February - April 2011

Outlook Graphic: GIF   PDF 

Latest Seasonal Assessment - The drought outlook for January 20, 2011 – April 2011 was based largely upon climate anomalies associated with a La Niña as it is expected to persist throughout the period. Drought is forecast to continue across the southeastern U.S. with development expected in coastal South Carolina. Drought persistence is also forecast across southern parts of Louisiana and southeast Texas, while improvement or some improvement is anticipated in northeast Texas, northern Louisiana, Arkansas, and the lower Ohio Valley. During the past month, drought has expanded across the central and southern Plains, west Texas, and southern parts of Arizona and New Mexico. Drought persistence and additional development can be expected in the southwestern U.S. and the central/southern Plains. Drought relief has recently occurred in Hawaii, courtesy of winter rains 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 dry season combined with a lack of tropical cyclone activity resulted in expanding drought across Florida. 2010 rainfall departures below normal include 12.58 inches at Melbourne (3rd driest year on record) and 14.89 inches at Vero Beach (5th driest year on record). Much needed rainfall occurred on January 17 when 2 – 5 inches fell in parts of the Florida peninsula. Heavy rainfall (more than 2 inches) was also recorded in eastern North Carolina. Across the southeast U.S., La Niña composites indicate the highest negative precipitation anomalies in southern Georgia and the Florida panhandle. The CPC monthly and seasonal outlooks indicate increased chances for below median precipitation across much of the southeast U.S., with the highest chances across the Florida peninsula. Although the CPC 6-10/8-14 Day outlooks favor above median rainfall, drought is expected to persist or develop across much of the southeast U.S.. This outlook is based primarily on the ongoing La Niña and its associated dry signal.
Forecast confidence for Florida and southern Georgia is high, and moderate across Alabama, the Carolinas, central Georgia, and Mississippi.

During the past month, northerly flow resulted in drier than normal conditions across the lower Ohio Valley and the middle Mississippi Valley. Despite the recent dryness, cold temperatures have led to little change in drought status across these regions. The short and extended range forecasts for the next two weeks indicate a persistently dry pattern for the lower Ohio Valley and middle Mississippi Valley. Despite this expected dryness, La Niña composites along with the CPC monthly and seasonal outlooks favor above median rainfall in these areas. Across Arkansas, mixed signals exist among most precipitation tools, but the outlook period is a relatively wet time of year. Improvement is forecast for the lower Ohio Valley, middle Mississippi Valley, western Tennessee, while some improvement is forecast across Arkansas.
Forecast confidence for the lower Ohio Valley, middle Mississippi Valley, and western Tennessee is moderate and low for Arkansas.

From January 1 – 17, above median rainfall occurred in northwest Louisiana along with eastern and southern Texas, while below median rainfall was observed in southern Louisiana. The recent increase in rainfall has reduced drought severity and coverage in eastern and southern Texas. 1-5 and 6-10 day forecasts indicate additional rainfall across the western Gulf region, while CPC monthly/seasonal outlooks predict low chances for below median rainfall closer to the Gulf Coast. Some improvement is forecast in northeast Texas and northern Louisiana due to prospects for more rainfall during January. Persistence is forecast across southeast Texas and southern Louisiana where monthly/seasonal outlooks tilt the odds slightly towards below median precipitation.
Forecast confidence for the western Gulf region is low.

Little if any precipitation has occurred across the central/southern Plains and western Texas during the past month. Therefore, drought conditions expanded or intensified across western Nebraska, eastern Colorado, Kansas, Oklahoma, and 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, a relatively dry climatology, and initial conditions, drought is likely to persist and develop across the central/southern Plains and western 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. River basin snow water content values are currently 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.

Heavy rainfall has recently reduced drought conditions across the Hawaiian Islands which is typical for a La Niña winter. Although above median rainfall is expected to continue and bring additional drought relief, long-term drought effects may linger.
Forecast confidence for Hawaii is high.