Published 8:30 AM EST Monday, December 21, 2020
Welcome to winter. Now that winter is officially here, it seems appropriate that we have a couple of winter weather systems to talk about today.
After a brief bit of clearing overnight, a clipper system will travel across the Great Lakes region today. Clouds have already spread back over east-central Ohio ahead of this system and they will continue to lower and thicken as the system approaches.
Daytime temperatures today look to remain in the upper-30s for the area so precipitation locally this afternoon and early evening will fall as light rain. At some point tonight – probably after 6:00 PM – rain will change over to snow showers. All totaled, we should see less than an inch of snow in the Valley from this system through Tuesday morning.
Any residual snow showers will taper off Tuesday morning as the system exits to the east. Expect another cloudy day Tuesday with afternoon temperatures warming to around 40°.
Clouds may thin some late in the day as high pressure nudges into the region late Tuesday. Wednesday will be the warmest day we will see in the Valley for some time as daytime highs climb to the upper-40s to near 50° behind a warm front. Wednesday will also bring our best opportunity to see some sunshine. If you have any last-minute Christmas shopping or errands to do, this would be the best day to wrap those up.
CHRISTMAS EVE – CHRISTMAS DAY
There remains much uncertainty with regards to the late week forecast and many issues and discrepancies to work out with regards to timing and snow amounts over Christmas. However, I can offer some general guidance on what I think we can pretty much count on.
- A storm system will develop and travel east across the Upper Great Lakes region Wednesday through Friday. This will initially spread warm air into eastern Ohio Wednesday through Christmas Eve.
- With warm moist southerly air arriving behind the warm front, widespread rain will become likely Wednesday night into Christmas Eve.
- Christmas Eve will start out warm and rainy. The system’s cold front will sweep east across the region sometime on Christmas Eve. (There are timing issues related to this feature. Today’s models say this will happen Christmas Eve afternoon.)
- Rain will change over to snow showers behind the cold front. (Again, there are timing issues.) At this time, snow amounts look to be light as the cold dry air takes hold Thursday night.
- Mainly lake effect snow showers will set up behind the front for Christmas Day. Snow amounts and intensity in the east-central Ohio region will be highly dependent on wind strength and direction.
- Temperatures will turn sharply colder Thursday night through Christmas night then moderate some by Saturday.
I will say that a White Christmas is looking more and more likely. Normally, our odds for measurable snow on Christmas Day are about 30%. If I had to put odds on a White Christmas in the Valley today, I’d this year it looks more like 60%. I’m not quite ready to put numbers on snow amounts yet, but things are starting to come together for measurable snow amounts on Christmas Day.
What does look certain is that whether we see measurable snow or not, it is going to get very cold over the holiday. Temperatures locally will plummet quickly from the mid-40s early in the day to the mid-teens Thursday night. Anything wet – including roads and sidewalks – will do flash-freeze.
Daytime highs on Christmas Day may no better than 20°/22°. Add in the wind and wind chill values can very well be in the single digits.
As for snow amounts, I think we will start to see the models swing toward agreement on Tuesday. Then, we can at least look at modeling trends for snow amounts. The tricky part will be nailing down wind patterns which will determine whether we get any strong lake effect snow bands diving south.
Hang in there a bit longer, folks. The details are beginning to congeal and we’ll have better ideas in the next 24 – 36 hours on how this might play out. Updates will be posted here as our Christmas weather develops. Until then, as always, be safe (and kind) out there.