September 2009 will go down as one of the warmest and driest September on record. A warm and dry pattern setup across the Great Lakes region during the last couple days of August and continued into the third week of September. This warm and dry weather was due to an upper level ridge sitting over the western Great Lakes and a surface High Pressure covering most of the region. In fact, from August 30th through September 20, only a Trace of precipitation fell at the National Weather Service office in Negaunee Township. That 22 day period tied the 2nd longest stretch of days on record without measurable precipitation. The longest stretch with no measureable precipitation occurred in the spring of 1998 and lasted 24 days. Measurable precipitation is liquid precipitation that amounts to .01 inches or greater.
As you can see in the chart below, temperatures were well above normal through the month. There were only 6 days where the temperature was below normal, with 3 of those days occurring at the end of the month. Overall, September 2009 will go down as the 4th warmest and 6th driest September on record.
Additional Monthly Climate Graphs can be found here.
Preliminary September 2009 Climate Values and Records
Overall, September 2009 ended up with above normal temperatures and below normal precipitation.
Value Departure from Normal
Average Temperature 59.5 +5.3
Precipitation 1.84 -1.90
Here are the preliminary records that occurred in September 2009:
Note: the statistics and records for the National Weather Service office in Negaunee Township are based on records which began in October 1961. All climate data listed here are preliminary and unofficial.