Ag Weather Forum

Beneficial Mid-May Rain for Central Crop Areas

Bryce Anderson
By  Bryce Anderson , Ag Meteorologist Emeritus
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Many crop areas of the Plains and Midwest received moderate to heavy rainfall during the May 17-24 period.

For the first time this spring, I was able to talk about widespread rain over the central United States over a given seven-day period when I produced the DTN Market Impact Weather video on May 24.

The past seven days had rain over almost the entire central U.S. from the Rockies to the Great Lakes. Amounts were damaging along the Texas-Louisiana Gulf Coast with up to 8 inches of rain causing heavy flooding. Farther north, the rains were a bit less; many Midwest and Plains locales recorded 1 to 2 inches or more.

Of special note, the northern and western Midwest along with the Northern Plains shared the bounty of 1 to 2 or more inches of much-needed rain. The timeliness of this moisture is significant; almost all of North Dakota, northwestern South Dakota and eastern Montana had at least Extreme Drought (D3) in effect as of May 18; central North Dakota slipped into Exceptional Drought (D4) in this time frame.

For the Northern Plains, it is the driest in four years. There is also a swath of the northern third of the Midwest from the Great Lakes west to the Missouri River with some phase of drought in effect.

Rainfall in the Upper Midwest was lifesaving for many individual crops. South-central Minnesota producer Mark Nowak is already penciling in a reduction in his corn yield because of germination being affected by a double hit of cold and dry conditions during the past few weeks. Nowak estimated his corn plant population is down 10% from his optimum. "Our top-end yield is already down 20 bushels per acre," Nowak said, using a guide of seven bushels of yield per acre decline for every drop of 1000 plants per acre.

The balance of the week ahead promises to bring more precipitation into the central U.S. as well. "Two more systems will bring moderate rain ... through the coming weekend," DTN Ag Meteorologist John Baranick noted Monday morning. He said that rain of another 1 to 2 inches could total up again in the Plains and Midwest during this last full week of May.

This rainfall pattern has notably bypassed much of the western and the southeastern U.S. For the southeastern U.S., crops are using up residual soil moisture. That's not the case in the western U.S. with widespread Extreme to Exceptional Drought.

In addition, one week of rain does not take a crop's moisture needs through an entire season. Nowak in Minnesota is nervous about summer rainfall showing up at the right time when crops go through their various flowering and fill stages.

"We'll still need about 15 inches of rain through September to make (a) trend line crop," Nowak said.

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

Follow him on Twitter @BAndersonDTN

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CAMBERG211895871
5/25/2021 | 8:24 AM CDT
I HAVE the DTN weather station for 5 years now.... It showed .03”!!! Your radar shows boarder in .50”!!! This was NOT a widespread rain... PERIOD!!! And the market WILL be wrong AGAIN!!! There are 2 private weather forecaster I follow that AGREE that this was a BUST and the future rains are sceptical at BEST... Charles D. Amberg
Bryce Anderson
5/25/2021 | 7:41 AM CDT
The precipitation shown on the graphic is from a combination of rain gauge numbers along with satellite and radar imagery. This event shows once again that precipitation is highly variable--that's one reason why our DTN Ag Weather Station is so useful for many growers. In the large scale, there were many areas that received the moderate to heavy amounts, which the grain market viewed as beneficial. The next week does offer another system or two for the northern Corn Belt, and this will be important moisture. The 11-15 day GFS model shows only light amounts (less than a half inch) north of U.S. Highway 20.
DEAN SCHMIDT
5/24/2021 | 5:25 PM CDT
Iâ?™m wondering if this map is generated from radar estimates or from actual rain gauges. It looks like I should have gotten .5 inch, but my rain gauge only measured .15 inch. As has been the case all spring, what looks good on the radar is not what makes it to the ground.
CAMBERG211895871
5/24/2021 | 3:33 PM CDT
Bryce... Are you KIDDING ME??? 1)The rain in the Dakotas missed the "Major" cropping areas 2)You look at your map and the majority of the 'lime green is less than 1" and covers more than any other color!!!! 3)look at western MN eastern SD MI/OH/IN...those colors are ALL less than .50" Not much of a widespread rain to do much good especially when you failed to mention it has been 85 degrees for temps the last 4 days as well.... Just saying Charles D. Amberg West Central MN