November 2007 - January 2008

Latest Seasonal Assessment - By the middle of October, extreme drought covered nearly one-half of the Southeast, and critical water shortages had developed in a number of cities. With the hardest-hit areas needing more than a foot of rain to pull out of drought, this drought is not going away soon. The good news is that much of the drought region in the Southeast, Tennessee Valley, and mid-Atlantic can expect some temporary improvement during the last half of October, with locally heavy rains in a few locations. Unfortunately, the expected rainfall is unlikely to lead to lasting drought relief over the Southeast, as the ongoing La Niña should lead to below-normal rainfall during November-January, resulting in drought continuing or re-intensifying. The Outlook even indicates a good chance for drought to redevelop in parts of Florida. Drought is forecast to persist from northeastern Alabama to the mid-Atlantic States, while drought should improve over the Ohio Valley, the Northeast, and the Great Lakes region. In the West, improvement is expected from northern California into the interior Northwest, northern Rockies, and northern Plains, while drought will persist from southern California into Arizona. There is a chance that drought will develop by the end of January in New Mexico, southeastern Colorado, the western Oklahoma Panhandle, and the northern Panhandle of Texas. Drought relief is on the way for Hawaii.

Tools used in the Drought Outlook included the official CPC long-lead precipitation outlook for November-January, the updated CPC forecast for November, the four-month drought termination and amelioration probabilities, various medium and short-range forecasts and models such as the 6-10 day and 8-14 day forecasts, and the soil moisture tools based on the GFS model and the (CAS) Constructed Analogue on Soil moisture.

Over the Southeast, the forecast replaces the area of improvement with an area of drought ongoing/some improvement over the Florida Panhandle and along the coast of the Carolina's as rainfall is expected over those regions over the next 10 days but the monthly and seasonal forecasts indicate drier than normal conditions for those areas. In addition, along the coast of the Carolina's the soil moisture anomaly change for the next two weeks is expected to be negative and the probability of relief from tropical systems is decreasing. The area over the Florida Penisula that was indicating improvement is changed to drought ongoing/some improvement as short term forecasts through day 10 indicate the possibility of above median precipitation while the monthly and seasonal forecasts show drier than normal conditions likely for the state. Possible relief from tropical systems also becomes much less likely beyond the end of October for the region. An area of drought development has been added to the northwestern part of the Florida Penisula. Even though some rain is possible over this area in the shorter ranges, the November-January forecast indicates a fairly high probability of below normal precipitation for the region. Given that this region only recently recovered from drought it was felt that drought could redevelop fairly quickly over the area, especially when La Niña composites for moderate or strong events are taken into account.

Over the central Plains the area of drought ongoing /some improvement is changed to improvement over parts of Missouri, southern Illinois, western Tennessee and western Kentucky as precipitation is likely to be above normal over the next two weeks and soil moisture anomaly changes are forecast to be mostly positive. The monthly forecast for November and seasonal forecast for November-January show equal chances for precipitation for the region.

The area of persist over southern New England will be changed to improve as recent rains in the area have offered some relief and indications for the next 10 days suggest more precipitaton over the region.

For the west, the area of improvement over California has been shifted a bit to the north near the coast and to the south over the Sierra while over eastern Nevada and Northern Utah the area indicating improvement has been shifted a little to the south. An area of developing drought is specified for Arizona, New Mexico, southeast Colorado and the Panhandle regions of Texas and Oklahoma. This assessment is consistent with the longer range precipitation forecasts and La Niña composites.