Tools used in the U.S. Monthly Drought Outlook (MDO) included the updated Climate Prediction Center (CPC) temperature and precipitation outlooks for March 2019, various short- and medium-range forecasts and models such as the 7-day quantitative precipitation forecast (QPF) totals from the Weather Prediction Center (WPC), the 6-10 day and 8-14 day CPC extended-range forecasts (ERFs), the Week 3-4 outlooks, tools from CPC, dynamical models on the monthly time scale, the 384-hour total precipitation forecasts from several runs of the GFS, March climatology relative to other times of the year, El Nino temperature and precipitation composites, predicted soil moisture anomalies from the GFS model, and initial conditions from the February 26 US Drought Monitor. 

During February, a series of atmospheric river events brought repeated storm systems to the western U.S., nearly eliminating drought conditions over California, and substantially reducing drought coverage over coastal Oregon, the Great Basin, and parts of the northern and central Rockies. Outside of the northern Cascades and southern Rockies, snowpack conditions are well above normal across much of the West, including a mean water content of 36 inches (150 percent of normal) over the Sierras. Temperatures during this period ranged below normal, promoting a lower elevation of snow coverage. During the first part of March, the active pattern is anticipated to continue, with WPC QPF forecasts depicting widespread precipitation across coastal California, the Cascades, and further east over the Great Basin and central Rockies. The CPC 8-14 day outlook maintains this wet pattern and shifts it southward, and accordingly, the updated March monthly outlook shows increased chances for above-median precipitation across most of the Western Region. However, equal chances for below-, near-, and above-median precipitation remain across the Northern Tier and the southern half of New Mexico. This increased uncertainty for above-normal precipitation, combined with remaining areas of below-normal snowpack coverage over the northern Cascades, makes drought persistence more likely for central and northern Oregon and northern Washington. Additionally, persistence is favored across parts of central and western New Mexico where basin snow content is even lower. Short term drought development is favored across the High Plains of southeastern New Mexico, and the reasoning for this forecast is discussed in more detail in the Southern Region section.

Forecast confidence for the Western Region is moderate to high.

Across the High Plains region, current drought coverage is limited to south-central Wyoming and much of Colorado. As discussed in the Western Region section, an influx of Pacific moisture resulted in widespread snowfall across the central Rockies, reducing drought intensity and coverage over the mountains, although short term dryness and a small pocket of moderate drought developed over the central High Plains of Wyoming and Colorado. During the first week of March, in addition to widespread heavy mountain snowfall, moderate snow (0.1 to 0.5 inches liquid equivalent) is anticipated to fall across the central Plains. Both the CPC 8-14 day outlook and updated March outlook show enhanced chances for above-normal precipitation across the High Plains region, with the exception of the Dakotas and northern Wyoming. This outlook favors continued drought reduction for southern Wyoming and Colorado. Furthermore, due to deep snow cover across the northern Plains and the anticipated presence of bitterly cold air for at least the first half of the month, no drought expansion is anticipated.

Forecast confidence for the High Plains Region is high.

The Southern Region is the sole area of the CONUS that experienced substantial increases in drought coverage during February. 30-day percent of normal precipitation data from AHPS shows a large area of below-normal precipitation across Texas, Oklahoma, and Louisiana, and impacts have begun mounting across western and southern Texas where winter wheat fields are already showing signs of stress. Due to these deteriorating conditions, drought (D1+) and abnormal dryness (D0) depictions expanded across the western half of Texas on the U.S. Drought Monitor. Dry weather is favored to continue during the first week of March, and the updated March outlook from CPC maintains equal-chances for below-, near-, or above-median precipitation. Although March is a relatively dry time of year for northern and western Texas, the building impacts from the short term dryness make drought expansion more likely in the absence of a clear wet signal. Therefore, drought persistence and development of areas currently depicted as D0 are favored in areas of northern and western Texas where the March outlook maintains equal chances. This development area also extends into southeastern New Mexico. It should be noted that while the seasonal outlook issued a week prior to this monthly outlook forecasted drought reduction across the Southern Region, the seasonal discussion noted the potential for short term drought development early in the period, with the anticipated relief more likely to occur during May, when climatological precipitation is at its highest across Texas. Therefore, this outlook does not represent a substantial change in the overall reasoning that underpinned the seasonal outlook.

Forecast confidence for the Southern Region is low to moderate.

There are no drought or abnormal dryness depictions for the Midwestern Region on the 26 February U.S. Drought Monitor, and with the updated March outlooks from CPC depicting enhanced chances for below normal temperatures and no areas favoring below-normal precipitation, drought development is not anticipated. 

Forecast confidence for the Midwestern Region is moderate to high.

With the removal of the last remaining moderate drought area across Florida's Treasure Coast, there is currently no drought depicted on the U.S. Drought Monitor across the Southeast Region. 30-day percent of normal precipitation data from AHPS shows a large area of below-normal precipitation extending from southern Alabama and central and northern Florida northeastward to the coastal Carolinas. Due to this short term dryness, D0 depictions have expanded right along the coast from the Georgia-South Carolina border to the South Carolina-North Carolina border. The 7-day QPF forecast from WPC shows widespread heavy precipitation across the southern Appalachians and Piedmont regions, with lesser amounts (0.75 to 1.5 inches) along the coastal plain. These amounts may help delay drought development, but would not be sufficient to ease the short term deficits. Above-normal precipitation is favored in both the CPC 8-14 day and updated March outlooks. Based on these longer range outlooks, drought development is not anticipated.

Forecast confidence for the Southeast Region is moderate.

There are no drought or abnormal dryness depictions for the Northeast Region on the 26 February U.S. Drought Monitor. The updated CPC March outlooks favor below-normal temperatures, with enhanced chances for above-normal precipitation extending from the mid-Atlantic to southern New England. Based on climatology and these outlooks, drought development is not anticipated.

Forecast confidence for the Northeast Region is high.

Periods of rain and below-normal temperatures resulted in drought reduction across Hawaii, where drought depictions remain only on the leeward sides of the Big Island and Kauai. Due to the recent moisture, drought development is not anticipated; however, in the absence of a clear wet signal, further drought relief is also uncertain. Therefore, persistence of the existing drought areas is maintained. Across Alaska, dry weather over the Panhandle region has resulted in below-normal snowpack and low reservoir levels. the Updated March outlook from CPC maintains enhanced chances for below-normal precipitation. Therefore, drought persistence is the most likely outcome. Across Puerto Rico, drought has slowly expanded during the past 30 days. El Nino conditions generally promote a suppressed convective regime over the Caribbean, and this pattern is borne out by dynamical model forecasts. Therefore, continued drought expansion is favored.

Forecast confidence is low for Hawaii, moderate for Alaska, and moderate to high for Puerto Rico.

Forecaster: Adam Allgood

Next Monthly Drought Outlook issued: March 31, 2019 at 3pm EST