Posted: 7:04 am Monday, January 15th, 2018
By Kirk Mellish
Most interesting from a meteorological standpoint is that we have a CHANCE of snow, but NOT from a winter storm, there is no low pressure system. Instead it’s a very strong cold front that will work with upper level energy in the jet stream (cyclonic positive vorticity) to squeeze out what little moisture it can in a relatively dry air mass.
This is a very rare pattern for our region of the country (more common up North), and a very “sketchy” or iffy set-up for snow.
I suspect there will be a hole where nothing sticks or even falls, thanks to the “down-sloping mountain shadow effect”. However, where that hole will be can’t realistically be determined, it may be centered in areas around Lake Lanier to Athens, or maybe most areas Southeast of I-85.
Notice that in the precipitation (liquid equivalent) chart below IF this were just rain, it would barely be enough to wet the ground, that’s how little total moisture is anticipated as of now anyway…
Quantitative precipitation chart:
TUESDAY MORNING SURFACE WEATHER CHART:
TUESDAY EVENING SURFACE WEATHER CHART:
A blast of arctic air follows Wednesday with lows in the teens, wind chill factor in the single digits, and highs struggling to get above 32F.
UPPER-LEVEL ENERGY COMING OUR WAY TUESDAY NIGHT:
WEDNESDAY AM SURFACE WEATHER CHART:
Its important to remember the odds or probability of this is far from 100%. In fact, its only in the range of 30 to 60% for accumulation. Doing the math as they say, that’s the same as 40 to 70% odds against.
Obviously forecasts can do and will change. So follow the updates to come here and on the radio and twitter.
The estimated AMOUNTS in the above map may in reality end up Northwest or Southeast by 20-30 miles: normal and expected margin of error or zone of uncertainty. Likewise, the range of snow outside of the mountains is really from Zero up to 1 inch for the Atlanta Metro area.
Even the “worst-case” scenario is not much more than my current estimate, so that’s good news. But because temps drop below freezing tomorrow night and stay there into Thursday morning IF something sticks it will remain.
The other GOOD NEWS is that thanks to the timing expected, baring any changes, at least we WILL KNOW first thing Wednesday if not before, whether there will be any closings or road problems in spots.