On Jan. 9 and 10, a low- pressure system tracked along the Gulf Coast and resulted in widespread precipitation (1 to 2.5 inches, liquid equivalent) from eastern Texas and the Lower Mississippi Valley east to the Florida Panhandle. On the northern extent of this storm, snow blanketed areas from Oklahoma and Arkansas to north Georgia.

This precipitation during the second week of January supported drought improvement. However, drought expanded and intensified for the Florida Peninsula, eastern North Carolina, west-central Texas, and the Southwest. During the first two weeks of January, multiple Arctic surface highs shifted south from Canada and temperatures (Jan. 1 to 13) averaged 4 to 8 degrees Fahrenheit below normal for much of the Great Plains, middle to lower Mississippi Valley, and Southeast.

A very dry start to the wet season continued to affect southern California with worsening drought conditions, periodic Santa Ana winds, and large wildfires. Enhanced trade winds, typical during a La Niña winter, resulted in improving drought for the windward side of the Hawaiian Islands.

The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the U.S. Department of Agriculture and the National Oceanic Atmospheric Administration. (Map courtesy of NDMC.)

South

More than 1 to 1.5 inches of precipitation (liquid equivalent) supported improvements for portions of eastern Texas and Arkansas.

For central Texas which received generous precipitation for this time of year, low 28-day streamflows (below the 20th percentile in D1 and 10th percentile in D2) precluded a larger area for a 1-category improvement. D2 to D3 drought was expanded across the Edwards Plateau of Texas due to 28-day average streamflows below the 10th and 5th percentile, respectively.

Midwest

Although precipitation was light (less than 0.5 inch, liquid equivalent), a 1-category improvement was made to parts of central and northeastern Indiana based on a consensus of indicators. 28-day average streamflows are generally near or above the 20th percentile throughout central to northern Indiana.

Elsewhere, no changes were made to the Midwest as early to mid-January is typically a drier time of year. Based on the NOAA’s National Operational Hydrologic Remote Sensing Center on Jan. 14, a large swath of snow (water equivalent near or or than 1 inch) extends from northern Missouri eastward to the Ohio Valley.

Much of the Dx areas designated for the Midwest are related to a signal of abnormal dryness (D0) or drought (D1+) at 120 days or six months.

High Plains

The central High Plains continued to have worsening drought conditions and moderate drought was expanded across portions of southwestern Nebraska using 60-day SPI, soil moisture below the 10th percentile, and the NDMC short-term blend.

Although light precipitation (less than 0.5 inch, liquid equivalent) fell across parts of south-central to southeastern Kansas, this precipitation was too low to justify any improvements. Elsewhere, across the central to northern Great Plains, no changes were made as early to mid-January is a dry time of year. D1 was expanded across southwestern Colorado due to low snow water equivalent and 60-day SPI.

West

A 1-category improvement was justified for a portion of central Montana, based on 90-day SPEI along with snow water equivalent above the 75th percentile. SWE remained well below-normal across the Four Corners Region.

Severe drought was expanded to include all of southern California due to the very dry start to the water year to date from Oct. 1to Jan. 13. The D2 coverage coincides with where WYTD precipitation has averaged less than 5 percent of normal.

A number of locations, including San Diego, are having their driest start to the water year. The D2 covers Los Angeles and Ventura counties which are being affected by periodic Santa Ana winds drying out vegetation and large wildfires. Following the two wet winters, the large reservoirs throughout California are at or above-normal.

Looking ahead

Another Arctic air outbreak is forecast for the central and eastern U.S. during mid-January as surface high pressure shifts south from Canada. By Jan. 20, subzero minimum temperatures are expected as far south as the central Great Plains. During Jan. 16 to 20, little to no precipitation is forecast from the West Coast to the Mississippi Valley with light to moderate precipitation amounts (0.5 to 1 inch) limited to the Southeast.

The Climate Prediction Center’s 6- to 10-day outlook (valid Jan. 21 to 25) favors below-normal temperatures to persist for much of the contiguous U.S. with the largest below-normal temperature probabilities (exceeding 80%) extending from the Mid-Atlantic and Ohio Valley south to the Gulf Coast.

Elevated above-normal precipitation probabilities are forecast for the northern Great Plains, Gulf Coast, and portions of the Southeast. Below-normal precipitation is favored for the West, central Great Plains, Midwest, and New England.

Brad Pugh is with the National Oceanic Atmospheric Administration and the Climate Prediction Center.