SO FAR TODAY TO EARLY WEDNESDAY MORNING:
We have seen a few spotty showers & t'showers mainly in Clinton County today with warm, muggy conditions & bubbling, towering, low-based cumulus clouds. Up to 1.20" of rainfall has occurred in places in Clinton County from this rainfall today.
In this moist, tropical environment with low cloud bases with weak, weak wind fields in the lowest 10,000', but sharp directional shear, a funnel or two cannot be ruled out this evening. If one of these touches down, it would be a landspout tornado (EF0) & could result in a random, brief tornado warning. Most of these just tend to dissipate as the rain falls around them.
Any of these showers/t'showers will dissipate with time this evening followed by mostly cloudy skies & patchy dense fog tonight.
Lows will vary from upper 50s in the lake breeze front in the northwest to 60s to near 70 elsewhere.
A couple of isolated showers & t'showers may pop late, late tonight or early tomorrow morning.
Then some scattered showers & storms will increase through the morning & into the afternoon with an isolated severe storm possible in muggy, tropical airmass with highs 79-84. There will also be a lack of wind, which will make it feel a bit stifling.
Isolated severe storm threat is largely brief, weak tornado with low-level shear with low LCL along frontal boundary.
Severe risk will increase some in the evening as the core of the rather deep low pressure system passes through. Wind fields when then increase at low levels with a broader scale of lift. Overall wind will also increase over the area with gusts to 20 mph. A couple/few severe storms are possible.
Best severe risk is south of our area where parameters suggest ENHANCED RISK, while parameters in our southern counties suggest SLIGHT with MARGINAL elsewhere.
There is a corridor of pretty substantial tornado risk actually over southern Illinois, southwestern Indiana & western Kentucky. It is quite a strong low pressure system for the time of year.
Right now, SPC has MARGINAL area-wide & SLIGHT south of our area.
WEDNESDAY EVENING-THURSDAY MIDDAY:
The most widespread rainfall is expected Wednesday evening-night with some of that severe risk initially winding down by midnight.
Windy, rainy conditions will be the story after that.
Rainfall looks to exit Thursday morning with temperatures 59-65 through midday with strong northwest winds to 35 mph & lows of low, gray, dreary clouds.
Total rainfall looks to run 0.60-1.30" with this system
Gradual clearing will occur in the afternoon & evening with highs eventually reaching 67-75 with northwest winds at 20-35 mph decreasing to 15-25 mph by evening.
As quickly as we see the stratocumulus/cumulus clouds completely clear, high & mid clouds will move right back in Thursday evening-night as front very quickly begins to lift back northward as a warm front.
So, lows will level off at 55-62 with a light south wind developing overnight. Some temperatures may even rise a few degrees late.
Friday looks humid with highs 80-86 with partly cloudy skies & southwest winds 15-25 mph.
An MCS or a complex of storms will ride the warm frontal zone south & southeastward into & through the area Friday night-Saturday morning. Some severe weather is possible (wind).
On this complex's outflow boundary, some new storms may fire southwest of our area Saturday. The boundary should then move back northward with a few more storms possible Saturday afternoon-evening. Highs will run 85-90 with heat indices 91-100 after a warm Friday night at 67-72.
A very well-developed MCV with front in the area could bring round of storms Sunday afternoon-evening. Severe risk is possible. Main threat is wind, but a tornado or two cannot be ruled out.
Highs will run 85-90 with heat indices 92-100.
Storms are possible Monday PM & then again Wednesday & Thursday of next week.