Record and near-record breaking temperatures dominated the eastern two-thirds of the US, contributing to the warmest March on record since 1895 for the contiguous United States, according to the National Oceanic and Atmospheric Administration (NOAA) in its monthly State of the Climate report.
The average temperature of 51.1 °F was 8.6 degrees above the 20th century average for March and 0.5 °F warmer than the previous warmest March in 1910. Of the more than 1,400 months (117+ years) that have passed since the US climate record began, only one month, January 2006, has seen a larger departure from its average temperature than March 2012.
Other highlights from the report are:
Every state in the nation experienced at least one record warm daily temperature during March. According to preliminary data, there were 15,272 warm temperature records broken (7,755 daytime records, 7,517 nighttime records). Hundreds of locations across the country broke their all-time March records. There were 21 instances of the nighttime temperatures being as warm, or warmer, than the existing record daytime temperature for a given date.
A persistent weather pattern led to 25 states east of the Rockies having their warmest March on record. An additional 15 states had monthly temperatures ranking among their ten warmest. That same pattern brought cooler-than-average conditions to the West Coast states of Washington, Oregon, and California. Temperatures in Alaska during March, which are not included in the contiguous US average value, ranked as the tenth coolest on record.
The nationally-averaged precipitation total was 2.73 inches, which is 0.33 inches above average. The Pacific Northwest and the Southern Plains were much wetter than average during March while drier-than-average conditions prevailed in the interior West, Northeast, and Florida. Colorado had its driest March on record.
According to the US Drought Monitor, as of 3 April, 36.8% of the contiguous US was in drought, a decrease from 38.7% at the end of February and an increase from 28.8% a year ago on April 5, 2011. Above-average precipitation across the Southern Plains improved long-term drought conditions Texas, Oklahoma, and Kansas.
Warmer-than-average conditions across the eastern US also created an environment favorable for severe thunderstorms and tornadoes. According to NOAA’s Storm Prediction Center, there were 223 preliminary tornado reports during March, a month that averages 80 tornadoes annually. The majority of the tornadoes occurred during the 2-3 March outbreak across the Ohio Valley and Southeast, which caused 40 fatalities. Total losses from this event are estimated to exceed $1.5 billion dollars, making this the first event of 2012 to exceed one billion dollars in damages and losses.
The first three months of 2012 were also record warm for the contiguous United States with an average temperature of 42.0 °F, 6.0 °F above the long-term average. Twenty-five states, all east of the Rockies, had their warmest first quarter on record, and an additional 16 states had first-quarter temperatures ranking among their ten warmest.
Alaska had its ninth coolest January-March period; temperatures were 5.2 °F below average.
The nationally-averaged precipitation total for January-March was 0.29 inches below the long-term average. States across the Pacific Northwest and Southern Plains were wetter than average, while the Intermountain West, parts of the Ohio Valley, and the entire Eastern Seaboard were drier than average.
NOAA’s US Climate Extremes Index, an index that tracks the highest 10% and lowest 10% of extremes in temperature, precipitation, drought and tropical cyclones, was 39%, nearly twice the long-term average and the highest value on record for the January-March period. The predominant factor was the large area experiencing extremes in warm daily maximum and minimum temperatures.