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NOAA REPORTS HURRICANES CAUSED RECORD WETNESS IN EAST
Contrasts with Dryness in Mississippi Valley, Early Snow in Alaska
Hurricanes Frances, Ivan and Jeanne, which battered the United States last month, were enough to break rainfall records for September in states throughout the Southeast and along the East Coast. Overall, temperature and precipitation were above average across the contiguous United States in September, according to scientists at the National Oceanic and Atmospheric Administration’s National Climatic Data Center in Asheville, N.C. NOAA is an agency of the U.S. Department of Commerce.
After a cool August, warmth returned in September, especially in the Great Lakes and upper Midwest, while Alaska was cooler than average for the month, compared to a record warm summer (June-August).
NOAA scientists report that the average temperature for the contiguous United States for September (based on preliminary data) was 66.5 F (19.2 C), which was 1.0 F (0.6 C) above the 1895-2003 mean, and the 28th warmest September on record. The mean temperature in 28 states was significantly above average, with six Midwestern states (and New Jersey) averaging much warmer than the long-term mean, in contrast to much cooler-than-average conditions for the Midwest in August. Alaska, which experienced a record warm summer, was cooler than average for September with a statewide temperature of –3.4 F (-1.9 C) below the 1971-2000 mean.
September was the 13th wettest on record averaged across the contiguous United States, with record wet conditions occurring in many areas of the East, resulting from several tropical systems. Pennsylvania, Georgia, West Virginia and many cities had a record wet September. Birmingham, Ala., set a record with 9.75 inches of rain falling in only 24 hours, breaking the previous 24-hour record of 8.84 inches set in July 1916 – a record also established from a tropical storm that crossed the state.
Hurricanes Frances, Ivan and Jeanne came ashore in the Southeast during September, on the heels of five tropical systems that impacted the eastern and southeastern states in August. Although wind damage was extensive with each of the September storms, flooding was a major impact, with states from Florida to New York feeling the effects.
Early snowfall was seen in parts of Alaska, with Anchorage having its greatest snowfall total for any day in September (6 inches) on September 24. This also was the largest monthly snowfall on record for the month of September.
Below-average September precipitation occurred from eastern Texas, northward to Michigan. Michigan, Indiana and Arkansas all had their second driest September since 1895. The drier-than-average conditions were combined with above-average temperatures in the upper Midwest. Although rainfall was near average in many parts of the West, long-term drought conditions continued across most the region. At the end of September, 64 percent of the western U.S. was in moderate-to-extreme drought, compared with 68 percent for August and 79 percent for last year at this time. These measurements were based on a widely used measure of drought, the Palmer Drought Index.
The average global temperature anomaly for combined land and ocean surfaces during September 2004 (based on preliminary data) was 0.92 F (0.51 C) above the 1880-2003 long-term mean. This was the fourth warmest September since 1880 (the beginning of reliable instrumental records). Land surface temperatures were anomalously warm throughout Western Europe, Scandinavia and much of Asia, with cooler-than-average conditions in northern Australia and Canada, while the global ocean surface temperature was the third warmest on record for September.
Weak El Niño conditions persisted into September, with sea-surface temperatures in much of the central and east-central equatorial Pacific remaining warmer than average for the month.
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Note to Editors: A digital version of the press release including links to data, graphics and analysis, in addition to further national and global data are online: http://www.ncdc.noaa.gov/oa/climate/research/2004/sep/sep04.html.
A detailed summary of hurricane and tropical storm activity can be
found on NCDC’s monthly hurricane summary page: