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Good morning! Expecting a warming trend to kick in today, as clouds increase. While I cannot rule out a stray flurry north this morning or sprinkle this afternoon, most areas remain dry with a decent day.
One thing you need to know about mid-week is increasing FOG! Especially Wednesday night and Thursday morning, thickest over northern areas where a deep snowpack is present. First off, we will see an area of showers lift into the southern portions of the state after midnight tonight, and continue through early afternoon Wednesday. Elsewhere, it stays mainly dry with some cloud cover and fog.
Fog becomes a bigger issue Wednesday night and Thursday, especially where deep snow is on the ground across northern Illinois. This formation of fog is a product of warmer air moving over the cold snowpack creating a low-level inversion (where air near the ground is colder than the air above). The snow pack will keep surface temperatures cooler, and I think there is a chance for some of this fog to freeze over northwest portions of the state, certainly something we’ll have to monitor.
Check out the temperatures for Thursday afternoon. It appears the warm front will be draped over north-central Illinois…locations south of there warm well into the 50s and 60s, while areas from Chicago to Rockford may only achieve middle 30s with continued fog/drizzle.
Rain will increase Thursday afternoon and night as the cold front moves through. Areas south may hear a rumble of thunder.
Rains will gradually exit southern areas Friday morning, with the state clearing out through the day. Here is a look at rainfall potential through Friday morning. Heaviest rains focus along/south of I-70 where over 1″ is possible.
As we head into the weekend, this is where model solutions start to diverge. Overall we are still trending for a mainly dry Saturday, with a rain chance far south. Sunday model solutions range from rain returning to sunshine and high pressure. Check back over the coming days as we try to nail this down. Guidance continues to suggest a very active pattern targeting the Ohio Valley next week with multiple rounds of precipitation. Illinois will be in the battle zone between very warm air south and east, to much colder air north and west. This can still fluctuate and change, but something to keep in mind.
