Storms are rolling through west-central Illinois with history of damaging winds & hail.
These will move eastward, but show weakening with time.
If they can hang on long enough, they will pose the risk of an isolated severe gust or two as the leftovers come through after midnight.
Unstable air is there, there is just capping that will work to inhibit the storms.
SPC still has much of the area in a MARGINAL RISK of severe weather to account for this.
Note the interesting small MCV that occurs from the Illinois storms right over the area as the storms eventually weaken & collapse over the area. It is that little comma shape over the area in the last frame.
Note second MCV spinning out of Iowa tomorrow (from all of the severe storms in that area, westward through Nebraska tonight).
That, with weak, diffuse outflow boundary with subtle wind shift from first MCV, will serve as foci for a few storms tomorrow afternoon-evening (highs 87-91 with heat indices 92-101).
I increased coverage up to 30% as it appears that capping will decrease in the afternoon.
A couple/few isolated severe storms are possible, so upgrade to MARGINAL RISK of severe weather in our area seems reasonable in the next SPC convective outlook.
As for Thursday, a couple isolated storms are possible in highly-unstable environment in the afternoon-evening (highs 88-92 with heat indices 96-102). Trigger is centered around either the weakening MCV in Illinois or the perturbation of a weakening gravity wave from all of the intense storms (MCSs) west & northwest of us the night prior.
Capping may still prove to be an issue (perhaps more so than Wednesday) as axis of upper ridge in the southeastern U.S. extends up into our area.
Nonetheless, put 20% POPs in for Thursday PM.
Friday-Saturday, multiple MCSs will track north of our viewing area. The remnant MCVs associated with these will also track north of our area. However, I did go ahead & keep the 20-25% POPs going. Highs will run 89-92 with heat indices 96-106.
This is due to a couple/three outflow boundary moving into area, which may serve to pop a few storms, even with some capping issues (given highly unstable airmass).
SUNDAY, JUNE 30-MONDAY, JULY 1:
Another axis of the upper ridge seems to emanate from not the southeast U.S., but the central U.S. Sunday-Monday.
This will force the corridor of MCSs waaaayyyy north to the Dakotas, Minnesota, northern Wisconsin, Michigan & Ontario.
We look capped, rain-free, hot, humid & breezy to windy (southwest winds) with highs 89-93 with heat indices 96-106.
TUESDAY, JULY 2-WEDNESDAY, JULY 3:
The upper ridge begins to break down some Monday night to Tuesday as a weak cold front approaches. However, despite the ridge breaking some, the strong mid & upper level winds will stay waaayyyy north of the area.
So, this looks like a sluggish, slow-moving front with pulsey storms that may congeal with a short-lived line of a cold pool Tuesday afternoon-evening. Isolated severe would occur in a pulsey way or as a briefly-organized cold pool line. 45-50% coverage of rainfall seems reasonable (highs 87-91).
Very high dew points may pool ahead of the front at 76-80, resulting in heat indices skyrocketing to 98-112.
The front may not completely clear the area until Wednesday night, so a some more storms (40-50% coverage) are possible Wednesday, July 3 (highs 85-90).
At the moment, Thursday, July 4 looks dry with slightly less humid, cooler weather (highs 82-85).
We look to turn hot & humid again July 5-7 with 89-92 with heat indices 96-105.
Near July 6-7, an MCS or two may affect us with severe weather risk. These will be a stronger cold front.
The trend will be to bring cooler, less humid weather in mid-July with normal rainfall.
Trends are for hotter than normal temperatures & normal rainfall with potentially widespread 90s.
END OF JULY TO EARLY AUGUST:
Cooler than normal temperatures are expected with above normal rainfall.
- June 25, 11:15 PM Weather Forecast Update
- June 11, 3 PM Weather Forecast Update
- June 21, 11 PM Weather Forecast Update
- June 25, 2:15 PM Weather Forecast Update
- June 12, 11:15 PM Weather Forecast Update
- June 15, 11:45 PM Weather Forecast Update
- June 9, 3 PM Weather Forecast Update
- June 14, 5 PM Weather Forecast Update
- June 20, 2 PM Weather Forecast Update
- June 21, 2 PM Weather Forecast Update