Crop & Pest Report


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Weather Forecast (07/16/20)

The July 16 to July 22, 2020 Weather Summary and Outlook

There were two main periods of thunderstorms in the region in the past week.  The first was Friday night into Saturday and the second was Sunday night into Monday.  The second wave was the stronger of the two and dropped significant rain across parts of northeastern North Dakota into far northwestern Minnesota (Figure 1).  Both days there was some severe weather, but fortunately it was not widespread.


The rain over the past week seemed to move along similar paths to other storms in the past several weeks.  Meaning wet areas remained wet and the drier locations tended not to record much precipitation.  Percent of average rainfall for the past 60 days can be found in Figure 2.



Temperatures have been well above average during the previous two weeks, but this past week temperatures were near or only slightly above average in eastern locations and noticably below average in western North Dakota into eastern Montana.   Temperatures during the next week look to be mostly below average across the NDAWN mesonet.


Like last week, there looks to be two main periods of precipitation in the next 7 days.  As of this writing, it looks to be on Friday and Friday Night, then next Monday night into Tuesday of next week.  The atmospheric waves that will trigger the storms are of a different origin than what has caused our thunderstorms over the last couple of weeks.  Both time periods may contain severe weather which is typical of this time of year.  The origins of these storms are associated with upper-level low pressure systems that are often attributed to cooler weather.  Therefore, as already mentioned this next week looks cooler than average and with additional precipitation it looks to be another week with significant hours with relative humidity (RH) above 85%.   Figure 4 is the estimated number of hours the region will experience with high RH values in the next 7 days. Areas that record the higher rain totals in the next week, or are already saturated, may record more hours than is indicated.


The projected growing degree days (GDDs) base 32°, 44° and 50° for the period of July 16 through July 22, 2020 can be found in Figure 5.


Using May 1 as a planting date, accumulated growing degree days for wheat (base temperature 32°) is given in Figure 6.   You can calculate wheat growing degree days based on your exact planting date(s) here:


Using May 20 as a planting date, accumulated growing degree days for corn (base temperature 50°) is given in Figure 7.   You can calculate corn growing degree days based on your exact planting date(s) here:


Soybeans also use base 50° like corn, but NDAWN has a special tool for soybeans that based on your planting date and cultivar can estimate maturity dates based on average temperatures, as well as give you GDDs based on your planting date(s) you set.  That tool can be found here:


The North Dakota Agricultural Weather Network (NDAWN) has added an additional 40 stations to our crop guidance and historical weather sections of our website (  Plus, those additional stations are also available on the Small Grain Disease Forecasting Model that uses NDAWN data but is run through the Plant Pathology department at NDSU (  There are an additional 20+ NDAWN stations still coming at a later date.  The entire NDAWN team appreciates the patience of our sponsors and stakeholders that were waiting for these stations to become fully integrated into our systems.


Daryl Ritchison


Director of the North Dakota Agricultural Weather Network

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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