Yesterday, August 30, the temperature dipped into the 30s for the first time since June 6. On June 6 we barely missed a very late frost when the official temperature at Hector Int’l dipped to 34 degrees. Our average first morning in the 30s this time of year is September 6, so although the 37 degree official low on Sunday was certainly chilly (other thermometers were warmer in town), it was only about one week earlier than normal. Last year our first morning with a temperature in the 30s occurred on September 8.
Back in 2004, the last year when summer temperatures were this cool, our first morning in the 30s fell on August 19 when the airport reported a low of 39 degrees which was followed by a low of 34 degrees on August 20. August 20, 2004 saw widespread frost that effectively ended the growing season for much of the area north of Fargo Moorhead.
The Sun continues to produce very few sunspots. The Sun, as of this writing, has gone 51 days without an observable spot. This ranks as the 4th longest stretch without a sunspot since 1849. The Sun is currently coming out of solar minimum, that time in the Sun’s eleven year cycle when it produces very few sunspots.
This particular solar minimum has lasted so long, that our current Sun cycle has lasted nearly 13 years instead of the average of 11. Historically, long solar cycles have attributed to cooler temperatures on Earth, which has been the case the past few years as planetary average temperatures have been declining slightly. As far back as 1801, William Herschel, the discoverer of Uranus, found a correlation between wheat prices and the number of sun spots.
New research published just last week may begin to give us a better understanding of the cause and effect relationship of this phenomenon.
UPDATE: There may have been a small spot on the Sun last evening ending the streak at 51 days.
The lack of severe weather this year has not only been a local phenomenon, but a national trend as well. The cool pattern that much of the north central and eastern part of the United States has experienced lately has inhibited the severe storm threat for much of the summer season.
This would be one attributing factor to a very positive statistic in which there has been no tornado fatalities since May 13th in the United States. Only one time since 1950 have there been no deaths associated with a tornado in the June through August timeframe in the country. But even with lower tornado numbers this year, around 500 tornadoes were reported since June in the lower 48 states (although most were rated EF0 and EF1). So another aspect to the low death rate this summer can probably be credited to better severe weather warnings and people understanding and taking appropriate shelter during the storms.
When August began, much of central Minnesota, including the Twin Cities, were experiencing severe drought conditions. For the second straight year that part of Minnesota continued to be missed by most rain events moving through the region. But so far this month, much of the rainfall deficits in that area have been erased. Anywhere from five to ten inches of rain has fallen over the Twin Cities and other portions of central Minnesota in August. With still nearly a week to go in the month, many cities are reporting one of their wettest Augusts on record. Chaska, Willmar and Lester Prairie, Minnesota have all received nearly ten inches of rain in the past three weeks.
The Twin Cities airport has measured 5.82 inches of rain this month which is more than fell the previous two months combined. One or two storms never end a drought, but recent rains have certainly helped ease it.
I was asked if this past July was only the second time on record that no site in Minnesota reported a 90 degree high. Although the major reporting sites did not reach 90 degrees last month, a few cooperative sites and the Red Wing, Minnesota airport did on July 10. It was, climatologically, unusual for the entire state of Minnesota to record so few 90 degree temperatures in the middle of summer.
It was the coolest July since 1992 and the third coolest on record for the state. The coolest July on record for Minnesota was back in 1915, which was also the coolest on record for Fargo Moorhead. Locally, no 90 degree days were recorded in July either, but that is not as unusual as you might think. In the early 1990s Fargo Moorhead had three consecutive Julys (1992-1994) with no 90 degree days recorded plus there are several other Julys reporting the same.
On a recent trip to Asia, our longest flight was one from Los Angeles to Shanghai which took nearly 14 hours to complete. Although my children were excited to fly for the first time, they both thought that particular leg of our trip was far too long.
On our way back home my eleven year old son was not looking forward to another 14 hour flight. I informed him that the flight back to the United States was going to be 2 hours shorter because in the mid-latitudes the upper-level wind generally blows from the west so we would have a tail-wind on the way home. Airlines of course take this all into account when scheduling flights.
The problem is, the wind is never the same from day to day, so often times a flight will either arrive earlier or late do to the wind speeds aloft which can bring much angst to both airlines and passengers.
The weekend rain was welcomed by many. Although the winter and early spring were very wet around the region, since April, Fargo Moorhead was running a rainfall deficit of around three inches since April. In typical thunderstorm fashion, rainfall amounts varied greatly over the past several days. The official total at Hector International was approximately 1.5 inches, whereas most cocorahs.org observers throughout the rest of Fargo Moorhead measured less than one inch.
Last year at this time rain was also needed, but very quickly the weather patterns changed and some of the wettest conditions on record dominated the weather throughout the autumn and winter seasons. So although many areas would still benefit from some additional rainfall (which will probably come tomorrow), we are only a couple of stronger storms away being very wet again. Continental climates tend to bring sudden changes in weather patterns and the past year has certainly been a good example of that.
The National Climatic Data Center (NCDC) released their official statewide statistics for July earlier this week. The data showed what a remarkably cool July most of the lower 48 states experienced. Six states, Iowa, Illinois, Indiana, Ohio, Pennsylvania and West Virginia all recorded their coldest Julys on record. Wisconsin, Michigan, Missouri and Kentucky all finished with their 2nd coldest July. Locally North Dakota as a whole recorded the 5th coldest July on record and Minnesota their 3rd.
NCDC has been recording such statistics since 1895 so it was indeed a very unique month historically for such a large portion of the United States to experience such temperature anomalies. On the opposite extreme, Texas, the southwest and extreme western part of the country experienced well above average temperatures with Arizona experiencing there 3rd warmest July in the last 115 years.