Ag Weather Forum

The last week of February was a wet week from the Ohio Valley south to the Gulf Coast. Moderate to heavy rain fell in these regions. Some areas had more than 3 inches total precipitation, along with localized flooding. This has likely put a delay on producers trying to get an early start to fieldwork and planting in the Delta and Southeast. This rain is easing and will be followed by mild and drier conditions through the coming weekend.

There will be close attention paid to a weak system currently well west of California which is expected to move through the Rockies on March 3, and then through the Central and Southern Plains March 4-5 before moving into the Gulf of Mexico.

This system could produce some good rainfall for drier areas of Kansas and Colorado with totals in the 0.50- to 1-inch range. It would not be enough to put an end to the drought in the region, which has continued to be dry through the winter months, but would at least offer some drought easing as temperatures warm and some wheat in the area begins to break dormancy. And, as dry as soils are, producers will take whatever moisture they can get. Beggars cannot be choosers, as the old saying goes.

These two disturbances are essentially the only precipitation chances for the growing regions east of the Rockies through March 9. A weak system March 8 may bring some isolated showers to the Plains and Midwest, but models are not very high on this prospect.

With temperatures rising above normal for much of the middle of the country during the next two weeks, we should see more winter wheat coming out of dormancy. In the western Plains, the drought in the region will be a large concern and more moisture is needed to support green-up.

But prospects are not promising for the rest of March. For the southwestern Plains, the minor system this week will likely be the only significant chance for moderate moisture until April, if you can believe the extended models.

Forecast models do produce strong systems moving out of the Rockies and through the Midwest this month, sometimes in rapid succession, but the track of these storms is important. Moderate precipitation events across the High Plains rely on easterly upsloping winds into the Rockies. The air being forced upward cools and produces precipitation. The opposite is true with westerly downslope winds. Air descending a mountain slope warms and dries. To get the upslope flow as a system moves through, the low pressure needs to be to the region's south as air flows counterclockwise around the center. When storm centers are located to the north, dry downslope winds are the result.

Keeping that track description in mind, the tracks for the predicted storms during the rest of March tend to be from Wyoming or northern Colorado, leaving the growing regions from southern Colorado to southwest Kansas and points southward rather dry.

These "Colorado Low" systems, as they are sometimes called, are better precipitation producers for the eastern Plains and Midwest. This bodes well for some of the pockets of dryness in the western Midwest and Northern Plains instead. However, these systems do not line up until the middle to end of next week, and models may develop these storms differently than the current forecast.

John Baranick can be reached at john.baranick@dtn.com

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