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. Some improvement is expected across
southeastern Montana and northern Wyoming. However, long term impacts are expected to persist.
Improvement is expected to continue across Nebraska, extreme eastern Wyoming and western South
Dakota. Further south, improvement is expected across eastern New Mexico, Texas and Louisiana.
However, periodic dry spells are possible.
|
Tools used in the drought outlook included: the official CPC long-lead precipitation outlook for
July-September, the Palmer Drought Index probability projections for September
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 Idaho, Montana, Wyoming and northern Colorado have helped to reduce long
term moisture deficits and ease drought impacts. Some further improvement is expected across
southeastern Montana, eastern and northern parts of Wyoming. 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 northern 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 will persist. Across most of Arizona, rainfall
typically increases during late July as the monsoon sets in. This will result in some improvement in the
drought situation. However, due to the long term nature of the drought, the improvement will be quite
limited as even a very wet monsoon will not break the current drought across much of the state. Across
eastern New Mexico and western Texas, the majority of annual precipitation falls during the summer.
With normal to above normal rainfall expected, improvement is expected in this area.
Across eastern Texas and western Louisiana, a dry April and May resulted in 90 day rainfall departures
of 100 to 200 mm by June 1 (25 to 50% of normal). However, recent rains have served to reduce
these deficits. The overall trend is for improvement across this area, although periodic dry spells are
certainly possible. The "wild card" in this outlook, especially during the last half of the period, is tropical
storms. One tropical system could eliminate any rainfall deficit very quickly. Further north, an active
spring weather pattern has resulted in improvement across western Nebraska and portions of South
Dakota. These areas are expected to continue to improve throughout the period. However, as with the
western Gulf Coast, periodic dry spells are possible.
Across northern Minnesota, winter and early spring were very dry. 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. Summer rains will result in some
improvement. However, only a exceptionally wet summer would result in a major reduction in these
deficits, which is not anticipated.
|