June - August 2003

Latest Seasonal Assessment - Large moisture deficits accumulated in recent years have resulted in severe to exceptional drought conditions (D2-D4) across Utah, Nevada, Arizona, northern New Mexico, southwestern Wyoming, southern and western Colorado. Long term drought conditions are expected to persist throughout the period in this region. Further north, significant improvement has been observed across northern Colorado, eastern Montana, northern and eastern Wyoming. Gradual improvement is expected across these areas. However, long term impacts are expected to persist. Improvement is expected to continue across the north-central U.S. The potential exists for improvement in the short term dryness across much of Texas. However, due to the non-existence of a strong indicator for wetness or dryness, there is a low confidence in the "drought likely to improve" forecast for Texas.

Tools used in the drought outlook included: the official CPC long-lead precipitation outlook for June-August, the Palmer Drought Index probability projections for August and various medium and short-range forecasts and models such as the 6-10 day and 8-14 day forecasts. The latest western water supply forecast is also considered.

Wet conditions across Montana, Wyoming and northern Colorado have helped to reduce long term moisture deficits and ease drought impacts. Improvement is expected to continue across eastern Montana, eastern Wyoming and northeastern portions of Colorado. However, large deficits accumulated in recent years continue to result long term drought conditions (D2-D4) across southwestern Wyoming, Utah, Nevada, southern and western Colorado and large portions of New Mexico and Arizona. With typically dry conditions expected during the summer across southwestern Wyoming, northern Nevada and northern Utah , long term drought conditions are expected to persist. Further south, conditions are typically dry during June and early July, with an increase in precipitation during the later part of July into August. Even if these rains are heavier than normal, they are unlikely to make a significant reduction in the long term moisture deficits across southern Nevada, Arizona, western Colorado, much of New Mexico and southern Utah. As a result, drought is likely to persist.

An active spring weather pattern has resulted in improvement across the Dakotas, Nebraska, the western Corn Belt and much of the Great Lakes region. Improvement is expected to continue across the Dakotas and Nebraska, with lingering long term impacts across western Nebraska and portions of western South Dakota. The long term impacts, such as low ground water levels and stream flows, are expected to slowly improve across these areas. Further south across much of Texas and southern Oklahoma, short term dryness has resulted in 90 day precipitation deficits ranging from 25 to 150 mm. In the short term, there are indications of relief across southern Oklahoma and northern Texas. There are some indications that the region may receive normal to above normal precipitation during the period. However, these indications are weak. As a result, the confidence in the forecast for "Drought likely to improve, impacts ease" is low across Texas and the immediate vicinity.

Across northern Minnesota, light precipitation has resulted in a very dry winter and early spring. However, the majority of the regions' annual precipitation falls during the warm season. As a result, impacts from the recent dry winter will likely ease with minimal moisture deficits expected. Long term dryness has resulted in a three year precipitation deficit of 18 to 24 inches across much of Maine. Spring and summer rains will result in some improvement. However, only a very wet spring and summer would result in a major reduction in these deficits, which is not anticipated.