AFTERNOON – TONIGHT: This morning a cold front has moved through the zones from north to south. Behind it an upper level trough of low pressure is moving towards the forecast zones. This will be our weather maker over the weekend.
Through the afternoon hours today we will see clouds start to increase from west to east across zones 6 and 7. This will be as that upper level trough approaches the forecast area.
Rain showers will start to develop and move into western portions of Illinois around 5-6 pm this evening. At this point I am not expecting anything to be really broad in coverage or high in intensity.
By 9-10 pm scattered areas of rain will continue to spread across zones 6 and 7. This will be as better upper level energy and support start to work into the area.
Through the overnight rainfall will increase in coverage across zones 6 and 7. While I am not anticipating any real heavy rainfall, with some strong vorticity advection at 500 mb, bursts of moderate to heavy rain can’t be ruled out. Especially early Saturday morning.
Lows overnight will be in the mid 30’s to low 40’s.
With temperatures falling into the mid 30’s to the north, there is a chance some very heavy, wet snowflakes could mix in. However, no accumulation is anticipated.
WEEKEND: Saturday morning rain will continue to fall across zones 6 and7, with perhaps some snowflakes mixing with it in zone 7.
Through the morning temperatures will moderate so any remaining snow will transition back over to all rain. However, by 10-11 am the rain will move to the east and we will see a bit of a break in the precipitation with only isolated to scattered rain showers lingering.
Through the late morning and early afternoon, the upper level low will start to deepen a little as it spins across the state. As this occurs more rain will develop around 3-4 PM Saturday afternoon.
Through the evening hours scattered areas of rain will persist across both zones 6 and 7. With perhaps better chances residing in zone 7 and eastern zone 6.
Highs on Saturday will be in the low 40’s to low 50’s.
Saturday evening into the overnight rain chances will continue across the forecast zones. By 1-2 am scattered areas of rain will be in place with perhaps a few wet snowflakes starting to mix in across northern zone 7.
Through the overnight temperatures will continue to fall across zones 6 and 7. Lows will be in the mid 20s north to mid 30’s south.
Through the overnight rain will change over to and/or mix with snow from north to south. By 7 am Sunday morning you can see that area of snow and rain/snow mix moving from northeast to southwest spinning around the low pressure.
Through the morning hours’ rain mixed in with some of those heavy, wet snowflakes will remain possible.
By late morning into the early afternoon temperatures will warm enough to change any remaining precipitation over to rain.
Regarding snowfall and accumulations. Overall I am not real concerned with accumulating snow at this point in time. Surface temperatures look to be right at or slightly above freezing, that coupled with the warm ground from the warm, sunny days will help snow to melt. However, I won’t rule out a coating of snow in some places locally on rooftops, cars, and grassy surfaces. Overall though, even if you do get snow overnight Saturday, it will quickly melt Sunday.
Sunday morning there could be a couple slick spots in areas where temperatures do fall right at, to just below freezing. So while not a major concern, a concern none the less.
Through Sunday afternoon the upper level low will move off to the forecast areas east and southeast.
As it does any remaining rain showers will start to come to an end across the zones. By 5-7 PM rain showers will be out of Illinois entirely. It even looks like skies will clear Sunday afternoon and some sunshine will get through.
Highs on Sunday will be in the mid 40’s north to low 50’s south. Winds will be a little gusty at times, with winds up to 30 mph possible.
While no major rainfall is anticipated across Illinois some areas of .60-1” of new rain could fall locally. However, .2-.5” of new rainfall will be more common. The best chances of the heavier rain look to be from I-70 southward.
MONDAY: Sunday night through Monday a strong area of high pressure will build northward into the forecast area. While some clouds will likely be in place through the day, Monday looks to be mostly sunny to partly cloudy across zones 6 and 7.
Highs on Monday will be in the low 40’s north to mid 50’s south.
TUESDAY: Late Monday night into Tuesday a warm front will lift northward through the forecast area.
As it does it will allow for a return to a warm, moist southerly flow of air on Tuesday. Highs Tuesday afternoon will return to above average, topping out in the mid 50’s to mid 60’s.
MID – LATE NEXT WEEK: Another strong area of low pressure will be developing across the Great Plains once again next week. As it does it will bring rain and t’storm chances to the region. Right now there’s some disagreement in modeling on timing and intensity so this is something we will have to iron out as we get closer to the forecast period.
7 DAY FORECAST
SATURDAY: PARTLY TO MOSTLY CLOUDY, ANY AM SNOW CHANGES OVER TO RAIN. 30% CHANCE OF PRECIPITATION. HIGHS IN THE LOW 40’S NORTH TO LOW 50’S SOUTH. NORTHEAST WINDS AT 5-15 MPH.
SATURDAY NIGHT: MOSTLY CLOUDY, 20-30% CHANCE OF SNOW SHOWERS, ESPECIALLY WEST. LOWS IN THE MID 20’S NORTH TO MID 30’S SOUTH. ISOLATED LIGHT SNOW ACC.
SUNDAY: MIX OF SUN AND CLOUDS, 30% CHANCE OF EARLY MORNING RAIN/SNOW SHOWERS, THEN CHANGING TO RAIN BEFORE ENDING. HIGHS IN THE MID 40’S NORTH TO LOW 50’S SOUTH. NORTHWEST WINDS AT 5-15 MPH, GUSTING TO 30 MPH. ISOLATED LIGHT SNOW ACC.
SUNDAY NIGHT: PARTLY CLOUDY WITH LOWS IN THE UPPER 20’S NORTH TO MID 30’S SOUTH.
MONDAY: MOSTLY SUNNY TO PARTLY CLOUDY. HIGHS IN THE LOW 40’S NORTH TO MID 50’S SOUTH. WEST TO NORTHWEST WINDS AT 5-15 MPH.
MONDAY NIGHT: MOSTLY CLEAR TO PARTLY CLOUDY WITH LOWS IN THE UPPER 20’S NORTH TO AROUND 40 SOUTH.
TUESDAY: MIX OF SUN AND CLOUDS WITH A 10% CHANCE OF AN ISOLATED SHOWER OR T’STORM NORTH. HIGHS IN THE MID 50’S NORTH TO MID 60’S SOUTH. WINDS FROM THE SOUTHWEST AT 8-16 MPH, GUSTING TO 30 MPH.
TUESDAY NIGHT: INCREASING CLOUDS WITH LOWS IN THE LOW 50’S NORTH TO NEAR 60 SOUTH.
WEDNESDAY: PARTLY TO MOSTLY CLOUDY WITH A 10-20% CHANCE OF RAIN OR A T’STORM NORTH. HIGHS IN THE LOW 60’S NORTH TO NEAR 70 SOUTH.
WEDNESDAY NIGHT: MOSTLY CLOUDY, SLIGHT CHANCE FOR RAIN AND T’STORMS. LOWS IN THE MID 50’S TO AROUND 60.
THURSDAY: PARTLY TO MOSTLY CLOUDY WITH A 20% CHANCE OF T’STORMS. HIGHS IN THE 60’S.
THURSDAY NIGHT: CLOUDY WITH RAIN AND T’STORMS WEST. LOWS IN THE LOW 50’S WEST TO LOW 60’S EAST.
FRIDAY: CLOUDY WITH RAIN AND T’STORMS MOVING EAST. HIGHS IN THE 60’S, BUT FALLING THROUGH THE DAY.
FRIDAY NIGHT: RAIN AND STORMS END, CLEARING. LOWS IN THE 30’S.