DETROIT – Wednesday night is where things start going downhill -- and they’ll go downhill real fast.
Rain showers will develop, and then mix with a few wet snowflakes late at night as a cold front sweeps across the area – this is the lead edge of the coldest air mass of the season to invade the Great Lakes.
Since the snow will be falling into above freezing temperatures and onto a wet ground from the rain, I don’t think we’ll see any accumulation. Temperatures will fall into the mid to upper 30s (3 degrees Celsius) by dawn Thursday, with wind gusts to 35 mph likely.
The chance for snow showers either on Christmas Eve day or Christmas itself is highly dependent upon the wind direction flowing over the relatively warm Great Lakes waters. If the wind is from more of a northwesterly direction, then this is not favorable for much lake effect snow to get down into southeast Michigan -- best chance is the northern Thumb.
Conversely, if the wind is more from the west, then that brings it across the wide southern part of Lake Michigan, and sometimes generates a noticeable lake effect band that extends eastward.
At this point, I don’t think we’ll see much in the way of snow shower activity on Christmas Eve Day. Sure, we could see a few flakes, but nothing that’ll have any impact (translation: that’ll give us a White Christmas Eve).
Temperatures will fall through the day Thursday, reaching the mid to upper 20s (-3 to -2 degrees Celsius) by late afternoon. Wind will blow from the west-northwest at 10 to 20 mph, so it’ll be breezy, but not as windy as on Wednesday.
Christmas Eve itself looks mostly dry with just a possible snow shower. Temperatures falling into the mid-teens (-8 degrees Celsius) by Christmas morning. One caveat: a big storm will be moving northward up the spine of the Appalachians Thursday into Thursday night, and some moderate to heavy snow will develop on its colder western flank. Right now, most computer models I’ve seen keep that heavier snow east of us -- perhaps getting as far west as between Windsor and London, Ontario. However, any jog westward in that storm would bring heavier snow (and a White Christmas!) to our far east side. This is a low probability right now, but certainly bears watching. It’ll be fun to watch that snow shield on the Local4Casters app’s radar.
Christmas Day itself will also be very interesting from a weather standpoint. It appears that we’ll have that favorable westerly wind plus an upper level disturbance potentially energizing that lake effect machine, so widespread snow showers looks likely. Highs will only be in the mid 20s, and it’ll be breezy with wind chills around 10 degrees (-12 degrees Celsius).
Kwanzaa begins on Saturday, and it’ll begin with a fairly quiet and typical winter day. We should see at least partial sunshine, with highs rebounding into the low 30s (0 degrees Celsius).
Sunday may start with some sunshine, but clouds will increase. Highs in the upper 30s (3 degrees Celsius).