U.S. experiences warmer than average September

Tropical Storm Lee drenches parts of the U.S. while extreme drought conditions persist in the Southern Plains

October 7, 2011

Significant events for September 2011.

Significant events for September 2011.

High resolution (Credit: NOAA)

During September, a persistent upper-level weather pattern brought above-average temperatures to the western third of the country, below-average temperatures to the central United States, and above-normal temperatures to the Northeast. The remnants of tropical storm Lee brought significant rainfall from the Gulf Coast into the Northeast, causing above-normal precipitation for most of the eastern United States, and alleviating drought across parts of the Gulf Coast. Dry conditions prevailed across the Plains and into the Northwest, with the national precipitation average near normal.

The average U.S. temperature in September was 66.9 degrees F, which is 1.5 degrees F above the long-term (1901-2000) average. Precipitation, averaged across the nation, was 2.43 inches. This was 0.10 inch below the long-term average, with large variability between regions. This monthly analysis, based on records dating back to 1895, is part of the suite of climate services NOAA provides.

September 2011 precipitation "divisional rank" map.

September 2011 temperature "divisional rank" maps.

High resolution (Credit: NOAA)

U.S. climate highlights – September

September 2011 precipitation "divisional rank" map.

September 2011 precipitation "divisional rank" map.

High resolution (Credit: NOAA)

July-September and year-to-date

NCDC’s monthly reports are based on preliminary data, which are subject to revision. Additional quality control is applied to the data when late reports are received several weeks after the end of the month and as new scientific methods improve NCDC’s processing algorithms.

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