Latest Seasonal Assessment -
Since mid-July, above-average monsoon convection eased long term drought conditions across southeastern Arizona, southern New Mexico, and western Texas. Precipitation was more variable over the Plains, with locally heavy rainfall easing drought and dryness, particularly across northern Texas, Oklahoma, and parts of South Dakota, while drier than normal conditions promoted drought expansion and intensification across parts of Kansas, Iowa, the Dakotas, and Montana. Exceptional drought (D4) lingered over parts of eastern Montana and western North Dakota. Impacts from persistent dry, hot weather increased across the northern Rockies and Northwest, and abnormal dryness (D0) spread into much of Washington and Oregon. Widespread heavy rainfall generally kept the East drought free, with the exception of Maine, where short term dryness reduced streamflows and promoted development of moderate drought. Abnormal dryness also crept into parts of Virginia and North Carolina, although recent rainfall kept deteriorating impacts at bay.
During the boreal fall months, climatological precipitation decreases across the Plains, and increases over the Northwest, while the transitional month of October is generally a drier time of year for much of the Nation. Above normal temperatures are favored to continue across much of the Northwest during the fall, and drought is therefore anticipated to expand across already abnormally dry portions of eastern Washington, Idaho, and western Montana. Short term drought may also develop across the Pacific Northwest early in the period, but as climatological precipitation increases later in the season, some relief becomes more likely. As climatological precipitation decreases, drought persistence is favored for Montana, North Dakota, western South Dakota, and northern Minnesota. A wet pattern over the next two weeks, however, favors drought reduction across the central Plains, Iowa, and eastern South Dakota. Drought reduction is also anticipated across southern Texas, where September is a wet time of year. CPC's official seasonal forecasts favor above-average precipitation across the southeastern US, making drought development unlikely. No tilt in the climate signal is favored for the Northeast, but drought removal is indicated on this outlook across eastern Maine, as soil and stream recharge from any precipitation that falls increases due to reduced evapotranspiration rates ahead of the winter freeze. This is a low confidence forecast, however, as any lingering subtle impacts from last year's drought conditions across New England may make current drought impacts more resistant to change.
Drought has expanded across much of Hawaii during the past several months, and persistence of drought conditions is favored ahead of the core rainy season during the winter months. No drought is indicated or expected across Alaska, and elimination of the small remaining drought area over southern Puerto Rico is favored due to wet conditions anticipated over the next several weeks, possibly related to tropical cyclone activity.
Forecaster: Adam Allgood
Next Seasonal Outlook issued: September 21, 2017 at 8:30 AM EDT
Seasonal Drought Outlook Discussion