Click on a thumbnail graphic to view a gallery of drought data from the US Drought Monitor. Click here to go to the US Drought Monitor website. Here’s an excerpt:
For the second consecutive week, moderate to heavy rainfall brought additional drought relief from the Midwest southward across the central Plains into Texas. Meanwhile, drought conditions prevailed from California into the central and southern Rockies.
Conditions remained largely unchanged on the central High Plains during the monitoring period, as hot weather (readings as high as 100°F) offset the light to moderate showers (0.1 to 1 inch) which dotted western portions of the region. A small expansion of Extreme Drought (D3) in southwestern Kansas reflected increasingly poor vegetation health as indicated by satellite, with potential for additional degradations in this area if rain fails to materialize soon. Farther east, however, locally heavy downpours — with totals averaging 2 to locally more than 4 inches — resulted in some removal of Moderate (D1) and Severe (D2) Drought in central and southwestern Nebraska. In these areas, precipitation over the past 30 days has averaged 150 to 260 percent of normal. In Kansas, showers were mostly too light to warrant any additional improvement on top of last week’s drought reduction, though locally heavy downpours (2 to 4 inches) allowed for minor decrease of Extreme Drought (D3) in southern portions of the state.
Moderate to heavy rainfall further reduced or eradicated drought but submerged low-lying fields and caused additional river flooding in western and central portions of the region. Persistent showers and thunderstorms doused areas from central Nebraska into Iowa and northern Illinois with 2 to 4 inches of rainfall, with locally higher amounts. The rain was more than sufficient to warrant additional 1-category improvements over the western half of the Corn Belt. Despite the additional heavy downpours, long-term precipitation deficits linger (less than 70 percent of normal over the past 12 months) in west-central and southeastern Iowa; consequently, a small area of Moderate Drought (with a Long Term, or “L”, designation) remained where shortfalls are most pronounced. In contrast, short-term dryness (90-day rainfall averaging 50 to 70 percent of normal) led to a small increase of Abnormal Dryness (D0) in southeastern South Dakota.
Southern Plains and Texas
Despite temperatures in the 90s, rainfall during the week was sufficient to warrant modest to significant reductions in drought from northern and central Oklahoma southward into Texas. Showers and thunderstorms dropped 2 to locally more than 4 inches of rain from the eastern Oklahoma panhandle southeastward into central Oklahoma and east-central Texas. In particular, there were numerous reports of more than 3 inches west of Oklahoma City, and several totals in excess of 7 inches southwest of Dallas-Fort Worth. Consequently, drought intensity declined in areas where the heaviest rain fell, although long-term impacts continue (i.e. reservoir storage and ground water supplies). Farther south, a slow-moving disturbance drifted north from northeastern Mexico along the Rio Grande River Valley, dropping moderate to excessive rainfall (2 to 5 inches, with localized amounts in excess of 8 inches) from Laredo to the western Edwards Plateau. Likewise, a separate area of showers and thunderstorms (1 to 3 inches) swept across Texas’ Trans-Pecos region later in the week. These two areas of rain resulted in notable decreases in drought intensity and coverage across southern and western Texas.
Variable conditions in the north contrasted with ongoing drought elsewhere. In addition, the return of hot weather in California and the Southwest accelerated moisture losses and increased irrigation requirements.
In northern portions of the region, a slow-moving Pacific storm generated locally heavy rain and mountain snow across the northern Rockies, with showers from this system (locally more than inch) spilling into northeastern drought areas of Washington. Consequently, modest reductions were made to drought intensity and coverage in the mountains and foothills of northeast Washington, where Water Year precipitation was mostly near normal (80-95 percent of normal). Appreciable rainfall bypassed southwestern portions of Columbia River Valley, where Moderate (D1) and Severe (D2) Drought were expanded to reflect poor crop conditions and much-below-normal Water Year precipitation (40-50 percent of normal). To further illustrate the drought’s impacts, the USDA-NASS reported Washington’s winter wheat slipped 1 percentage point to 27 percent poor to very poor as of June 22, with only 30 percent rated good to excellent.
Farther south, California and the Great Basin will most likely have to wait until the 2014-15 Water Year for drought relief. In northern and central California, Exceptional Drought (D4) reflected abysmal 2013-14 Water Year precipitation totals; from northern portions of the Coastal Range to Mt. Shasta, precipitation since October 1 totaled 30 to 50 percent of normal (deficits of 16 to 32 inches). The corresponding Standardized Precipitation Indices (SPI), which helps quantify precipitation in terms of drought and historical probability, are well into the Extreme (D3) to Exceptional (D4) categories. Similar precipitation rankings (D3 or D4 equivalent) are prominent for the past Water Year from San Francisco south to Santa Barbara and east to the Sierra Nevada, including most of the San Joaquin Valley.
In the central Rockies and Four Corners, there were no changes to this week’s drought depiction. Extreme Drought (D3) remains entrenched across west-central Arizona and along the Arizona-New Mexico border, with Water-Year precipitation in these locales totaling less than half of normal (locally below 30 percent of normal).
Warm, humid, and unsettled conditions will persist from the central and southern Plains to the Mid-Atlantic and Southeast Coast. Embedded within this large area of unsettled weather, the greatest potential for heavy rain will be over the Upper Midwest and northern Plains as well as the central and western Gulf Coast region. Showers are also expected across the Northwest — though the rain is expected to once again bypass primary Northwestern drought areas — and in the Northeast. The NWS 6-10 day outlook for July 1-5 calls for wetter-than-normal conditions east of the Mississippi and from the Four Corners into the central Plains as well as southern Texas. Conversely, drier-than-normal weather is expected from the Northwest east to the northern Plains. Above-normal temperatures are anticipated across much of the nation, with cooler-than-normal conditions confined to the Upper Midwest, Texas, and the coastal Pacific Northwest.
— jfleck (@jfleck) June 26, 2014