Thursday, September 2, 2010

August Climate Stats and MWN Forecast Accuracy

Memphis International Airport, Memphis, TN
August is typically a hot month in the Mid-South, but August 2010 set multiple daily heat records and will go down as the 3rd hottest August on record. Ten temperature records were tied or broken (listed below) and Excessive Heat Warnings were in effect on 14 days with Heat Advisories in effect another 4 days.

For the month, the average temperature was 86.6 degrees, which was 5.4 degrees above normal. The average high temperature was 95.8 degrees and the average low was 77.3, with 29 of 31 days reaching a high of at least 90. Typically, only 17 days reach highs of 90 degrees or higher. The maximum temperature for the month was 104 degrees on the 4th and the lowest was 66 on the 27th. There were 7 days in which the high temperature was at or above 100 degrees and 12 days on which the low never dropped below 80.

Temperature Records for August - Memphis Int'l
DateTemp.Record Set/Tied
8-182Record High Minimum
8-2100Record High (tied)
8-282Record High Minimum (tied)
8-3103Record High
8-384Record High Minimum / All-Time (tied)
8-4104Record High
8-483Record High Minimum
8-1880Record High Minimum (tied)
8-19100Record High (tied)
8-2181Record High Minimum

For the summer months (June-July-August), 2010 will go down as the 2nd hottest summer on record with an average temperatures of 85.4 degrees, behind only the much-maligned summer of 1980, which averaged 85.6 degrees. The average low temperature was 76.3 degrees - the warmest ever. Unfortunately, there were also 21 heat-related fatalities during the summer months in Shelby County (compared to 83 in 1980). In addition, 85 days (of 92) reported high temperatures of 90 degrees or higher. (Source: Commercial Appeal)

As far as precipitation was concerned, the month continued the mainly dry trend of the summer period. Precipitation totaled 2.32" or 0.68" below normal. There were 9 days with measurable rainfall, but 6 of those saw less than one-tenth of an inch. A total of 1.18" of rain fell on the 22nd, or just over 50% of the month's total. The peak wind gust was 49 mph, recorded in a thunderstorm on the 13th, while the average wind speed for the month was 6.9 mph. Humidity averaged 64%. Click here for the NWS climate recap for August.

Bartlett, TN
Bartlett also saw a very hot and dry month. The average temperature for August at the WXLIVE! station in north Bartlett was 83.7 degrees with a maximum of 103.1 on the 4th and a minimum of 57.5 degrees on the 27th. The high temperature failed to reach 90 on only 5 days, all occurring after the 24th.

August precipitation ended up well below normal with a precipitation total of 1.77", with only 5 days or measurable rainfall. A co-located manual gauge used for the CoCoRaHS program measured 1.79" in August. The peak wind gust was 25 mph on the 22nd. Click here for a daily statistical recap on MemphisWeather.net.

MWN Forecast Accuracy
For the month of August, the average temperature error in all MWN temperature forecasts was only 1.47 degrees, beating all compared computer models, including the National Weather Service, by 17% or more. It was also the most accurate month for MWN in over 2 years and MWN's 5th most accurate month ever (12+ years of daily forecasts)! Over 80% 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 was also the best of the data sources at 1.84 degrees average error and was within 2 degrees of the actual dewpoint almost 68% of the time. More detailed accuracy statistics can be found here.

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2 comments:

LoneStarSailor68 said...

Great monthly summary! Thanks for sharing.

Kevin said...

Great summary. I am wondering how far out our dewpoint were in relation to normal. There has got to be some record busters in there as well.