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NOAA drought update.January 21, 2003 — A thin snow pack is raising concerns that stream flows and water supplies will be low for the spring and summer in several Western states, forecasters at the NOAA National Weather Service said today.

In its latest drought assessment, the NOAA Climate Prediction Center said severe drought continues over most of the interior Western states and the central and northern Plains. Conditions ranging from abnormal dryness to moderate drought extend across the Midwest from western Missouri to the Great Lakes. Forecasters added that precipitation is plentiful across the South and Northeast, although drought persists in northern Maine.

“The dryness in the Midwest is expected to continue during the next several months, although lake-effect snows will bring local improvement,” said Douglas Lecomte, a NOAA climatologist. “Rain or snow should bring improvement from the Southwest into the central Plains, while little significant change in the drought situation can be expected across the northern Plains and northern and central Rockies,” he added.

Water Shortages Possible
Lecomte said the latest outlook raises concern that “serious water shortages” could occur this spring and summer in parts of the northern Rockies and northern Plains, if precipitation continues to be below normal. In contrast, forecast rain and snow later this winter should ease water concerns farther south from Arizona into New Mexico. “Some areas will continue to see low water supplies, even if normal or slightly above-normal precipitation occurs,” Lecomte said.

The worst prospects for drought relief are in Montana and Wyoming, which are
already mired in a multi-year drought, he added. Spring and summer stream flows are expected to be less than one-half of normal in several river valleys in both states.

Jet Stream Plays Role
“Because the last couple of years have been so dry, even normal snow pack this winter will not be enough to get many western states out of their drought, and snow pack is currently below normal in most states outside of California,” Lecomte said.

Additionally, conditions have been unusually dry across much of the Midwest since fall, allowing drought to persist in some areas or expand in others. The winter pattern of an active jet stream dipping southward into the eastern U.S. brought drought-ending rain and snow to the East, but this pattern has left areas in the central part of the country and interior West cut off from Gulf of Mexico and Pacific Ocean moisture sources.

Lecomte said: “We need to see the pattern change so that the jet stream extends farther southward in the Rockies and High Plains. This change shows signs of occurring, at least temporarily, resulting in snow spreading across the Midwest this week.”

In recent weeks, El Niño has contributed much-needed precipitation to many parched areas of the country. For example, fall and winter storms along the Gulf and East Coasts have nearly ended the drought from Texas to Georgia, and along the entire East Coast. The precipitation has many wells and reservoirs in the East at near normal levels, with some even above-normal.

Drought Doldrums Continue
Last summer, more than one-third of the nation experienced severe drought, making it one of the most expansive since the devastating droughts of the 1950s.

“Despite major improvement in the East, we still have severe drought covering more than one-fifth of the country, so it will take at least several more months to get back to a more normal situation,” Lecomte said.

The NOAA Climate Prediction Center, one of the NOAA National Centers for Environmental Prediction, is part of the NOAA National Weather Service. The Climate Prediction Center assesses national drought conditions as well as predicts and monitors El Niño. The center also produces the nation’s official long-range outlooks and medium-range weather forecasts.

NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of the nation’s coastal and marine resources. NOAA is part of the Department of Commerce.

Relevant Web Sites
NOAA Drought Information Center

NOAA Drought Products

Animated Indicator Maps for Drought Monitor

NOAA's U.S. Seasonal Outlook (temperature and precipitation)

Media Contact:
John Leslie, NOAA National Weather Service, (301) 713-0622