Sorry for the hiatus, Southern IL. I took a couple days to work on updating the verification graphics (still working on them) while the inclement weather was focused on the northern part of the state.
We do have some wintry weather in the forecast for us but it won’t have the significant impacts N IL is facing, nor will it equate to the nearly 1/4″ of icing we saw several days ago. Let’s first get to tonight.
A cold front is currently working its way south from the the central part of the state. It’s current location exists near I-70. As this cold front continues to push south, moisture is working its way north. Because of this, it’s possible some spotty showers will exist tonight. Locations south of Mt. Vernon should stay warm enough overnight to avoid freezing rain potential but Mt. Vernon and points north, including St. Louis and Vandalia have the potential to see some freezing drizzle. This won’t amount to much but I can’t rule out a light glaze.
Saturday should only warm up to near the freezing mark for locations along I-70 but farther south where the cold front hasn’t pushed through should approach 40. However, temperatures will begin falling once the cold front passes through. Given the scattered showers possible throughout the day Saturday, the same concerns exist tomorrow as they do tonight for the same locations. However, as we get into Saturday night, all locations have the potential to see frozen wintry precipitation. Currently, I expect all phases of winter weather to exist, especially along the I-70 corridor for locations like St. Louis and Vandalia. Overnight on Saturday the precipitation should start as light rain/freezing rain before enough cold air arrives to transition it over to sleet and eventually snow. Accumulations don’t look to0 significant, where most locations from St. Louis to Mt. Vernon and points east should see about 0.05-0.1″ of freezing rain, up to 0.2″ of sleet and a dusting of snow at most. The icing concerns will likely make travel hazardous in this area, especially on untreated roadways so if you have be out, use a great deal of caution this weekend. As we move farther south, precipitation should remain liquid longer which will limit the amount of freezing rain potential. I think 0.1″ of freezing rain will be a maximum value for locations south of Mt. Vernon right now.
Since the precipitation potential will exist until the shortwave moves through the area, we may be looking at scattered wintry precipitation through the day Sunday as well until it exits east of the area. Again, I’m not expecting a great deal of measurable precipitation on the day Sunday but scattered snow showers and patchy freezing drizzle/light snow may exist until Sunday evening. Sunday’s highs look to hover around freezing region-wide so precipitation types will be depending on the depth of the cold air which will be nailed down in future updates. This weekend looks more like a nuisance event than anything significant.
After the shortwave exits the area, a ridge will slide in to take over and bring a few days of dry weather. Lows on Sunday night will range from the middle teens in the north to the low 20s in the south. Highs on Monday will rebound into the upper 30s-lower 40s effectively melting any ice that won’t already be melted. Monday night will have lows fall to the middle-upper 20s before we rebound nicely on Tuesday with highs in the upper 40s touching 50 in spots. Tuesday night should fall back down to the freezing mark and cloud up ahead of our next potential weather system that should arrive mid-week. Fear not, temperatures look to remain above seasonal averages towards the end of the week so any precipitation that falls looks to be in the form of rain. I’ll keep an eye on that in case anything changes.