AFTERNOON-OVERNIGHT: Clouds, fog, and some mist are hanging around this morning across zones 6 and 7. The initial cold front is moving out of the forecast zones to the east, as another front still continues this way from the west.
Through the morning hours’ fog and mist will start to come to an end across the forecast area. Some models do show this giving way to some afternoon sunshine, but I’m a bit skeptical that it will be all that much.
The first cold front will still be in place across western Indiana by 12-1 PM this afternoon. By that time some isolated to widely scattered rain showers will be developing across very eastern Illinois.
By 4-5 pm more rain and storms will be developing across zone 6 and 7. This will be as the secondary front works across Illinois from the west.
By 9-10 PM the front will be moving eastward across eastern Illinois with rain and t’storms along/ahead of it. Behind the front some areas of rain associated with the low pressure system will be ongoing.
While I am not anticipating any widespread severe weather reports today I will not totally rule out a strong to low-end severe storm across eastern Illinois. There will be a pretty decent 500 mb wind maximum moving across the forecast area this afternoon that could aid in some strong storms.
The biggest question today will be how much instability is realized. Many locations will remain pretty stable. However, pockets of 900-1100 J/Kg of CAPE across eastern Illinois will be possible this afternoon, those areas would have the better chances at the stronger storms.
Through the overnight the surface and upper-level low will continue moving across Illinois. With the upper-level vorticity associated with this, some isolated to widely scattered areas of rain will remain possible through the overnight.
New rainfall totals across Illinois of .20-40” will be more common. However, some localized areas could see .65-1.10” through Friday morning.
Lows overnight will be in the upper 40’s north to mid 50’s south.
FRIDAY: The upper-level low will move to the east of the forecast area on Friday. While a few showers may be possible through early afternoon across eastern portions of the forecast area, many locations will be dry.
Through the day a high pressure system from the north will start to ridge in. This will allow for drier air to spread in and clouds to erode/move out through the afternoon/evening hours.
Highs on Friday will be in the mid 60’s north to low 70’s south. Winds will be from the north at 5-15 mph, some gusts of 20-30 mph will be possible.
Friday night an area of high pressure will take control of the weather across zones 6 and 7. This will allow for mostly clear skies across the forecast area.
Lows will fall into the low 40’s north to near 50 south.
SATURDAY: An area of high pressure in place to the northeast of the region will remain in control of the weather on Saturday. This will set us up for a very nice weekend as we start with sunny to mostly sunny skies.
Highs on Saturday will be in the mid 60’s north to mid 70’s south.
SUNDAY: The area of high pressure will move off to the east. To the west of the region an area of low pressure will be developing across the Great Plains/Rocky Mountains. To the north of the region a large warm front will be present. However, it will be far enough north it won’t bring any precipitation to the region.
However, what it will bring is a warm southerly flow of air, along with a mix of sunshine and clouds. Highs on Sunday will be very warm, topping out in the mid 70’s to near 80 in locations!
MONDAY – TUESDAY: An area of low pressure will be set to move through the Great Lakes region late Monday through Tuesday. On Monday this will allow for scattered rain and storms to form across the forecast area.
Highs will remain warm with temperatures in the 70’s.
Monday night into Tuesday the cold front will move through, so a better chance of some rain/storms will exist along the front overnight.
LONG RANGE (MID-LATE NEXT WEEK): Active weather looks to remain across the region. Rain, storms, and even severe weather are possible mid to late next week. The SPC has already outlined western Illinois in a severe weather risk next Wed. Obviously timing and exact locations will need ironed out over the next week or so.
Beyond that, the more active pattern will continue with perhaps another severe weather event around the April 30 – May 2nd time frame. The models have been persistent with a storm system; details are just too far off to pinpoint much at this time.