Latest Seasonal Assessment -
During the past month, across the Northeast, the coverage of abnormal dryness (D0 on the U.S. Drought Monitor) has dropped and no areas of moderate drought (D1) remains. The development of any new drought over this region during the Dec-Jan-Feb (DJF) winter season is considered unlikely. Dryness and drought have decreased in coverage over the Midwestern states during the past month, with the exception of Missouri, where moderate to severe drought (D1 to D2) now covers most of the southeastern half of the state. According to CPC's official 90-day precipitation outlook, prospects for improvement and/or removal of drought are best for northern and eastern portions of Missouri. Elsewhere across the Midwest, drought removal and/or improvement is expected. A comparison of the latest drought conditions with those from a month ago across the High Plains region reveals relatively small changes overall, especially in terms of spatial coverage. Despite CPC's 30-day and 90-day precipitation outlooks favoring above-normal precipitation in eastern Montana and the Dakotas this winter, precipitation amounts, though likely above normal, may not be enough to overcome prior dryness, as normal amounts in that area are low, therefore drought persistence and/or intensification is likely. For western Montana, the CPC monthly and seasonal precipitation outlooks also favor above-normal precipitation this winter, but this area has already received substantial precipitation this past month and is closer to seeing drought removal and/or improvement than areas farther east. In addition, typical La Niña winters favor the proximity of the polar jet stream and the associated storm track, which also supports the idea of improving conditions over western Montana.
Across approximately the southern third of the contiguous U.S., dryness and drought have expanded across the Southwest (especially Arizona), portions of the South (with widespread severe drought (D2) in Arkansas), and the Southeast during the past 30-days. Most precipitation outlooks on timescales out through 90-days, combined with historical wintertime La Niña-related circulation patterns, favor drought persistence and/or intensification across a broad swath of the southern tier states in DJF. This is due in large part to the polar jet stream and mean storm track usually being displaced well to the north of this region during La Niña winters. In Hawaii, DJF represents the climatological core of the rainy season, and with CPC outlooks favoring above-normal precipitation this winter, it's reasonable to expect drought improvement and/or removal across the Islands. There is currently no drought in either Alaska or Puerto Rico.
Forecaster: Anthony Artusa
Next Seasonal Outlook issued: December 21, 2017 at 8:30 AM EST
Seasonal Drought Outlook Discussion