The National Weather Service issued a Winter Storm Watch for the midlands of South Carolina Sunday afternoon. It is for the time period from Tuesday morning to Wednesday afternoon. Immediately everyone was jumping up and down for joy over the prospect for snow. Not so fast bucko! Everything is not as it seems.
It took quite a bit of careful analysis to decipher what the scenario would be. The computer models have been all over the place with this system; from no snow to more than 15” of snow. Even our own in-house model has seen big run-to-run swings with 2 to 4 inches of snow in one run to no snow the next. So what to do?
I have decided that the American model (GFS) seems to be preforming the best for now. The NAM model has been showing wild swings run-to-run and the European model (ECMWF) seems too cold. None of the models are perfect, but the GFS seems to be closest to actual observations in the forecast.
Thus, here is the forecast for Columbia, South Carolina over the next seven days. This was posted Sunday, January 26, 2014:
|The seven-day forecast posted Sunday, January 26, 2014 for Columbia, SC. Click on the image for a larger view. Image Credit: WLTX-TV.|
The scenario for the upcoming winter weather should be as follows:
|The surface forecast for the U.S. as of 18z Monday, January 27, 2014. Click on the image for a larger view. Image Credit: NOAA\WPC.|
A cold front is expected to pass through the Midlands around midday on Monday. Cold Arctic air will begin pushing into the region on brisk winds overnight. Temperatures will be near freezing by Tuesday morning. Precipitation will begin to spread northeast from the Gulf coast states and should begin to move into South Carolina during the afternoon.
The precipitation is likely to range from a light rain/sleet mix in the southern part of the Midlands to a snow/sleet mix in the north. There could be an extended period of sleet through the afternoon into the evening before the precipitation changes to snow. Thus, this storm is likely to be a mixed bag for the Midlands.
Here are two forecasts from the GFS model which cover the same storm, but break down the precipitation into snow and sleet. The sleet is expected first with the snow accumulation after the sleet accumulation.
|The forecast for sleet accumulation as of 7 pm Wednesday, January 29, 2014. The forecast is from the 18z run of the GFS model. Click on the image for a larger view. Image Credit: WLTX-TV.|
|The forecast for snow accumulation as of 7 pm Wednesday, January 29, 2014. The forecast is from the 18z run of the GFS model. Click on the image for a larger view. Image Credit: WLTX-TV.|
It gets worst for the coast. There is a significant possibility for an ice storm (freezing rain) for the coastal areas of South Carolina Tuesday night. In this area the ice could build up to a quarter of an inch. I cannot dismiss the possibility of freezing rain for Orangeburg and Clarendon counties. They may see it all, i.e. rain, freezing rain, sleet, and snow. However, the snow accumulation for these counties may only be a dusting.
Do not take the forecast numbers as the gospel truth as to what is about to happen. We have noticed significant variance for each run and they may not converge for another 24 hours.
Bottom-line: It is going to be a #wintermess Tuesday and Wednesday across South Carolina. Travel will become difficult Tuesday night as temperatures drop into the mid-20s and roads will be icy by Wednesday morning. There will likely be power outages for those areas that get freezing rain. Consider yourself lucky if all you have to deal with is sleet and snow. This is more likely to happen north of I-20.
Be sure to follow my updates on this storm on Twitter: @JimGandyWLTX and on Facebook at WLTX. Others to follow from the weather team are @amyaaronson, @Daniel_Bonds, and @ChristineWLTX. You can also check for #wintermess on Twitter.
This should be fun to follow. I will have an update on the impending weather tomorrow evening.