February - April 2009

Outlook Graphic: GIF   PDF 

Latest Seasonal Assessment - The drought over the southern Great Plains has expanded westward in recent weeks through much of the Texas Panhandle and western Oklahoma. Drought conditions are expected to develop across southwest Texas and southeast New Mexico during the next few months, with significant relief projected for central and eastern Oklahoma in the next two weeks. In southeast Colorado, mixed signals between various indicators makes for a lower confidence forecast, though at least some modest improvement appears likely. In the West, several inches of precipitation anticipated in the near-term over California will be beneficial in many respects, but this event is not expected to provide significant mitigation of drought conditions across the state. The only exception is the northwest portion of the state, where some improvement is indicated. Additional storm activity is expected to be concentrated mostly to the north, across the Pacific Northwest during February-April. Typically during late La Niña winters of moderate or strong intensity, the storm activity and the associated Pacific jet stream are focused across the Northwest. However, with a weak La Niña currently in progress and the expectation of weak La Niña or ENSO-Neutral conditions through the next few months, there is increased uncertainty about the location and strength of West coast precipitation events. At least some improvement is predicted for the interior Northwest and north-central states. For the upper Great Lakes area, there is a tilt in the odds towards improvement for southern and western portions of Wisconsin, and eastern Minnesota, with very limited improvement anticipated for northern and eastern areas of Wisconsin. Across the Southeast, rainfall amounts have been on the light side across parts of the southern Appalachians and southern Piedmont areas, along with reduced streamflows. Rainfall for the next few weeks is forecast to barely reach above normal in this region, according to CPC extended-range predictions. Limited improvement is indicated for this area. In Florida, despite recent rain, drought is likely to persist and expand across large portions of the state, which has some support from late winter La Niña composites.

Tools used in the Drought Outlook included the official precipitation outlook for February-April, various medium- and short-range forecasts and models such as the 6-10 day and 8-14 day forecasts, the soil moisture tools based on the GFS model and the Constructed Analogue on Soil (CAS) moisture, and climatology.

In recent weeks, heavy precipitation has fallen across much of the Eastern US, with Kentucky and West Virginia now above normal for precipitation for the past 30 days. The last vestiges of drought across northern Kentucky were erased during the ice storm a week ago. Further improvement of drought is forecast along the Virginia-West Virginia border. In the southern Appalachians/Piedmont region, some improvement is predicted, though the heaviest rain/snow amounts are expected to be west of the mountains. Over Florida, there is a tilt in the odds for persisting drought over west-central and southeastern portions of the state, with expansion deemed a good bet across most of the remainder of Florida, and extending up the southern Atlantic coast to include most of the coast of South Carolina. The updated 30-day precipitation outlook for February 2009, issued by the Climate Prediction Center on January 31st, calls for elevated chances of below average rainfall across the south Atlantic and Gulf coast regions, including all of Florida. The prominent dry signal over the Southeast (as well as the Ohio Valley wet signal) is consistent with historical La Niña cases for moderate and strong events. With a weak La Niña currently in progress, the odds for dryness are lower than for moderate or strong cold episodes.
Confidence for Appalachians: Moderate Confidence for Florida and southeast Georgia: Moderate to High

In Wisconsin and adjacent portions of Minnesota and upper Michigan, the best chances for improvement are for the southern and western portions of the drought area, which have been closer to the storm track over the Midwest in recent weeks. Areas more to the north and east should still experience some improvement, especially with the near-term forecast of an active storm track through the region.
Confidence for Great Lakes region: Moderate

Across the southern Plains, drought has intensified and expanded westward in the past few weeks throughout much of the Texas Panhandle and western Oklahoma. Drought conditions are expected to develop across far western Texas and southeast New Mexico during the next few months. This is indicated by CPC's February 2009 and Feb-Apr 2009 rainfall forecasts, as well as 1-month, 2-month, and 3-month soil moisture forecasts from the University of Washington. Significant relief is projected for central and eastern Oklahoma (from several storm systems) especially in the next two weeks. Slight expansion of the Texas drought area is forecast across the upper Texas coast and into southwest Louisiana. For southeast Colorado, the drought outlook is unclear due to conflicting indications between various model forecasts and CPC extended-range forecasts.
Confidence for southern Plains: High in western areas; moderate in eastern areas
Confidence for southeast Colorado: Low to Moderate

The Drought Outlook for February-April 2009 calls for an improvement in the long-term drought over southwest portions of North Dakota.
Confidence for North Dakota: Moderate

In northwest Montana, La Niña-related storminess is expected to be offset somewhat by the climatological rain shadow just east of the Divide. Therefore, some improvement is forecast.
Confidence for northwest Montana: Moderate

Across the widespread drought areas covering California and the Great Basin, prospects for beneficial rain/snow are good in the near-term, but for the three month forecast period as a whole, little mitigation in drought conditions is expected. It is thought that the mean jet stream and associated storm track will reside mainly north of this area, though some of this precipitation will probably reach across northwestern parts of California.
Confidence for the West: Moderate

For Hawaii, significant relief has occurred during the past few weeks. Based on MJO phase and La Niña considerations, the Hawaiian Islands will likely experience continued improvement in drought conditions.
Confidence for Hawaii: Moderate to High