AFTERNOON – EVENING: A stationary front is in place across Illinois this morning. This has kept conditions partly to mostly cloudy across the forecast area with a few rain showers around.
Through the day the stationary front will slowly start to drift northward as the low and attendant cold front approach from the west. By 12 pm areas of rain and perhaps a few storms will be moving northeastward across the zones.
Through the afternoon scattered rain and some storms will be moving across Illinois. By 4-5 PM scattered rain and storms will continue, especially closer to the warm/stationary front and farther west closer to the initial cold front.
By 9-10 PM rain and some t’storms will continue to move to the east and northeast across zones 6 and 7. At this time the cold front will be entering western Illinois and surging eastward.
The cold front will move to the east through the overnight and will be in place across eastern Illinois by 3-4 am Thursday morning. Along and ahead of the front scattered rain and a few storms will continue.
Lows tonight will fall into the low to mid 50’s.
THURSDAY: By 8-9 AM Thursday morning the initial cold front and associated precipitation will be pushing into Indiana. As it does at least a brief period of dry time will move in ahead of the secondary cold front.
Through the day on Thursday a few isolated showers will remain, especially across northern zone 6 into zone 7. However, these will be pretty isolated in nature.
Highs on Thursday will be in the mid 60’s to low 70’s across the area. Winds will be strong at times with gusts of 25-30 mph possible.
Through the afternoon a secondary cold front will approach from the west and northwest. By 4-5 PM the cold front will be moving across zones 6 and 7. Along the front scattered rain and some storms will develop.
By 7-8 pm Thursday evening the front will extend from north to south across the zone forecast area. Rain and some t’storms will be ongoing along the front.
Through the evening the front and associated rain/storms will exit the region to the east and southeast. By 12—1 AM they will be completely out of the area.
While I am not anticipating any significant severe weather Thursday evening, there are some indications there will be enough dynamics for some strong storms with perhaps some low-end severe storms in the afternoon/evening. The latest NAM model does show 1000 J/Kg of CAPE Thursday afternoon.
Aloft, 500 mb winds will be moving in from the southwest at 45-55 mph. The biggest limitation will be low-level winds, 850 mb winds look pretty weak, with 20-30 mph winds forecast there. The better risk for any strong to severe storms would be in eastern/southeastern Illinois.
Through the overnight a few very isolated light rain showers may linger. However, any better chances of rain will exit with the front.
New rainfall totals will vary across the forecast zones. I do think places across zone 6 will have more rain with an average total of .30-.70” will be more common. However, places that get under the heavier and more persistent rain/storms could see 1.75-2.25” locally!
Farther north across zone 7, rainfall number don’t look to be as dramatic with .25-.50” average rainfall totals. Some localized areas could see .75-1” there where the heaviest rains/storms occur.
Lows Thursday night into Friday will be near 50 north to the mid 50’s south.
FRIDAY: An area of high pressure will start to work its way into the forecast area through the day on Friday. This will allow for skies to clear and some sunshine to get through across the zones.
Highs on Friday will be in the upper 60’s to mid 70’s across Illinois. Winds from the north will be breezy at times, with gusts of 20-25 mph possible.
Friday night the surface high pressure will continue to work to the south keeping skies clear to mostly clear.
Lows overnight will be chilly, falling to around 40 north to around 50 south.
WEEKEND: High pressure in place to the regions northeast will remain in control Saturday. This will give us a very nice opening to the weekend with mostly sunny skies and nice temperatures.
Highs on Saturday will be in the mid 60’s to mid 70’s.
Sunday the high pressure system will move off to the southeast. As it does a warm front will be in place to the north of the region as a low pressure system gets itself together to the west.
However, a dry day is expected Sunday. With the warm front to the north and the return of the southerly flow, temperatures will once again warm.
Highs on Sunday will be in the 70’s to perhaps near 80 in some locations!
LONG-RANGE (NEXT WEEK): The pattern through next week looks to remain active as low pressure systems continue to load up and move across the United States. That isn’t to say there won’t be some dry days next week too. However, rain and t’storms will be possible as well.