U.S. Drought Outlook: Improvements Expected for Central California, Texas
The Seasonal Drought Outlook calls for drought removal where it exists in the Northeast where the last half of February is expected to be somewhat wetter than normal. Drought should persist in southeast North Dakota, and in the small areas that recently developed in southern Texas, as spring is a relatively dry time of year. I
n central Texas, however, spring precipitation is more robust, and with odds tilting toward above-normal precipitation in the region for March-May, drought removal is expected there. Enhanced chances for above normal precipitation should bring at least some improvement in central and upper southern parts of California, all but northwestern Nevada, northern Utah, and the area extending from northern Wyoming into southern Montana. Climatologically increasing rainfall is the primary consideration in the latter area.
In Arizona and southern California, March begins a drier time of year, and precipitation probably won’t be sufficient to bring any improvement there despite odds favoring wetter than normal conditions.
In the Northwest and west-central part of the country, forecasts on all time scales favor near- to below-normal precipitation, and persistence is expected there.
Drought is expected to expand further through much of Hawaii, where a dry spring is anticipated, and dryness should worsen or intensify where it exists in Puerto Rico.
Forecast confidence for The West is generally high, but moderate across the extreme to exceptional drought areas in California, where drought may require substantially more precipitation than normal to significantly improve.
- With subnormal precipitation expected until March, the forecast across the West hinges on the March-May outlook.
- Improvement is forecast for areas where odds favor spring wetness, and persistence where either subnormal precipitation is favored or neither precipitation extreme seems more likely.
- The exception to this rule is across Arizona, southernmost Nevada, and southern California.
- Despite enhanced probabilities of wetter than normal spring conditions in these regions, March-May typically contributes only about 15 percent of the annual precipitation total, which has been particularly true for the past 15 years. Even above normal precipitation would likely be insufficient to change drought conditions in the region.
Forecast confidence for Texas is moderate.
- The forecast for the new areas of drought in Texas basically hinges on how much March-May precipitation typically contributes to the annual total. Forecasts call for dry weather through the end of February, and enhanced odds for above-normal precipitation thereafter.
- However, persistence is anticipated in southern Texas, where March-May is a relatively dry time of year; however, drought removal is expected by the end of May in central Texas, where March-May climatology is wetter.
Forecast confidence for the Northern Plains is moderate.
- The small area of drought in North Dakota is expected to persist.
- Dry conditions should dominate through the last half of February while neither dry nor wet conditions are favored during spring.
- The wetter time of year is starting to get underway in late spring, but uncertainty in the long term and dryness in the short term favor a continuation of present conditions.
Forecast confidence for the northern High Plains is low to moderate.
- In the northern High Plains and adjacent Rockies, odds favor wetter than normal weather in the southern reaches of the region with no discernable tilt of the odds elsewhere.
- The forecast is based on spring being a wet time of year in the region, bringing better chances for improvement than deterioration.
Forecast confidence for the Northeast is low.
- In the Northeast, remaining areas of drought should be resolved by the end of May.
- Relative wetness in the short term and low confidence depicted in the March-May outlooks favors improvement given the effectiveness of precipitation recharge this time of year, particularly if it increases snowpack.
Forecast confidence for Hawaii is high in areas of existing drought and moderate in areas of expected drought expansion, which are always tough to pinpoint in seasonal forecasts.
- El Niño conditions also favor continued dryness across most of Hawaii, so persistence or deterioration, including substantial drought expansion, is expected.
- Only some windward areas are expected to remain out of drought by the end of May.
Forecast confidence for Puerto Rico is low.
- El Niño conditions favor a wetter than average dry season across Puerto Rico, but this has not been the case in drought areas for the last 3 months.
- Precipitation increases markedly as spring progresses, with more than half of the seasonal total usually falling during May.
- While the later spring time scale is uncertain to say the least, the entrenched nature of the drought implies that a substantially wetter than normal May would be necessary to bring significant improvement, so persistence is forecast.
- Still, El Niño enhances the likelihood of a wetter than normal May, leading to reduced confidence in the forecast.
Source: : http://www.cpc.ncep.noaa.gov/products/expert_assessment/sdo_summary.php