Crop & Pest Report


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Weather Forecast (07/11/19)

The July 11 through July 17, 2019 Weather Summary and Outlook

Almost all the rain that was recorded in the past week fell on Monday, July 8 and Tuesday, July 9.  Rain totals from North Dakota Agricultural Weather Network (NDAWN) stations each of those two days is presented in Figure 1 and Figure 2. 

wthr.1 2

Several NDAWN stations recorded over 3 inches those two days with a few stations even exceeding 5 inches.  Although much of the region recorded beneficial, or even excessive rainfall, the northeastern part of North Dakota was a noticeable exception.

The rain and cloudiness associated with the rain, attributed to temperatures being near or even below average for the past week (Figure 3).  These next 7 days should bring in much warmer temperatures with many days recording highs in the 80s and even a day or two at or above 90 degrees. 


There will be a subtle shift of the weather patterns over North America this week.  This will allow warmer temperatures to surge northward.  Temperatures are expected to be slightly above average through the middle of next week.  There will be a couple of weaker disturbances with most locations not recording much rain through the weekend.  Next week temperatures may exceed 90 degrees over parts of the region ahead of a cold front that looks to be moving through next Tuesday or Wednesday.  That transition may in turn bring in another widespread rain across North Dakota and northwestern Minnesota.  Until then, in the short term, any thunderstorms look to be more hit and miss. 

My projected growing degree days (GDDs) for the next seven days for Base 32°, 44° and 50° is presented in Figure 4.   With warmer temperatures expected to move into the northern plains, most locations are expected to record 10% to 20% more GDDs this week than the past 7 days.


Although less rainfall is expected than what was recorded during the past week, the rain from earlier this week will add moisture to the lower atmosphere.  This will mean high humidity most nights and mornings during this upcoming forecasted period that will keep the hours with relative humidity (RH) above 85%, above seasonal averages.  This will keep the risk of plant diseases at higher levels than average for the time of year.  My projected hours with high RH through July 17 are presented in Figure 5.


Using May 5 as a planting date, accumulated growing degree days for wheat (base temperature 32°) are given in Figure 6.   You can calculate wheat growing degree days based on your exact planting date(s) here:


Using May 15 as a planting date, accumulated growing degree days for corn (base temperature 50°) are 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:


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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