September 2011 Climate Data and MWN Forecast Accuracy

With one of the hottest summers on record in Memphis in the history books (3rd warmest behind 1980 and 2010), a welcome change arrived in September - temperatures averaged below normal for the month! After temperatures of 96 or higher the 1st through 3rd, fall arrived with only two 90+ degree readings the rest of the month. Precipitation was also slightly below average. No daily records were broken during the month.

Memphis International Airport, Memphis, TN

The average temperature for the month of September was 73.3 degrees, which was 1.9 degrees below normal and over 10 degrees cooler than August. The average high temperature was 83.6 degrees and the average low was a pleasant 62.9. The coolest temperature of the month was 55 degrees on the 7th and again on the 27th, while the highest temperature was 99 degrees on the 1st.  There were just 5 days in which the high temperature reached at least 90.

Precipitation for the month totaled 2.56", which was 0.53" below average.  There were just 5 days with measurable rainfall and most of that fell on 2 days that measured more than one inch each (the 19th and 25th). The greatest 24-hour total was 1.32" on the 25th. The peak wind gust was 39 mph on the 14th with an average wind speed for the month of 6.8 mph. Click here for a daily statistical recap for Memphis International Airport.

Cirrus Weather Solutions, Bartlett, TN

The average September temperature at Cirrus Weather Solutions in north Bartlett was 69.9 degrees with a maximum of 99.2 degrees on the 1st and a minimum of 48.2 degrees on the 9th. September precipitation was about an inch more than the Memphis airport, totaling 3.50". A co-located manual gauge used for the CoCoRaHS program measured 3.70". The peak wind gust was 28 mph on the 5th. Average relative humidity was 70%. Click here for a daily recap on MemphisWeather.net.

MWN Forecast Accuracy

For the month of September, the average temperature error in all MWN temperature forecasts was 2.22 degrees, lower than all compared computer models, including the NWS. Nearly 65% of the MWN temperature forecasts for the month were within 2 degrees of the actual temperature. MWN's forecasts extend out five periods (or 2.5 days). For dewpoint accuracy, the MWN forecast beat all data sources, averaging 2.42 degrees error and falling within 2 degrees of the actual dewpoint 62% of the time. Historical accuracy statistics can be found here.

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