According to the National Drought Monitor, very little change in the overall drought footprint occurred last week, with 60.12% of the contiguous U.S. still covered by some form of drought, which compares to 60.21% last week. This is about equal to last year at this time when 59.42% of the nation was covered by drought.
However, the monitor notes that periods of locally heavy rain provided drought relief in central and southern portions of the nation. Meanwhile, dry weather with sharp temperature contrasts exacerbated drought from the Central High Plains into central and western Texas. The Upper Midwest continued to deal with long-term precipitation deficits despite seasonal spring flooding, while an early end to the western Water Year caused drought to intensify across the Southwest. Short-term dryness was also beginning to have an impact in parts of the Northeast and Mid-Atlantic.
For the Northern Plains and Upper Midwest, long-term drought lingered despite seasonal snow melt and river flooding, although some improvements were made using updated precipitation data and reports from the field. "A narrow band of 0.50 to 1.50 inches of rain eased D0 (Abnormal Dryness) and D1 (Moderate Drought) from south-central North Dakota into northwestern Minnesota. In addition, updated 90- and 180-day precipitation data supported reducing or eliminating areas of D0 and D1 in southeastern South Dakota and neighboring environs, with totals now at or above 100% of normal (locally up to 150 percent) at both time scales. Likewise, D3 (Extreme Drought) was reduced in northeast Wyoming and southwestern South Dakota, where near-normal precipitation over the past three months has eased drought impacts," notes the monitor. "Despite the general consensus that conditions continue to improve, long-term indicators, including the 6-, 9-, and 12-month Standardized Precipitation Indices, show underlying, long-term drought persists in the core D1 and D2 areas of the Upper Midwest. In contrast, short-term dryness has reduced soil moisture in north-central North Dakota, where a small area of D0 was added."
Drought intensified over the central High Plains, while rain provided additional drought relief to eastern portions of the region. "Widespread showers (0.75-2.0 inches) in eastern Kansas and southwestern Missouri eased drought, with 2-week totals exceeding 4 inches in eastern-most D0 and D1 areas. Meanwhile, above-normal precipitation in northeastern Colorado improved winter wheat conditions, and drought impacts continued to lessen in this area; consequently, Extreme Drought (D3) was mostly eliminated from this corner of the state. In contrast, dry, hot weather (upper 80s and lower 90s, degrees F) prevailed from Nebraska into southeastern Colorado, where drought intensity either held steady or increased," it notes. "In particular, Exceptional Drought (D4) expanded across southeastern Colorado, where poor pastures and winter wheat conditions reflect the ongoing impacts of protracted dryness (6-month precipitation locally less than 30 percent of normal); the Colorado winter wheat crop was rated 54 percent poor to very poor as of April 28, 2013, while Kansas wheat stood at 39 percent."
In its near-term weather outlook, the monitor predicts: "A developing storm over the nation’s mid-section will become cut off from atmospheric steering, causing the system to drift eastward into the Mid-South by week’s end and the Southeast early next week. Five-day precipitation totals could reach 2 to 4 inches across the east-central Plains, upper Midwest, lower and middle Mississippi Valley, and eastern Gulf Coast region. In addition, late-season snow will fall from the central Rockies into the Upper Midwest. In contrast, little or no precipitation will occur in the Northeast and west of the Rockies. Unusually cool air will trail the storm, resulting in widespread freezes on May 2-3 as far south as the southern High Plains. Warmth will linger, however, from the eastern Corn Belt into the Northeast. The NWS 6- to 10-day outlook for May 7-11 calls for above-normal temperatures in the West and Northeast, while cooler-than-normal conditions will prevail across much of the Corn Belt and from the central and southern Plains into the Southeast. Meanwhile, near- to below-normal precipitation from the Northwest into the northern Plains and western and northern Corn Belt will contrast with wetter-than-normal weather in the central and southern Rockies, portions of the Intermountain West, and much of the eastern third of the nation."