September 2008 Saint Cloud Weather Summary

After a summer that had a lot of relatively cool weather, September 2008 in St. Cloud had temperatures that were the most above average of any month this year. According to the Saint Cloud Regional Airport statistics, the average temperature was 59.4°F, 2.0°F above normal. While the temperature was never warm than the Labor Day high of 88°F, every day between September 16 and September 29 had an average temperature of normal or higher with 5 days at least 10 degrees warmer than normal. The first week of September was cooler as high temperatures were cooler than 70 degrees all but one day between September 2 and 9. On the morning of September 9, there was a hard freeze in parts of northeastern Minnesota and frost just to our north. If the temperature had fallen to freezing on that morning, it would have ranked in the earliest 10% of first frosts in St. Cloud. Instead, the low temperature never reached below 40 degrees until the last day of the month. When we get that frost (possibly on the 3rd or the 4th, it will rank among the latest 15% of frosts.

The milder mid-month weather also helped to break the prolonged dry spell. September's St. Cloud rainfall totalled 3.35 inches, .42 inch above normal. The month was off to a dry start, but heavy thunderstorms produced a total of 2.30 inches between September 11 and 14. That rainfall helped to ease the very dry conditions we've seen in central Minnesota since mid-June. The rainfall deficit between June 15 and September 10 in St. Cloud was 4 inches, not as severe as last year, but still enough to knock river levels to the lowest 10% of levels from St. Cloud to the Twin Cities in early September. The heavy mid-month rains eased the conditions in the St. Cloud area, but streamflow in the Twin Citie and parts of the Upper Mississippi River Basin, including Leech Lake and Lake Winnibigoshish, still rank in the lowest 10% of flows. Only 28% of topsoil moisture, as noted in the Minnesota Ag News, ranks as being short, compared to 50% early in the month. The relatively dry and warm September conditions helped many crops to catch up from the cool, wet spring conditions. The good moisture supply is also responsible for a more uniform foliage season that is just peaking in central Minnesota right now, according to the Minnesota DNR foliage report.

The weather pattern during September was quite changeable with a taste of mid-summer heat and humidity during that two week warm spell during the second half of the month. Before that, the southwest steering winds pumped enough moisture into central Minnesota to produce the heavy rainfall on September 11-14 and another period of good rainfall between September 25 and 28. This dominance of warm air pushed the tropical storm pattern into the Gulf Coast and the East Coast. This caused the major hurricane strike of Gustave in south Louisiana on the first, Ike in the Houston-Galveston area on September 13 and the close approach of Hurricane Kyle along the East Coast. However, the weather pattern had a major change to a northwest-southeast steering wind, allowing the cooling trend that has continued into early October. It's much too early to try and figure out which of these weather patterns will be more consistent.

    September 2008 Statistics