The New 1981-2010 Climate Normals
The new 1981-2010 climate normals for thousands of locations across the United States have been released by the National Climatic Data Center (NCDC). The new climate normals data, along with a more comprehensive explanation about the new climate normals, can be found here. The new normals are available for viewing now by the general public, but won't officially go into effect until August 1st, 2011. That is when climate products issued by the National Weather Service will begin to reflect these changes. For example, the climate normals currently issued in the daily climate (CLI) and preliminary local climatological data (CF6) products for Huntsville and Muscle Shoals still contain daily climate normals from the 1971-2000 base period. However, starting August 1st, the daily, monthly, seasonal, and annual normals within these products will reflect the latest 1981-2010 base period. (For access to the CLI or CF6 products issued by the National Weather Service, click here. From this page, select the CLI or CF6 product, then select the location and timeframe and then press Go. The appropriate product will open in a new window.)
So, how have the climate normals changed for Huntsville and Muscle Shoals? Well, for nearly every month, temperatures have increased for both locations. This is because we have swapped the relatively cool 1970s for the warmer 2000s. On the other hand, normal precipitation totals have decreased...overall. General decreases in normal precipitation amounts were noted for the spring months, but months in other seasons were mixed. Annual snowfall normals decreased only modest amounts: 0.1 inches at Huntsville and 0.2 inches at Muscle Shoals. Because of the increase in normal temperatures, heating and cooling degree day normals changed accordingly, with lower monthly heating degree days, and higher monthly cooling degree days.
The new daily and monthly normals for Huntsville and Muscle Shoals can be found by clicking the links below.