Tools used in the U.S. Seasonal Drought Outlook (SDO) included the official Climate Prediction Center (CPC) temperature and precipitation outlooks for July through September (JAS) 2017, 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), Weeks 3-4, dynamical models (CFSv2, NMME, IRI, IMME, and ECMWF), the 384-hour total precipitation forecasts from several runs of the GFS, the four-month Palmer drought termination and amelioration probabilities, climatology for the JAS season, and initial conditions (the 6/13/2017 U.S. Drought Monitor). ENSO-neutral conditions are expected for the next few months.
Currently, no dryness exists on the latest Drought Monitor in either The Northeast nor the Middle Atlantic States, and no drought is forecast to develop in any specific areas within these regions; however, due to long-term precipitation shortfalls in the Northeast, and modest deficits on a variety of time scales in the Middle Atlantic States, these areas will be monitored closely over the next few months, as any significant period of heat and below-normal precipitation could cause drought to develop and intensify quickly. At this time, a warmer-than-normal July-September period as a whole is forecast, but rainfall is expected to be near or above normal through the last half of July, and there is no tilt of the odds toward either wetness or dryness for the remainder of the period.
Confidence is low for the Northeast and Middle Atlantic States
Drought has declined in extent and intensity over the last few months across the Southeast and is now restricted to scattered patches from northeastern Mississippi into central and northern Georgia, and some larger areas in southern Georgia and central Florida. The wet climatology from southern Georgia through the Florida Peninsula and the anticipated near- to above-normal rainfall through the end of June lead to a fairly confident forecast for removal there. Farther north, wet-leaning forecasts through the end of the month and a nondescript forecast from July onward imply continued improvement, though with less confidence as this is not a particularly wet time of year in the upper Southeast.
Confidence is high across southern Georgia and Florida, and low to moderate farther north.
Patchy drought exists in several relatively small areas across Texas and a small part of adjacent Oklahoma near the central Red River. Relief is expected in all areas except those near the Red River. In northwestern Texas, July-September is wet climatologically, with around 35 to 40 percent of annual precipitation typically falling during this period. In the absence of any compelling reason to expect a substantial period of drier-than-normal weather, improvement is more likely than persistence or deterioration. Farther southeast, this time of year has been neutral to slightly wetter than others climatologically, but the 3-month outlook shows enhanced chances for above-normal rainfall, thus implying improvement. In contrast, short-term conditions look relatively dry along the Red River Valley and indeed much of central and eastern Oklahoma, and this is not a particularly wet 3-month period in those regions. Neither dryness nor wetness is favored in the 3-month outlook here. In sum, persistence seems a bit more likely than improvement along the Red River. There is potential for development in central and eastern Oklahoma and parts of northeastern Texas near the existing drought areas, but similar to the situation in the Middle Atlantic States and Northeast, confidence is low, and there are no compelling signals indicating drought development in any specific location; however, any substantial period of dryness and heat could cause development and intensification to occur quickly.
Confidence is moderate to high in southern, central, and northwestern Texas; low in northeastern Texas and Oklahoma.
Drought developed in late May in the central Dakotas and has quickly spread and intensified to cover much of those state as well as eastern Montana and northern Minnesota. This is a fairly wet time of the year for the region, especially early in the period, and there are enhanced chances for above-normal precipitation for July-September 2017 as a whole. As a result, improvement is the only reasonable forecast, though uncertainty increases slightly toward autumn. Farther south, moderate drought recently developed across much of northern Missouri. With a few inches of rain anticipated in the near-term, removal is forecast, but uncertainty increases later in the forecast period, particularly with odds somewhat favoring above-normal temperatures July-September 2017 as a whole.
Confidence is high in the northern Plains; low in northern Missouri.
Compared to conditions a year ago, there is very little drought coverage in the Southwest, and what exists is significantly reduced in intensity. June is a dry time of year and no significant rainfall is expected through the end of the month; however, July-September is a very wet time of year across most of southern Arizona and New Mexico, with over half of annual rainfall typically falling during this 3-month period in the drought areas east of Yuma, AZ. Farther west, southern California typically receives little if any monsoonal rainfall, especially outside far southeastern areas. The forecast is based entirely on climatology, with improvement expected where the forecast period tends to be wet and modeled soil moisture increases more often than it declines, and persistence anticipated farther west outside the regions typically affected by monsoonal rainfall .
Confidence for the West is high.
Drought has developed across interior southwestern Alaska over the last couple of weeks. July-September is a relatively wet time of year there, with 40 to 50 percent of annual precipitation typically observed. In addition, there are enhanced chances for above-normal precipitation in southwestern parts of the drought area, and the last four times drought developed in Alaska during the spring, it was relieved by the first week of October, so removal is forecast with high confidence although some expansion and/or intensification is possible in the near-term. Drought also covers most of the western Big Island of Hawaii, where removal is anticipated in climatologically wetter sections across the northwesternmost parts of the Island, and persistence is forecast elsewhere.
Confidence is high in Alaska and moderate in Hawaii.
Forecaster: Rich Tinker
Next Seasonal Outlook issued: July 20, 2017 at 8:30 AM EDT