Increasing coverage of thunderstorms early in the week, humidity remains

 While storms have been relatively isolated in nature lately, chances will be higher Sunday and Monday. A large-scale upper level low pressure system will force abundant and rich Gulf moisture our direction, resulting in continued humidity and increased rain and storm chances. Water vapor imagery shows this feature very well, with the dry slot across Texas already getting filled in by thunderstorms.

So what does that mean for our local area? As the increase in moisture reaches Northern Illinois, isolated to scattered thunderstorms will be possible. There will be lots of dry time, but any time of the day may feature a gusty downpour with some lightning possible. The overall severe risk will remain relatively limited, but a couple storms may be able to pulse up to produce localized instances of 60 mph winds or quarter sized hail.

Sunday's storm coverage looks overall similar to Saturday, with a few more storms compared to the relatively dry Saturday. Higher coverage looks to be possible early afternoon through evening, but only 30-40% coverage may be realized at the highest. Strongest storms may be able to produce gusty winds and heavy rain, but the severe threat will remain very limited.

Monday will bring a bit higher coverage of storms, meaning there will be less dry time and fewer dry areas. Highest chances for rain and storms will again be centered around the afternoon and evening hours. Similar to Sunday, strongest storms may produce gusty downpours, but widespread severe weather is not expected.

The majority of Tuesday will end up dry, but hot and humid like Saturday was. The change this time around comes with the potential for a round of storms late in the evening and into the night. These storms would hypothetically be in a weakening state but could have better organization and higher risk for severe weather compared to Sunday or Monday.

Regardless of storm coverage, humidity will not go anywhere. Dew points will likely rise near or above 70 degrees each day, keeping the uncomfortable feel to the air mass. Temperatures may temporarily drop with any storms, but humidity will not.