AFTERNOON – OVERNIGHT: After two cold fronts brought rain and some storms to the forecast area over the past 12-24 hours, those have since moved out and drier conditions have moved in.
Clouds will likely thin out some through the daytime hours across zones 6 and 7. While I won’t call for completely sunny skies, a mix of sun and clouds looks likely later on in the day.
Through the afternoon the models are pretty dry regarding precipitation. However, with steep lapse rates aloft and at low levels I think some showers will get going across the region despite model ideas. While isolated showers will be possible, there will be lots of dry time too.
Better rain chances may exist across eastern Illinois closer to the upper air disturbance. However, these will be scattered about, so no all-day rain is expected.
Through the evening and into the early overnight any showers around will start to fade. This will be as we lose daytime heating/instability.
Through the overnight a few showers may move in from the north, but these will likely be weakening too. So mostly dry conditions will continue across zones 6 and 7 into Friday.
Lows tonight will be in the low 30’s north to near 40 south.
FRIDAY: Friday morning some isolated to very scattered light rain showers will be ongoing across Illinois. This will be thanks to a front that will be pushing eastward across the state. By 7-8 AM the front will be across far eastern Illinois.
Through late morning to early afternoon on Friday conditions will remain dry as the front moves off to the east of the forecast zones. In fact, some sunshine will likely get through once the front exits the forecast zones.
Highs on Friday will be in the mid 40’s north to mid 50’s south. Winds will remain strong with gusts of 40-50 mph possible at times.
Through the afternoon an upper-level vorticity max will start to move to the southeast across the region. This coupled with afternoon instability aloft will allow for some rain to form across the region. By 3-4 PM some isolated showers will be possible across zones 6 and 7.
However, I think better chances of those isolated to widely scattered areas of rain will develop after 5-6 PM. At 7 PM the NAM 4 km does depict these showers across the forecast zones.
Late evening into the overnight showers will fade pretty rapidly across Illinois as there will be no upper level or surface features to support them as instability wanes. So a dry overnight is expected Friday into Saturday.
The main story for Friday night will be the very cold temperatures as lows will dip into the mid 20’s north to mid 30’s south. For this reason, a Freeze Watch is in effect Friday night through Saturday morning across all of zones 6 and 7.
Weekend: High pressure will build into the forecast area late Friday into Saturday. While this will yield dry conditions under sunny to mostly sunny skies on Saturday, it will also keep us very chilly too.
Highs on Saturday will only be in the low 40’s north to low 50’s south.
Saturday night clouds will start to increase across the region as a warm front moves into the vicinity of the forecast area. The clouds will likely prove to be a good thing and will hopefully allow more temperatures to remain closer to or above freezing through the overnight.
Right now we will call for lows in the low 30’s far east to low 40’s west. So there will still be a threat for some freezing conditions Saturday night into Sunday.
Sunday a warm front will start to move across Illinois to the north and northeast. As it does rain and a few t’storms will become possible.
Better chances of rain and a few storms will come through the afternoon hours on Sunday.
Highs on Sunday will be in the mid 50’s to mid 60’s.
Sunday night into Monday the low will move to the north. As it does the associated cold front will start to sag south. Rain and thunderstorm chances will increase across the region from north to south along the front.
MONDAY: The cold front does look to be relatively slow in exiting the forecast region Monday. For this reason, rain and t’storm chances will linger through most of the day.
Highs on Monday will be in the mid 50’s to upper 60’s. However, temperatures will be highly dependent on the placement/timing of the cold front.
7 DAY FORECAST
FRIDAY: PARTLY SUNNY EAST TO MOSTLY SUNNY WEST, 30% CHANCE OF A RAIN SHOWERS. HIGHS IN THE MID 40’S NORTH TO MID 50’S SOUTH. WINDS FROM THE NORTHWEST AT 8-16 MPH, GUSTS UP TO 30-40 MPH.
FRIDAY NIGHT: PARTLY CLOUDY WITH A 20-30% CHANCE OF RAIN AND/OR SNOW SHOWERS. LOWS IN THE MID 20’S NORTH TO MID 30’S SOUTH.
SATURDAY: MOSTLY SUNNY, 10% CHANCE AT AN ISOLATED RAIN SHOWER. HIGHS IN THE UPPER 30’S NORTH TO LOW 50’S SOUTH. WINDS FROM THE NORTH TO NORTHWEST AT 6-12 MPH, GUSTS OF 25-30 MPH.
SATURDAY NIGHT: CLEAR EAST, CLOUDS INCREASING WEST, 10% CHANCEO OF RAIN SHOWERS WEST/NORTHWEST. LOWS IN THE LOW 20’S EAST TO NEAR 40 WEST.
SUNDAY: INCREASING CLOUDS WITH A 20-30% CHANCE OF PM RAIN. HIGHS IN THE LOW 50S NORTH TO MID 60’S SOUTH. WINDS FROM THE SOUTH AT 5-15 MPH, GUSTING TO 35 MPH.
SUNDAY NIGHT: CLOUDY WITH A 50% CHANCE OF RAIN AND STORMS. LOWS IN THE MID 40’S TO MID 50’S.
MONDAY: MOSTLY CLOUDY WITH A 50-60% CHANCE OF RAIN AND STORMS. HIGHS IN THE MID 50’S TO UPPER 60’S. WINDS FROM THE SOUTHWEST TO NORTHWEST AT 5-15 MPH, GUSTS OF 30-40 MPH.
MONDAY NIGHT: CLOUDS CLEARING WEST TO EAST, RAIN ENDS. LOWS IN THE LOW 30’S TO LOW 40’S.
TUESDAY: SUNNY WITH HIGHS IN THE UPPER 40’S TO UPPER 50’S.
TUESDAY NIGHT: CLEAR AND COLD. LOWS IN THE MID 20’S TO MID 30’S.
WEDNESDAY: MOSTLY SUNNY, CLOUDS LATE? HIGHS IN THE MID 40’S TO MID 50’S.
WEDNESDAY NIGHT: CLEAR TO MOSTLY CLEAR. LOWS IN THE LOW 30’S TO MID 40’S.
THURSDAY: MOSTLY SUNNY WITH HIGHS IN THE LOW 50’S NORTH TO NEAR 60 SOUTH.
THURSDAY NIGHT: MOSTLY CLEAR NORTH WITH INCREASING CLOUDS SOUTH, ISOLATED RAIN SHOWERS SOUTH. LOWS IN THE MID 30’S NORTH TO MID 40’S SOUTH.