Click here to go to the US Drought Monitor website. Here’s an excerpt:
Summary
Frontal and thunderstorm activity provided moderate to heavy rain (at least 0.5-inch) over northern, eastern, and central portions of the CONUS this past week. A weakness in the mid-tropospheric subtropical ridge over the Gulf of Mexico and southeastern states contributed to the influx of subtropical moisture across this region. Over the weekend, a cold front moved into the mid-Atlantic area and stalled, providing a lifting mechanism for the inflowing moisture. This resulted in heavy rain (generally 2-6 inches, locally greater) across much of Virginia, Maryland, eastern West Virginia, and southern Pennsylvania. Temperatures were near to above average across practically the entire contiguous U.S., with the greatest departures (6-12 degrees F above average, locally greater) for a large portion of the southern Great Plains, the Mississippi Valley, the Dakotas, the Great Lakes region, and the Ohio Valley…
According to ACIS, measured precipitation during the past 7-days was less than 0.5-inch over much of the South. Weekly temperature departures generally ranged between 4-10 degrees F above average. Significant 30-day precipitation deficits and near-record warm temperatures prompted the expansion of D0 across portions of Texas. In fact, the entire Texas drought depiction experienced another major overhaul this week. Low stream flows have been an issue in the Texas Hill Country for several months already. The position of the impacts line was adjusted to approximately bifurcate the state into a western portion (now SL, with longer-term deficits appearing), and an eastern portion (still S). Across the deep South Texas counties of Willacy and northern Cameron, conditions were degraded this week from D1 to D2, based on stressed fields of cotton (despite ongoing irrigation), high KBDI levels (600-700), and a 120-day SPI blend. In Oklahoma, continuing degradation of conditions led to an expansion of both D0 and D1 in southeast parts of the state. A few tweaks were made to the depiction in western Oklahoma as well, based on recent rainfall. Hot, relatively dry conditions prompted a broad expansion of D0 across most of Louisiana, western Arkansas, and adjacent portions of western and southern Mississippi this week. Current NLDAS soil moisture anomalies for the root zone (top one-meter) indicate values ranging from 1-3 inches below normal. Shreveport, LA, reported its warmest May on record, 78.4 degrees F, which supplanted the old record of 77.8 degrees F set back in 1933. Two areas of D1 were introduced in northwestern and south-central Louisiana this week. Topsoil moisture (Very Short to Short) for a few states include: Louisiana (73% this week, 55% last week), Arkansas (34%, 21%), Mississippi (22%, 14%) and for the Contiguous U.S. as a whole (28%, no change from last week). For Rangeland/Pastures, the percentages rated Very Poor to Poor this week compared to last week include: Louisiana (30% this week, 17% last week), Arkansas (6%, 8%), Mississippi (11%, 11%)…
Heavy rain (2-6 inches, locally greater) fell over portions of North Dakota this week, with the highest amounts over the northwest part of the state. Much of the heaviest rain actually fell north of the Canadian border in extreme southeastern Saskatchewan. Slight alterations (both improvement and deterioration) were rendered to the depiction in western, north-central, and southeastern North Dakota, based in part on the 1-month EDDI, which takes into account evaporative demand. Both improvements and degradations were also made to the South Dakota depiction, which received much less rain this week than its northern counterpart. For example, Aberdeen reported only 0.52-inch of rain in May (2.59 inches below normal), making it the seventh driest on record. An area of severe drought (D2) was introduced to northeastern South Dakota, based on 60-day precipitation deficits, 30-day and 60-day SPI, recent warm temperatures, and increased water demand through evapotranspiration. A spectacular dust storm, attended by 50-80 mph winds, blew through this region (Hand and Faulk Counties) on June 1st. In southeastern Colorado, a one-category degradation was made to the depiction in Kiowa County. Decent soil moisture from the wet summer and fall of 2017 is now gone, due to the recent hot, dry weather. This, in turn, has taken its toll on crops. Although welcome rains fell across eastern Nebraska this week, it was decided not to make any changes to the state depiction until more information is at hand next week…
Minor adjustments were made this week to the D0 area along the eastern Montana state line. In northwestern Montana, it was eventually decided to postpone the introduction of D0 to the region. Although some drying has occurred, this area experiences healthy stream and river flows, due to continuing snow melt. In nearby northern Idaho, recent flooding precludes the introduction of any D0 at this time. This area will continue to be monitored for the possible inclusion of D0 in the next week or two. In western Oregon and western Washington, an extended dry pattern set in ahead of schedule, with rapidly declining stream flows (most are now within the lowest quartile of the historical distribution for the day of the year). There is a notable degradation in the SPI maps going from 60- to 30-days out. The more recent SPI values in this region range between -2.0 and -2.5. Accordingly, D0 was expanded across western portions of both Oregon and Washington this week. Finally, in southwestern New Mexico, water restrictions were initiated as storage in the Elephant Butte and Caballo reservoirs (along the Rio Grande in Sierra County) dropped below 400,000 acre-feet…
Looking Ahead
For the ensuing 5-day period (June 7-11, 2018), the northern and eastern CONUS are generally predicted to receive 0.5-1.5 inches of rain. Heavier amounts are forecast over portions of the western Corn Belt, the southern Great Lakes region, and the Florida peninsula. A relative maximum of 3-4 inches is possible in Iowa, likely due to nocturnal thunderstorm clusters (MCS) which are common at this time of year. Little to no precipitation is expected elsewhere during this period. For the subsequent 5-day period (June 12-16, 2018), CPC predicts elevated odds of above normal rainfall across the southern CONUS, with a weak tilt toward above running northward across the Mississippi Valley and eastern Great Plains region. Elevated odds of below normal rainfall are highlighted over the Northwest, the northern High Plains, and most of the Atlantic Coast states from Maine to Virginia.