1/15 Drought Monitor; Spotty Western Snowpack Improvements; Plains Largely Locked In Drought

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National Drought Summary -- January 15, 2013

The discussion in the Looking Ahead section is simply a description of what the official national guidance from the National Weather Service (NWS) National Centers for Environmental Prediction is depicting for current areas of dryness and drought. The NWS forecast products utilized include the HPC 5-day QPF and 5-day Mean Temperature progs, the 6-10 Day Outlooks of Temperature and Precipitation Probability, and the 8-14 Day Outlooks of Temperature and Precipitation Probability, valid as of late Wednesday afternoon of the USDM release week. The NWS forecast web page used for this section is: http://www.cpc.ncep.noaa.gov/products/forecasts/.

This U.S. Drought Monitor week saw overall improvements as significant rain fell across portions of the South, Southeast, lower Midwest, and portions of the Mid-Atlantic states. In the West, heavy snow fell over the Wasatch Range in Utah as well as in the Northern Rockies and North Cascades. Conditions continued to deteriorate in parts of the Southeast, Southern Plains, and Colorado. Overall, temperatures continued to be well below normal across the West, while the eastern half of the conterminous U.S. experienced temperatures well above average – especially in the Southeast and portions of the Upper Midwest and New England. In Alaska, temperatures were well above normal throughout most of the state, while precipitation was slightly above normal except in southeastern Alaska, which continued to be drier than normal. Temperatures and precipitation in the Hawaiian Islands last week were generally near normal.

The Northeast: Overall, the region was dry during the past week, and conditions on the map remain unchanged. Temperatures throughout the region were well above normal, especially in the northern half of New York, northern Vermont, and large portions of Maine during the past seven-day period.

Mid-Atlantic: The Mid-Atlantic region saw minor improvements as rainfall in excess of two inches fell over southwestern and south-central Virginia. Streamflow conditions in these regions saw improvement leading to one-category improvements in areas of Abnormally Dry (D0) and Moderate Drought (D1). Average temperatures in the region were above normal.

The Southeast: The northwestern half of the Southeast received abundant rainfall during the past week. Areas including the northern two-thirds of Alabama, northwestern Georgia, and western North Carolina saw rainfall totals ranging from two-to-five inches, helping to ease drought conditions. However, Florida, southeastern Alabama, most of Georgia, and South Carolina remained dry. In northwestern Georgia, one-category drought intensity improvements were made in areas of Abnormally Dry (D0), Moderate Drought (D1), Severe Drought (D2), and Extreme Drought (D3). In western North Carolina, moderate precipitation totals in combination with improving reservoir and streamflow conditions led to improvements in areas of Abnormally Dry (D0) and Moderate Drought (D1), while extreme western locations returned to normal conditions. In Florida and southern Georgia, continued short-term precipitation deficits led to the expansion of Moderate Drought (D1) and Abnormally Dry (D0). Portions of southwestern and northwestern Alabama saw areas of Abnormally Dry (D0) removed. Temperatures during the past week were well above normal throughout the region.

The South: Widespread heavy rainfall over Arkansas, Louisiana, Mississippi, and Texas led to improvements throughout the region. Areas of Arkansas, Louisiana, Mississippi, and the eastern half of Texas saw rainfall totals ranging from two inches to more than ten inches in southern Louisiana. In Texas, this week’s heavy rains and short-term (30-day) gains led to a widespread re-evaluation of drought conditions statewide. In the Panhandle, overall cooler than normal temperatures during the past 30 days in combination with snow on the ground helped to improve soil conditions. Areas of Exceptional Drought (D4) and Extreme Drought (D3) saw categorical improvements in the Hill Country, north-central Texas, the Panhandle, and South Texas. East Texas and southwestern Texas saw areas of Abnormally Dry (D0) return to normal condition while areas of Severe Drought (D2) and Moderate Drought (D1) in the Coastal Plains retreated westward. In Mississippi, four-to-six inches of rain this past week helped northern portions of the state return to normal conditions from Abnormally Dry (D0). The western half of Arkansas saw one-category improvements in areas of Extreme Drought (D3) and Severe Drought (D2), while western Tennessee saw improvements from Moderate Drought (D1) to Abnormally Dry (D0).

Midwest: The southern portions of the Midwest received heavy rainfall during the past seven days. Substantial precipitation was concentrated over southern Illinois, Indiana, western Kentucky, and southeastern Missouri with totals ranging from two to five inches. Improvements were made in southeastern Missouri from Severe Drought (D2) to Moderate Drought (D1) as well as a south and westward retreat of Moderate Drought (D1) in southern Illinois, western Kentucky, and southeastern Missouri. Much of the Upper Midwest – including Iowa, Minnesota, the Upper Peninsula of Michigan, and Wisconsin – remained dry. Temperatures throughout the region were well above normal for the period.

The Plains: The region continued to experience an overall dry pattern during the past seven-day period with the exception of some light-to-moderate rainfall over portions of Oklahoma and southern Kansas. In Oklahoma, conditions in the extreme southeastern region saw improvements from Extreme Drought (D3) to Severe Drought (D2) as two-to-three inches of rain fell. Conversely, in north-central Oklahoma persistent dry conditions and record low reservoir conditions led Payne County to declare a state of emergency as Lone Chimney Lake receded to eleven feet below normal. The reservoir provides water to nearly 16,000 residents in seven counties. In south-central Kansas, recent rains led to a minor reduction in an area of Exceptional Drought (D4), while the rest of the Plains region is unchanged on this week’s map. Temperatures were below normal over the western half of the Plains, while the eastern half was above normal for the week.

The West: During the last seven-day period, the southern half of the West was generally dry. The northern half saw snowfall over the mountains of the eastern Great Basin, Idaho, northwestern Wyoming, southern Oregon, southwestern Colorado, western Montana, Utah, and Washington. Heavy snowfall in excess of twenty inches was observed in the Wasatch Range of Utah and the North Cascades of Washington. Current snowpack conditions show significant deficits in snow water content persisting over the mountains of Colorado, New Mexico, northeastern Nevada, eastern Oregon, eastern Wyoming, southeastern and west-central Idaho, and sections of northern Montana. Conversely, notable surpluses exist over the Cascades of Washington, northwestern Great Basin, Sierras, Sawtooths, Uintas, and the mountains of Arizona. Short-term precipitation accumulations during the last 60 days led to one-category improvements in areas of Abnormally Dry (D0) and Moderate Drought (D1) over the Bay Area, northern portions of the Central Coast, and northern San Joaquin Valley of California. Continued lack of snowfall over Colorado led to expansion of Extreme Drought (D3) over central Colorado as well as deterioration of the Moderate Drought (D1) region over the northern Front Range. Temperatures throughout the West continued to be well below normal, especially over large portions of Arizona, California, Colorado, New Mexico, Utah, and Wyoming.

Hawaii, Alaska, and Puerto Rico: The Hawaiian Islands saw some slight improvements on the island of Kauai as pasture conditions continued to improve with recent rainfalls. On Kauai, one-category improvements were made on the map. On the Big Island, deteriorating pasture conditions on the western side led to the expansion of areas of Severe Drought (D2) and Moderate Drought (D1). In Alaska, temperatures during the past week were well above normal in parts of western Alaska, while the southern portion of Southeast Alaska experienced below- normal temperatures. Precipitation during the last 30 days in Southeast Alaska was well below normal, while western Alaska, the Aleutians, and South-central was above normal. Alaska and Puerto Rico remain status quo on the map this week.

Looking Ahead: The NWS HPC 5-Day Quantitative Precipitation Forecast (QPF) shows moderate precipitation amounts over the Southeast and Mid-Atlantic states, while snowfall is expected over the North Plains, Upper Midwest, and New England. The 6–10 day outlooks call for a high probability of below-normal precipitation across much of the conterminous U.S. with exception of portions of the Upper Great Lakes Region and the southern half of Alaska. Temperatures forecasted on the 6–10 day outlooks call for a high probability of below-normal temperatures in the eastern U.S, particularly in the Midwest and New England, while most of the West has an elevated probability of above-normal temperatures except for the Intermountain regions. Temperatures in Alaska have a high probability of being above normal.

Author: David Simeral, Western Regional Climate Center

Dryness Categories

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)