Scattered pulse storms will continue this afternoon & taper this evening. Isolated microburst or two is possible, along with some small hail. For example, the Fort Wayne Airport just measured at gust to 67 mph from one of these pulse storms. Torrential, blinding rainfall is also possible.
These will lead to highly-variable rainfall with your neighbor down the road getting 1.50" & you getting very little. A few places will get a quick +1.75" in less than 1 hour.
At 1:30 p.m., a storm in Lafayette (Creasy & South Street) was producing gusts to 40 mph, pea hail & torrential rainfall with sun appearing at the same time!
Isolated storms are possible Thursday moring through afternoon. However, coverage will tend to go up in the evening as a small, subtle MCV pivots through eastern & northeastern Illinois.
So, 25% coverage should go up to 50% at that time.
An isolated severe storm (microburst) is possible at any point Thursday with that risk also occurring in the evening.
Meanwhile surface low & MCV & a surface cold front will be approaching from Iowa, Missouri & Illinois as a complex of storms with severe weather risk (mainly wind there) develops.
Thursday will be very hot at 92-98 with heat indices at 99-109.
Heat Advisories are being issued all around. Excessive Heat Warning is up for Minneapolis-St. Paul area.
This comma heat complex of storms will pass Thursday night to early Friday.
A couple isolated severe gusts are possible.
Within that comma heat of the low/MCV combo, there will be will a pocket of enhanced low-level shear. So, I included low risk of isolated brief tornado. We saw a similar situation in the morning hours back on July 10, 2014 when one of these comma heads produced an EF1 tornado in Miami County that injured two people. It spun up so incredibly fast that it occurred between radar scans & no NWS warning was issued.
Following these showers & storms in the morning, it looks like there will be alot of sinking air limiting any storm development, so I went dry for late morning, midday & right to early afternoon.
However, there is a disturbance on the backside of the low/MCV in the mid-afternoon to evening. So, I then re-inserted a 25% POP for storms in the forecast for that time period.
Otherwise, it looks cooler at 84-90, but still a bit humid. Heat indices will run 88-97. There will be a nice northwest wind of 15-25 mph, however.
Saturday-Sunday is tricky. There is a shortwave that pivots through with cold air aloft.
However, timing is in question.
Some data suggests a Saturday passage, while others are more in line with Sunday.
For now, kept persistence forecast with 40% POPs for Saturday with low confidence noted on exact timing.
Highs of 85-91 are likely this weekend with heat indices 89-94.
Monday is dry & 85-90 with sun, followed by a significant heat wave ensuing next week.
It is looking like the potential of our first 100-degree high since 2012 for Greater Lafayette Thursday &/or Friday of next week.
Highs area-wide look to run 96-102 with heat indices 100-112.
At the same time, a derecho may rake areas from South Dakota to the Northeast U.S. We need to monitor & make sure the far southern end of it does not skim our northern or northweastern counties.
Line of storms with some severe weather risk is possible around July 20, followed by some relief.
We may see one more heat wave in late July, followed by a much more significant, sustained relief as we begin August. Multiple days with highs in the 80s are likely.