February - April 2011

Outlook Graphic: GIF   PDF 

Latest Seasonal Assessment - The drought outlook for February 3, 2011 – April 2011 was based largely upon climate anomalies associated with La Niña as it is expected to persist throughout the period. Although improvement may occur during early February, the CPC seasonal outlook indicating enhanced odds for below median precipitation favors drought persistence in southern Georgia and the coastal plain of the Carolinas. Drought persistence and development are forecast across Florida. Prospects for improvement are higher away from the Gulf Coast with some improvement predicted for central Georgia and the piedmont areas of the Carolinas and Virginia. Except for northeast Oklahoma, heavy snow that occurred on February 1 was generally east of the drought areas in the central and southern Plains. Drought persistence and development can be expected across parts of the central/southern Plains and eastern Colorado. Drought conditions continue to worsen in Arizona, New Mexico, and west Texas where persistence and additional development is expected. Drought relief has occurred in Hawaii this winter, courtesy of heavy rainfall associated with La Niña. Continued improvement is forecast for the Hawaiian Islands.

Tools used in the U.S. Drought Outlook (USDO) included the official CPC precipitation outlook for February 2011 and the long lead forecast for February - April 2011, 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, the Climate Forecast System (CFS) seasonal precipitation forecasts, La Niña composites for the December - February season, the four-month Palmer drought termination and amelioration probabilities, climatology, and initial conditions.

An early start to the 2010-11 dry season combined with a lack of tropical cyclone activity during 2010 resulted in expanding drought across Florida. 2010 rainfall departures below normal included 12.58 inches at Melbourne (3rd driest year on record) and 14.89 inches at Vero Beach (5th driest year on record). During mid-to-late January, two periods of rainfall prevented further worsening of drought conditions across Florida. However, river flows (according to the USGS) in the Big Bend area and the north-central peninsula remain at or below the 25th percentile. During early February, additional rainfall can be expected across the Florida Panhandle, while model guidance indicates a return of mostly dry weather across the Florida peninsula. Since La Niña precipitation composites and the CPC seasonal outlook strongly favor enhanced odds for below median precipitation, drought is expected to persist or develop across Florida.
Forecast confidence for Florida is high.

Across the southeast U.S., La Niña composites indicate the highest negative precipitation anomalies in southern Georgia. The CPC monthly and seasonal outlooks indicate the highest odds for below median precipitation closer to the Gulf Coast and along the coastal plain of the Carolinas. Therefore, drought is expected to persist across southern Georgia and the coastal plain of the Carolinas. Due to relatively wet forecasts during the first two weeks of February and weak signals among the precipitation tools beyond mid-February, some improvement is forecast in central Georgia, the piedmont of the Carolinas, and Virginia.
Forecast confidence for the Southeast is moderate.

During January, northerly flow resulted in drier than normal conditions across the lower Ohio Valley and the middle Mississippi Valley and a slight expansion of moderate drought across northern Arkansas and southern Missouri. On February 1, a major winter storm resulted in widespread precipitation amounts of more than 1 inch (liquid equivalent) across these regions. The CPC monthly and seasonal outlooks favor a slight tendency for above median precipitation across the lower Ohio Valley and Arkansas where improvement is forecast. Improvement is also forecast in northern Louisiana, while persistence is forecast in southern Louisiana. The persistence forecast in southern Louisiana is based on the CPC monthly and seasonal outlooks favoring below median precipitation.
Forecast confidence for the lower Ohio Valley is high and moderate for western Tennessee, Arkansas, and Louisiana.

Since January 1, near to above normal rainfall has resulted in reduction of drought coverage and severity across the gulf coast areas of Texas and south Texas. However, precipitation forecasts favor drier than normal conditions during February and continuing into the early spring. Due to these relatively dry forecasts, drought is expected to persist or return to many areas along the Texas gulf coast and south Texas.
Forecast confidence for eastern and southern Texas is moderate.

Following a drier than normal January, heavy snow fell across parts of the central/southern plains on February 1 but missed the key drought areas. Some improvement is forecast in northeast Oklahoma where heavy snow occurred and precipitation tools are noncommittal during the outlook period. Otherwise, little or no change was made to the previous outlook issued on January 20. Since the beginning of the year, severe drought has expanded in western Texas. Precipitation tools at all time ranges indicate an elevated chance for below median precipitation in these regions. Based upon the good agreement among precipitation tools and a relatively dry climatology, drought is likely to persist and develop across western Nebraska, eastern Colorado, and western parts of Kansas, Oklahoma, and Texas.
Forecast confidence for the central/southern Plains and western Texas is high.

Since mid-December, drier than normal conditions have affected much of Arizona and New Mexico. As of February 1, river basin snow water content values are running 25 to 75 percent of average in southeast Arizona and most of New Mexico. Precipitation tools at all time ranges indicate enhanced odds of below median precipitation. Due to a lack of adequate snowfall so far this winter, a tendency for dryness during a La Niña, and forecasts of below median precipitation, drought persistence and development can be expected across much of Arizona and New Mexico.
Forecast confidence for Arizona and New Mexico is high.

During the 2010-11 winter, heavy rainfall reduced drought conditions across the Hawaiian Islands which is typical for a La Niña winter. Enhanced rainfall during early-to-mid February and the ongoing La Niña favor additional improvement in Hawaii.
Forecast confidence for Hawaii is high.