North Georgia Winter Storm Threat 2/15-2/18 UPDATE

Good afternoon everyone.

I’m watching the latest run of the Euro come out as I type this (and listening to some Bobby Darin, FWIW) and there is a lot to talk about. I can say with certainty that my confidence for a major winter storm, and possibly major ice storm, is going up considerably. The latest runs of all the major models show winter weather, in the form of snow and ice, impacting the region beginning as early as 7AM Monday, but more likely around noon Monday, and lasting through the afternoon and overnight hours. There is some uncertainty in regards to a second wave of precip on Tuesday, and I have mentioned that down below. I have the system broken down similar to yesterday below, where I’ll go over timing, precip types and amounts, and my first call maps. In the short term, don’t forget  there is a wind chill advisory in effect from midnight through noon tomorrow, and highs tomorrow likely won’t break freezing for much of the area, especially those in and close to the higher elevations.

TIMING: Somewhat surprisingly, there is still a bit of doubt in regards to the exact timing of the precip arrival. This is partly due to the differences in the models otherwise, but the general consensus at this point is to expect the first precip to begin working into the area by early Monday morning, around 7AM, with full coverage by mid-day.

GFS Valid 1PM Monday

The precipitation should last all afternoon and through much of the overnight, with some lingering snow showers as far as Wednesday morning possible, depending on how exactly the “second” wave plays out (see precip type below for more on that).    So…… if you have anything to take care of regarding potential power loss, burst pipes, limbs you can safely take down ahead of time, do it today or tomorrow.

PRECIP TYPE: This will be the hardest question forecasters have to answer over the next 48 hours, because the answer will have a huge effect on the effects felt from this storm.  The Euro just came out and has ticked north with the low pressure system, allowing some rain to work into areas south of roughly Hartwell->Gainesville->Cumming. However, this is the first run it has jogged so far north and I’d like to see a bit more consistency with that solution, as well as agreement from it’s ensembles before putting too much stock in it. Even still, it shows a major ice storm for much of the area despite it’s further north track so we have a bit of breathing room from a forecasting perspective as far as a northward jog is concerned. My guess is that it is too strong with the system leading to it’s more northern track.

The NAM is slowly getting this system into it’s “good” range and has a radically stronger system and would be nothing short of catastrophic were it to verify. Verbatim, it shows a few inches of sleet/snow for most everyone, followed by a changeover to freezing rain with well over 1″ of ice falling with a good feed of cold/dry air. There is a pretty good chance that the NAM is too strong with the system, but it will certainly need to be watched.

This leads me to the solution of the CMC/GFS. Both of these models favor a further south solution than the Euro, and therefore a colder solution with the snow/freezing rain line farther south. If these models verify everyone north of a Cornelia->Clermont->Jasper  line will stay predominantly snow for much of the event, with a changeover to freezing rain and sleet mix possible during the last few hours. The rest of the area would start off briefly as snow/sleet and change to freezing rain.

My call map for predominant precip types is below, but be advised this is subject to change as we grow closer to the event.

type

PRECIP AMOUNTS: As far as just precip totals are concerned, without taking into account type, the lconsensus is somewhre in the .6-1″ range, and right now I’m leaning towards the .75-.8″ range of straight up water content. As far as how much snow/ice, which is what you people are wanting to know….

MY FIRST CALL MAPS: We are getting close to the 48 hour mark (or past it by this point for the early Monday precip) so here is a first peek at a call map for what I expect to see. Keep in mind this is a southern snow storm so things will be changing up until, and while, the precip is falling. But nevertheless, I have them broken down into snow and ice below.

ice snowmap

Again THESE TOTALS ARE SUBJECT TO CHANGE, and may go UP OR DOWN as we grow closer to the event. DO NOT treat these maps as gospel and refer to the NWS for all official information regarding this storm. 

I’ll be keeping close tabs on things as new models roll in and probably move updates over to the FB page tonight. ~TW

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