Interesting system coming in Saturday after 7am give or take a couple hours, ending after 1pm give or take a couple hours.
Some snow some rain, no freezing rain.
Highest odds of just rain near and South of a line from Newnan to Covington, but that line could end up being 20 miles or more further North or Further South (normal margin of error).
Highest odds of significant accumulation near and North of a line from Rome to Gainesville, likewise that line could actually end up being 20 miles or more South OR North of that estimate (normal and expected margin of error).
The difficulty is how much the various numerical equations vary on how much moisture the system will carry with it or whether dry surface air (low dew points) will dry up a lot of what moisture the clouds bear.
The other question is the vertical structure of the temperature profile of the atmosphere. (long time followers and blog readers know all about this, I’ve explained thermodynamic diagrams many times in the past, sorry if you are knew).
Just a couple degrees difference from the projected profile above will spell the difference between just curiosity snow then rain or something more impactful, a few degrees is well within the normal margin of error for any forecast.
The ground temperatures are likely to be near 32F to start the day (freezing AND melting point).
Sadly our models to not predict what ground temperatures will do in the future, they don’t forecast that just air temperatures. Which are expected to start the day in the 30s then rise into the 40s (outside of the mountains) in the afternoon.
Based on this we expect snow that falls, if any, will not stick around long.
As of now accumulation where it occurs seems more likely on roofs, decks, grass and plants although some on roads in Metro Atlanta can’t be ruled out.
Keep in mind I only forecast for the Atlanta area not the mountains.
Here is where the National Weather Service has posted the WINTER WEATHER ADVISORY:
Current best guesstimate of snowfall accumulation (subject to change in future updates overnight and Saturday):
History tells us when it comes to snow always expect LESS or none in Metro Atlanta, that happens more often than the other way around.
The average of multiple models is much less:
PROBABILITY OF SOME KIND OF PRECIP A TENTH INCH OR MORE REGARDLESS OF TYPE:
JUST ONE MODELS IDEA AT 10AM (don’t take literally) Pivotalweather chart:
NOTICE GOOD AGREEMENT ON THE RAIN/SNOW LINE IN THE MODEL OUTPUT:
Always expect the unexpected. Plan for the worse hope for the best. Can’t go wrong with that formula in weather or anything else.
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