Weather Forecast (07/15/21)
Temperatures mostly finished within a couple of degrees from average during the period of July 7 through July 13, 2021 (Figure 1). The area with the highest anomalies were in the southern Red River Valley into west central Minnesota where temperatures were around 4° below average. These next 7 days look quite warm with all locations likely recording temperatures well above average. Western portions of North Dakota will probably record the highest temperature anomalies during this forecasting period.
Widespread rains were recorded this past week across central and western North Dakota (Figure 2). Some severe weather was associated with these storms, but damage was not widespread. As mentioned, this next week looks quite warm and, with the heat, will come few opportunities for rain. In turn, high stress levels on area crops with several days of 90° or higher temperatures are expected.
The warm temperatures during this forecast period will be a “dry heat”. This will mean increased evaporation potential and few hours with high relative humidity. My forecasted number of hours with relative humidity greater than 85% can be found in Figure 3.
The projected growing degree days (GDDs) base 50°, 44° and 32° for the period of July 15 through July 21, 2021 can be found in Figure 4. Another reminder that growing degree day calculations stop at a maximum temperature of 86°. With most or all days exceeding that temperature from this weekend into next week, the main differences with GDDs this week will be associated with the minimum temperatures.
Using May 1 as a planting date, the accumulated growing degree days for wheat (base temperature 32°) is given in Figure 5. You can calculate wheat growing degree days based on your exact planting date(s) here: https://ndawn.ndsu.nodak.edu/wheat-growing-degree-days.html
Using May 10 as a planting date, the accumulated growing degree days for corn (base temperature 50°) is given in Figure 6. You can calculate corn growing degree days based on your exact planting date(s) here: https://ndawn.ndsu.nodak.edu/corn-growing-degree-days.html
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) that you input. That tool can be found here: https://ndawn.ndsu.nodak.edu/soybean-growing-degree-days.html
Director of the North Dakota Agricultural Weather Network (NDAWN)