The Winter Storm Watch remains in place for the South Sumter area as of 12 Noon Saturday.  The primary weather forecasting models from the NWS remain in great agreement that the entire Southeast United States will be impacted by a major winter storm.  What type of precipitation and how much are never easy to forecast and most people will simply leave this on alone.  However, we are not forecasting anything, but putting the array of area forecasts before you so let’s get started.

As stated before the models are in good agreement that we will have the ingredients required to have a winter storm in the area.  Both the GFS and the NAM (two primary models for the NWS) are in good agreement on the position of the low and the temperature profile at 850MB.  Remember the freeze line on these charts are a very good indicator of the rain and snow line (not always correct, but generally very good).


The 12Z run of the GFS puts the freeze line just along or slightly south of the US 82 corridor.  The low is off the Mississippi coast and is spreading a nice field of precip back into the area.  This look means that the Sumter are would recieve no snow, but this is not the entire story.

The 12 Z run of the NAM has a much colder and bullish look with the precip.  The NAM has the critical freeze line along the US 80 corridor at midnight on Sunday.  This look puts the area firmly in the snow camp.  I would rather see the NAM correct that deal with ice, which is what the GFS suggests.  The next chart we will see is the surface chart from the GFS at the same time frame as the images above.

Notice at the surface that the freeze line is all the way down to the Highway 84 corridor and this is a classic look for ice storms in the area.  This is clearly the scenario that would be best avoided, but the GFS and a few other models have been solid on this idea for the past few days.  The burning question is how much of what might we expect and when.  The when appears to be from 1800 Sunday to 0600 Monday.  How much is covered by the following graphics.

The NWS Jackson calls for the above.  I would find this to be correct if the GFS is spot on.  The ice accumulations might be rather light if this is a freezing rain event only.

Birmingham has adjusted their snow numbers down greatly since Friday.  I am not exactly sure what they are seeing, but they seem to have a better handle on the ice potential than any of the others.

The Ice potential from Birmingham.  The numbers are coming up here.

Last but not least is James Spann’s forecast.  I beleive he has the better precip accumulation forecast and is being used as a ensemble between the two NWS offices.  Most troubling with Spann’s product is the bullish ice numbers. 

Bottom line…  We should prepare for a winter weather event that will likely involve significant ice accumulations for the area.  These preparations should involve charging of portable equipment, fueling trucks (generators/saws) and checking all other emergency backup power and such at repeater sites and the like.  If things still look as threatening as they do now we will likely have a briefing and IAP meeting at Cuba Town Hall or Siloam Station Sunday afternoon around 1500.  The next update should be made this evening around 2100 hrs.