Skip Navigation Links 
NOAA logo - Click to go to the NOAA home page National Weather Service   NWS logo - Click to go to the NWS home page
Climate Prediction Center


February - April 2003


Latest Seasonal Assessment - Very dry conditions persisted over the central portion of the nation until a snowstorm crossed the region on January 15-16, offering several states a respite from the dryness. Forecasts suggest that improvement should be continuing for the central and southern Plains during the next three and one-half months, with beneficial rain or snow most likely in Kansas and adjacent portions of Missouri, Nebraska, and Iowa. In contrast, with below-normal precipitation forecast over the Great Lakes region from February to April, drought is expected to continue from northern Illinois into Michigan and northern Indiana and Ohio, with some expansion southward and northward. The exception to the general forecast would be in snow belt areas downwind of the Great Lakes, as cold air over-running the mostly-open waters could trigger locally heavy snowfalls. In the northern Plains, drought is expected to persist from the Dakotas westward into eastern Washington and Oregon and southward into northern Utah and Colorado. Occasional storms will bring periodic breaks in the dry weather pattern, but it does not look like the region will see enough significant precipitation to substantially improve the drought picture. Farther south, the odds for relief improve, as above-normal rain and snow is forecast across the Southwest during February-April. Water shortages will likely continue into April in many parts of the West regardless of rain or snow amounts in the next several months. In the East, drought persists in northern Maine, but improvement is on tap in coming months. Hawaii, on the other hand, should see continued drought expansion.

Discussion for the Seasonal Drought Outlook

Tools used in the drought outlook included: the official CPC long-lead precipitation outlook for FMA, El Niño soil moisture composites, warm ENSO composites for FMA, the Palmer Drought Index probability projections for April, and various medium and short-range forecasts and models such as the 6-10 day and 8-14 day forecasts. For this outlook, an in-house modified version of the Palmer Drought Projections applied to historical El Niño's was given considerable weight.

The forecast for persisting or expanding drought in the Great Lakes region and Ohio Valley is consistent with the below-normal precipitation pattern expected for FMA during El Niños or positive PDO occurrences. The dry signal is especially strong during periods with negative AO, and that is the way this winter is shaping up so far. The forecast is also consistent with last month's drought outlook and recent precipitation trends. Locally heavy lake-effect snows will significantly boost moisture conditions in favored downwind areas, but no attempt was made to account for such local impacts on the national map.

Confidence in the outlook is much less for the Plains states. There is an El Niño or PDO signal for above-normal precipitation in the southern and central Plains, but forecast signals are much weaker or absent to the north in the Dakotas and to the east in Missouri. Past Palmer Drought Index changes during El Niños for this time of year show a tendency for improvement into South Dakota and southern Iowa, and the forecast map reflects this. Somewhat less improvement is shown this month than last month due to recent trends toward dryness, but the mid-January snowfall and the recent shift of the upper level ridge westward are consistent with a wetter pattern.

The outlook for the western states is again largely driven by the FMA precipitation outlook and Palmer drought projections based on previous years with El Niño conditions and similar initial drought indices. The latter tools show a tendency for the drought indices to improve by April across the Southwest. Confidence for improvement is less this month, given the lack of an influx of El Niño-related tropical moisture into the Arizona area so far this season. Also, the SST anomalies for the ENSO 1+2 region off the South American coast are small relative to those near the dateline, and this could reduce the odds of heavy precipitation. Some numerical models also point to below-normal precipitation for the Southwest. A wet pattern is still the best bet, but it is by no means assured. To the north, the forecast for persisting drought across the northern Rockies and interior Northwest is consistent with last month's outlook and recent trends toward below-normal snowfall. The depiction also considered the January 1 spring and summer streamflow forecasts produced by USDA/NRCS.

In the Northeast, the outlook continues to call for improvement in Maine, based largely on past El Niño composites. Palmer indices tend to improve during El Niño periods in Maine.

In Hawaii, a tendency toward El Niño-related dryness during the February-April period results in a continued forecast of drought development. This is also consistent with recent trends toward expanding dryness.

NOAA/ National Weather Service
NOAA Center for Weather and Climate Prediction
Climate Prediction Center
5830 University Research Court
College Park, Maryland 20740
Page Author: Climate Prediction Center Internet Team
Page last modified: January 16, 2003
Information Quality
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities