We’ve been waiting for it to happen and it looks like colder and whiter scenes may be ahead. Below normal temperatures have been showing up in the 11 to 15 day forecast for about 2 weeks now, but by the time that timeframe rolled forward into the 6 to 10 day forecast, trends were much warmer. The weather pattern has supported a cold December, but it’s been on delay and only a matter of time before it gets here. We are seeing signs that it is finally on its way. Here is a look at the latest run of the EPS (European Model Ensemble Mean) showing colder than normal temperatures across much of the U.S. in the 6 to 10 day timeframe. This image is courtesy of the Tropical Tidbits Website:
This is valid for the December 16th through 21st, timeframe, where the 5-day temperature is forecast to average colder than normal. We will likely see a Low-Pressure system bring a wintry mix of freezing rain, sleet, and snow to mid-Michigan on Thursday, December 15th, which will be followed by a cold front that brings in this cold air. How cold is cold? Well, so far this month, we have seen highs mainly in the 30s, so at the very least, this should give us more highs in the 20s and lows in the teens. This being said, it also depends on how much snow we can get on the ground. The more snowpack we have, the higher the potential to see even colder air. The arctic air coming down from Canada is no doubt cold, but the airmass is inevitably modified as it travels across different continents. Aside from just our ensemble computer models, we also have support from the East Asia weather pattern that favors colder than normal temperatures between December 19th and 23rd, as shown here:
This cold should help make the environment favorable for lake effect snow since the lakes are still relatively warm during early winter. This isn’t all, though. The cold may reload right around the ~23rd or ~24th just in time for Christmas. We may see a Low Pressure system move through right around this time on Christmas Eve or the day before, which would probably be snow given how cold it will likely be. A key note here is there is no way to know the exact path of this storm. It could hit Michigan or it could stay south in Indiana…we don’t know for sure, but this storm system should exist in this timeframe and drag down colder air behind it. We do have agreement from the two major ensemble forecasts systems (GEFS and EPS) on below normal to perhaps well below normal temperatures in place right around Christmas. Again, the specifics on exactly how cold depend on many variables that need to be ironed out as we get closer, however, I would not be surprised to see at least as few days with highs in the teens and lows in the single digits. If we get enough snow on the ground and clear out the clouds at some point, it wouldn’t be impossible to drop below zero. The bottom line is, the second half of December is looking colder than normal with a better chance at seeing a white Christmas this year than in most recent years.
Wintry Mix Possible Wednesday into Thursday
We start out this week under mostly cloudy skies, as winds shift to easterly due to a high-pressure system over Canada. This brings in moisture from off Lake Huron helping clouds hang around. Look for highs in the mid-30s. Partly to mostly cloudy skies continue into Tuesday with highs again in the mid-30s. Our major concern this week is for Wednesday as our next system approaches the area. A low-pressure system forms off the Rocky Mountains today, moving towards the Great Lakes and arriving on Wednesday. This low brings a complex weather pattern that brings changes of rain, snow, freezing rain, and sleet to central Michigan Wednesday and Thursday.
Forecast model soundings, or graphs that show us how temperature and moisture will be in the atmosphere, suggest that the best chance for wintry weather will be areas north of I-96 including Mount Pleasant while it should stay more rain further south. Who gets wintry weather and who gets rain is dependent on how much warm air is above the surface, and if temps at the surface are below freezing. This wintry weather could cause travel impacts but what type of precipitation and how much is still uncertain. Confidence will grow the closer we get to Wednesday so follow our page for the latest weather information. The big story is that wintry weather could cause problems with travel on Wednesday and Thursday, so students finishing exams should be aware of this.
What is a white Christmas?
We’ve all heard the song and have the nostalgia of looking out the window on Christmas to see a blanket of snow across the ground, but what exactly is a white Christmas? A white Christmas means we have at least one inch of snow on the ground on Christmas morning. That means that if snow fell on Christmas but melted, it wouldn’t be considered a white Christmas. According to the National Weather Service, we see a white Christmas around 60% of the time in Mount Pleasant. It’s not as common as the upper peninsula where they get large amounts of lake effect but it’s more common than not. Will we see one this year? It’s too soon to say, but stay with our team for the Christmas forecast, and the other 364 days of the year as well.
Mt. Pleasant Almanac for This Week:
Almanac Information is a way to look at normal and record high and low temperatures for this time of year. The normal temperatures are based on the 30-year average high and low for that date between 1991 and 2020. For example, if you take the high temperature for every December 12th between 1991 and 2020 and calculate the average of all 30 values, the result would be 36. Therefore, the normal high for today is 36°. Record high and low temperature data goes back to 1895. Sunrise and sunset data is also provided. All information is valid for Mount Pleasant.
December 12th
Normal High/Low: 36°/23°
Record High: 57° 1899
Record Low: 0° 1962
Sunrise: 8:03AM
Sunset: 5:03PM
December 13th
Normal High/Low: 35°/23°
Record High: 57° 1991
Record Low: -8° 1986
Sunrise: 8:04AM
Sunset: 5:03PM
December 14th
Normal High/Low: 35°/23°
Record High: 58° 2015
Record Low: -13° 1917
Sunrise: 8:03AM
Sunset: 5:02PM
December 15th
Normal High/Low: 35°/23°
Record High: 61° 2021
Record Low: -5° 1989
Sunrise: 8:06AM
Sunset: 5:03PM
December 16th
Normal High/Low: 35°/22°
Record High: 63° 2021
Record Low: -6° 1951
Sunrise: 8:06AM
Sunset: 5:03PM
December 17th
Normal High/Low: 34°/22°
Record High: 67° 1984
Record Low: -5° 1919
Sunrise: 8:07AM
Sunset: 5:04PM
December 18th
Normal High/Low: 34°/22°
Record High: 49° 1939
Record Low: -13° 1926
Sunrise: 8:08AM
Sunset: 5:04PM
Mid-Mitten Weather View’s Mission is to serve people by providing timely information to help keep you safe and make decisions based on the weather. We are passionate about educating both our forecasters and our followers about how weather forecasting works and how we can be best prepared when impactful weather threatens. Our team consists of both CMU alumni degreed meteorologists and current student forecasters from the University. For daily updates, we welcome you to check out our Facebook Page! We look forward to catching you back here next week for another weekly 7-Day forecast update.
-Weather Forecast by CMU Student Forecasters Isaac Cleland & Scott Thomas
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