September 2009 Saint Cloud Weather Summary

For the second straight year, the most above normal month of the warm season ended up being September in Saint Cloud. According to the Saint Cloud Regional Airport statistics, the average temperature was 63.3°F, 5.9°F above normal. That tied 1922 as the 11th warmest September out of the 119 years in St. Cloud records and was 0.1°F short of breaking into the top 10 warmest Septembers. Through September 25, the St. Cloud average temperature was 65.5°F, ranking as the third warmest September and the warmest in 70 years. Still, the warmth dominated the month and was in sharp contrast to the summer (June 1-August 31) Through September 27, St. Cloud had only one day's high below 70 degrees. After having a summer with only 26 days warmer than normal out of 103 summer days, September had 23 consecutive warmer than normal days with 10 days at least 10 degrees above normal.

On the other hand, there were no September 90-degree highs, leaving the warm season of 2009 with only two such days. In fact, the warmest day of the warm season was still May 20, when the high temperature was a record-breaking 92.

The late month chill produced some widespread frost on September 30, but St. Cloud avoided its first frost in September. That first frost didn't actually occur until October 8, the second latest first frost in St. Cloud records.

The warm weather came with near record dryness. September 2009 only produced 0.61 inch of rain at the Saint Cloud Regional Airport, adding 2.32 inches to the growing season shortfall. That 0.61 inch ranked as the second driest September in the 106 years of precipitation records. The only drier September was in 1952 when only 0.07 inch fell. This pushed the growing season (April 1-Sept 30) rainfall deficit at the Saint Cloud Airport to 4.91 inches (actual: 14.90 inches; normal: 19.81 inches). The spotty nature of thunderstorm rains produced even larger rainfall deficits of 5-7 inches as close to us as Santiago and Milaca. There are several parts of Minnesota with rainfall deficits of 6-9 inches (gray and white areas on the rainfall deficit map). That has lead to a worsening drought condition from Washington County and Taylors Falls through northwestern Wisconsin on the 12-week loop of the National Drought Monitor.

The lack of rain took its toll on area rivers. Much of central and northeastern Minnesota had below normal streamflow, as seen on the September 28 DNR map. This led to the Mississippi River level at St. Cloud dropping to 4.13 feet, the fifth lowest river stages seen at this gauge (note that the third lowest level of 3.71 feet was seen in September 2007, which isn't listed in the records). The Sauk River in Waite Park dropped to 1.01 feet, the 5th lowest stage seen on that river. (In August 2007, the Sauk River was down to 0.37 feet).

Shockingly, October was an entirely different month than September, producing consistent cold conditions and one of the rainiest Octobers in St. Cloud records, beginning right away with over 2 inches of rain on October 1.

    September 2009 Statistics

The low rainfall is quite evident in the river level reports issued this week. The weekly DNR map shows streamflow in the lowest 10% from St. Cloud through most of Sherburne and Benton Counties. Currently, the Mississippi River level at St. Cloud is 4.17 feet, among the 5 lowest stages seen at this gauge (note that the third lowest levels were seen in September 2007, which isn't listed in the records). The Sauk River in Waite Park is down to only 1.17 feet, the sixth lowest stage seen on that river. (In August 2007, the Sauk River was down to 0.37 feet) The streamflow from the USGS shows that the Mississippi River basin is now below the 25% mark in the Mississippi River basin at most stations from Aitkin to the Twin Cities, in the St. Croix basin, and in the central and lower Minnesota River basin. Stream flow is now in the lowest 10% in north central Minnesota, including the Duluth, Grand Rapids, and Ely areas.

Meanwhile, temperature data shows that this September is the summer we didn't have. So far , St. Cloud is working on the warmest September in more than 70 years. Through yesterday, the average St. Cloud temperature has been 65.5°F, 7.1°F warmer than normal. If we remained this warm, this September would be the third warmest September in St. Cloud records and the warmest since 1931.