Monthly Report Summary Information

National Summary Information - September 2016

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For extended analysis of regional temperature and precipitation patterns,as well as extreme events, please see our full report that will be released on October 12^th.

Significant climate events for September 2016

U.S. had ninth warmest September; second warmest year to date

4 new billion-dollar disasters bump year-to-date total to 12

The contiguous U.S. September average temperature was 67.2°F, 2.4°F above the 20^th century average, making it the ninth warmest September in the 122-year period of record. Record warmth was observed across parts of the Southeast, Midwest, and Mid-Atlantic with below-average temperatures across parts of the interior West. The year-to-date (January-September) contiguous U.S. average temperature was 57.8°F, 2.8°F above average, making it the second warmest on record, behind only 2012. A warmer than average September in Alaska contributed to a record warm first nine months of 2016 for the state.

The September precipitation total for the contiguous U.S. was 2.70 inches, 0.21 inch above the 20^th century average, and ranked near the median value in the 122-year period of record. Above-average precipitation was observed across parts of the Rockies, Great Plains and the Mid-Atlantic to Southeast Coast with below-average precipitation in the Far West, Southeast and Northeast. The year-to-date (January-September) contiguous U.S. precipitation total was 24.77 inches, 1.57 inch above average, and the 19th wettest.

Through the end of September, there were 12 weather and climate disaster events with losses exceeding $1 billion each across the U.S. in 2016. These included four flooding events (doubling the previous annual record) and eight severe storm events. Overall, these events resulted in 68 fatalities and had significant economic effects on the impacted areas.

This analysis of U.S. temperature and precipitation is based on data back to January 1895, resulting in 122 years of data.

Supplemental September 2016 Information

• September temperature and precipitation grid rank maps

U.S. climate highlights: September

Temperature

September 2016 Temperature Departure from Average
(top) and Precipitation Percent of Average (bottom)

• Above-average temperatures were observed for most locations east of the Rockies. Twenty-eight states across the Midwest, Southeast and Northeast were much warmer than average. Alaska was also warmer than average. Ohio was record warm, with a monthly temperature 4.9°F above average.
• Near- to below-average temperatures were observed from the Rockies to the West Coast.

Precipitation

• Above-average precipitation was observed across the interior West, Northern Plains and Rockies, Upper Midwest and parts of the Southeast and Mid-Atlantic. Delaware, Iowa, Montana, North Dakota, South Carolina, Utah and Wisconsin were much wetter than average.
• Hurricane Hermine formed in the Gulf of Mexico and made landfall along the Florida Panhandle on September 2 as a Category 1 hurricane with sustained winds of 80 mph. Hermine was the first hurricane to make landfall in Florida since Wilma in 2005. Hermine quickly weakened after making landfall, but its remnant low pressure system moved across the Southeast, bringing flooding rains to Florida, Georgia, and the Carolinas. At least five fatalities were attributed to Hermine.
• In late September, extremely heavy rainfall impacted central and northeastern Iowa causing record and near-record river levels across the state. Five-day precipitation totals exceeded 10 inches for some locations. The Cedar River in Cedar Rapids, Iowa crested at its second highest level, shy of the 2008 record, with water inundating large parts of the city.
• Below-average precipitation was observed across parts of the West Coast, Central Rockies, Southeast and Northeast. Maine and Vermont each had monthly precipitation totals that were much below average.
• According to the September 27 U.S. Drought Monitor report, 19.0 percent of the contiguous U.S. was in drought, down about 0.6 percent compared to the end of August. Drought conditions worsened and expanded across parts of the Southeast, Northeast and Great Basin. Drought reduction was observed across parts of the Southwest, Great Plains and coastal Southeast.

U.S. climate highlights: year-to-date (January-September)

Temperature

Jan-Sep Temperature Departure from Average
(top) and Precipitation Percent of Average (bottom)

• All 48 states across the contiguous U.S. observed much-above-average temperatures for the first nine months of the year. This contributed to the second warmest year to date on record, with only 2012 being warmer. No state in the contiguous U.S. had a record warm year to date.
• The Alaska year-to-date temperature was 37.0°F, 6.9°F above average, surpassing the previous record warm January-September of 1926 by 2.8°F. Record and near-record warmth engulfed Alaska for much of 2016.

Precipitation

• Above-average precipitation was observed across parts of the Great Plains, Lower Mississippi Valley and Midwest. Kansas, Louisiana, Michigan, Minnesota, Texas and Wisconsin were much wetter than average. Below-average precipitation fell across parts of the Southwest, Southeast, and Northeast where Connecticut and Massachusetts were much drier than average. No state was record wet or record dry for the year to date.

Extremes

2016 Billion Dollar Disasters through September

• Four new billion-dollar disasters were added during the third quarter of 2016, bringing the year-to-date event total to 12. This represents the second highest total number of events in any calendar year, surpassing the 11 observed in 2012. The record number of events in one year (since 1980) is 16, as observed in 2011.
• The U.S. has already experienced four billion-dollar inland flood events to date during 2016, doubling the previous annual record, as no more than two inland flood events have occurred in a year since 1980.
• In total the U.S. has now sustained 200 weather and climate disasters since 1980 where overall damages/costs reached or exceeded $1 billion (including CPI adjustment to 2016). The total cost of these 200 events exceeds $1.1 trillion.
• The U.S. Climate Extremes Index (USCEI) for the year to date was 65 percent above average and the fifth highest value on record. On the national scale, extremes in warm maximum and minimum temperatures, the spatial extent of wetness and one-day precipitation totals were above average. The USCEI is an index that tracks extremes (falling in the upper or lower 10 percent of the record) in land-falling tropical cyclones, temperature, precipitation and drought across the contiguous U.S.

For extended analysis of regional temperature and precipitation patterns, as well as extreme events, please see our full report that will be released on October 12^th.