Drought Update - 9/5 - Some Easing In N. Plains, Southeastern States

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National Drought Summary -- September 5, 2006


The discussion in the Looking Ahead section is simply a description of what the official national guidance from the National Weather Service (NWS) National Centers for Environmental Prediction is depicting for current areas of dryness and drought. The NWS forecast products utilized include the HPC 5-day QPF and 5-day Mean Temperature progs, the 6-10 Day Outlooks of Temperature and Precipitation Probability, and the 8-14 Day Outlooks of Temperature and Precipitation Probability, valid as of late Wednesday afternoon of the USDM release week. The NWS forecast web page used for this section is: http://www.cpc.ncep.noaa.gov/products/forecasts/.

The Southeast, Gulf Coast, and Mid-Atlantic: Tropical storm Ernesto was the weather maker this week for the region. First making landfall over southern Florida and then again in the Carolinas, Ernesto brought significant rainfall to the Mid-Atlantic region that was D0 and D1. Rainfall amounts along the coast were between 6 and 8 inches in much of Virginia and North Carolina, with some reports of more than 10 inches. Wilmington, North Carolina, reported 10.19 inches of rain for the week, while Kinston, North Carolina, had 11.10 inches and Elizabeth City recorded 14.49 inches. In Virginia, North recorded 13.58 inches, Norfolk 12.21 inches, and Powhatan 12.78 inches. Farther inland, rainfall amounts were less, but still in the 3-4 inch range. This event allowed for an elimination of all the D1 in the region and a reduction of the D0. Longer-term hydrologic concerns remain in North Carolina, as the rains missed the most critical areas.

The Plains and Midwest: Cool temperatures prevailed over much of the Plains and Midwest, with temperatures 5-10°F below normal this week. Many locations also recorded precipitation this week, with the heaviest rains reported in North Dakota and Minnesota. With the continued wet pattern in South Dakota, the D4 region was eliminated and D3 conditions were also reduced in the central part of the state. In eastern South Dakota, D1 and D0 conditions were also improved because of a recent surplus in precipitation. In Brookings, South Dakota, more than 9 inches of rain has been recorded over the last month. Drought categories were also improved in southeast North Dakota into western Minnesota as 1-2 inches of rain were recorded in these particular areas. In Illinois, the D1 conditions were improved in the west-central portion of the state.

In Oklahoma, the entire D4 region that remained in the state was eliminated, with categorical improvements for the remaining drought categories. The recent change to a wetter pattern has provided relief to drought conditions, with longer-term impacts slower to respond.

Changes in drought categories were abundant in Texas this week. Continued heavy rains over much of west Texas and the Panhandle allowed for vast improvements to take place. In west Texas, the areas of D0, D1, D2 and D3 were all reduced and shifted farther to the east. Midland, Texas, set a record for total precipitation for the month of August with 5.92 inches. For the year, Midland has received 12.92 inches of precipitation, which is 3.15 inches above normal. The area of D4 in northeast Texas was also reduced in size with the western edge shifting to the east.

The Rockies, West, and Southwest: It was again a dry week over much of the West and Rocky Mountains. In Idaho and Washington, the D0 conditions were expanded to the west in response to the dry conditions. The D3 conditions in Wyoming expanded along the North Platte River valley out of Nebraska and also in the north-central portions of the state. A mix of both long- and short-term dryness has impacted the agricultural industries in Wyoming and played havoc on water supplies. D3 conditions were also expanded in Montana in response to the increasing fire danger situation.

New Mexico again showed improvements over much of the southern and northeastern portions of the state. The monsoon season has been beneficial to improvements in the drought situation for New Mexico. In Arizona, southern California and Nevada, conditions have continued to be dry, with much of this area missing out on the rains that other areas received. Yuma, Arizona, has recorded only 0.23 inches of rain this year, which is 12 percent of normal. Las Vegas, Nevada, has recorded only 0.50 inches of precipitation this year, which corresponds to 15 percent of normal. In response to the dryness being observed, D0, D1 and D2 conditions were expanded to the west.

Hawaii: Continued dryness in the Hawaiian Islands this week. With few or no impacts being reported as a result of the dry conditions, the D0 conditions over much of the state will continue.

Looking Ahead: The next five days (September 7-11) has a slow moving trough and associated upper-level low moving east across the United States. The upper-level low is anticipated to become cut-off over the upper Mississippi Valley during this progression. With this system, cool temperatures are projected over much of the country, excluding the northern Rocky Mountains. Temperature departures should approach 3°F over much of the High Plains and Desert Southwest. Warm temperatures over the northern Rocky Mountains should push temperatures to 9-12°F above normal for this time of year. The monsoon rains should continue over Arizona, New Mexico and Colorado, while convective precipitation should bring further drought relief to parts of the High Plains and upper Midwest. Conditions look favorable along the Gulf Coast and Florida to see multiple rain events through the period.

For the ensuing 5 days (September 12-16) a broad trough is forecast to dominate the eastern two-thirds of the United States and along the California coast. A weak ridge is expected to develop over the Southwest. Temperatures are expected to be above normal over much of the West, with cooler temperatures prevailing over the Plains, Southeast and Great Lakes regions. The best chance for precipitation during this time is forecast to be in the Plains to Midwest regions and along the Mid-Atlantic. For Alaska, above-normal precipitation is anticipated over much of the state. In Hawaii, an increase in the trade winds should help increase precipitation chances on the windward sides of the Islands.

Author: Brian Fuchs, National Drought Mitigation Center

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