Ag Weather Forum

Unsettled Weather Pattern to Continue

Bryce Anderson
By  Bryce Anderson , DTN Senior Ag Meteorologist
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A trough west and ridge southeast upper air setup looks set to form again going into late October. (Tropical Tidbits graphic)

The big storm system of the Oct. 11-12 weekend that brought record-breaking snow to the Northern Plains, rain to the Midwest, and season-ending freezing conditions as far south as the Texas Panhandle appears to be an indicator of how the month of October will finish up across the central U.S.

Forecast models indicate a likelihood that unsettled conditions -- low temperatures, periods of rain, and occasional blustery winds -- will be primary features during the last two-thirds of the month.

The upper-air pattern forecast that was featured during the Monday-through-Wednesday time frame, Oct. 7-9, indicated that the main air flow would be zonal across the Plains and Midwest. That outlook has changed notably during the last part of the week.

"(Forecast) models are showing that zonal flow breaking down," said DTN Senior Ag Meteorologist Michael Palmerino Friday. "There are signs of more trough forming in the Rockies and the Plains, along with (high pressure) ridging coming back into the Southeast."

The breaking down of the prevailing flow is important. With the trough west and ridge southeast configuration, circulation around the western U.S. trough (counterclockwise) and the southeastern U.S. ridge (clockwise) offers a corridor for moisture from the Gulf of Mexico to stream northward into the Midwest. At the same time, the western U.S. trough allows seasonally colder conditions to move southward from Western Canada. In addition, the southeastern U.S. ridge offers very warm conditions. "This sets up a strong thermal boundary for showers and thunderstorms," said Palmerino. The location of that boundary is in the western Midwest.

Slow harvest is likely to continue with this pattern. U.S. corn harvest is only 15% complete as of the weekend of Oct. 6, compared with a five-year average of 27%. The soybean harvest was less than half the five-year average at 14% complete versus 34% for the five-year average. Of course, following the big storm going into the Oct. 11-13 weekend, many fields are already unable to be harvested for at least a week or longer.

The ideal forecast at this point would likely be very cold and dry, to force crops into maturity and firm up wet ground for combines and grain carts. An unsettled pattern does not accomplish either of those objectives -- which makes the 2019 harvest season take on a strong resemblance to just one year ago, 2018.

Meanwhile, the flash drought in the southeastern U.S. shows hardly any sign of relenting, especially given the prospect for upper-air ridging to redevelop. In fact, almost the entire Southeast and Delta, along with central and southern Texas, have drought forecast to remain in place through the next month, and continue through the end of the year in many of these areas.

Bryce Anderson can be reached at bryce.anderson@dtn.com

Follow him on Twitter @BAndersonDTN

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