Thread by @ScottIrwinUI

1. Next thread on corn planting progress. Actually forecasting planting progress for this week, which is week #18 on the USDS/NASS calendar. Start with these historical averages.

2. If last week was "average" we would have 3.9 suitable field days, plant 5.3% per suitable field day, and have total progress of 20.5% (3.9 X 5.3). Rounded this would put total US corn planting at 48% as of Sunday. This is our "base rate" forecast.

3. Our position is that the best forecast of rate of planting progress per day is the historical average. Maybe John Deere knows how much ground is being covered per day but I don't have any data to do better than the historical average of 5.3% per suitable field day.

4. But I can look at the weather data and ask if there is evidence that we had more or less suitable field days than the historical average of 3.9 in the US last week.

5. This map shows observed precip for US the last 7 days. Pretty much some rain almost everywhere. Yellow and dark green were real problem areas last week for planting. Light blue areas probably not slowed much.

6. Remember,we are trying to guess the weighted-average suitable field days across the entire Corn Belt. Looks to me like less than the historical average of 3.9 days for planting. I am going to SWAG it at 3.0 days. Think is could be lower.

7. Drum roll please. My forecast of US corn planting progress this week is: 3.0 suitable days X 5.3% per day = 15.9% or +16% rounded. That would put total US corn planting progress as of Sunday at 43%.

8. Certainly plenty of scope for error in my forecast of planting progress. Can get the # of suitable days wrong or the rate of progress per day. But I think our method will usually get you in the ballpark.

9. All the details of our simple method of forecasting weekly corn planting progress can be found in this #FDD from last week farmdocdaily.illinois.edu/2020/04/a-simp…