Another round of winter weather

It appears Punxsutawney Phil was on to something when he predicted six more weeks of winter.

We are anticipating another round of winter weather in the Carolinas this week. The timeframe is Tuesday – early Thursday. The trick is…what type of wintry weather??

A cold front will pass on Monday, allowing a cold-air-damming (CAD) event to set up behind it Monday night into Tuesday morning.

Moisture will increase behind the front. We could see precipitation, probably rain, start to fall as early as Tuesday morning. Then changing to a mix Tuesday afternoon/evening. As usual with the CAD events and winter precipitation, it all depends on the cold air. How deep will it be? What about a layer of warm air aloft?

Here is why all of that matters… a lot!

Winter precip types
Winter precip types

Then on Wednesday, an area of low-pressure will develop. The question is…where? The European model thinks over the coastline of SC Wednesday night…the GFS thinks off the coast of SC Wednesday. That will make for a different forecast depending on where the low forms/timing. My gut now is to have it forming just off the coast on Wednesday.

12z GFS. Low off the coast on Wednesday. Icy scenario for the Midlands.
12z GFS. Low off the coast on Wednesday at 1pm. Icy scenario for the Midlands.

That will give the Midlands a more icy scenario as I believe there will be a layer of above freezing temperatures in the mid-levels of the atmosphere. Depending on how deep that layer is… will determine our precipitation type.

Here is the 12z GFS thinking on the 850 mb temperatures (ºC) at about 5,000 ft. off the ground on Wednesday at 1pm.

12z GFS 850 mb temperatures (ºc)
12z GFS 850 mb temperatures (ºC)

And at the surface… temperatures are below freezing, according to the GFS deterministic model.

12z GFS surface temperature (ºF) on Wednesday at 1pm.
12z GFS surface temperature (ºF) on Wednesday at 1pm.

Snow is not out of the question for the central Midlands. Frankly, it’s just as likely from Columbia (1″), northward to begin the event. But I believe this will be more of a freezing rain/sleet event for us as time goes on, unfortunately. The northern Midlands could see the best chance for 1-3″ of snow to begin with as it stands now. Then the icy stuff takes over. However, the Sunday 12z GFS deterministic run wants to have snow over Columbia. The 12z European model is the most bullish solution with snow. Not going to show that for now.

You should be advised that if you see a crazy looking European model snowfall forecast map on social media…please note that it takes into account all frozen precip. types. (freezing rain/sleet/etc). That over does the amounts you see on the map.  

0.50″-0.75″ of ice isn’t out of the question for the central Midlands. The eastern Midlands could see 0.75″ plus. It should be noted that some models have more…which is just as likely as the previous amounts. A LOT of moisture is expected with this system. More detailed maps coming Monday.

Tune into “Good Day Columbia” from 5-9 a.m. each day. I will have our latest thinking with accumulations. As it stands now, it looks like significant travel troubles for much of South Carolina (especially towards the Pee Dee). Power outages could also be an issue with the ice. A busy week ahead in the SkyWACH Weather Center.

A Winter Storm Watch will likely be issued sometime Sunday or Monday for some counties in South Carolina. 

This forecast will likely change as this is a difficult scenario to forecast. Will continue to update here and on social media. 

Leave a Reply to wxgarrett