AFTERNOON – OVERNIGHT: A surface warm front continues into the state from the west. Quickly arriving behind it is the cold front. Rain has developed along these surface features and continues to work its way into Illinois.
Through the day rain and t’storm chances will increase from west to east as the cold and warm front move into zones 6 and 7.
By lunchtime rain and storms will be in place across Illinois. We will likely see an increase is rain coverage around mid-day to early afternoon as well. That is because the cold front will catch the warm front and occlusion will take place. So an occluded front will be moving across the area this afternoon.
Through the afternoon the front and associated rain/storms will be moving to the east. By 4-5 PM front will already be across Indiana. The heaviest area of rain looks to be across extreme eastern Illinois and into Indiana by this time. However, some isolated to scattered areas of rain will remain this evening behind the occluded front.
Through the evening, showers will continue across Illinois, this will be ahead of a secondary cold front that will make its way south and southeast across Illinois this evening into the overnight. By 9-10 PM the front will be moving across northern zone 7.
Winds today will be very strong with gusts of 40-50 mph possible!
Overnight the secondary cold front will continue to the south and southeast across the zones. Rain shower chances will continue across the area until about 3-4 AM, at which time the second cold front will exit out of the forecast zones completely.
Lows overnight will fall into the mid 30’s north to mid 40’s south.
New rainfall totals through Thursday morning look to average about .25-.50”. However, models are picking up on this heavier swath of rainfall from the St. Louis area northeastward toward Shelbyville, Illinois. Where the heavier rain does occur I won’t rule out local areas of 1-1.25” of new rainfall.
THURSDAY: Through the morning hours on Thursday conditions do look to be mostly dry across the forecast area. However, as we continue under an active upper-level trough it is hard for me to not at least leave in some chance of some isolated showers Thursday morning.
Through early afternoon on Thursday conditions looks to remain mostly quiet across zones 6 and 7. However, we will be watching a surface wave of low pressure associated with an upper level vorticity maximum that will be moving to the southeast over the region. These features coupled with some impressive lapse rates will allow showers and perhaps a couple t’storms to develop during the afternoon.
By 3-4 PM rain and perhaps a couple t’storms will develop under/along these features. It looks like the western half of zones 6 and 7 will have the better chance for a scattered rain or storm to impact you Thursday afternoon. However, with impressive low and mid-level lapse rates in place, more isolated showers will be possible elsewhere too.
Highs on Thursday will be mid 40’s north, but near 60 across southern Illinois where more sunshine is likely. Winds will remain breezy at times Thursday, with gusts of 25-35 mph possible.
Scattered areas of rain will continue into the evening across both zones 6 and 7. By 10 PM those scattered areas of rain will be moving off to the southeast.
As we get later into the overnight and lose that daytime heating/instability showers will begin to fade. Anything that does last will be isolated, light, and brief in nature.
Thursday night a few isolated light showers will remain possible, with perhaps a light snow shower or flurry across northern zone 7. However, these look to be extremely light and isolated.
Lows overnight will be in the low 30’s north to around 40 south.
FRIDAY: We will start the day off rain free once again on Friday and possibly with some sunshine as well, especially across western portions of the zone.
However, yet another upper level disturbance and surface low will be moving through the region as we continue to be influenced by the trough. As this disturbance moves to the south in the afternoon I do think rain chances will increase, at least across northern and western portions of the area.
Models are currently pretty dry Friday. However, I think with daytime heating, the upper level trough, and a 500 mb vorticity max rolling through, at least isolated showers should develop Friday afternoon across eastern Illinois. The extent of which will be determined by how much sun is present earlier and where the vort. max. tracks.
Highs on Friday will be in the mid 40’s to mid 50’s. Strong winds will continue with gusts of 30-40 mph possible.
Overnight Friday into Saturday precipitation chances will come to an end as the upper-level energy rotates off to the east.
However, with lows overnight dipping into the low 20’s north to mid 30’s south, freezing conditions will once again become a concern.
WEEKEND: Friday night through Saturday an area of high pressure will move into the forecast zones. As it does this will help clear out clouds and really limit precipitation chances Saturday. While a few isolated sprinkles or a light shower will be possible, Saturday looks to be mostly sunny and dry.
Temperatures will remain chilly to start the weekend with highs in the upper 30’s north to low 50’s south. Gusty winds will still be possible despite the area of high pressure. Gusts up to 35 mph or so will be possible.
Saturday night the high will start to move off to the west. However, it still looks to remain in control for the most part. Some clouds may increase from the west across Illinois, but overall clear skies will remain.
This will make for another cold night for April with lows in the low 20’s to mid 30’s. So another possibility for freezing conditions will exist. The only “Light at the end of the tunnel” so to speak is, the models are a little quicker with the high exiting. If this trend continues and more cloud cover should be realized, then more widespread temperatures above freezing will be possible.
Sunday an area of low pressure will develop to the west. As it does a warm front will be in place across portions of the region. This will allow clouds and some rain to develop through the day. While i’m not expecting a total washout, isolated to widely scattered showers will be possible.
Highs on Sunday will be in the mid 40’s north to around 60 in southern portions of Illinois. The spring winds will continue to be relentless, as wind gusts of 30-35 mph will be possible.
7 DAY FORECAST
THURSDAY: PARTLY CLOUDY WITH A 30% CHANCE OF RAIN SHOWERS. HIGHS IN THE MID 40’S NORTH TO AROUND 60 SOUTHWEST. NORTHWEST WINDS 5-15 MPH, GUSTING TO 25-35 MPH.
THURSDAY NIGHT: PARTLY TO MOSTLY CLOUDY WITH A 10% CHANCE OF AN ISOLATED RAIN SHOWER, PERHAPS A LIGHT SNOW SHOWER NORTH. LOWS IN THE UPPER 20’S NORTH TO AROUND 40 SOUTH.
FRIDAY: MIX OF SUN AND CLOUDS, 30% CHANCE OF A RAIN SHOWERS. HIGH 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 SNOW SHOWERS. LOWS IN THE LOW 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 5-15 MPH, GUSTS OF 25-35 MPH.
SATURDAY NIGHT: CLEAR EAST, CLOUDS INCREASING WEST. LOWS IN THE LOW 20’S EAST TO MID 30’S WEST.
SUNDAY: INCREASING CLOUDS WITH A 10-20% CHANCE OF PM RAIN. HIGHS IN THE MID 40’S NORTH NEAR 60 IN SOUTHERN IL. WINDS FROM THE SOUTHEAST AT 5-15 MPH, GUSTING TO 35 MPH.
SUNDAY NIGHT: CLOUDY WITH A 20-30% CHANCE OF RAIN. LOWS IN THE UPPER 30’S TO LOW 50’S.
MONDAY: MOSTLY CLOUDY WITH A 50-60% CHANCE OF RAIN AND STORMS. HIGHS IN THE MID 50’S TO UPPER 60’S.
MONDAY NIGHT: CLOUDS CLEARING WEST TO EAST, RAIN ENDS. LOWS IN THE LOW 30’S TO MID 40’S.
TUESDAY: MOSTLY SUNNY WITH HIGHS IN THE UPPER 40’S TO UPPER 50’S.
TUESDAY NIGHT: CLEAR AND COLD. LOWS IN THE UPPER 20’S TO UPPER 30’S.
WEDNESDAY: MOSTLY SUNNY, CLOUDS LATE? HIGHS IN THE MID 40’S TO LOW 50’S.
WEDNESDAY NIGHT: CLEAR NORTH, INCREASING CLOUDS SOUTH. LOWS IN THE 30’S.