Following are highlights of the NOAA U.S. Climate Report for October. Some big temperature variations are featured as well as a historical ranking of the early-October snowstorm that brought tremendous damage to the livestock industry in the Northern Plains.--Bryce
U.S. climate highlights - October
Below-average temperatures dominated west of the Mississippi River. Oregon had its 11th coolest October, with a monthly temperature of 46.3°F, 3.0°F below average. No state had October temperatures that ranked among the ten coolest.
Above-average temperatures were observed across the Mid-Atlantic and Northeast. Delaware tied its tenth warmest October with a monthly temperature 3.5°F above average. Near-average temperatures were reported across much of the Midwest and the Southeast.
The Alaska statewide average temperature during October was 8.8°F above the 1971-2000 average marking the warmest October on record in the 95-year period of record. The previous record warm October occurred in 1925, when the temperature was 7.7°F above average. Locally, the Fairbanks average October temperature of 36.1°F was 11.9°F above normal. In addition to the above-average temperatures, many low elevation locations received much below average snowfall.
The near-average October precipitation total for the contiguous U.S. masked both wet and dry extremes. The East and West Coasts were drier than average during October. California and Oregon both had their 11th driest October. Rhode Island and Massachusetts had their fourth driest and ninth driest Octobers on record, respectively.
Much of the central U.S. was wetter than average, stretching from the Southern Plains, into the Northern Plains and Midwest. Nebraska, North Dakota, South Dakota, and Wyoming each had a top ten wet October.
An early-season blizzard hit northeastern Wyoming and western South Dakota on October 3rd-5th, dropping up to three feet of snow with winds in excess of 70 mph. Rapid City, South Dakota received 23.1 inches of snow, breaking several October snowfall records for the city. An estimated 20,000 head of cattle died during the event in South Dakota, approximately 15 to 20 percent of the state's entire cattle population. The storm was rated a Category 3 (or Major) on the Regional Snowfall Index.
According to analysis by the Rutgers Global Snow Lab, the October snow cover extent across the contiguous U.S. was the fifth largest in the 46-year period of record at 132,000 square miles, more than 60,000 square miles above average. Conversely, the Alaska snow cover extent was 53,000 square miles below average, and the ninth smallest October snow cover extent on record.
According to the October 29th U.S. Drought Monitor report, 34.7 percent of the contiguous U.S. was in drought, down 6.5 percent compared to the beginning of the month and down 26.4 percent since the beginning of the year. Drought improved for parts of the Central Rockies and Great Plains, while drought conditions developed across parts of the Northeast.
U.S. climate highlights - year-to-date (January-October)
The year-to-date contiguous U.S. temperature was 55.7°F, 0.7° above the 20th century average, and the 32nd warmest January-October on record. Above-average temperatures were observed in both the West and the Northeast. California had its 12th warmest January-October. New Hampshire and Vermont had their ninth and tenth warmest year-to-date period, respectively. Below-average temperatures stretched from the Upper Midwest, through the Ohio River Valley, and into the Southeast.
The year-to-date contiguous U.S. precipitation total of 27.01 inches was 2.23 inches above the 20th century average and the 14th wettest January-October on record. Most locations, from the Rockies to the East Coast, were wetter-than-average during January-October, while the Far West was drier than average.
Record and near-record wet conditions during the first 10 months of 2013 were observed across the Northern Plains, the Midwest, and the Southeast. South Dakota, Kentucky, Virginia, Tennessee, South Carolina, and Georgia each had a top ten wet January-October. North Dakota and Michigan both had the wettest January-October on record. The North Dakota precipitation total of 23.41 inches was 7.13 inches above average, and the Michigan precipitation total of 33.66 inches was 6.95 inches above average.
California had a record dry January-October with 5.90 inches of precipitation, 10.36 inches below average. The previous record dry year-to-date period for the state occurred in 2002, when the 10-month precipitation total was 7.19 inches.
The components of the U.S. Climate Extremes Index (USCEI) that examine extremes in 1-day precipitation totals and the spatial extent of drought ranked as the 12th and 14th highest on record for January-October, respectively. When combining all components of the USCEI, the index was slightly below average. The USCEI is an index that tracks the highest and lowest 10 percent of extremes in temperature, precipitation, tropical cyclones, and drought across the contiguous U.S.