Ag Weather Forum              07/29 12:43

   Corn Belt Rain Forecast Upgraded: System to Bring Widespread Moisture During 
Critical Crop Growth Stage

   A small but powerful storm system is forecast to produce widespread heavy 
rain through the Corn Belt later this week and weekend.

John Baranick
Staff Meteorologist

   Models have increased the rainfall with a system moving through during the 
final days of July and into the first couple days of August, which should help 
to raise soil moisture for a lot of areas during a very important time for both 
corn and soybeans.

   That bumps the accumulated-plus-forecast July total to 3.65 inches, an 
increase of 0.23 inches from the forecast of just two days ago. Though the 
improvement appears small, that is averaged over all corn acres in the country, 
a marked improvement for the last couple days of the month. You can read more 
about the July precipitation from DTN's Ag Meteorologist Emeritus Bryce 
Anderson here: 
https://www.dtnpf.com/agriculture/web/ag/blogs/ag-weather-forum/blog-post/2026/0
7/27/july-brought-12-year-low-us-corn.

   If not for an overall good month of June across the U.S. Corn Belt, the 
lower July rainfall would correlate to widespread drought growth. In some 
places, it has, with coverage of dryness and drought increasing across parts of 
the northern and Western Corn Belt. However, interspersed in there are pockets 
where drought has improved in parts of South Dakota and southeast Minnesota, as 
well as along the southern periphery from Arkansas through North Carolina. 
Though overall rainfall has been disappointing, some areas have gotten the rain 
they needed. An update to the U.S. Drought Monitor on Thursday, July 30, may 
change that for some areas, however, as overall dryness was a major factor in 
areas like Minnesota, Wisconsin, Iowa and Illinois during the past week.

   Crop conditions have been falling this month with the overall drier and also 
hotter conditions as crops go through their most vulnerable stages of growth. 
Corn good-to-excellent ratings declined four percentage points this week, the 
largest drop in ratings for any week dating back to June 2023. Soybeans also 
dropped significantly by three percentage points. Though ratings are still 
fairly high in many states, the momentum is key to watch, especially during 
this most vulnerable time for corn during pollination and early grain fill. 
It's somewhat less concerning for soybeans, though more and more of the crop is 
setting pods and the critical month of August is on the doorstep for filling 
those pods out.

   Earlier this week, it looked like another concerning week for weather. 
Though temperatures would be falling to give some areas a break, precipitation 
looked rather unimpressive. However, on July 28, models began to increase their 
precipitation forecast with a small system that will travel the Corn Belt July 
30 through Aug. 2. Much more widespread and heavier rain was forecast, a trend 
that was maintained July 29.

   The system will move slowly and give potential for some longer-duration 
rainfall that could add up to some significant totals. Showers will actually 
begin Wednesday across the Northern and Central Plains but should be spotty. 
The system will gather strength Thursday as it slows down, bringing widespread 
precipitation to the Dakotas and parts of Nebraska. The storm will push into 
Minnesota, Iowa and Missouri Thursday night into Friday, Wisconsin and Illinois 
on Friday, and then from Michigan into Tennessee on late Friday and Saturday. 
The system will settle into the Southeast U.S. into early next week and some 
southern areas could pick up additional rainfall.

   Rainfall amounts will be scattered as they usually are, but widespread areas 
of more than an inch are forecast in a band from eastern South Dakota and 
Nebraska through Indiana, Ohio, Kentucky and Tennessee. Locally heavy rainfall 
of more than 2 inches is a likelihood within that overall band. Outside of the 
band, there may still be areas that pick up more than an inch due to scattered 
thunderstorms. But there could be some areas that are left out.

   This forecast is generally expected from the European model, but not all 
models agree on the heavy rainfall potential across the Corn Belt. The general 
location and timing for the heavier rain is the same, but the overall coverage 
is significantly lower. The American GFS model is much less aggressive on the 
coverage of these heavier amounts, instead limiting it to patchy areas across 
the same band from eastern South Dakota and Nebraska through the Tennessee 
Valley.

   However, even if the rainfall disappoints in the overall coverage of the 
heavy rain, the GFS still provides widespread coverage of at least 0.25 inches. 
That may not seem like a lot, but any rainfall would be preferred over none. 
And the rain will not end with this one system. A cold front is forecast to sag 
into the northern tier of the country next week, splitting the Corn Belt in 
half from west to east. More showers are forecast along it while the front 
stalls out in the region, creating more opportunities for rainfall that need it 
in early August.

   To stay up to date with weather conditions and your local forecast for free 
from DTN, head over to 
https://www.dtnpf.com/agriculture/web/ag/weather/interactive-map.

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




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