Marek Kučera 
While central and eastern USA will suffer in next mornings severe late-season frosts and ground frosts, in Rocky Mountains, the next snowfall is forecasted.
In International Falls, last 5 mornings temperature dropped below 23°F / -5°C (-5,0 to -5,6°C / 22 – 23°F) and extremely cold air is quickly moving to the southern regions at the weekend.
Around Monday, 10. May, significant snowfall is moreover forecasted in parts of Rocky Mountains (mainly Wyoming and Colorado, some snow will appear too in Utah, Montana or Idaho).
Late frosts in southern regions should bring damages into sensitive plants.
Mass of very to extremely cold air is forecasted to shift into southernmost parts of the USA, including Texas and Gulf Coast until Friday, 14. May 2021.
Temperature anomalies from long term average will reach regionally up to -12°C / -20°F.
Similarly, such as in Europe /https://mkweather.com/snowing-in-the-netherlands-on-7-may-extremely-rare-snowstorm/; https://mkweather.com/snowing-in-potsdam-berlin-germany-in-may-after-50-years/; https://mkweather.com/scotland-and-northern-england-under-the-snow-in-may-exceptionally-cold-spring-2021-continues/; https://mkweather.com/finland-hit-severe-snowstorm-with-30cm-of-fresh-snow-oulu-only-3-days-above-10c-since-winter-year-without-spring//, snowing should appear in lower situated regions in north-central and northeastern USA, locally, near minimum temperatures around 32°F / 0°C and showers.
Predominant cold weather patterns in last months across the world are strongly associated with powerful La nina event /https://mkweather.com/global-temperatures-dramatically-went-down-the-sharpest-jump-since-1990s-la-nina//, which moreover brings strong Tornado and Hurricane season in the USA (and North America) in 2021 /https://mkweather.com/hurricane-and-tornado-season-2021-in-the-usa-above-average-expected-thanks-to-la-nina-forecast/; https://mkweather.com/accuweather-summer-2021-forecast-for-the-usa-agrees-with-mkweather/; https://mkweather.com/summer-2021-forecast-for-north-america-hot-stormy-east-and-dry-west//.
According to current long-term forecasts, the second half of May 2021 should be in the USA warmer, but without widespread and heavy heatwaves.
In northern and eastern USA, severe storms should appear, mainly in belt from Iowa to New York, according to the newest GFS outputs.
Source: wxcharts.com
Marek Sadowski 
Marek Kučera 
