Update to Tonight-Tomorrow & Thursday-Friday ForecastDecember 18th, 2012 at 9:55 pm by Chad Evans under Chad's WLFI Weather Blog
With thick, low stratus deck & brisk southwest winds, that push of warm air from Illinois & Missouri (60 today at St. Louis & 56 at Evansville, Indiana) is overspreading area.
So, temperatures are actually at their highest levels all day as of 10 p.m. We just hit 44.6 degrees at WLFI. Figured this warm air push would arrive more this afternoon & give us a high in the mid 40s, but it is occurring more so now. The afternoon high was just 41 & we continue to rise tonight towards the mid 40s. Thinking we may hit 46 soon, then fall off pretty quickly due to colder weather just to our west arriving overnight. The fall may begin in the next hour to hour-and-a-half.
Temperatures around Champaign are quickly dropping into the middle 30s with clear skies, so thinking as skies clear somewhat, that a low near 31 is still attainable (verified in GFS MOS 18z output). Temperature still looks to level off very late with some fog (nothing dense, though).
Wednesday actually looks quite cloudy, compared to previous data & data today did not handle all the cloud cover very well lastnight. I am going to word it as “mostly cloudy” & shave a couple of degrees off of it as a result from 52 to 50. Winds look more southeast than south, preventing a really nice influx of warm air.
Temperatures may fall a degree, level off, then rise to 54 by late in the night-early Thursday morning with approach of rain band with some thunder. I raised it one more degree given the degree of warm air transport up into area with strong southeast to south winds up to 32 mph by early Thursday morning.
Scattered showers very late Wednesday night will transition to a solid band of rain with embedded thunder Thursday morning. With this the wind will increase Wednesday night, right through Thursday morning. The rain band will exit by early Thursday afternoon & there may be a bit of a lull as much cold air roars in from the west & southwest. Winds will increase to gusts of 45-50 mph.
Wave of snow still looks likely with 1″ or less of accumulation. Some additional snow from Lake Michigan may deposit 1-3″ in our northeastern counties.
Some snow showers may hang on for a while in our northeastern counties Friday & a few flurries may still occur with a mix of sun & clouds in the area. It still looks windy with gusts to 35 mph. Wind chills may drop to near -1 Friday morning & 10 in the afternoon.