This Week's Drought Summary (4/26)

April 26, 2018



The southern High Plains’ second wildfire outbreak in less than a week preceded the arrival of storm system that provided much-needed rainfall on April 20-21. Rainfall in the Plains’ drought-affected areas generally totaled around an inch or less. (Additional rain fell across portions of the central and southern Plains on April 24-25 but will be largely reflected next week.) The fires peaked in intensity on April 17, when southwesterly winds fanned flames amid soaring temperatures, but continued into the following day when winds shifted to a northwesterly direction. Oklahoma’s two largest April wildfires—the Rhea Fire (in Dewey County) and the 34 Complex (in Woodward County)—were nearly fully contained by April 24 after destroying more than seven dozen structures and charring approximately 350,000 acres of brush and grass. Meanwhile, drought continued to intensify in parts of the Southwest, where dry, windy weather prevailed. In contrast, another round of heavy rain struck portions of the South and East, as the slow-moving storm system that had produced beneficial rainfall on the southern Plains eventually drifted eastward.


There were no changes to the Northeastern depiction since rain arrived on April 24, after the drought-monitoring period had ended. As a result, a small area of abnormal dryness (D0) and moderate drought (D1) persisted across southern end of the region, covering southern Maryland and environs. From March 1 – April 24, precipitation in Salisbury, Maryland, totaled 4.69 inches (64% of normal).


Late in the drought-monitoring period, rain soaked many of the existing areas of dryness (D0) and moderate to severe drought (D1 to D2) from Alabama to the Carolinas. The rain, which fell heavily in some areas for the second time in less than 10 days, brought further reductions in the coverage of dryness and drought. Savannah, Georgia, received 4.33 inches of rain from April 1-24, accounting for more than one-half of its year-to-date sum of 8.38 inches (66% of normal). Savannah measured 3.13 inches of rain on April 23, marking its wettest day since September 11, 2017. Farther south, spotty showers in Florida provided local drought relief. However, some modest expansion of moderate to extreme drought (D1 to D2) was noted in parts of southern Florida. Through April 24, year-to-date rainfall in Fort Myers, Florida, totaled just 3.53 inches (40% of normal).


A striking contrast between drought and non-drought areas persisted in a southwest-to-northeast oriented band stretching across north-central Texas and central Oklahoma. Rain provided modest drought relief in Oklahoma and northern Texas, but did not reach most of the region’s other drought-affected areas. Amarillo, Texas, received precipitation totaling 0.49 inch on April 20-21, boosting its year-to-date total to 0.74 inch (20 percent of normal). Meanwhile, some expansion of dryness (D0) and moderate to extreme drought (D1 to D3) was observed across western, central, and southern Texas. By April 22, the U.S. Department of Agriculture indicated that topsoil moisture was rated 67% very short to short in Texas and 53% very short to short in Oklahoma. The value in Oklahoma represented a 19-point improvement from the previous week’s value of 72% very short to short. The southern Plains’ rain also aided wildfire containment efforts. Through April 24, U.S. year-to-date wildfires had consumed 0.96 million acres of vegetation, compared to the 10-year average of 0.85 million acres, according to the National Interagency Fire Center. Just to the east, wet weather persisted in the mid-South, where topsoil moisture was at least one-third surplus on April 22 in Mississippi (49%), Tennessee (46%), and Arkansas (35%).


Following a record-setting, mid-month snow storm, some additional snow fell in parts of the upper Midwest on April 18. On that date, La Crosse, Wisconsin, received 6.0 inches of snow. A few days later, rain fell across the southern tier of the region. However, dry weather persisted across northern Missouri and southern Iowa, where there was some expansion of abnormal dryness (D0) and moderate drought (D1). Through April 24, year-to-date precipitation in Saint Joseph, Missouri, totaled just 2.04 inches (31% of normal). By April 22, the U.S. Department of Agriculture reported that topsoil moisture was 19% very short to short in Missouri, up from 12% a week earlier.

High Plains

Following the previous week’s significant drought reductions across the northern Plains, there were no further changes during the drought-monitoring period that ended on the morning of April 24. However, some short-term precipitation deficits have been observed during the last month near the Canadian border in North Dakota and Minnesota, and this area will be closely monitored. Through April 24, month-to-date precipitation totaled 0.15 inch (21 p