Drought - July 2003
U.S. Drought Highlights:
- On the national scale, severe to extreme drought affected about 20 percent of the contiguous United States as of the end of July 2003
- moderate to extreme drought affected about 31 percent of the contiguous U.S.
- Short-term conditions were dry across much of the West and central and southern Great Plains, as well as a few locations along the east coast
- Above-normal precipitation in July improved the moisture conditions in some dry areas of the Great Lakes
- Long-term moisture deficits persisted across parts of the Great Lakes to central Plains, northern Maine, and much 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 20 percent of the contiguous United States as of the end of July 2003, an increase of about 6 percent compared to last month
- about 31 percent of the contiguous U.S. fell in the moderate to extreme drought categories (based on the Palmer Drought Index) at the end of July
- 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 13 percent of the contiguous U.S. fell in the severely to extremely wet categories at the end of July
- 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).
Above-normal rainfall in July 2003 improved the moisture conditions in some dry areas of the Great Lakes. However, the month was dry across much of the West and central and southern Great Plains, as well as a few locations along the east coast. The primary stations in southern Alaska and most of Hawaii were drier than normal during July, and most of the stations reporting in Puerto Rico had below-normal rainfall for the last 4 weeks to 8 weeks.
Some regional highlights:
- New Mexico had its driest July, and four other states had ranks in the top ten driest for July, in 2003, based on statewide records going back to 1895
- Washington and Oregon had their 3rd driest and 5th driest May-July, respectively, and their second driest June-July, in the 109-year record
- Maine had its 7th driest August-July in the 109-year record
- unusually hot temperatures accompanied the dryness, with many stations in the West and Great Plains reporting record high temperatures in July
- according to early August reports from the USDA,
- 55% or more of the topsoils were classified in "poor" or "very poor" ("short" or "very short") condition for all of the reporting states from North Dakota to Texas then westward to the Pacific coast
- 40% or more of the pasture and range land was classified in "poor" or "very poor" condition for several central Plains and Far West states
- end-of-July reservoir storage for all of the western states averaged below the long-term mean percent of capacity for this time of year
- as noted by the National Interagency Fire Center , more than four dozen significant wildfires had broken out across the southern Plains and western states by the end of July