ST. LOUIS — A warm and somewhat humid day is on tap for Tuesday, with temperatures reaching the 80s. This sets us up for what appears to be two waves of storms to watch.

The first one is late Tuesday afternoon and evening. It should remain well northwest of St. Louis but that forecast may change over the next day. The most likely spot for these spotty but extreme severe storms will be along the border between Missouri and Iowa. These are likely to be hail and tornado producers.

Threat: Spotty to scattered severe storms with high winds and a tornado possible.

Tuesday severe weather risk timing:

• Tuesday evening: Severe weather northwest of St. Louis.
• Late Tuesday night into Wednesday morning: Widespread severe weather for the entire region.

The storm threat that is likely to impact the entire St. Louis region will come late Tuesday night into early Wednesday morning. This threat will include widespread damaging winds and possibly a couple of quick hitting tornadoes. The greatest concerns for both are approximately along and north of I-70. The timing on this is anywhere from as early as 3 a.m. to as late as 10 a.m. Wednesday.