August 2010 Saint Cloud Weather Summary

Wet And Wild Summer Finishes Warm and Wet

7th Warmest, 11th Wettest August in St. Cloud Records

Saint Cloud Weather Summary for August 2010 and Summer 2010

Issued: Wednesday, November 3, 2010 8:19 AM

A very wet and persistently warm summer ended in August 2010 with the warmest and wettest month of the three in central Minnesota.

The average temperature at the St. Cloud Regional Airport was 72.7°F, 5.5°F warmer than normal. This made August 2010 the 7th warmest August in St. Cloud records and the warmest since 1983. It was only the second August to crack the top 10 since 1947.

Tied for Most August 90-Degree Highs In Past 40 Years

There were 7 highs of at least 90 degrees in August 2010, more than double the normal number of 90-degree highs. This August tied with August 1978, August 1988, and August 2003 for the most August 90-degree days in the past 40 years. The record for the most 90-degree days in August is 14, set in 1900.

So far this warm season, St. Cloud has had 13 90-degree highs. That's now a bit above the normal 90-degree highs for the summer and the most since there were 20 90-degree highs in 2006 and 2007. This is still far fewer than the last really hot summer in St. Cloud in 1988, when there were 33 days with a high of 90-degrees and 7 days with a high of 100-degrees. Despite all of the 90-degree highs in August, St. Cloud has never been as warm as the 94 degree high set on May 24, the warmest temperature of the summer.

Very Mild Low Temperatures

Because of the persistent wetness and storminess to be described below, the average August low temperature in St. Cloud was a very mild 61.7°F, 5.3°F warmer than normal. That's the 5th warmest August average low temperature and the warmest since 1947. Low temperatures only dropped below 60 degrees 9 times out of the 31 August days. In contrast, the low temperature on August 30 was 70 degrees, tying the daily record warm low set in 1969. That low temperature was also the 4th low of 70 degrees or warmer of this summer, the most since 2006.

Summer Warm, But Misses Top 10

The warm August pushed the meteorological summer average temperature (June 1-August 31) to 70.2°F, 2.8°F warmer than normal, but about a degree cooler than the 10 warmest summers in St. Cloud records. That's far enough down on the list, however, to rank only as the 24th warmest out of the 130 summers in St. Cloud records. In recent years, 2005 (70.4°F) and 2006 (70.5°F) were warmer. In 1988, temperatures were much warmer (72.0°F, tied for 4th warmest). On the other hand, many of St. Cloud's recent summers have been much cooler, including 2009 which tied for the 9th coolest. The average summer temperatures bottomed out in 1991 and 1992, thanks to the extra dust thrown into the atmosphere by the Phillippine volcano Mt. Pinatubo. Still, there have been several cool summers in the past 20 years, including 2009, which t ended up tied for the 9th coolest, and 2004 which ended up tied for the 4th coolest. Note that the five-year running average was about as cold as it has been in the early 1990's, but has since recovered thanks to the warm summers of 2005-2007 and this year.

Persistently Stormy Weather Continued in August

Along with the very warm conditions, August 2010 and the entire summer was known for its wetness. The August 2010 rainfall at the St. Cloud Airport was 6.36 inches, 2.43 inches above normal. That made this past month the 11th wettest August and the wettest since 1995, but fell three-tenths of an inch of short of climbing into the 10 wettest Augusts. Since the heavy rainfall was triggered by thunderstorms, rainfall amounts varied widely, but some areas got much more rain than St. Cloud. During the past 4 weeks, Melrose has been more than 5 inches of rain above normal with Willmar, Hinckley, Morris, and Collegeville more than 3 inches above normal.

The St. Cloud Airport often missed the heaviest rain earlier in June and July, so the total summer rainfall was 14.43 inches, 2.75 inches above normal. However, much of central Minnesota has been doused all summer, according to the State Climatology Office. There has been more than 16 inches of rain since June 2 along Hwy. 23 to the northeast of St. Cloud and through Mille Lacs Lake to Aitkin. Areas like Hinckley, Pine City, and Detroit Lakes have received over 20 inches of rain (normal for the whole year in St. Cloud is a little over 27 inches), likely making it the wettest summer on record. This will go down as the wettest summer on record in much of eastern South Dakota and parts of southeastern Minnesota (including Wabasha and the Winona Dam).

This rainfall was, believe it or not, badly needed in parts of central Minnesota. Going into August, the St. Cloud Airport was two and a quarter inches short on rainfall since the snow melted in mid-March. As of August 31, the St. Cloud rainfall since March 12 is now 17.96 inches, above the normal growing season rainfall (17.62 inches). Still, the Arrowhead of Minnesota continued its multi-year drought. Rainfall this season has been 4-6 inches below normal. Drier than normal conditions continue near Lake Traverse and Wheaton and south central Minnesota near Albert Lea and Austin. This shows up in the National Drought Mitigation Center's Drought Monitor as part of the overall drought conditions in the Lake Superior basin. On the other hand, these conditions have eased from the severe drought conditions seen in late June.

Severe Weather Marches On, With Direct Hit in St. Cloud Area on August 12-13

All of the thunderstorms also continued the severe weather outbreaks we've seen so often in Minnesota. Central Minnesota received direct hits from the two largest outbreaks: August 7-8, which included tornadoes near Evansville and wind damage in Milaca, and August 12-13. The second storm included two tornadoes touching down in Stearns County, one near Brooten and the other on the east side of St. Augusta. The next afternoon, there was also a widespread straight line wind damage event from Holdingford and St. Stephen through Rice and Little Rock Lake. There were widespread wind gusts over 60 MPH and one gust to 81 MPH along the north side of Little Rock Lake. Another area of tree damage was along the southeast side of St. Cloud from Riverside Park and Killian Blvd eastward to Talahi School and the St. Cloud city maintenance building. There was also some flooding in St. Cloud. A total of 2.71 inches of rain fell at the St. Cloud Airport from the evening of August 12 through the afternoon of August 13, including 1.97 inches in an hour. That was the heaviest 24-hour rainfall at the St. Cloud Airport in 4 years. A total of 2.34 inches fell during August 13, breaking the daily record rainfall. The rainfall at SCSU was 3.14 inches, the 9th heaviest 24-hour rainfall since 1991.

Tornado County Uncertain In Minnesota, but Likely Headed for a Record Total

Minnesota has had 724 preliminary reports of severe weather, including 145 initial tornado reports. That's the most tornado reports of any state so far this year, partly due to the high number of tornadoes and partly due to how thickly settled the population is in Minnesota. Damage surveys, which narrow down the number of tornadoes and distinguish straight-line wind events, like the one just to our north on August 13 from tornadoes, take quite a while. The National Weather Service still isn't done surveying the tornado damage in the Red River Valley and eastern North Dakota from that June 17 outbreak. There were an estimated 45 tornadoes touched down, but only 20 have been confirmed so far. The record 4 tornadoes rated EF-4, for the first time in one day in Minnesota. In a normal year, 25.8 tornadoes are recorded in Minnesota. The most tornadoes in a calendar month was 38 tornadoes in June 2001. The record for a tornado season is 72 tornadoes.

September Begins Cooler, But Stormy Pattern Isn't Over Yet

Are we done with the summer heat and storms? The steering winds are in the process of shifting from high pressure in the east to high pressure in the west, allowing northwest flow from Canada on the NWS HPC three-day steering wind forecast to bring in cooler and drier air for the Labor Day weekend. However, by late in the weekend, the southwest upper-level flow will try to resume. At this point, that would put Minnesota and the Dakotas in the main belt of the westerlies, which would be the boundary between hot, sticky air to the south and east and cooler air in the northwest. That will at least keep the active weather pattern going. I don't know if we will see any more hot, humid days, but with the warm air so close, I could see the possibility of breaking out into the 80's. Note that 90-degree highs and even a few 100-degree highs have been observed in St. Cloud as late as the 17th of September.

    August 2010 Statistics

Summer (June 1-August 31) 2010 Statistics