EVENING – TONIGHT: Clouds are starting to thicken up from west to east across zones 6 and 7. This is ahead of a developing low pressure system that will bring rain and heavy snow to the forecast zones over the next few days.
Tonight Clouds will continue to build in across the forecast area. Rain will start to enter southern Illinois around 5-6 PM this evening and spread through to the north into the overnight.
By midnight rain looks to be in place from the I-70 corridor and points southward.
Lows overnight will be in the mid to upper 30’s. So most of the precipitation overnight looks to fall as rain.
WEDNESDAY – THURSDAY: Cold air will start to filter in from the north and northeast. As it does temperatures will drop right at to just below freezing early Wednesday morning. At this time rain will start to change over to snow across western and central zones 5 and 6. This looks to occur around the 7-8 AM timeframe.
Through the morning rain will continue changing over to snow across Illinois, some of this snow will be very heavy at times. Snowfall rates exceeding 1” an hour will not be out of the question in locations. By 12-1 PM Wednesday afternoon most of the region should be seeing snow with perhaps very eastern zone 6 still seeing rain.
Across zone 6 heavy rain will be a threat before changing to snow Wednesday afternoon/evening. Model guidance has suggested upwards of 1.5-2” of rain with locally more will be possible across southern Illinois. This would be through mid-afternoon to evening Wednesday. For this reason I will at least mention the threat of flooding across southern Illinois.
Through the afternoon the heavy snow will continue to move to the northeast across Illinois and into northwestern Indiana. Again, times of 1” or more an hour snowfall rates will be possible as the deformation banding sets up over the forecast area.
Highs on Wednesday will be in the low to mid 30’s in most locations.
Winds through the day will be very impressive as the blow out of the north and northwest. Sustained winds of 15-25 mph will be likely along with gusts of 35-45 mph. A few gusts may exceed that reaching 45-55 mph in strength.
As the low moves to the east and northeast away from the forecast zones Wednesday evening the strong northwesterly winds will usher in some drier air behind the system. It does look like by 7-8 PM areas of snow will still be occurring, especially across eastern Illinois.
Through the late night more dry air will work into the forecast zones. I do think this will shut a lot of the snow off, especially across western and central zone 5/6. However, some periods of snow will likely remain the eastern portions of the zones with only some light snow showers/flurries elsewhere.
Lows overnight will be in the mid-teens to mid 20’s. Winds overnight will remain strong with gusts of 35-45 mph possible.
Thursday morning I expect only a few remaining snow showers to continue. These will come to an end by late morning to mid-day.
By the time the snowfall is over total accumulations of 1-3” look like a good bet area wide with 3-6” of new snowfall across the I-57 corridor. With the heavy snow that will be occurring there is a chance that places along the I-57 corridor could see 6” or more of snow. However, the main question is how much snow will stick? So for now we will call for 3-6” with isolated higher amounts possible.
Remember any little fluctuation in the low track, temperatures, or moisture could shift the highest and lowest totals one way or the other. We will continue to watch this system and bring you updates as needed.
Thursday afternoon looks to remain mostly cloudy to overcast with little, if any, sunshine. Winds will be from the northwest with gusts of 25-35 mph still being possible.
Highs will be in the upper 20’s to upper 30’s.
FRIDAY: An area of high pressure will move into the forecast area. However, with an upper level disturbance moving through it looks to keep partly to mostly cloudy skies around. The good news is the winds will let up Friday with westerly winds of 5-15 mph expected.
Highs on Friday will be in the low 30’s to mid 40’s.
7 DAY FORECAST
WEDNESDAY: PRECIPITATION STARTS AS RAIN, THEN CHANGES TO SNOW ACROSS ILLINOIS & WESTERN/NORTHERN INDIANA, SOME HEAVY. HIGHS IN THE LOW 30’S WEST TO MID 40’S SOUTHEAST. SNOW WILL ACCUMULATE IN AREAS. NORTHWEST WINDS AT 15-25 MPH, GUSTS OF 35-45 MPH.
WEDNESDAY NIGHT: CLOUDY, RAIN CHANGES TO ALL SNOW, SOME WILL BE HEAVY. LOWS IN THE MID 20’S NORTH TO LOW 30’S SOUTH. SNOW ACCUMULATIONS LIKELY.
THURSDAY: SNOW SHOWERS CONTINUE, THEN END LATE. HIGHS IN THE UPPER 20’S TO UPPER 30’S. SOME ACCUMULATION POSSIBLE. NORTHWEST WINDS 12-20 MPH, GUSTS OF 25-35 MPH.
THURSDAY NIGHT: SNOW ENDS, OTHERWISE PARTLY CLOUDY AND COLD. LOWS IN THE MID TEENS TO MID 20’S.
FRIDAY: PARTLY TO MOSTLY CLOUDY. HIGHS IN THE LOW 30S NORTH TO MID 40’S SOUTH. WESTERLY WINDS AT 10-15 MPH.
FRIDAY NIGHT: MOSTLY CLEAR. LOWS IN THE UPPER TEENS TO AROUND 30.
SATURDAY: MOSTLY SUNNY WITH HIGHS IN THE MID 40’S NORTH TO MID 50’S SOUTH. SOUTHWEST WINDS 5-15 MPH, GUSTING TO 25 MPH.
SATURDAY NIGHT: MOSTLY CLEAR WITH LOWS IN THE MID 30’S TO LOW 40’S.
SUNDAY: PARTLY CLOUDY, HIGHS IN THE UPPER 40’S TO LOW 60’S.
SUNDAY NIGHT: MOSTLY CLOUDY WITH A CHANCE OF RAIN AND/OR SNOW. LOWS IN THE LOW 30’S TO LOW 40’S.
MONDAY: PARTLY CLOUDY, RAIN LATE. HIGHS IN THE UPPER 40’S TO UPPER 50’S.
MONDAY NIGHT: MOSTLY CLOUDY WITH RAIN CHANGING TO SNOW? LOWS IN THE MID 20’S TO MID 30’S.
TUESDAY: CLOUDY WITH A CHANCE OF RAIN AND SNOW. HIGHS IN THE UPPER 30’S TO UPPER 40’S.
TUESDAY NIGHT: CLOUDY WITH SNOW POSSIBLE? LOWS IN THE UPPER 20’S TO UPPER 30’S.