Yes, this spring has been and will be (in the near-term) a lot cooler than normal.

Northwest Minnesota weather resource.  

We in northwest Minnesota have an incredible weather resource scattered throughout the region, the North Dakota Agricultural Weather Network (NDAWN) has 16 weather stations located on the Minnesota side of the Red River.  Let’s take a look at data from eleven of these Minnesota NDAWN stations and the station located in Grand Forks, ND to see how this spring’s temperatures relate to normal (Figure 1).

Figure 1. Locations of twelve of the weather stations in the North Dakota Agricultural Weather Network.

Many daily minimum and maximum temperatures far below normal.  

The majority of the daily maximum temperatures for seven of the NDAWN weather stations were at least 5 degrees below normal during the 36 day period from April 1 through May 6, with individual daily maximums as much as 32 degrees below normal  (Table 1).  Fewer daily minimum temperatures were at least 5 degrees lower below normal for this same time period, although on one day at the Ada location, the daily minimum temperature was 34 degrees below normal (Table 2).  One can see a graphical representation of the deviations from normal daily maximum (red lines) and minimum (blue lines) temperatures in Figures 2 and 3. 


Table 1. The number of days from April 1 and May 6, 2020 with daily maximum temperatures at least 5, 10, 15, 20 and 25 degrees below normal and the largest daily deviation of the daily maximum temperature from normal at 12 locations in northwest MN and eastern ND

* Data can be found on the North Dakota Agricultural Weather Network (NDAWN) Center website.

Table 2. The number of days from April 1 and May 6, 2020 with daily minimum temperatures at least 5, 10, 15, 20 and 25 degrees below normal and the largest daily deviation of the daily maximum temperature from normal at 12 locations in northwest MN and eastern ND

* Data can be found on the North Dakota Agricultural Weather Network (NDAWN) Center website.

Figure 2. Departure from normal daily minimum (blue lines) and maximum (red lines) temperatures at NDAWN weather stations located in Sabin, Ulen, Ada, Eldred, and Mavie MN and Grand Forks, ND from April 1 through May 6, 2020 (Data source: NDAWN Center).

Figure 3. Departure from normal daily minimum (blue lines) and maximum (red lines) temperatures at NDAWN weather stations located in Warren, Stephen, Kennedy, Roseau, Greenbush and Humboldt, MN from April 1 through May 6, 2020 (Data source: NDAWN Center).

 

Near-term forecast.  

According to the National Weather Service’s near-term forecasts for daily low temperatures, at least some part of northwest Minnesota is to see below freezing temperatures tonight through next Wednesday morning (Figure 4). 

Figure 4. Minimum temperatures forecast for the nights of Friday, May 8 through Tuesday, May 12, 2020 (Map source: National Oceanic & Atmospheric Administration: National Weather Service).

This news, while unwelcome, should also not come as that much of a surprise, as there is a coin-flip (50%) probability of a 32 degree frost occurring after May 10 in Ada, May 15 in Hallock and Argyle, May 16 in Thief River Falls and May 17 in Roseau (MDA; Table 3, Figures 4 and 5).  There is a much lower probability of reaching the 23 degree low temperatures forecasted for much of the region on the night of May 10 (Figure 4).   There is a 20% probability of a temperature of 24 occurring in Argyle, Hallock and Thief River Falls after May 6, and after May 7 in Roseau and only a 10% probability of a temperature of 24 occurring in Ada after May 8 (MDA).

Figure 5. Northwest Minnesota locations for which the National Weather Service’s National Environmental Satellite, Data and Information Service has determined the probability of spring freeze dates.

Table 3. Spring freeze dates for Ada, Argyle, Thief River Falls, Hallock and Roseau, MN, or a 50% probability of a 36 to 16 degree temperature occurring on a date later than listed (Data source: NWS)

* Note: Probability of observing a temperature as cold or colder, later in the spring than the indicated date (Data source: NOAA-NWS through MN Dept. of Agriculture website).

How will this affect the corn, soybean or sugarbeet crops?  

In casual communication with several farmers in NW MN over the last couple of days, many of those that had planned on growing corn in 2020 have already made significant progress in getting seed sown.  No one had yet begun sowing soybean.  For more information about how the corn, soybean and sugarbeet crops may be affected by these freezing temperatures check out this article.

References

Minnesota Department of Agriculture. Final Spring/First Fall Freeze & Frost Date Probabilities. Online location of NOAA-NWS spring freeze probability data. Online. Accessed May 8, 2020. https://www.dnr.state.mn.us/climate/summaries_and_publications/freeze_date.html

National Weather Service. Graphical minimum temperature forecast. Online. Accessed May 8, 2020. https://digital.weather.gov/

North Dakota Agricultural Weather Network. Daily maximum and minimum temperatures. Online. Accessed May 6, 2020. https://ndawn.ndsu.nodak.edu/weather-data-daily.html