Latest Seasonal Assessment -
Since mid-August, surplus rainfall throughout the middle third of the Nation led to a decent reduction of drought coverage and severity in much of the Plains, Midwest, and Southeast. Wet weather also eased or eliminated drought in Alaska, Hawaii, and Puerto Rico. Heavy rains from minimal Hurricane Hermine reversed the drying trend along the southern Atlantic Coast and brought some relief to the eastern edge of the Southeastern drought area. Although temperatures averaged near to slightly below normal the past 30-days, short-term drought increased in parts of Idaho, Utah, and Colorado in response to impacts from a warm and dry Spring and much hotter weather earlier this summer. In the northeastern quarter of the U.S., spotty rainfall plus abnormal warmth maintained or intensified the drought in much of New England, New York, and New Jersey, but heavy rains fell on most of the eastern Great Lakes region (MI, OH, PA), leading to improvement there. However, not all areas in the middle third of the Nation saw improvement as central Oklahoma experienced minimal rain and warmth, producing short-term drought.
The drought outlook valid from September 15 to December 31, 2016 is based on the CPC October-December precipitation and temperature outlooks, precipitation forecasts during the remainder of September, recent precipitation anomalies, and climatology. ENSO-neutral conditions are now forecast for this fall and winter (55-60% chance), a change from last month's La Niña Watch. However, La Niña winter impacts are mostly incorporated in this forecast, albeit in a reduced capacity.
Although development and intensification of drought becomes less likely as temperatures and evapotranspiration decrease during the fall, persistence is favored across the long-term drought areas of the Northeast as there was no tilt either way in the precipitation outlooks. Prospects for drought removal improve toward the west in the eastern Great Lakes region where surplus rains have recently fallen, and drought is more short-term in duration. Drought persistence and expansion is forecast across the interior Southeast and northward into Virginia as recent warmth and dryness (especially in northern locales), coupled with favorable odds of submedian October and OND precipitation, should occur by the end of December. Recent excessive rainfall in the lower Mississippi Valley and along the southern Atlantic Coast should keep these areas drought-free and prevent the Southeastern drought from expanding westward and eastward. Improvement or removal of drought is favored across the Plains, except in northwestern South Dakota which has missed the recent excess rains in the region. The northern Rockies should see some improvement based upon favorable OND precipitation odds with increasing precipitation normals during the fall and winter. Persistence is forecast across the long-term drought areas of the West (OND climatology is still dry), while removal is favored along the Pacific Northwest Coast where the climatology is quite wet during November and December.
The small remaining drought area in south-central Puerto Rico is likely to be removed by the end of December. Drought removal or improvement is also forecast across the leeward sides of Kauai, Molokai, Lanai, Kahoolawe, and Maui. Alaska is drought free and should remain that way.
Forecaster: David Miskus
Next Seasonal Drought Outlook issued: October 20, 2016 at 8:30 AM EDT
Seasonal Drought Outlook Discussion