The worst U.S. drought in decades continues its iron-fisted grip across much of the nation's key farming states, though some relief could come from the first major snowstorm of the season trekking eastward across the Midwest.

Thursday's weekly U.S. Drought Monitor update shows that roughly 62% of the continental U.S. remains in some form of drought, unchanged from the previous week. That number has been above 60% largely since July.

Nearly 22% of the lower 48 states are in extreme or exceptional drought, the two worst categories. That's up a half of a percentage point from a week earlier.

The latest numbers are as of Tuesday, before the arrival of the Midwest's first winter snowstorm.

All of South Dakota, Nebraska, Iowa, Kansas and Oklahoma are in drought.