Fall 2009 Outlook and July to September Summary

By Brian Fuchs, Climatologist, National Drought Mitigation Center

Drought classifications are based on the U.S. Drought Monitor. For a detailed explanation,
please visit http://drought.unl.edu/dm/classify.htm. The outlook integrates existing conditions
with forecasts from the National Oceanic and Atmospheric Administration’s Climate Prediction
Center: http://www.cpc.ncep.noaa.gov/

Drought classifications are based on the U.S. Drought Monitor. For a detailed explanation, please visit http://drought.unl.edu/dm/classify.htm. The outlook integrates existing conditions with forecasts from the National Oceanic and Atmospheric Administration’s Climate Prediction Center: http://www.cpc.ncep.noaa.gov/

Outlook: The forecast continues to show a high probability of a weak to moderate El Niño developing for the late fall and early winter. Most models show the current event continuing to intensify, peaking in December or January and subsiding by late spring. The outlook is showing a warm trend over the western half of the United States and Alaska, and better than normal chances of above normal precipitation continuing along the Gulf Coast and into Texas. As fall comes to an end, the western United States should continue to be warm, with cool and wet weather over the Gulf Coast.

July: Drought worsened across the United States during July. The intensification of drought over Texas and Wisconsin coupled with short-term dryness across the plains and southeast accounted for the overall expansion of drought this month. July started off with 30.6 percent of the country in D0-D4 status and ended with 32.1 percent in that range. This is a vast improvement over last July, when 42.9 percent of the United States was in D0-D4 status. This year Texas was at the epicenter of extreme and exceptional drought in July. By the end of the month, 24.7 percent of Texas was in extreme or exceptional drought, with 18.7 percent experiencing exceptional drought, which according to the United States Drought Monitor is a 1 in 50 year event. What was unique about Texas’ experience is that overall, the area affected by D0-D4 conditions actually improved from 71.8 percent to 61.1 percent, but the core area of drought intensified.

Drought intensified and expanded in Wisconsin and portions of eastern Minnesota during July. By the end of the month, D2 (severe drought) covered almost half of Wisconsin, and 80 percent of the state was designated as being in D0-D4 status. Along with many areas of the High Plains and upper Midwest, cool summer temperatures helped keep most dry areas from succumbing to significant drought. Wisconsin and Minnesota had temperatures during July that were 4 to 6 degrees Fahrenheit below normal for the month.

August: The cool, wet summer continued into August for much of the High Plains and Midwest. Areas along both coasts observed temperatures above normal for August, with New England, the Pacific Northwest, and the Southwest all well above normal. During the month of August, the status of drought for the United States improved slightly, with 30.1 percent of the country being classified as D0-D4 at the end of the month, versus 32.1 percent at the beginning. Portions of Texas improved, but the core regions of D3-D4 remained unchanged for the month. With the intensity and extent of the current extreme-exceptional drought in Texas, conditions for some locations are surpassing the drought of record for the area from the 1950’s, becoming the new drought of record with billions of dollars in agricultural losses already. Washington and Montana had new areas of D2 introduced due to a warm and dry summer. The first part of the monsoon season for Arizona has been fairly dry. Along with warm temperatures, D0-D1 conditions were expanded and introduced into most of Arizona during August, while D0 was introduced into the Four Corners region and southwest Colorado.

September: Rain was the common theme for the month, with major improvements to several drought areas across the country. Flooding rains in the Southeast eliminated all drought through Georgia and the Gulf Coast states. Rains also improved much of the drought in Texas and allowed for fall planting and late season forage growth. The D4 region in Texas was reduced, eliminating all but two pockets of exceptional drought. The core area of D3-D4 drought in southern Texas was improved by several intensity levels in most instances and the core area was also reduced in spatial extent. Dryness continued through portions of the upper Midwest with D1-D2 being expanded in Minnesota and Wisconsin and a new D3 area introduced in Wisconsin. D0 expanded in Ohio, Indiana, Pennsylvania and West Virginia with D1 introduced in Ohio and Indiana and also in West Virginia and Pennsylvania. D0-D1 expanded through the Carolinas and into Virginia, with a new area of D2 introduced in South Carolina. Additional improvements from the recent rains are likely, as we see how much soil moisture recharge and recovery occurred.  

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