Latest Seasonal Assessment -
During the past 4 weeks, seasonably drier and warmer weather returned to most of the Far West. Although decent
spring reservoir recharge and mountain snowpack conditions resulted in widespread drought reduction across northern California and Nevada in May, continued above-normal temperatures and subnormal precipitation in the Northwest greatly diminished or melted out the snow pack and promoted short-term dryness by early June. Surplus rains continued across the southern Plains with flooding in Texas, but drier conditions in parts of the north-central Plains and upper Midwest resulted in abnormal dryness development. Deficient 30-day rainfall in portions of the Southeast, Appalachians, and Northeast, combined with subnormal March and April precipitation, led to dryness and drought expansion in the eastern Tennessee Valley and southern Appalachians, and parts of New England. Tropical Storms Bonnie (late May) and Colin (early June) brought locally heavy but mostly beneficial rains to the southern Atlantic and eastern Gulf Coasts. An increase in windward showers aided some improvement of drought across eastern and central sections of the Hawaiian Islands.
The CPC seasonal outlook for July-September has favorable odds of above-normal temperatures across Alaska and CONUS. A tilt toward enhanced precipitation exceeding climatology was found in the north-central Great Plains and upper Midwest, along the Gulf Coast, and in western Alaska. Below-median precipitation is favored in the Northwest. Drought development is forecast for much of Washington and Oregon due to the melt out of most mountain snow packs, subnormal precipitation since April, and the warm and dry monthly and seasonal outlooks. Although drought development or expansion is also possible during the next several weeks due to expected dry and warm weather (e.g. flash drought) in parts of the north-central Plains (D0-D2), Midwest (only D0 in the latest USDM), and Southeast (D0-D2), the possibility of wetter conditions later this summer prevented a SDO forecast (valid Sep. 30) of drought expansion in these regions; however, uncertainty of the wetness also precluded removal of drought, hence persistence was drawn. An exception to this was the Northeast as surplus rains are expected the next 2 weeks, along with a favorable precipitation climatology that tends to prevent prolonged and expansive droughts. In addition, although there is uncertainty (EC) regarding the southwestern summer monsoon (unlike the past 2 seasons where wetness was greatly favored), a favorable climatology (improved areas normally receive half their annual total during JAS) makes drought removal more likely across southeastern Arizona and southern New Mexico, and not so much elsewhere. In Hawaii, some improvement is favored for the leeward (west) side of the Big Island based upon the seasonal outlooks and wet summer climatology. Elsewhere, however, although the seasonal outlook tilts toward above-median rainfall, the dry season is underway and leeward sides typically receive less rainfall as compared to the windward, hence persistence is likely on the remainder of the islands. In Puerto Rico, the demise of El Niño and an expected return to La Niña this winter should translate to a more active tropical Caribbean and Atlantic season this year, hence more convection and rainfall this summer.
Forecaster: David Miskus
Next Seasonal Drought Outlook issued: July 21, 2016 at 8:30 AM EDT
Seasonal Drought Outlook Discussion