Triple Digit Temps Expected in Plains States
Weather Summary: For several days in mid-May, corn planting and other Midwestern fieldwork accelerated in advance of a developing storm. Producers planted 43% of the U.S. corn crop during the week ending May 19, tying a weekly record set from May 4-10, 1992. However, heavy rain eventually overspread the northern Plains and Midwest, halting planting progress but providing further drought relief or eradication.
The same storm responsible for the rain in the north-central U.S. contributed to a multi-day severe weather outbreak. Iowa’s longest stretch without a tornado (359 days from May 25, 2012, to May 18, 2013) ended when several twisters were spotted on May 19. Previously, Iowa’s longest spell of tornado-free weather lasted 355 days in 1955-56. One day after Iowa’s tornadoes, tragedy struck Moore, Okla., on May 20 in the form of a devastating EF-5 twister—the nation’s first category five event since a similarly powerful tornado struck El Reno, Oklahoma, on May 24, 2011.
Several days of warmth preceded the storm across the western and central U.S. On May 14, a phenomenal surge of heat reached the central Plains and western Corn Belt, resulting in several monthly record highs and widespread readings above 100°F. Later, triple-digit heat developed and persisted in the south-central U.S.
In addition, rainfall largely bypassed the southern High Plains, resulting in further deterioration in the condition of rangeland, pastures, and winter wheat. Hot, mostly dry weather also prevailed from California into the Southwest. Farther north, however, scattered showers provided beneficial moisture for crops and pastures in the Northwest. More significant precipitation dampened the northern Intermountain West, particularly across portions of Wyoming and southern Montana.
Looking Ahead: During the next five days (May 23-27), the slow-moving storm system that has been affecting the Midwest — and was responsible for the tragic tornado in Moore, Okla. — will drift eastward. The system will reach the Atlantic Seaboard by May 24. Additional rainfall totals—in the form of locally severe thunderstorms — could reach 1 to 3 inches in the Northeast, and cool air will trail the storm into the Midwest and East.
Meanwhile, an early-season heat wave will develop on the High Plains. During the Memorial Day weekend (May 25-27), temperatures will approach or reach 100°F as far north as the central High Plains. Elsewhere, cool, showery weather will persist in the Northwest, while thundershowers will return to the Plains. More substantial rain (possibly 1 to 3 inches) may develop during the Memorial Day weekend in the western Corn Belt, including parts of Iowa and eastern Nebraska.
The NWS 6- to 10-day outlook for May 28 – June 1 calls for above-normal temperatures from the Plains to the East Coast, while cooler-than-normal conditions will prevail in the West. Meanwhile, below-normal rainfall across most of the southern half of the U.S. will contrast with wetter-than-normal weather across the nation’s northern tier from the Pacific Northwest to the Great Lakes region.