Following is the summary of Drought Outlook comments from the NOAA Climate Prediction Center published Jan. 19. These comments are optimistic about drought conditions either letting up or completely going away by the time spring crop season rolls around. That is no surprise considering the heavy precipitation that we have seen in many of the dry areas from late December through mid-January. Comments were authored by CPC forecaster Adam Allgood.
-- Bryce Anderson
WEST AND SOUTHWEST
The new year ushered in a series of storms across the West, with multiple episodes of heavy rain and mountain snowfall across California's coastal regions and the Sierra Nevada mountains. Snowpack water content values are between 175 and 200% of normal across the Sierras, and for the first time in four years, California's average reservoir storage is above normal for the time of year. The unrelenting storminess promoted drought improvements, including two to three class changes on the U.S. Drought Monitor (USDM) across north-central California during the past month.
While some improvements occurred, extreme to exceptional drought remained entrenched across the central coast and San Joaquin Valley, regions that were south of the heaviest precipitation footprint. Drought conditions also eased somewhat over parts of Arizona and New Mexico, although below-normal mountain snowpack values remain across the far southern Rockies.
During the next week, another atmospheric river event is anticipated to bring widespread substantial precipitation to the Southwest. The latest seven-day Quantitative Precipitation Forecast (QPF) outlook from the Weather Prediction Center (WPC) depicts 10-to-12-inch accumulations across the entire coastal region of California, and a foot of liquid equivalent precipitation in the Sierras. Should this event unfold as forecast, there is a high potential for additional drought reductions, especially for central and southern California. The drought outlook for California is therefore based heavily on this short-term forecast.
Beyond Week 1, a pattern change is forecast, with drier conditions favored across California. The CPC monthly outlook favors below-median precipitation across California and the Southwest, while the February-March-April (FMA) outlook maintains equal chances for below-, near-, and above-median precipitation. Despite the pattern change, the short-term precipitation should be sufficient to improve drought conditions through the end of April. Beyond the forecast period, conditions will become more dependent on snowmelt from the Sierras.
Drought persistence is favored across the desert regions of California and Arizona due to less forecasted short term precipitation, and a dry tilt in the FMA seasonal outlook. Forecast confidence for California and the Southwest is moderate to high.
During the past month, widespread precipitation promoted drought reduction across eastern Oregon and western Montana. During the next seven days, the WPC QPF forecast depicts widespread precipitation across Oregon and the northern Rockies. The CPC six-to-10 and eight-to-14 day outlooks show an abrupt pattern change, with dry conditions overspreading much of the West. Below-normal temperatures are also favored during this period, which would help mitigate any impacts of the drier period. The CPC monthly outlook for February maintains equal chances for below-, near-, and above-median precipitation, while the FMA seasonal outlook shows enhanced chances for above-median precipitation. Therefore, based on both the short-term forecast and the seasonal outlook, removal of the small remaining drought areas is anticipated. Forecast confidence for the Northwest is moderate.
PLAINS AND MIDWEST
During the past seven days, widespread storminess overspread a swath of the nation's midsection from New Mexico northeastward to the Great Lakes. Four-week percent of normal precipitation amounts exceeded 200% across most of New Mexico, northern Texas, Colorado, Kansas, Nebraska, and the Dakotas. The rain and snow resulted in substantial short-term drought reduction across the High Plains. In contrast, precipitation largely missed the eastern Plains, including the more entrenched drought areas of eastern Oklahoma. Drought conditions recently worsened across parts of Missouri as well.
During the next two weeks, Global Forecast System (GFS) forecasts show additional precipitation (1 to 3 inches) falling from northeastern Colorado through the upper Midwest. Lighter amounts (up to 0.5 inch) are anticipated across western Kansas and Oklahoma. Based on recent conditions, this precipitation should be sufficient to continue the trend of improvement across the central High Plains.
The February-March-April (FMA) seasonal outlook depicts enhanced chances for above-median precipitation across the Northern Plains, which increases confidence for improvement across the longer-term drought areas of northeastern Wyoming and western South Dakota as well. Further east, drought persistence is favored to continue across eastern Oklahoma, northern Arkansas, and Missouri, as these regions are anticipated to receive less precipitation in the short term, and there is no clear signal in the monthly and seasonal guidance favoring wetness. Forecast confidence for the Plains and Midwest is low to moderate.
Following a similar pattern of reasoning to the West and central High Plains, the seasonal drought outlook for the Southeast is based largely on short-term forecasts. During the upcoming week, a slow-moving area of low pressure is forecast to bring copious amounts of rainfall from eastern Texas northeastward across much of the eastern Seaboard. According to the WPC seven-day QPF forecast, the heaviest amounts (possibly exceeding 5 inches) may fall over the regions where drought is most severe, including northern Alabama, northern Georgia, and southwestern North Carolina. Although unlikely to completely dislodge entrenched drought conditions across the Deep South, this moisture is likely sufficient to yield widespread 1-category or more U.S. Drought Monitor (USDM) improvements. Further south, a sharp cutoff in precipitation totals is anticipated to set up somewhere over North Florida, limiting prospects for improvements where abnormal dryness has been expanding.
Beyond the short term, the Week 2 to seasonal guidance all depicts enhanced chances for below-median precipitation. Therefore, drought development is favored across the Florida Peninsula, and far south Texas, where conditions are already abnormally dry. There is low confidence for persistence of the D1 area in southern Georgia, due to uncertainty regarding the southward extent of the heavy precipitation forecasted in the short term. Forecast confidence for the Southeast is low across southern Georgia and northern Florida, and moderate elsewhere.
During the past 60 days, precipitation has been generally near normal across the Northeast. Slight improvements have been made to drought areas from north-central Pennsylvania through Maine, while severe to extreme drought remained entrenched across southern New England. During the upcoming week, widespread heavy precipitation is forecast, with total liquid accumulations exceeding 2 inches along coastal regions of the Northeast, and higher amounts (4 to 5 inches) possible from the New York City metro area through southern New England. Accumulations of an inch or more are favored across interior New England. This precipitation will favor continued erosion of drought conditions in the short term. The CPC six-to-10 and eight-to-14 day outlooks both favor above-median precipitation across most of the Northeast, while the FMA seasonal outlook maintains equal chances for below-, near-, and above-median precipitation.
Based on the anticipated wetness through the end of January, and an evenly distributed wet climatology through the Spring, further drought reduction is favored for the Northeast. Forecast confidence for the Northeast is moderate.
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