Temperatures are the key to what we'll see

Temperatures at the surface and aloft are all key as to what type of precipitation we'll receive later today and tonight.  The initial push of warm air this morning was experienced in the form of cloud cover and fog.  While we've still got the fog (dew points continue to rise) the clouds are beginning to depart and this will mean we've got a better shot of highs this afternoon reaching the lower 40s. 

The cloud cover will begin to move back in tonight ahead of a surface low currently lifting east/northeast out of the Texas/Oklahoma panhandles.  This low will move into Missouri by late this afternoon and then into southern Illinois overnight.  Southerly winds out ahead of the low will continue to bring a warm air mass in not only at the surface, but several thousand feet above.  Light rain may begin to spread northward by this afternoon, but the chance for rain will increase this evening and overnight.  Temperatures are likely to remain mild enough to support rain through the majority of this event; totals could possibly near 0.25".  A cold front will move in from the northwest with the northern branch of the jet stream, however, there really isn't that big of a punch of colder air behind it.  So, without that cold air in place it may be difficult to get a complete change over to snow.  It's likely we'll have a rain/snow mix overnight with some wet snow flakes flying Thursday morning.  Another aspect to consider will be our dew points.  These numbers will be rising into the low 30s and typically when you have dew point readings near 30° or higher it's hard to get a complete change over to snow.  Of course, as this system evolves today we'll continue to provide updates here as needed.  But, I think the fact that we've got sunshine this morning and the possibility of reaching the low 40s this afternoon will be in our favor once the precip does start to fall.