AFTERNOON-OVERNIGHT: We have started Tuesday clear across Illinois, this as an area of high pressure moves into the region today. This area of high pressure will allow for sunny skies to remain sunny throughout the day.
The bigger changes in the environment are occurring aloft even as we speak this morning. The pesky upper-level trough that has stuck around giving us cold and unsettled weather is starting to move off to the northeast. This trough will continue to do so throughout the day allowing for more a quieter weather pattern.
Through the overnight clear skies will remain in place as the area of high pressure continues to control the weather pattern.
However, with light to no winds, clear skies, and high pressure over the top of the region it will result in some cool temperatures once again. Lows overnight will be in the lower 30’s north to around 40 south.
WEDNESDAY: At the surface the area of high pressure will be off to the northeast. However, it will strengthen into a 1034 mb high. With a high that strong it will still have a major influence on the weather across the Midwest including in zones 6 and 7.
Wednesday sunny to mostly sunny conditions will remain in place. Highs will start to moderate somewhat from what we have been experiencing. Temperatures will rise into the upper 50’s north to mid 60’s south.
The bigger change in the weather will be occurring in the mid-levels of the environment where a ridge of high pressure will start to build to the west and spread east.
This ridge will allow far calmer conditions and warmer temperatures across zones 6 and 7 this week.
WEDNESDAY NIGHT: Overnight Wednesday we will remain mostly to completely clear across Illinois with better chances for clouds across southern zone 6. However, I do expect it to be a dry night.
Lows overnight Wednesday into Thursday will be warmer than what we have been experiencing. Lows will be in the upper 30’s north to upper 40’s south where clouds help lock some warmth in.
THURSDAY: At the surface on Thursday we are still going to be under the influence of that area of high pressure, so no major disturbances will impact us there.
Aloft we will have a couple features in place on Thursday. The upper-level ridge that was building to the west will spread to the east and over the zone forecast area. However, to the south most models have been persistent with a bit of an upper-level low that gets cut-off from the jet stream as the ridge builds in.
With the upper-level low in place to the south on Thursday this would add some cloud coverage and perhaps an isolated shower chance across southern zone 6. However, I’m not anticipating any widespread or all day rain by any means.
Highs on Thursday will be in the low to mid 60’s across Illinois. With mostly to partly sunny skies.
FRIDAY: The upper-level ridge will continue to pump up across the eastern United States on Friday. As it does warmer air will continue to surge into the region.
The big question regarding the weather Friday will be the placement of what is left of the upper-level low. It does look to weaken throughout the day on Friday. As it does weaken it will be picked up by the jet stream and will get pushed to the north as it dies out.
Depending on the timing, location, and overall strength of this low, it could have an impact on the weather across zone 6 and possibly 7 on Friday. While I’m not anticipating any all-day rains at least some isolated to scattered rain chances would be possible, along with more cloud cover than originally thought.
In areas where rain and cloud cover is realized on Friday it would likely hold highs down into the upper 50’s to low 60’s. However, if more sunshine and little to no rain occurs highs will likely warm into the mid 60’s to low 70’s.
Right now there are still a lot of questions regarding the upper-level low at the end of the week. Timing, strength, and placement will be major factors in determining what impacts it will have on our weather. These things can be very hard to predict because they can be erratic in nature, but it’s something we will fine-tune over the next day or two.
LONG RANGE (WEEKEND): The models do have some differences to start the weekend as the EURO continues to show the upper-level disturbance moving through Illinois. As it does some slight chances of rain would remain across zones 6 & 7.
Again, places that get under the rain and clouds would see highs held down into the upper 50’s to lower 60’s. This while places with more sunshine and less rain/clouds would likely see highs in the upper 60’s and 70’s.
The GFS model is a much different story on Saturday. Via its model solution the upper-level low will quickly weaken and fade. As it does, it will very quickly be ushered out of the forecast area.
This solution would yield more sunshine, no rain, and warmer temperatures Saturday.
Highs via the GFS would be in the upper 60’s to mid 70’s.
Personally I would lean more towards the GFS regarding solution with the upper-level low. With large trough across the western U.S., it would make more sense for the weakening low to get swept up in this and quickly ejected out of the forecast region instead of just lingering as some models would suggest.
Regardless, it’s something we will watch closely and fine-tune as we get closer to the weekend.
Sunday will prove to be the nicest day of the weekend despite what that solution is for Saturday’s weather. This will be thanks to a very impressive upper-level ridge that will really push in at the end of the weekend!
This will really allow unseasonably warm air to move into the forecast area. Highs in Sunday will be in the low to possibly upper 70’s across Illinois under mostly sunny to partly cloudy skies.