Washington, January 11, 1999
NOAA announced today that global temperatures in 1998 were the warmest
in the past 119 years, since reliable instrument records began. The previous
record high surface temperature was set last 1997. The global mean temperature
in 1998 was 1.20 °F (0.66°C) above the long-term average value
of 56.9°F (13.8°C). This was the 20th consecutive year with an
annual global mean surface temperature exceeding the long-term average.
"The persistent 1997-1998 El Niño, which lingered into the
first half of the year, and the unprecedented warmth of the Indian Ocean
contributed to this record warm year," said NOAA Administrator Dr.
D. James Baker
Both land and sea surface temperatures were above the long-term average.
Sea surface temperatures were 0.92°F (0.51°C) above normal, while
the land surface experienced even greater warmth at 1.84°F (1.02°C)
above normal. Tropical latitudes (30°N - 30°S) established a new
record by a wide margin, averaging 1.76°F (0.98°C) above the long-term
mean, 0.68°F (0.38°C) above the previous record set in 1987. The
Northern Hemisphere (30°N - 90°N) also set a record at 2.16°F
(1.20°C) above mean. The Southern Hemisphere (30°S-90°S) did
not experience record heat, although temperatures averaged 0.65°F (0.36°C)
above the long-term mean.
Regional and Seasonal Variations
in Global Temperatures
An examination of global temporal and regional temperature anomalies
reveals many distinct patterns. For instance, while most of the tropical
land mass and ocean surface temperatures averaged above normal, a persistent
flow off the Indian Ocean brought relatively cool, cloudy weather to equatorial
east Africa during the first half of the year. Many areas in Western Europe
and North America experienced their warmest February in 100 years. In June,
a record-breaking heat wave in central Russia resulted in huge fires. Australia
recorded its highest annual mean temperature since high-quality records
began in 1910. Canada reported one of its warmest years since 1948.
A rapid reversal in the sea surface temperature anomaly pattern occurred
in the eastern equatorial Pacific as warm anomalies (El Niño) transitioned
to cold anomalies (La Niña) during the latter half of the year.
Annual temperatures averaged below the 1880 - 1997 mean over northern
sections of Eurasia and southern South America. The cold weather in northern
Eurasia was accompanied by excessive spring and autumn snow cover. While
Europe and northern Asia experienced harsh early winter conditions late
in 1998, much of North America had unusually warm autumn weather. Mild
conditions in eastern North America came to an abrupt end as a major arctic
blast spread south during the last couple weeks of the year.
Temperatures in the United States
The United States average temperature in 1998 was 54.62°F (12.57°C),
which placed the year in a virtual tie with1934 as the warmest year in
records dating to1895. The average temperature in 1934 was 54.67°F
(12.59°C) and the third warmest year on record was 1921 with an average
of 54.42°F (12.46°C). Several regional and seasonal records were
also set throughout the year. For example, the region from the Northeast
to the Great Lakes experienced its warmest January-May. The Southern Plains
experienced its warmest July-September while the Far West saw its third
warmest. From the Southern Plains to the Gulf Coast, the warmest May-November
was established in 1998. The protracted summer heat wave resulted in extraordinary
runs of daily temperatures 90°F or hotter in several Texas and Florida
cities. In contrast, California and Nevada experienced their second coolest
April-June. September monthly anomalies show that nearly two-thirds of
the contiguous United States was much warmer than normal.
Global Precipitation
The 1998 global average precipitation anomaly for the land surface was
less than 0.1 inches (2.5 mm) above the 1900-1997 mean. However, considerable
differences were evident in precipitation departures across latitude bands
with an average surplus of precipitation in the majority of the Northern
Hemisphere, and a deficit elsewhere. Land areas between 30°N and 55°N
averaged 2.31 inches (58.7 mm) above normal, more than the equivalent volume
of water flowing through the Mississippi River during an entire year. Precipitation
also averaged above normal in the Northern Hemisphere high latitudes (55°N-85°N).
Conversely, the equatorial zone (10°S -10°N) averaged 7.18 inches
(182.4 mm) below the long-term mean.
The 1997-98 El Niño event was one of the two strongest this century.
It was associated with extremely dry conditions and devastating fires in
many areas of the world, including Indonesia, eastern Russia, Brazil, Central
America and Florida. The El Niño was also associated with extensive
flooding in parts of northern Argentina and coastal Peru. The rapid shift
to La Niña conditions at mid-year was associated with extremely
heavy rains in many parts of Asia. The Indian monsoon season started later
than usual, but ended with massive flooding along the Ganges river valley.
Devastating late summer flooding developed on the Yangtze River in China,
causing massive damage and killing more than 3000 people. Rain in the African
Sahel got off to a slow start, but rainfall was greater than normal across
much of the region during the latter half of the season.
Although many regions of South Asia received ample rains during the
summer monsoon season, the watersheds along the Mekong River of Southeast
Asia and the Indus River in Pakistan experienced extensive droughts. Summer
heat and dryness plagued the Ukraine, Kazakhstan, and southern Russia.
Canada reported one of the ten driest January-November periods since records
began in 1948.
Precipitation in the United States
The United States had the fifth wettest year on record in 1998 with
a national average of 32.61 inches (828 mm) of precipitation. The wettest
year was 1973 at 33.99 inches (863 mm). Considerable regional and seasonal
variation in precipitation anomalies occurred throughout the year. For
example, the Southeast and Great Lakes regions had their wettest January-March
in 1998, and the West had its wettest January-June.
A record dry April-June resulted in drought conditions from the Southern
Plains to the Gulf Coast states. The spring and summer heat and drought
led to massive wildfire outbreaks in Florida. Late summer and autumn rains
from tropical systems helped abate the dry conditions in the South, while
drought intensified in the eastern U.S. The region from the central Atlantic
Coast to New York experienced the second driest July-November on record.
Natural Disasters
Numerous weather-related natural disasters occurred in 1998. A January
ice storm caused widespread power outages in eastern Canada and the northeastern
United States. The deadliest Florida tornado outbreak on record occurred
the night of February 22. A frontal system moving across the Central Plains
spawned 20 tornadoes in Oklahoma on October 4, setting a national record
for the most twisters ever during a single day in October. The preliminary
annual count of tornadoes observed in the United States was 1239 (the average
is 1186).
El Niño contributed to the late start of the 1998 Atlantic Hurricane
season which, under the influence of La Niña, ended as one of the
deadliest in history with 14 named storms. Three hurricanes and four tropical
storms caused billions of dollars of damage to the United States. Hurricane
Georges devastated the northern Caribbean in late September. Hurricane
Mitch, one of the most powerful Atlantic hurricanes on record, devastated
many Central American countries in October, and resulted in a staggering
loss of life. In the Pacific, October's Supertyphoon Zeb inundated the
northern Philippines, Taiwan, and Japan. Only eight days later, Supertyphoon
Babs struck the Philippines, submerging parts of Manila.
For more information, refer to...
The
Global Temperature Anomalies
NOAA's National Climatic Data Center is the world's largest active archive
of weather data. The preliminary temperature and precipitation rankings
are available from the center by calling: 828-271-4800.
NOAA works closely with the academic and science communities on climate-related
research projects to increase the understanding of forecasting techniques.
NOAA's Climate Prediction Center monitors, analyzes and predicts climate
events ranging from weeks to seasons for the nation. NOAA also operates
the network of data buoys and satellites that provide vital information
about the ocean waters, and initiates research projects to improve future
climate forecasts. The long lead climate outlooks are available on the
Internet at
The 1998 statistics are available at
For more information contact Stephanie Kenitzer at (301) 763-8000 ext.
7007 or Patricia Viets at (301) 457-7007
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