Forecast Discussion :
TONIGHT – EVENING: The area of high pressure that has been in control of our weather pattern is continuing off to the east today. While we are continuing with dry weather, upper level clouds are working in across the forecast zones.
This afternoon and evening clouds will continue across the region, likely starting to thicken up across western portions of zone 6/7. However, dry conditions will persist through the evening.
Overnight most locations will remain dry. However, after midnight isolated to widely scattered areas of rain will be possible across very western Illinois. As temperatures fall overnight some light freezing rain or drizzle will be possible across western Illinois closer to sunrise. Overall little to no accumulation is anticipated.
Lows overnight will be in the mid 20’s east to around freezing west.
THURSDAY: Clouds will continue to thicken up from west to east across the region. I do believe most of the daytime hours will be dry across the forecast zones, with the exception of western portions of zones 6/7 early in the morning as mention earlier in the discussion.
Rain chances will be on the increase across western Illinois after 6-7 PM Thursday evening.
By 10 PM to 12 AM rain will continue to work across zones 6/7 moving off to the northeast.
After midnight rain will continue to the east across Illinois and into Indiana.
By 4-5 AM Friday morning there may be just enough cold air in place across northern zone 1 for some sleet or a brief time of freezing rain to occur. This is something we will have to fine tune over the next 24 hours or so.
FRIDAY: Isolated to scattered areas of rain will continue across the forecast zones on Friday. Better chances of rain look to be in the morning through the early afternoon as the area of low pressure moves in from the west and a warm front lifts through.
Friday afternoon the area of low pressure will move to the forecast regions north and west. This will allow for drier air to surge in and only isolated rain chances to continue Friday evening.
Highs on Friday will be in the upper 30’s north to around 50 south.
WEEKEND: All eyes will be on an area of low pressure this weekend that will move into the region from the Texas Panhandle. Models are coming into some agreement with the track of the low. However, there is still a wide range of forecast solutions.
The morning run of the NAM places the low across western Indiana by 4-5 PM Saturday afternoon. This scenario would bring snow to Illinois, but mostly rain to much of Indiana and Ohio.
The GFS takes the low across western Illinois, but keeps air warm enough at the surface that most of the precipitation falls as rain.
The UKMET shows an impressive low pressure system that tracks along the Ohio River, that would be more favorable for snowfall across Indiana.
Last nights run of the EURO model came in with a mix between the GFS and UKMET. It tracks the low across western Ohio/eastern Indiana. However, like the GFS keeps temperatures warm enough that rain would be the more likely precipitation type.
Keep in mind with this system that models will likely show at least some warm air bias since they are accounting for the El Nino. So cold air may be stronger than anticipated. None the less, this is an ever evolving situation so make sure to check back for the latest forecasts!