The Northeast and Mid-Atlantic: Light to moderate rains (up to 2 inches) fell across much of New England, central and western New York, and northwestern Pennsylvania, with little to no rainfall elsewhere. With adequate precipitation, and near to above-normal stream flows, no changes were made to the regional drought depiction for this week.
Southeast: Precipitation was on the light side (0.5 inch or less) across the region during this past week, which resulted in a 1-category deterioration across portions of west-central North Carolina, extreme western South Carolina, and both northeastern and southwestern portions of Georgia. In South Carolina, soil moisture conditions fell to 11-percent very short, 45-percent short, and 44-percent adequate, and there was an average of 6.4 days suitable for fieldwork. Statewide topsoil moisture conditions in nearby Georgia were similar; 16-percent very short, 43-percent short, 38-percent adequate, and 3-percent surplus, with an average of 6.2 days suitable for field work. Farther west, abnormal dryness (D0) was expanded slightly into extreme northeastern Alabama (northern Jackson County) and the neighboring counties of Lincoln and Franklin in southern Tennessee. Short-term (3-month) and especially long-term (9-month) SPI maps, as well as the Lowest of the Drought Indicator Blend Percentiles clearly show the persistent dryness/drought across the Southeast, as do low USGS stream flow percentiles.
Lower Mississippi/Ohio Valleys: Widespread heavy rains (2-5 inches) were reported over north-central and northwestern Arkansas this past week, which helped boost stream flows. Much of this region has seen a 1-category improvement, from moderate drought (D1) to abnormal dryness (D0). Over nearby parts of extreme western Kentucky, light to moderate rains (up to 1.5 inches) have helped eliminate moderate drought conditions (D1), leaving a small remnant of abnormal dryness (D0).
Midwest: Recent storms have significantly replenished surface water supplies across this region, and have also helped to recharge soil moisture after the recent harvesting. Agricultural impacts in western Illinois are virtually undetectable, with corn and soybeans at 97 and 98 percent harvested, respectively. A sharp delineation exists between areas like western Illinois and southeastern Iowa which received beneficial precipitation, and the much drier conditions of northwestern Iowa, northeastern Nebraska, eastern South Dakota, and southern Minnesota. For these latter areas, short-term (3-month) SPI values reveal substantially worsened conditions during this period, most notably centered over southern Minnesota and extreme eastern South Dakota. A continued lack of rain also warranted a one-category deterioration (from D0 to D1) over the remainder of Cook County in extreme northeastern Minnesota.
The Central and Southern Plains: Widespread dryness persisted across large portions of Texas, though fairly scattered light to moderate showers (up to 1 inch) fell across parts of south-central, northern and eastern Texas. Minor adjustments were made to the Texas drought depiction in these areas. In addition, a slight upgrade was made in the extreme northwestern part of the Panhandle, with conditions improving from D2 to D1. In Oklahoma, October through early November rains have replenished soil moisture in most of the state except primarily for west-central/northwestern and southeastern Oklahoma. In the past two weeks, a number of reservoirs in eastern Oklahoma have rebounded substantially. Along the Red River however, places like McCurtain County, still suffer from 3-month precipitation deficits ranging from 6-12 inches. Along the northern border, the area of extreme drought (D3) in southern Kansas was extended southward into northeastern Osage County, and northern portions of Washington and Nowata Counties in Oklahoma. Skiatook Lake (Osage County) has not seen an increase of inflows like the other lakes farther east and south, and sub-soil moisture is still extremely dry. Two-month precipitation is running around 60-percent of normal, as this region has missed much of the autumn rains. In east-central Kansas, moderate rains (0.5 to 2 inches) fell this past week, but surface water supplies remain in serious condition.
The West: Although precipitation has been heavy (2 inches or greater, liquid equivalent) in the Cascades and Coastal Ranges of Washington and the Bitterroots of northern Idaho, relatively light rains (near 0.5 inch) have fallen this past week across eastern Washington state. Some negative impacts of late summer and autumn precipitation deficits (up to 5 inches for the past 90 days) to the winter wheat crop were reported in the Spokane area. Accordingly, the abnormal dryness (D0) region in northeastern Washington was extended southward to include Lincoln County. No changes in the drought depiction were made this week to south-central Oregon. In the Southwest, recent rains (within the past 2 weeks) have not been enough to justify any improvements in the regional drought depiction, but it was enough to temporarily offset further degradation.
Alaska, Hawaii and Puerto Rico: The Alaska panhandle experienced heavy precipitation (2 inches or greater, liquid equivalent) during the past week, while light precipitation (up to 0.5 inch) was reported over south-central Alaska. Stream flows across the state are near to above normal, so no changes were made to the drought depiction. In Hawaii, rainfall amounts were generally light, except for northeast facing (windward) slopes, where heavy showers dropped 2 to 3 inches of rain. The east Oahu area in D2(L) is now under a mandatory 20-percent restriction on water use from the Waimanalo Reservoir, up from 10-percent earlier. Water levels have dropped from 60 feet in the middle of May 2011 to around 22 feet this week. Puerto Rico reported mostly moderate to heavy rains (1-4 inches) during the week. No alterations were made this week to the drought depiction for Hawaii or Puerto Rico.
Looking Ahead: Over the next five days (November 17-21), temperatures are expected to drop as much as 15-20 degrees below normal across the northwestern quarter of the lower 48 states, and rise 10-15 degrees above normal from the southern Great Plains to the Great Lakes region. Moderate precipitation (0.5 to 2 inches) is anticipated from northeastern Texas and eastern Oklahoma generally eastward and northeastward to the mid-Atlantic region.
The CPC 6-10 day forecast (November 22-26) continues to show the influence of a trough over the western CONUS and a ridge over the eastern CONUS. Temperatures are predicted to be above normal for nearly all areas east of the Rockies, and near to below normal west of the Rockies. The best chances for above-median precipitation are in the West, and from eastern Oklahoma northeastward through the mid-Atlantic region. The best chances for below-median precipitation are over the southern Rockies and southern High Plains, most of the central and northern Plains, and over the southern Atlantic Coast region.
Author: Anthony Artusa, NOAA/NWS/CPC
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
S ... Short-Term, typically <6 months (e.g. agricultural, grasslands)
L ... Long-Term, typically >6 months (e.g. hydrology, ecology)