Thanks in large part to a very wet April, the April 25, U.S. Drought Monitor had the smallest CONUS drought (D1-D4) on record (6.1%) - which dates back to January 2000. In addition, the smallest CONUS D2-D4 was also established (1.07%), along with D3-D4 at a near-record 0.03% (0% D3-D4 has occurred before). The greatest concentration of drought (D1 or drier) was confined to the Southeast, namely Alabama, Georgia, and Florida. ENSO-neutral conditions are favored to continue through at least the Northern Hemisphere spring 2017, with increasing chances for El Nino development by late summer and fall. 

In the West, with the climatological transition (spring to summer) from wet and cool to dry and warm, small areas of pre-existing drought (D1) in southern sections of California and Arizona should persist during May.

Climatology for May favors increased precipitation across the middle third of the lower 48 States (Plains and Midwest) with many areas normally receiving 15-20% of their annual precipitation during May. The few small remaining drought areas (D1) in Wyoming, Nebraska, and Colorado should be gone by the end of May with nearly all of the forecasts (QPF, ERFs, Weeks 3-4, and 1-month LLF) favoring above-median precipitation. A possible small exception includes extreme southern Texas where persistence is favored - only Weeks 3-4 favor wetness while the other outlooks tilt toward dryness or EC.

Drought removal of small D1 areas is predicted for the Northeast (coastal New England and mid-Atlantic) based on the QPF, 6-10 day ERF, and 1-month updated precipitation LLF which all favor above-median rainfall, along with probable sub-normal temperatures in the first half of the month. In addition, slow improvement has been the trend in the Northeast during the past 3-4 months with near to above normal precipitation and a gradual recovery of hydrologic conditions.

In the Southeast, although drought has eased across western and northern sections during April, it also contains some of the few areas in the U.S. to worsen and/or expand recently - mainly across the eastern Gulf and southern Atlantic coastal regions. Based upon the QPF, early May should bring heavy (3-6 inches) rainfall to western and northern sections of the Southeast, hence the continuing improvement there. To the southeast, however, much smaller QPF totals (<1 inch) are expected, and with 6-10 and 8-14 day ERFS tilting dry (EC for Weeks 3-4 and 1-month LLF precipitation), existing drought should persist and develop where D0 exists. In Florida, their normal dry season typically ends in late May or early June. Recent conditions (dry and warm) have favored deterioration, and with the short-term outlooks (QPF, ERFs) maintaining subnormal rainfall, persistence and some drought development of existing D0 is likely by the end of May.

For the leeward slopes of the Big Island of Hawaii and parts of Maui, with no tilt of rainfall odds (EC) for May, drought is predicted to persist as the climatological dry season continues. No drought is expected to develop in either Alaska (some current D0 across southern sections) or Puerto Rico (no D0).


Forecaster: David Miskus


Next Monthly Outlook issued: May 31, 2017 at 3pm EDT