Map released: July 2, 2020|Data valid: June 30, 2020
This week’s drought summary: Precipitation was hit-or-miss this week for many locations east of the Great Plains. Much of the Midwest, South, and Southeast saw combinations of D0 additions and removals based on seven-day rainfall accumulations. Most areas with D0 removal observed at least two to three inches of rainfall. Some short-term dryness crept into southern Georgia and the Florida Gulf Coast. The Mid-Atlantic coast saw some D0 expansion near the Delmarva Peninsula. Portions of New England saw more than three inches of rainfall, drastically reducing 30- and 60-day deficits and warranting some D1 removal. However, USGS seven-day average stream flows remain below normal for much of the Northeast. The High Plains and northern Rockies also received some beneficial rainfall. Many locations in Idaho saw one-category improvements (D1 to D0 and D0 removal), but much of the northern High Plains Region did not receive enough rainfall for much improvement. Some degradation from D3 to D4 occurred in southeastern Colorado and southwestern Kansas in areas where little or no precipitation fell and temperatures averaged above normal for the week. The wildfire risk remains high for many locations that remain in drought, particularly in the West.
South: In the Southern Region, the story remains the short-term (30-60 day) dryness. Northwestern Arkansas and northeastern Oklahoma saw D0 and D1 expansion, as little to no rain fell and most of these areas have received only 10-25% of normal precipitation in the last 30 days. Seven inch rainfall deficits in the last 60 days have been observed near Tulsa and Creek Counties in Oklahoma, warranting the addition of a small area of D2. USGS seven-day stream flows are also below normal (10th-24th percentile) for areas around Tulsa County, OK. In western areas of Texas and Oklahoma, heat, low humidity, and lack of rainfall continue to exacerbate existing drought conditions, leading to some D1, D2 and D3 expansion. Widespread D2-D4 SPIs over several time periods for many of these locations.
Looking ahead: During the next five days (July 2-6), WPC’s QPF showed increased probabilities for precipitation across many of the northern tier states, much of the Mississippi Valley, and Southeast, where many areas are favored to receive up to and exceeding one inch of precipitation. The Northern High Plains and the Middle Mississippi Valley are expected to see some of the heaviest rainfall (two to four inches in some cases). Probabilities drop off quite a bit for many locations just east of the Rockies, where below normal precipitation, high winds, low relative humidity, and above normal temperatures continue to be the driving factors for maintenance and exacerbation of drought conditions. Luckily, temperature anomalies are favored to be near to slightly above normal for much of the next week over the western Plains. Much of the Great Lakes is also favored to miss out on some beneficial rainfall in the upcoming week, in addition to positive temperature anomalies of 8-10 °F.
The Climate Prediction Center’s 6-10 day outlook (July 7-11) shows an amplified pattern with a mean ridge over the central CONUS, and troughing over the West Coast and over the eastern CONUS. Enhanced probabilities of below normal temperatures are favored along the West Coast and interior Pacific Northwest, in association with a mean mid-level trough over the West. Above normal temperatures and below normal precipitation are favored in much of the central CONUS, with probabilities for above normal temperatures extending to the Great Lakes and Northeast, underneath a mean ridge. The active storm track is favored to continue for the northern tier states, with elevated odds for above normal precipitation centered over the Upper Midwest and Great Plains.