NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

November 5, 1998

October Rainfall Favorable for 1999 Crop Year

Widespread rains across North Dakota in October slowed fall field work, but most of it has infiltrated and become stored soil water for next year's crop. As a result the soil water outlook for the 1999 crop is good, according to John Enz, agricultural climatologist at North Dakota State University.

The storm system that covered the state in early October produced rain at every one of the 50 North Dakota Agricultural Weather Network (NDAWN) stations on the fourth and fifth, and at all but four stations on the sixth. Then, on Oct. 11, it happened again.

"These are rare events," Enz said.

Enz finds it interesting that the last time heavy widespread rain fell in North Dakota was in 1982, the autumn prior to the major 1982-83 El Nino event that caused severe flooding and mud slides in California. Many meteorologists attributed the heavy October rainfall to El Nino conditions. However, this October's heavy rains followed the 1997-98 El Nino winter, the largest since the 1982-83 event.

"This should make meteorologists and agriculturalists more careful about blaming all extreme weather conditions on El Nino," said Enz.

Predictions for a warm dry winter due to a rapidly developing, intense El Nino did prove reasonably accurate across the Northern Plains in 1997-98. Snow melted in southern North Dakota, in late February but the aftermath of a late February blizzard in the north and west persisted until the end of March.

Temperatures ranging from 4 to 8 degrees above the long term average provided ideal drying weather, and scattered field work started in early April. The statewide average starting date for fieldwork was April 18, about two weeks earlier than the previous three years.

According to data compiled by Enz and research specialist Radu Carcoana, May rainfall was less than half of normal in the western two-thirds of the state, accompanied by above normal temperatures. By mid May western crops were about two weeks ahead of recent years, but concern about dry soil conditions was growing. Dry conditions persisted until mid June, when heavy rains arrived.

In the east, widespread storms dropped heavy rains in May and June, with unprecedented total rainfall amounts in many areas. For example, Enz says, in the very wet southeast, May-June totals at McLeod, Fargo and Forman were the highest on record, ranging from just under 14 inches at Fargo to 14.29 inches at Forman. Heavy totals were also recorded in other regions, including Langdon with a record May-June total of 11 inches, and Dickinson, Bottineau and Stanley ranging from 8.41 to 9.13 inches.

July rainfall was near normal in many areas, but uneven distribution made the month seem dry, Enz says. The eastern two-thirds of North Dakota received 1.5 to over 3 inches of rain during the first week, but less than an inch fell the remainder of the month. The wet early July prompted great concern about scab and other possible disease epidemics, but incidence of crop disease was generally not as bad as expected.

August provided warm, dry harvesting weather in many areas, with scattered locations recording less than half an inch of rain, only about 20 percent of normal. However, 4 to 6 inches and more fell in the north central and south central regions, including an August record 9.29 inches at Bismarck. This was the greatest August total at Bismarck since weather records were first kept in 1879, eclipsing the previous record of 5.59 inches set in 1903.

In summary, total growing season precipitation ranged from 9 to more than 21 inches across North Dakota. The central and extreme west areas were driest with only 9 to 12 inches, 80 to 100 percent of normal. The extreme southeast was the wettest with 16 to 21 inches. Another wet spot with 16 to 20 inches of rain was eastern Bottineau and most of Rolette counties.

For the future, a major La Nina event, the opposite of an El Nino, is forecast for the 1998-99 winter. Enz says that preliminary National Weather Service research suggests that a La Nina winter has a high probability for precipitation extremes—either very dry or very wet with a lot of snow. Also, January was found to be colder than average in most La Nina winters.

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Source: John Enz (701) 231-8576

Editor: Gary Moran (701) 231-7865

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