This Week's Drought Summary (11/1)
The U.S. Drought Monitor week ending on October 30, 2018 was marked by several weather events. The first, Hurricane Willa, made landfall as a category 3 storm on Mexico’s Pacific Coast just after the cutoff for last week’s map (8:00 AM ET, Tuesday). The remnants of this storm brought heavy rain and thunderstorms to Texas, which had already been saturated with excess rain over the last several weeks, and to other states in the southern tier of the country. These rains brought improvements to areas impacted by drought, including the long-term drought areas of Arizona and New Mexico. Moisture from Willa helped fuel the season’s first nor’easter, which soaked the Northeast and brought snow to the higher elevations of New England over the weekend, helping to ameliorate drought and abnormal dryness across the regions. Storms also brought precipitation to the Pacific Northwest, the upper Midwest, and the Ohio Valley, bringing drought relief to these areas. Virtually no degradations occurred this week, except for an expansion of abnormal dryness across the Florida Panhandle
The recent nor’easter, with its heavy precipitation and cooler weather, brought improvements to the Northeast. New York and Vermont saw improvements to moderate drought while Maine and coastal Massachusetts saw the elimination of areas of abnormal dryness.
This week brought cooler temperatures to much of the Southeast this week, with swaths of rainfall occurring along the Gulf Coast and from central Alabama into Virginia. Evidence from indicators, such as rainfall deficits, soil moisture, and streamflow, led to improvements in moderate drought conditions in northeast Georgia and northern Alabama.
Widespread precipitation fell this week across the South as the remnants of Hurricane Willa moved across the southern United States, with the largest totals occurring in parts of Texas and along the Gulf Coast. The recent rainfall led to the removal of moderate drought in northwest Mississippi, where soil moisture conditions improved and short-term rainfall deficits lessened. This week’s rainfall also led to general 1-category improvements in west Texas, including the removal of extreme drought from west Texas and adjacent southeast New Mexico, where long-term precipitation deficits and groundwater conditions were improving. In the Texas Panhandle, severe drought was removed and moderate drought reduced as precipitation deficits have been recovering. Note that the short-term designation of drought was removed from this area as any remaining deficits are only apparent at longer time scales.
Over the last week, widespread precipitation fell over the northern two-thirds of Minnesota, and from central Missouri eastward through Ohio, with more widespread moderate to heavy amounts occurring in Ohio and eastern Kentucky. Generally, cooler than normal conditions were found over the northern half of the region, and warmer than normal weather occurred over the southern half of the Midwest. Moderate drought was slightly reduced in mid-Missouri as longer-term precipitation deficits lessened. Moderate drought was eliminated in western Minnesota and reduced over adjacent eastern North Dakota, where recent precipitation decreased short- and long-term precipitation deficits.
The trend toward improvement continued across the High Plains this week as recent moisture helped to improve both short- and long-term deficits. Broad reductions were made in North Dakota as precipitation deficits were reduced, soil moisture was replenished, and ground and surface water conditions improved. Changes include the elimination of extreme drought and a reduction of severe and moderate drought. South Dakota saw 1-category improvements to the drought depiction east of the Missouri River due to reductions in precipitation deficits, increases in soil moisture, reduced evaporative demand and feedback from local experts. Since remaining deficits are at longer time scales, the drought designation was changed from SL to L to reflect this.
Heavy precipitation in the Pacific Northwest, with amounts of 5 to 10 inches, brought 1-category improvements to the moderate and severe drought areas in western Washington. The excess rainfall helped increase streamflow, replenish soil moisture, and recover precipitation deficits. Likewise, improvements were made in south-central Idaho this week, where above-normal precipitation over the last 30-days was enough to improve soil moisture and precipitation deficits. Drought conditions in Montana remained unchanged, though the short-term designation was removed from the easternmost drought area because moisture deficits are only apparent at longer time scales. Colorado saw improvements in response to recent moisture, which reduced short- and long-term precipitation deficits and helped surface and soil moisture recover. Changes were limited to the eastern half of the state, which saw the removal of extreme drought and reductions in severe and moderate drought. Farther south, rain and thunderstorms associated with the remnants of Hurricane Willa helped to chip away at the long-term deficits in the southwest. The Rio Grande Valley in New Mexico saw 1-category improvements to moderate, severe, and extreme drought areas as most indicators in these areas are beginning to show recovery. Locally heavy rain in south-central Arizona led to an improvement in moderate drought conditions.
Alaska, Hawaii, and Puerto Rico
The map remained unchanged in Alaska, Hawaii, and Puerto Rico this week. Hawaii remains drought free. Puerto Rico continues to show rainfall deficits in the eastern part of the island and a lingering area of abnormal dryness. In Alaska, moderate drought remains in the Panhandle in response to continued precipitation deficits and low streamflow.
The greatest chances for precipitation in the coming week are in the Pacific Northwest, Northern and Central Rockies, and across the eastern half of the continental U.S., particularly in a band stretching from east Texas to New England. In the West, this could impact drought-affected areas in western Washington and Oregon, northern Idaho, and parts of Colorado and New Mexico. Much of the rainfall in the eastern half of the country is expected to fall in areas that are currently drought free, with the exception of northeast New York and northern Vermont.