Snow or No?  The last couple of runs of our two main American computer models have trended farther south with the area of low pressure in the Gulf of Mexico.  This means two things – colder and drier.  This is a good news/bad news situation for those looking for snow.  The colder air is obviously a plus, but lack of moisture could be an issue.

Here is the 6z (overnight) run of the GFS, valid around lunchtime Friday:

If this were to verify, we would likely see some light snow, perhaps a dusting, but not much more.  There isn’t much moisture available.

However, the NAM is much, much wetter with this system.  Here’s it’s output, valid at the same time:

The NAM develops the surface low into a much stronger system.  Note the heavy precip over S. MS, likely falling as snow for places like Meridian and Jackson, while the GFS struggles to generate any measurable precipitation.

Why the Difference?  The upper level charts on both models look very, very different.  Those differences aloft translate to the significant difference you see in the charts above.  Here’s a comparison:

And now, the NAM:

So, Which Model Is Correct?  The other models are trending slightly drier, but not as dry as the GFS.  I also note that the 6z GFS ensembles are slightly more moist than the operational GFS (seen above). 

I believe much of south and central Alabama will at least see some  light snow falling on Friday.  How much remains a very difficult question to answer at this point.  I think the highest potential for accumulation in Alabama will come along and south of a line from Demopolis to Montgomery, with the potential reaching its maximum in our state near the MS state line.

Still too early to talk amounts…but I will crank out a first guess accumulation map sometime tomorrow morning.

Filed under: Montgomery, Regions, Weather, Winter Weather