Christmas 2018: What we Know (And What we Don't)
- Zack Richards
- Dec 20, 2018
- 3 min read
The all-important questions of the chance of a White Christmas and weather's impact on this year's Holiday travel plans are coming into focus - in the short term.
If we've learned anything about the way, way too-early prediction of a White Christmas, it might be the fact that making educated guesses based on long-winded statistics about as useful as spinning the bottle or rolling a dice. Even with supercomputers that churn out millions more calculations per second than Einstein worked in his lifetime, figuring out when and if (let alone how much) it will snow in a particular location can be quite tricky.
The official definition of a White Christmas is having one inch of snow on the ground Christmas day. The snow does not have to fall on Christmas or Christmas Eve, and temperatures can melt the snow throughout the day, so long as there was at least an inch at some point...
As for the opening week of Winter 2018, it looks to be a stormy one. The models generate new lows to impact the Eastern half of the US every 3 to 5 days for the next two weeks, at least. As far as significant snowfall is concerned, the moisture aspect is there. The only lacking ingredient to a winter wonderland is getting the all-important freezing temperatures to coincide with this abundance of moisture. So far this autumn, this has been sporadic at best in the higher elevations, rarer still in the foothills and Ohio River Valley. Unfortunately for snow lovers, this setup does not appear to be changing for the upcoming week. However, the chance of a White Christmas is not 0% for everyone in the Mountain State! With that tease out of the way, lets look at the upcoming storms and holiday forecast...
The Overview
American Model (GFS) - Surface Pressure and Precipitation
Although likely not correct on every detail, the GFS does a good job of illustrating the unsettled holiday week ahead for the Mid-Atlantic. In total, there are three possibilities for messy conditions in the next 10 days:
Storm #1: Thursday 12/20 - Saturday 12/22
The first storm system coming in this afternoon appears to be the strongest and most organized of the upcoming systems according to this run of the model. This may not be totally accurate but what is critical is the placement of the low pressure in accordance to West Virginia. As you can see, the two-part system tracks somewhere between directly overhead and 50-75 miles east of the majority of the state. Due to above-average highs throughout the Eastern US, this storm will be a soaker rather than a whiteout, bringing a fair amount of rain to the Mountain State and beyond. Highs will range from the low 50s in some lowland locations to the mid 40s above 2500 feet. Regardless, there is little chance of snow until the system departs our region late Saturday. Once the storm moves to our north and east, a northwest flow of chillier air will filter in, finally allowing temperatures to settle close to the freezing mark overnight.
The tricky part is, just how much cold air comes in while precipitation is still falling? Also, how thick will the layer of cold air be? Scenarios like this are infamous for "busting" when predictions even a few days out call for snowfall accumulations. Right now, indications and previous experience point to a shallow layer of cold air somewhere in the mid-to-lower 30s, with temps around 30 in the highest elevations. The point here? Any snow that does fall Saturday will likely not stick in most locations, and where it does, expect marginal (<1-2 inches) results.
Disturbance #2: Christmas Eve
In the latest model runs, this smaller, less-organized system is arriving a couple of hours earlier than previously shown. Effects will likely be felt as rain or a mix of rain and snow early Monday morning, but turning over to snow where the temps are cold enough to support it (likely The Mountains, Northern Panhandle, and Mountaineer Country). There are still many factors to consider before we can confidently put out a White Christmas map, but some places will pick up a quick inch or two of snow before the disturbance departs quickly to the northeast. Any effects from the system should be light in nature and wrap up by early afternoon.
Storm #3: Wednesday 12/26 - Friday 12/28
A slowly-intensifying low and associated cold front will move into the region Wednesday afternoon. Likely to be primarily a rainmaker, warm temperatures will keep the latter half of the Christmas week feeling damp. Periods of gusty rain are possible Wednesday afternoon through the day Thursday and Friday until after the front passes. Despite the surge of cold, Canadian air on the approach behind the system, all of the precipitation should slide to the east before temperatures cool off enough to produce anything frozen.
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