Drought - November 2003
U.S. Drought Highlights:
- On the national scale, severe to extreme drought affected about 19 percent of the contiguous United States as of the end of November 2003
- moderate to extreme drought affected about 37 percent of the contiguous U.S.
- Near- to above-normal precipitation fell across parts of the drought areas during November, especially in the West, bringing short-term relief
- November was dry across parts of the Great Plains and Southeast
- Long-term moisture deficits (last 6 to 24 months) persisted across parts of the Great Lakes to central and northern Plains, and most of the West
Please Note: The data presented in this drought report are preliminary. Ranks, anomalies, and percent areas may change as more complete data are received and processed.
On the national scale,
- severe to extreme drought affected about 19 percent of the contiguous United States as of the end of November 2003, a decrease of about 9 percent compared to last month
- about 37 percent of the contiguous U.S. fell in the moderate to extreme drought categories (based on the Palmer Drought Index) at the end of November
- on a broad scale, the last two decades were characterized by unusual wetness with short periods of extensive droughts, whereas the 1930s and 1950s were characterized by prolonged periods of extensive droughts with little wetness (see graph below right)
- about 14 percent of the contiguous U.S. fell in the severely to extremely wet categories at the end of November
- a file containing the national monthly percent area severely dry and wet from 1900 to present is available
- historical temperature, precipitation, and Palmer drought data from 1895 to present for climate divisions, states, and regions in the contiguous U.S. are available at the Climate Division: Temperature-Precipitation-Drought Data page in files having names that start with "drd964x" and ending with "txt" (without the quotes).
Near- to above-normal precipitation fell across parts of the drought areas during November, especially in the West, bringing short-term relief. The month was dry across parts of the Great Plains, upper Midwest, and Southeast. The primary stations in Hawaii were near to drier-than-normal while the pattern in Alaska was mixed with wet stations predominating. The stations in Puerto Rico were wetter than normal during the last 4 weeks to 8 weeks.
In spite of the November wetness, long-term moisture deficits (last 6 to 24 months) persisted across parts of the Great Lakes to central and northern Plains, and most of the West. In the three-month timeframe, the Southeast and West experienced drier-than-normal conditions and September-November was especially dry in the central Plains.
Some regional highlights:
- End-of-November reservoir storage for all of the reporting western states averaged below the long-term mean percent of capacity for this time of year.
- The percent area of the western U.S. (Rockies westward) experiencing moderate to extreme drought (as defined by the Palmer Drought Index) decreased during November to about 71%, which is still near record historical levels.
- Several weather systems brought substantial snowfall to parts of the West and northern Plains. Although the valley airport stations did not reflect this moisture, the high elevation mountain SNOTEL stations indicated both above-average precipitation and snow water content in parts of the Pacific Northwest and northern and central Rockies.
- The November wetness was a welcome change, but significantly more precipitation is needed to bring about a full recovery from the drought. Considerable dryness was still evident in western reservoir levels, modeled soil moisture across the West, Great Plains, and Midwest (both surface and deeper layers), streamflow runoff (both modeled and measured), long-term precipitation percentiles, and drought indices such as the Palmer Hydrological Drought Index and 6-month to 24-month Standardized Precipitation Index.