Hope you have enjoyed the last few days and plan on taking full advantage of the next couple of days. Wed/Thu will be quite mild, but after that things will start getting interesting once again as another round of very cold air is headed this way along with the potential for some wintry weather.
First things first and that is the sunshine and mid 60s that are expected for Wednesday as our winds return to a more southerly direction. Strong southerly winds for Thursday will result in a very mild start with morning lows near 50 and back into the 60s that afternoon under a low stratus deck of clouds. However, with the possible exception of a few sprinkles we should be dry.
Thursday night a strong cold front will be pushing across the state followed by sharply colder temperatures through the weekend and into next week. The initial frontal passage may produce a few showers and the cloudy skies all day Friday may result in some drizzle or a few sprinkles. The chances are quite low for that time frame, but temperatures may be near freezing which could create some travel issues for early Friday morning, particularly for the more NW counties. The shallow cold air will then be firmly entrenched as a disturbance aloft comes this way from the SW and moves across the state for Saturday into early Sunday.
That this will be a very wet system is a given as the 7 day QPF map on the right shows we stand to get a good soaking. The big question is how cold will the surface temperatures be? Keep in mind the main trouble maker is still out in the Pacific Ocean and has not been sampled by our observational network; just remote sensing from satellites, so lots can still change. Also, the initial surge of cold air will not be nearly as cold as what we experienced earlier in the month as the strength of this surface ridge is much weaker than the last system. Even so, the shallow nature of the cold air often leads to an under-estimate of just how cold it really is.
The numerical guidance is all over the place with some of the products suggesting we will stay below freezing all day Friday and Saturday and some of the other guidance keeping us closer to 40 for Fri/Sat. Obviously, that has huge implications regarding precipitation type. By the way, the colder guidance has exhibited a rather strong cold bias recently which makes those numbers suspect, but on the other hand the warmer guidance often underplays the strength of these shallow, cold air intrusions.
Bottom line is a forecast nightmare as we will have shallow, cold air at the surface with much warmer, very moist air lifted over the top of it. This could lead to a significant ice storm or just a cold rain for Friday night and Saturday. Right now, am trying to split the difference but hedging toward the colder solution which would produce at least some freezing rain in our more NW counties, a mixed bag possible along the I-44 corridor, and a cold rain further SE for Saturday. As the system lifts out to the NE, colder air at the surface and aloft will spread over the state which would then provide a rather brief opportunity for some snow Saturday night into Sunday morning. Right now, it appears amounts would be on the light side, but again later data runs may change that significantly.
Our skies should be clearing later Sunday as the system quickly moves on out followed by chilly but dry conditions leading into Christmas Day itself. So, stay tuned and check back for updates.