Tools used in the U.S. Monthly Drought Outlook (MDO) included the updated Climate Prediction Center (CPC) temperature and precipitation outlooks for June, 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), CFSv2 monthly forecasts of temperature and precipitation, the 384-hour total precipitation forecasts from several runs of the GFS, climatology for June, and recent precipitation. The May 23 U.S. Drought Monitor (USDM) was used for existing drought areas (D1 or drier) in the MDO.
ENSO-neutral conditions are favored to continue through at least June 2017, with increasing chances for El Niño development by late summer and fall. To be consistent with the U.S. Drought Monitor, narratives will use the NCEI region definitions (Northeast, Southeast, Midwest, South, High Plains, and West), with outside CONUS states (AK & HI) and territory (PR) grouped together.
Long-term precipitation shortages continue in parts of the Northeast. Over the last two years, precipitation amounts are several inches to over a foot below normal from the southern half of New England into parts of northern New Jersey and Pennsylvania; however, short-term conditions continue to keep any drought impacts to a minimum for the time being, with near- to above-normal May precipitation keeping the trend intact. The region will continue to be monitored closely for any drought development given the extant long-term moisture shortages in place.
In the Southeast, a trend toward improving drought conditions and decreasing coverage is expected to continue. Moderate to heavy precipitation is expected to be widespread through at least the first week of the month, likely extending to mid-month in Florida and adjacent Georgia. The month as a whole is favored to have above-normal precipitation across the interior Southeast, and climatologically this is one of the wetter months of the year from southern Georgia southward, with over 15 percent of annual rainfall typically recorded during June. For all these reasons, drought improvement or removal is forecast across existing areas of drought.
Forecast confidence for the Southeast is high.
Small patches of drought are scattered across central and eastern Texas and a small part of northwestern Louisiana. Near- to above-normal precipitation is likely through mid-month in much of Texas, and for June as a whole in northeastern parts of the state, and northwestern Louisiana. Climatologically, June is neither particularly wet nor particularly dry, except in Deep South Texas, where June is slightly drier than most months. As a result, drought is expected to persist in Deep South Texas, but removal is forecast in the rest of the region.
Forecast confidence for the South region is moderate (southern TX) to high.
Drought covers central sections of the Dakotas, and with warm and dry conditions expected through early June, drought is expected to expand. Later in June, some indicators point toward cooler and possibly wetter weather developing. Currently, confidence in this scenario is low, but it does bring down the likelihood that developing drought will persist through the end of the month. Climatologically, this is the wettest time of year for the Dakotas, with 15 to 25 percent of annual precipitation typically falling in June, so drought conditions have the potential to change rapidly.
Forecast confidence for the Dakotas is moderate.
This is a dry time of the year for the Southwest. In the areas experiencing drought, only 3 to 5 percent of annual precipitation falls during June in southern New Mexico, declining to 1 or 2 percent across southern Arizona, and less than 1 percent in southern California. With no indications that dramatically unseasonable rainfall will occur, persistence is the only reasonable forecast.
Forecast confidence the Southwest is high.
In Hawaii, the onset of the dry season usually occurs in late spring, but begins to increase as June progresses. With drought present on the leeward side of the Big Island, and with no guidance from the monthly outlook (EC), persistence was drawn for the existing drought areas, though with less certainty across interior southeastern sections of the drought region, where conditions are wetter climatologically and therefore provide more opportunity for relief. Drought neither exists nor is expected to develop in Alaska and Puerto Rico.
Forecast confidence for Hawaii is moderate, except low for climatologically-wetter areas across interior southeastern parts of the drought area.
Forecaster: Rich Tinker
Next Monthly Drought Outlook issued: June 30, 2017 at 3pm EDT