Metro Detroit weather: Winter storm to arrive before Christmas

4Warn Weather – We are still on track for a major winter storm later this week that will strongly impact holiday travel. I’ll discuss in detail below, but let me take you through the forecast for the week ahead in chronological order.
Today : Expect lots of clouds, although some models try to develop some breaks by afternoon. Highs in the low-30s (0 degrees Celsius), with west winds at 5 to 10 mph.
Today’s sunrise is at 7:58 a.m., and today’s sunset is at 5:03 p.m..
Tuesday : Mostly cloudy, with highs in the mid-30s (1 to 2 degrees Celsius).
Wednesday : Mostly cloudy, with highs in the low-to-mid-30s (0 to 1 degree Celsius).
The Christmas Storm :
I want to be clear that the upper level system that will generate this storm is still over the Pacific, and will not cross the west coast, where it can be studied by our weather balloon network, until Tuesday night. Until then, I cannot get too specific about the exact timing and type of precipitation we’ll receive. However, since last Thursday I have been very confident that this will be a significant winter storm that will impact holiday and vacation travel across much of the northeastern part of the country.
The trickiest part of the forecast comes into play on Thursday: what type of precipitation we get. The European model has insisted for the past two days that we’ll get rain first, then transition to snow on Friday. Meanwhile, the American model kept us all snow – until the latest overnight model run came in…it now has trended toward the European solution with rain developing first. The Canadian model’s storm track has been similar to the European model for the past couple of days, and that hasn’t changed with the latest model run. So confidence is increasing (but not to the point that I’m certain…minor changes in the storm’s morphology could have major changes in the weather we get) that we’ll have some rain showers develop on Thursday, with a steadier rain Thursday night into Friday morning, with rain then changing to snow by Friday afternoon,.
Obviously, no meteorologist can confidently tell you how much snow we’ll get, because of the potential for that rain…that cuts into the amount of moisture available to fall as snow. How soon that changeover occurs is also important (the European model changes us over a little quicker than the American model). But several inches of snow are possible Friday afternoon into Friday night.
Another aspect of this storm that hasn’t been talked about as much is wind…this will be a powerful winter storm, and I think we’re going to see some significant wind gusts…possibly 45 to 55 mph gusts either Friday or Saturday (or both).
Something else we need to monitor is the potential for Lake Michigan lake effect snow bands…some of those bands are likely to extend all the way across the state on Saturday, with moderate to heavy snow underneath those bands. Not everybody gets them, and the exact wind vector (direction) determines where those bands set up. Stay tuned.
Furthermore, a severe blast of Arctic air will be pulled down behind this storm. Highs Friday will be in the mid-30s (1 to 2 degrees Celsius) at midnight, and then fall to near 20 degrees (-7 degrees Celsius) by 5:00 p.m. We then don’t even reach 20 degrees this weekend, with bitter cold wind chills.
I’ve already heard from relatives and friends who are flying south later this week. If you are doing the same, be aware that this Arctic air will dive all the way south to the Gulf Coast and Florida. For example, Myrtle Beach, South Carolina this weekend will have highs in the upper-30s to low-40s (4 to 5 degrees Celsius). Sarasota, Florida will have highs only near 50 degrees (10 degrees Celsius). Miami, Florida will have highs in the low-60s (16 degrees Celsius). New Orleans, Louisiana will have highs in the mid-to-upper-30s (2 to 4 degrees Celsius) Friday and Saturday, and only in the low-40s (5 degrees Celsius) on Sunday. So be prepared for this if you’re heading south before this weekend. And if you need more incentive, I will be in touch with the Detroit Lions today about getting the team out of town ahead of the storm before their game this weekend at Carolina.