US Drought Monitor Update

Drought Monitor:  Precipitation remains light for much of the CONUS

Summary

At the beginning of the period, a slow moving cold front draped itself across the CONUS from the Great Lakes stretching down into the Southern Plains. Along its boundary were scattered showers and thundershowers. As the front stalled out, another stronger cold front ushered in cool dry air, providing the first taste of autumn across areas of the eastern half of the US. Oppressive heat continued into the first half of the period in the Northwest where the average temperatures were 10-20 degrees F above normal. Cooler temperatures moved in during the latter half of the week. In the West and Southwest, scattered showers and thunderstorms kicked off with the arrival of an upper-level disturbance.

Alaska and Hawaii

With the recent persistent rains along southeastern Alaska, the remaining D0 was removed. For Hawaii, the remnants of tropical cyclones contributed to improvements this week. A one-category improvement was made on the big island. The remaining D0 was removed on Oahu while on Kauai, the western edge of D0 was trimmed.

East

Temperatures were slightly below average with the exception of eastern North Carolina and Virginia. Departures there were as much as 6 degrees F above normal. Precipitation was variable in the region. The driest area was in north central South Carolina where less than 5 percent of normal precipitation fell during the last 7 days. In Virginia, deficits of 25 to 75 percent of normal are showing up at 30 to 60 days with streamflows reflecting the pattern. As a result, drought expanded into southwest Virginia and into western West Virginia. In North Carolina, drought conditions expanded slightly across the state reflective of decreasing reservoir levels. Some areas of the Piedmont area saw one-category degradation. Severe drought expanded slightly to the north along the foothills of North Carolina. Slight improvements were made in Florida where recent rains have trimmed the drought in the western Everglades as well as areas in the Panhandle.

High Plains

Conditions as a whole were drier and warmer than average across the region. The exceptions occurred in the southeastern part of the region where average temperatures were dampened by above normal precipitation. In excess of four inches fell in northwest North Dakota which is about 700 percent of normal for the 7-day period. This resulted in the removal of D0 for that area. Abnormally dry conditions resulted in an introduction of D0 in southeast North Dakota, stretching into Minnesota and South Dakota.

Midwest

Much like the rest of the country, precipitation in the Midwest was variable. Where rain fell, amounts were as high as 400 percent of normal. On the dry side, total amounts were as low as 2 percent of normal. Average temperatures were generally 2-4 degrees cooler than normal. Degradation occurred in northwest Kansas while a small area in north central Kansas improved.

Northeast

Conditions during the period were variable and somewhat regional. Some areas received heavy downpours while locations only a few miles away were dry. As a whole, precipitation was 150-300 percent above normal. The dry areas were 5-25 percent below normal. These conditions were compounded by average temperatures that were as much as 15 degrees F above normal. Temperatures in the latter half of the period cooled with the arrival of the strong front. Slight one-category adjustments were made around Albany and Long Island, New York.

South

The week was mostly dry, though cool. Temperatures were 2-4 degrees below normal in most of the south with Texas being the lone exception. Precipitation was spotty across the region as some areas received anywhere from less than 5 percent to as much as 400 percent of normal rainfall during the period. One category degradation occurred in parts of Mississippi while D0 and D1 was expanded in portions of Alabama. Flash drought remains active in southern Arkansas, northern Louisiana and western Mississippi. Based on the 60 day and year-to-date percent of normal, degradations were needed. Recent precipitation along the Louisiana coastline provided some relief, constituting a one-category improvement in the area.

West

Average temperatures were 4 to 8 degrees above average across the region. Precipitation amounts reached 800 percent of normal in southern California and 200% in southeastern Oregon, southern Idaho, southwestern Nevada and southern Utah. Precipitation was non-existent elsewhere. For the region as a whole, no changes were made in this week’s Drought Monitor.

Looking Ahead

For the immediate period, precipitation remains light for much of the CONUS. Several smaller systems track from the Northwest through the High Plains and exits out into Canada just north of the Great Lakes. For the next 6-10 day period, chances of above average temperatures are likely for the majority of the CONUS. The greatest chances are in the High Plains and down into the Great Basin and Southern California. Chances are likely that a small portion of the Northwest will experience below normal temperatures as well as Alaska. Chances of below normal precipitation are likely for the Midwest, Great Lakes and Northeast regions. The probability of precipitation increases to the northwest and southwest.


Author(s):
Chris Fenimore, NOAA/NESDIS/NCEI