2012 sets dubious U.S. weather records
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January 11, 2013 |
2012 was warmest and second most extreme year on
record for the contiguous U.S., according to an
analysis
http://www.ncdc.noaa.gov/sotc/
released by National Oceanic and Atmospheric
Administration's National Climatic Data Center.
2012 was a historic year for extreme weather
that included drought, wildfires, hurricanes and
storms; however, tornado activity was below
average
2012 marked the warmest year on record for the
contiguous United States with the year
consisting of a record warm spring, second
warmest summer, fourth warmest winter and a
warmer-than-average autumn. The average
temperature for 2012 was 55.3 degrees F, 3.2
degrees above the 20th century average, and one
degree above 1998, the previous warmest year.
The average precipitation total for the
contiguous United States for 2012 was 26.57
inches, 2.57 inches below average, making it the
15th driest year on record for the nation. At
its peak in July, the drought of 2012 engulfed
61 percent of the nation with the Mountain West,
Great Plains, and Midwest experiencing the most
intense drought conditions. The dry conditions
proved ideal for wildfires in the West, charring
9.2 million acres — the third highest on record.
The U.S. Climate Extremes Index indicated that
2012 was the second most extreme year on record
for the nation. The index, which evaluates
extremes in temperature and precipitation, as
well as landfalling tropical cyclones, was
nearly twice the average value and second only
to 1998. To date, 2012 has seen 11 disasters
that have reached the $1 billion threshold in
losses, to include Sandy, Isaac, and tornado
outbreaks experienced in the Great Plains, Texas
and Southeast/Ohio Valley.
The Annual Climate Report for the United States
has several pages of supplemental information
and data regarding some of the exceptional
events 2012.
-- Every state in the contiguous United States
had an above-average annual temperature for
2012. Nineteen states had a record warm year and
an additional 26 states had one of their 10
warmest.
-- On the national scale, 2012 started off much
warmer than average with the fourth warmest
winter (December 2011-February 2012) on record.
Winter warmth limited snow with many locations
experiencing near-record low snowfall totals.
The winter snow cover for the contiguous U.S.
was the third smallest on record and snowpack
totals across the Central and Southern Rockies
were less than half of normal.
-- Spring started off exceptionally warm with
the warmest March on record, followed by the
fourth warmest April and second warmest May. The
season’s temperature was 5.2 degrees above
average, making it easily the warmest spring on
record, surpassing the previous record by 2
degrees. The warm spring resulted in an early
start to the 2012 growing season in many places,
which increased the loss of water from the soil
earlier than what is typical. In combination
with the lack of winter snow and residual
dryness from 2011, the record warm spring laid
the foundation for the widespread drought
conditions in large areas of the United States
during 2012.
-- The above-average temperatures of spring
continued into summer. The national-scale heat
peaked in July with an average temperature of
76.9 degrees F, 3.6 degrees above average,
making it the hottest month ever observed for
the contiguous United States. The eighth warmest
June, record hottest July, and a
warmer-than-average August resulted in a summer
average temperature of 73.8 degrees, the second
hottest summer on record by only hundredths of a
degree. An estimated 99.1 million people
experienced 10 or more days of summer
temperatures greater than 100 degrees F, nearly
one-third of the nation’s population.
-- Autumn and December temperatures were warmer
than average, but not of the same magnitude as
the three previous seasons. Autumn warmth in the
western United States offset cooler temperatures
in the eastern half of the country. Although the
last four months of 2012 did not bring the same
unusual warmth as the first 8 months of the
year, the September through December
temperatures were warm enough for 2012 to remain
the record warmest year by a wide margin.
-- The nationally-averaged precipitation total
of 26.57 inches was 2.57 inches below average
and the 15th driest year on record for the lower
48. This was also the driest year for the nation
since 1988 when 25.25 inches of precipitation
was observed.
-- Each season of 2012 had precipitation totals
below the 20th century average: Winter brought
below-average precipitation to both coasts and
above-average precipitation to the Southern
Plains, slightly lessening drought conditions
that plagued the region in 2011. The winter
precipitation total was 89 percent of normal.
-- Spring precipitation was 95 percent of the
20th century average with below-average
precipitation in the Rockies and Midwest and
above-average precipitation in the Northwest and
Upper Midwest.
-- Summer precipitation was 88 percent of normal
with dry conditions in the central United
States. The West Coast, Gulf Coast, and
Northeast were wetter than average.
-- Autumn was drier than average for most of the
central U.S., with wet conditions in the
Northwest, Ohio Valley, and Northeast. The
autumn precipitation total was 85 percent of
average.
-- Tropical cyclone activity across the North
Atlantic in 2012 as above-average with 19 named
storms, ten hurricanes, and one major hurricane
(Category 3 or stronger). This is the third
consecutive North Atlantic tropical cyclone
season with 19 named storms and ties with as the
third most active season for the basin. Isaac
and Sandy made landfall along the U.S. coast
during 2012 causing significant impacts. Isaac
brought large storm surge and torrential rains
to the Gulf Coast. Sandy caused significant
damage to the Northeast, with 8 million homes
losing power and 131 fatalities reported.
-- The widespread drought conditions of 2012
peaked in July with approximately 61 percent of
the country experiencing drought conditions. The
footprint of drought during 2012 roughly equaled
the drought of the 1950s which peaked at
approximately 60 percent. The size of the
current drought and the drought of the 1950s are
smaller than the drought episodes of the 1930s.
The current drought has yet to reach the
intensity or duration of the 1950s and 1930s
national-scale droughts.
-- Wildfire activity during 2012 was
above-average with 9.2 million acres burned the
third most in the 13-year record. Numerous large
and destructive wildfires impacted the western
U.S. throughout the year. The Waldo Canyon fire
near Colorado Springs, Colorado destroyed nearly
350 homes and was the most destructive fire on
record for the state. The Whitewater-Baldy
Complex fire charred nearly 300,000 acres and
was the largest on record for New Mexico.
-- Tornado activity during 2012 was below the
1991-2010 average of approximately 1,200. The
year got off to a busy start with large tornado
outbreaks in March and April causing significant
damage in the Ohio Valley and Central Plains.
May and June, typically the most active tornado
months of the year, both had less than half of
average tornado counts. The final 2012 tornado
count will likely be less than 1,000 — the least
since 2002.
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