This Week's Drought Summary (3/21)
A historic major winter storm impacted much of the country this past week with blizzard conditions, category-2 hurricane-force winds, heavy rain, thunderstorms, tornadoes, and flooding. Funnel clouds and tornadoes were seen in south central Arizona and southeastern New Mexico. Up to a foot of snow fell across the Denver, Colorado, area, while up to two feet fell over southeastern Wyoming, western Nebraska, and into southwestern and central South Dakota. To the south, thunderstorms rolled across Texas and parts of the lower Mississippi River Valley into the Tennessee and Ohio Valleys, including eastern Arkansas, southwestern Tennessee, and northwestern Mississippi. Heavy rainfall melted snow and led to flooding from Kansas, Nebraska, and South Dakota to the western Great Lakes. Much of the South, however, from southern Texas eastward, missed out on most of the precipitation and conditions continue to dry.
No changes were made this week to the depiction of the Northeast. This region currently remains free of drought, although precipitation has been below normal from northern Pennsylvania to Maine over the past month or so. Abnormally dry conditions appear soon if dry conditions persist.
A strong gradient of wet versus dry areas has built across the region over the past two to three months, with wet conditions from northern Mississippi, Alabama, and Georgia into the western Carolinas and most of Virginia. The southern portion has missed out on most of the precipitation and more abnormal dryness (D0) is becoming apparent. Areas depicted as D0 last week remained so this week and expanded slightly northeastward in southern Alabama and to both the south and west in Georgia. Additionally, some areas are beginning to show concerning soil moisture deficits, an important consideration as planting season gets underway. In the driest areas--encompassing parts of Jenkins, Emanuel, Candler, and Bulloch Counties in Georgia and parts of Allendale, Hampton, and Jasper Counties in South Carolina--moderate drought (D1) was introduced.
Heavy precipitation from a major storm system on the 13th fell over abnormally dry (D0) and drought areas in western Oklahoma and northern and central Texas, where conditions widely improved by 1 category, and even 2 categories from western Swisher County northeastward to western Gray County. Those areas received enough rainfall to alleviate deficits at both long- and short-term time scales. The precipitation largely missed southern parts of Texas, Louisiana, and Mississippi. Abnormally dry conditions spread from southern Alabama into the southeastern corner of Mississippi and an area was introduced from the southwest corner of the state southwestward through Lafayette Parish to the northern tip of Vermillion Parish near the Gulf of Mexico. Dryness and drought expanded eastward in southern Texas, and three pockets of severe drought (D2) were introduced: two center on Zavala and Atascosa Counties and one area sits on the border of Jim Hogg and Starr Counties in the far south.
For the fourth consecutive week (since February 26), the Midwest has no regions in drought or abnormal dryness. In fact, it is quite the opposite. Many areas this week faced blizzard conditions, heavy rain, and floods as a major winter storm impacted the area.
Most of the High Plains were impacted by a major winter storm early in the drought week that brought blizzard conditions, heavy rain, and dangerous flooding. Except for the western region where abnormally dry conditions (D0) are present, the remainder of Colorado saw widespread improvement, due to the recent storm and a generally very active weather pattern since February that has left excellent.
Last week, California emerged from drought conditions for the first week since December 11, 2011, breaking its 376-week streak. Reservoirs continue to slowly replenish in areas of the state still experiencing abnormal dryness (D0) and no further changes were made here. However, areas of abnormal dryness and drought continued to decline in other western states this week, due to recent above-average precipitation and excellent snowpack conditions at higher elevations. Arizona and New Mexico in particular saw widespread 1-category improvements. Notably, exceptional drought (D4, the worst category depicted on the drought map) was eliminated and extreme drought (D3) broadly contracted in northern New Mexico. In Oregon, the small area of severe drought (D2) in Deschutes County was eliminated. Moderate drought in the rest of the state remains unchanged as temperatures begin to warm and soil moisture is still dry when considering conditions over the past year or so. In contrast to other parts of the West, western Washington and along the northern coast of Oregon have seen below-normal precipitation over the past few months on average and stream flows are quite low here, even record low in some places. Abnormally dry conditions were expanded across this area. Reports indicate that the dry weather has caused an increase in brush fires in Whatcom, Mason, Grays Harbor, Cowlitz, and Clark Counties in Washington.
Alaska, Hawaii, and Puerto Rico
In Hawaii, severe drought (D2) was introduced to the lower leeward slopes of Kuwai. This area has lacked the rainfall received over other areas. The USDA Farm Service Agency recently reported pastures in the Waimea and Makaweli areas of southwestern Kauai were in poor condition.
No changes were made in Puerto Rico or Alaska this week, although it is noted that record heat was observed in southeast Alaska. Among other records, the temperature at the Juneau airport reached 59 degrees F, smashing the old record of 49 degrees F set in 1981.
Over the week beginning Tuesday, March 19, according to NOAA’s Climate Prediction Center, light rain is generally expected over much of the contiguous United States, with regional and localized amounts of around an inch or so anticipated across several states, from California to Arkansas, along with most of the eastern seaboard from North Carolina to Maine. Already dry areas in the Southeast are expected to continue to dry. Looking further ahead to March 25-29, there is a high probability Alaska will see above-average temperatures and precipitation. The central contiguous U.S. and Pacific Northwest may also see above-average temperatures, while most of California, eastern Nevada, and the Northeast may have below-average temperatures. This timeframe may also be wetter than average across most of the region, with the exception of the upper Northeast and northern Michigan. Please note the forecast confidence for this period is below average.