Ag Weather Forum

Cooler and Drier Weather Coming to Corn Belt?

John Baranick
By  John Baranick , DTN Meteorologist
Though rain is forecast throughout much of the Corn Belt next week, models are predicting it to be light and amounts to be below normal, like the ECMWF shown here. (DTN graphic)

We have seen some ups and downs, but most of the country, especially the Corn Belt, has seen above-normal temperatures for the last few months. In some cases, it has been extremely hot like mid-June in the Eastern Corn Belt, and recently in the Southern Plains and Gulf Coast. In other cases, it has been just a few degrees above normal more consistently than not. However, analyses from DTN and the Iowa Environmental Mesonet show almost all areas east of the Rockies have had above-normal temperatures since the first of April. Only the northern High Plains areas in Montana and Wyoming along with the Black Hills in South Dakota have had temperatures below normal. To go along with that, most areas have also had above-normal precipitation. Those in the Mid-Atlantic and parts of the Southeast and Central and Southern Plains have not been as lucky, but the vast majority of the Corn Belt has seen above-normal precipitation. Of course, some areas have had too much rain, which has caused flooding, and others have had too little rainfall, causing flash drought. Precipitation has ebbed and flowed over the last three months, as it typically does. But it certainly has been an active period of weather, and some areas could really use a break from the rainfall.

You can find more from the Iowa Environmental Mesonet and create your own plots of their data here:…

We continue to have a very busy pattern across the U.S. over the next week. System after system will move through Canada or the northern U.S. and send cold fronts through the Corn Belt. We have already seen some areas of heavy rain in southeastern Nebraska on July 1, and we are poised to see more from this system the rest of the week. Temperatures across the South and Gulf Coast will continue to be hot and challenge the 100-degree threshold. But we are going to see a change in the pattern for next week.

In the upper levels of the atmosphere, we have a ridge of high pressure across the South and Southeast. That is creating the intense heat this week. A trough of low pressure is currently found across the Canadian Prairies and Northern Plains on July 2. The ridge will keep that trough northward the next few days, and another trough will move in right behind it to end the week, creating more rain for the Corn Belt.

But we will be watching a trough in the North Pacific and another coming down from northern Canada this weekend. A piece of energy will escape the Pacific trough and get pushed southward by the Canadian trough, splitting the ridge and forcing the majority of it into the Western U.S. where temperatures are forecast to spike into British Columbia going into next week. At the same time, a more consistent troughing feature will be spread out across the Central U.S. while the second part of the ridge will remain off the East Coast.

Usually, the presence of a trough means the draining of cooler air from the north, and this looks to be the case. We've already seen cooler temperatures in the Canadian Prairies and into the Northern Plains with the troughs moving through the region. But next week's setup should push those milder temperatures farther south and a little bit east as well. Triple-digit temperatures are likely to leave the South and Southeast, being replaced by more seasonable temperatures. At the same time, this should redirect the storm track farther south as well. This sort of setup does not favor a lot of large storms, but fronts moving through the Corn Belt are unlikely to tap into much moisture until they get to the South or East, when precipitation would be more likely to occur and be widespread. The result should mean a milder and drier Corn Belt with a wetter southern tier. Like all things weather, there will be some caveats to this forecast.

For those in the Corn Belt, it will not be completely dry. Being underneath a trough can spark isolated showers from time to time. The European ECMWF has plenty of that potential next week, and the supply of above-normal soil moisture in much of the region could be enough to spark additional showers. Southern and eastern areas of the Corn Belt may see the enhanced nature of some of that moisture from the Gulf of Mexico. Although precipitation is likely to be below normal for a one-week period in mid-July, it probably will not be completely dry. Overall, that should be a fair outlook, even if it is a little drier.

Another feature to watch is Hurricane Beryl, which as of 5 a.m. EDT Tuesday reached Category 5 hurricane strength as it is quickly moving through the Caribbean. The storm is forecast to reach the Yucatan Peninsula on Friday and weaken before then, but it should go into the bathwater temperatures of the Gulf of Mexico this weekend. With the ridge going away, it may drift northward depending on its speed. The slower it is, the more likely it would be to make a northward turn toward Texas and could restrengthen. That will bear watching and could bring flooding rains if it were to do so. That is too far out to have any confidence in the forecast right now.

And of course, this pattern will not last forever. Both the American GEFS and European ECMWF models show the western ridge drifting eastward late next week and weekend, getting into the Plains by the middle of the month. While cooler temperatures will be in place next week, we could see them rising in the Plains next weekend or the following week, and models are unsure how quickly they will spread eastward.

The moving ridge can be thought of as a good thing. As long as it does not stay parked in one particular area for a long stretch of time, changing conditions will allow for some heat followed by cool, dryness followed by showers, and overall, a good weather pattern for crop development during the summer. Local conditions will always vary from the overall pattern, however.

To find more weather conditions and your local forecast from DTN, head over to….


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John Baranick can be reached at


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