ranging from 22°F to 32°F. Tower reported an afternoon high of only 56°F while Duluth only made it to a high of 57°F.

Outlook: 

Generally warmer than normal Saturday with a chance for widespread showers and thunderstorms, heavy in some areas. Drier and cooler on Sunday and Monday. Cooler temperatures will be prevail for much of next week with chances for showers and thunderstorms from later on Monday night into Wednesday and Thursday.




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