Potential is increasing for a possible significant winter storm or blizzard to unfold by Thursday and Friday across portions of the the Ohio Valley and Great Lakes. Before we dig into details, this event is 3-4 days away, so there are some limitations in the science of weather forecasting as far as how detailed and specific we can get at this point. This being said, the large scale synoptic weather pattern supports a winter storm with heavy accumulating snow, which means confidence on the storm occurring is rather high, but the exact track that it takes and how exactly it will impact any given area or your back yard is yet to be determined.
There a few reasons why we believe a significant winter storm or blizzard is becoming a strong possibility at this point. The first thing is the polar jet stream is dipping into the central U.S., which is going to allow bitter cold air to move into nearly all of the central and eastern United States by the end of the week. The subtropical Jet Stream will phase or nearly phase with this Polar Jet, allowing moisture from the Gulf of Mexico to stream northward towards the Low Pressure system. It doesn’t take as much moisture to produce snow storms as it does severe thunderstorms in the spring, so there is plenty of moisture to work with to create a snow storm somewhere.
The next piece of the puzzle is a potent trough that becomes highly amplified over the Midwest, Great Lakes, and Ohio Valley by Thursday into Friday. On the map below, check out the dark purple colors showing up on the weather model data, indicating a unusually strong trough will form. It is not very often we see a trough this intense. Interestingly, this trough is essentially the same thing as a low pressure system, except it is halfway up through the troposphere, rather than at the surface where we live. Our weather patterns are driven by what is happening tens of thousands of feet up in the atmosphere, so we must investigate what will happen up there first in order to determine what will happen on the ground where we live. Based on the position and forecast evolution of this about 20,000 feet aloft, the surface low will most likely take a path south and east of Michigan. A specific track is not set in stone, but this is the general idea.
Next, check out this map below where we have drawn two possible surface Low Pressure tracks for this system. The first one moves through IN and directly into MI, while the second one moves through southwestern OH and western PA. Both tracks would give us some snow. It is also possible that the low goes somewhere in between these two tracks. Because we have it narrowed down to a track somewhere in between these two, snow certainly appears likely, but how much is the question. The bottom line is, there is the potential for a Major Winter Storm of Blizzard inside the blue highlighted area.
Another thing to note is this could be more than a winter storm, but could be classified as a blizzard in some areas. Why is this the case? It’s all about the wind. How do we know it will be windy with this system? Well, again, specific locations are uncertain, but somewhere will likely experience blizzard conditions. The wind will come from the fact that the trough significantly amplifies, which leads to an intensifying low pressure system. As the Low intensifies, winds increase. Furthermore, a potent area of arctic high pressure will settle in across the western U.S., which will increase the pressure gradient even more and lead to strong gusty winds. All the ingredients are on the table, now we just have to fine-tune the details over the next couple of days.
Will Holiday Travel be Impacted?
Christmas is 6 days away. This storm is setting up to impact the aforementioned regions Thursday and Friday with lingering impacts possible Saturday and Sunday for Christmas Eve and Christmas Day, depending on who gets hit the hardest. If you have travel plans today, tomorrow, or Wednesday, you are good to go, but if you plan to travel Thursday or later, you may want to reconsider and move them to earlier in the week. Definitely monitor the latest forecast on our Facebook page “Mid-Mitten Weather View” for the very latest this week.
What is a Blizzard?
It may come as a surprise, but a blizzard does not depend on how much snow occurs. As long as there is enough snow falling from the sky to blow around in the gusty winds and cause near whiteout conditions for at least 3 hours, the event can be classified as a blizzard. The official definition from the National Weather Service states that sustained winds or frequent gusts over 35 MPH and visibilities less than a quarter of a mile for at least 3 hours must occur in order to be considered a blizzard. There could be 2 inches of snow or 2 feet of snow. The amount doesn’t matter. This is why, regardless of whether we see a lot of snow or a little snow locally in central MI this week, if we get strong winds, significant travel impacts and power outages could still result.
Bitter Cold Air Arrives for Christmas
Once the storm exists the region between the 23rd and the 24th, bitter cold arctic air will spill into the area. If there is any good news, Lake Michigan will keep us warmer relative to neighboring states, but it won’t be warm at all. Furthermore, air this cold advancing over the Great Lakes will result in Lake effect snow, so even more snow will be likely on Christmas Eve and Christmas Day across the state even after the main storm moves away. I’ll illustrate the cold right here by showing this forecast temperature map for Christmas morning. Notice everyone is below 0 except for Michigan because of the Lakes. So again, it won’t be warm, but relative to our surrounding areas, we won’t be as cold. With the potential for strong winds, though, we could see wind chills drop below 0, so being outside late this week into the weekend, will not be pleasant...just in time for Christmas.
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 19th between 1991 and 2020 and calculate the average of all 30 values, the result would be 34. Therefore, the normal high for today is 34°. Record high and low temperature data goes back to 1895. Sunrise and sunset data is also provided. All information is valid for Mount Pleasant.
Normal High/Low: 34°/22°
Record High: 51° 1957
Record Low: -7° 1916
Normal High/Low: 34°/21°
Record High: 57° 1957
Record Low: -6° 1942
Normal High/Low: 33°/21°
Record High: 57° 1967
Record Low: -6° 1989
Normal High/Low: 33°/21°
Record High: 59° 1697
Record Low: -6° 2000
Normal High/Low: 33°/21°
Record High: 53° 1957
Record Low: -7° 2000
Normal High/Low: 33°/20°
Record High: 58° 2015
Record Low: -12° 1897
Normal High/Low: 33°/20°
Record High: 56° 1982
Record Low: -6° 1958
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 Forecaster Isaac Cleland