Overview: With Tropical Storm Nate missing the mark in the Gulf Coast region, a much quieter weather pattern prevailed over the majority of the Lower 48 states last week. This gave some areas a chance to dry out while some others could still use a lot of help.
Mid-Atlantic and Northeast: Early period rains were heavy in places and brought flooding along with more in the way of drought relief. Locales in eastern Virginia, Maryland, the West Virginia Panhandle, southern and eastern Pennsylvania and south-central New York state saw anywhere from 3 to 8 inches of precipitation or more. This leads to the removal of all D0-D1 in the region except for a few pockets of D0 in northern New York and southeastern West Virginia.
Southeast and Delta: Last week was unseasonably cool (5-10 degrees below normal), and all but the central Gulf Coast region and southern Florida was dry as well. This led to some improvement in southern Florida with a reduction of D0-D1, but longer-term deficits and low lake levels (Lake Okeechobee in particular) and surrounding ecosystem stress is still of concern heading into the dry season. To the north, drought continues to expand in South Carolina with a push of D1-D3 to the east and north and into central North Carolina as well, which fell between the rains of Hurricane Irene to the east and Tropical Storm Lee to the west. This leads to expansion of D0 across south-central North Carolina, and some D1 has pushed more into southwestern and south-central North Carolina along the South Carolina border as well.
Midwest and Great Lakes: Continued dryness over the past 30-60-days continues to lead to some early off-season soil recharge worries, although it is very much welcomed during the harvest season. Some slight changes on the heels of Tropical Storm Lee bring some more reduction of D0 in eastern and south-central Kentucky along with some slight expansion in the northern tier counties for the Bluegrass State.
To the north, an expansion of Severe Drought (D2) leads to a band connecting Indiana with Illinois and Iowa to the west across the heart of the Corn Belt. A slight expansion of D1 is also noted in the same region. Although this won’t affect this year’s corn crop, it has stressed beans and pastures and will have us keeping an eye on the off-season soil moisture recharge heading into next growing season.
The Great Lakes region continues to be plagued with above-normal temperatures and lack of any significant precipitation. This brings more D0 and D1 to Michigan’s Upper Peninsula along with the introduction of D2 around the Marquette region. The same pattern is responsible for the spread of D0 across northern Wisconsin and led to the expansion of D0-D2 in the Arrowhead and International Falls regions in northern Minnesota. Southern Minnesota also saw a degradation in their conditions with a push of more D0 and D1 into those counties. The same holds true for northern Iowa with a slight expansion of D0 in the northeast, and some minor increase in D1 is noted in northwest Iowa as well.
Northern and Central Plains: Unseasonably warm temperatures and dryness over the past couple of months continue to cause issues in northeastern South Dakota, and this has brought an expansion of D0 and D1 here and across the Minnesota border to the east and south. Nebraska also sees their dry pattern continue, bringing about a larger area of D0 in the state’s mid-section and also an expansion and connection of the D0 between the Nebraska Panhandle and northeastern Colorado.
Southern Plains: Cooler weather was welcomed across most of Kansas and down into Texas, but it failed to bring much, if anything, in the way of rainfall this past week. A slight push northward of D0-D2 is depicted this week across northern Kansas, and northeastern Oklahoma saw an increase from D2 to D3 as well. Texas conditions continue to deteriorate what little they can from abysmal, with expansion of D3-D4 noted in the southeast, central, south-central, Big Bend region, and extreme south around Brownsville. The lack of tropical activity (Nate fizzled out and drifted into Mexico well to the south this week) and better odds of a second consecutive La Niña winter only add fuel to this well-fed and entrenched drought.
Four Corners Region: A bit of respite for some and nothing for others leads to a mixed bag of changes this week. Slow improvement after some good September precipitation means D4 is gone from southern Colorado’s San Luis Valley. Arizona saw some better monsoonal activity across the central parts of the state, but it wasn’t enough to improve the picture there this week. In fact, those areas that didn’t see the rains are marked by degradation this week as D1 and D2 spread north and west into Maricopa, eastern La Paz, and southern Yavapai as well as a slight push to the north in Gila county, which falls just south of the better rains of last week.
Alaska, Hawaii, and Puerto Rico: Conditions across Hawaii, northern Alaska and Puerto Rico remain unchanged from last week.
Looking Ahead: The next 5 days (through September 19) show a good chance for cooler weather across all but southern Texas, the northern Rockies and across Montana and Wyoming. Precipitation is expected to be favorable across Colorado, eastern New Mexico, the central Plains (eastern Kansas and northern Oklahoma in particular) and into Missouri and the middle Mississippi Valley. Some of the coastal regions in the mid-Atlantic could also see some more in the way of the wet stuff.
The CPC 6-10 day forecast (September 20-24) is calling for a change in the short-term pattern with above-normal temperatures likely across the majority of the country (including central interior Alaska) except for the Southeast, which looks to be below-normal during the period as does western Alaska. Precipitation is more of a mixed bag with most of the West, Great Plains, lower Mississippi Valley and western coastal Alaska more likely to see below-normal readings while the Northeast and southern Alaska are forecast to be above-normal.
Author: Mark Svoboda, National Drought Mitigation Center
D0 ... Abnormally Dry ... used for areas showing dryness but not yet in drought, or for areas recovering from drought.
Drought Intensity Categories
D1 ... Moderate Drought
D2 ... Severe Drought
D3 ... Extreme Drought
D4 ... Exceptional Drought
Drought or Dryness Types
A ... Agricultural
H ... Hydrological