Jump to content
  • Forum Image
NorthGeorgiaWX

Potential Winter Threat - December 6-11

Recommended Posts

It's always about timing. We'll see if that high to the north of us can get in just the right position to help us out. I'm still not seeing a large CAD signal though

Share this post


Link to post
Share on other sites
55 minutes ago, KingOfTheMountains said:

Very few models show us going back to cold rain once things set in heavy Saturday night. For the most part flipping between different wintry precious at times. And right now the trend is our friend on the short term models, the globals, and their ensembles.

Definitely agree from another Rabunite. The NAM which was very aggressive on the freezing rain yesterday is definitely trending that way. The soundings look interesting to support that claim as well. 

Share this post


Link to post
Share on other sites

NWS Atlanta - Friday AM

Quote

LONG TERM /Saturday Night through Thursday/...

Attention turns to winter storm potential for Sat night into Sun
and unfortunately, still seeing a wide array of model solutions.
We are just beginning to see some of the hi res guidance entering
into the picture for this time period and not surprisingly, they
are a little more bullish in developing and maintaining the wedge
for this event. GFS on the other hand holds onto almost none of
the cold air and keeps most all areas above freezing and
consequently no ice accretion. ECMWF is somewhat of a middle
ground of the guidance and at least indicates some ice potential
for the forecast area.

It is always a tough call with dynamics suggesting a relatively
quick erosion of wedge and diabatic processes suggesting it may
hold longer than models suggest. For this cycle, we have favored
the NAM12 blended with some hi res guidance which does allow for
some below freezing temps for the NE corridor. This occur mainly
after 06Z Sun over Towns and White but does spread all the way
into the NE metro by 12Z. QPF values continue high, so would not
take long to see issues assuming we do remain below freezing in
those locations.

We may prove in the end to be too high with our
ice accretions but are advertising a shade over a tenth of an inch
of ice for this event. This would be below warning criteria but we
are also anticipating some snow and sleet at higher elevations as
well. The areas that have the most overlap of ice and snow are
Towns, White, Union and Lumpkin counties and will be issuing a
watch with this issuance for those locations. It should be noted
that most locations North of I20 and east of I75 are only a degree
or two away from also seeing significant icing issues so please
stay tuned for any changes to the forecast.

Still anticipating multiple shortwaves both Sun night and Mon
night to affect the area. Colder temps aloft will allow for a
rain/snow mix Sun night and snow showers Mon night. QPF by this
time period is quite low and accumulations should be confined to
the higher elevations once again.

20

Hydrology...

Storm total QPF continues to increase for this event with values
over 3 inches now anticipated. This would likely produce some
localized flooding issues, especially with recent rains and
saturated grounds. Will let day shift issue watch as we still have
some time until heaviest of the activity begins.

 

  • Like 1

Share this post


Link to post
Share on other sites

Since the Atlanta NWS is putting some credence int he 12km NAM, here's a loop showing the progression of the precipitation. It appears that after midnight Saturday and into Sunday morning will be the best chance for frozen precipitation. 

Share this post


Link to post
Share on other sites
25 minutes ago, Preston said:

Definitely agree from another Rabunite. The NAM which was very aggressive on the freezing rain yesterday is definitely trending that way. The soundings look interesting to support that claim as well. 

I just don't see the temps playing along. I expect we will see 2-4 inches fall, but by Sunday 6-8:00 PM, I think much will have washed away depending on how much actually does stick to begin with. And the NAM has a consistent history of overdoing moisture and types. I think we will transition to snow at some point early sunday morning (and that greatly depends on your definition of early morning) but will then transition back and forth between sleet and snow by mid morning before taking a turn towards rain. Right now, the temps that we are looking at do not support a dumping.

Share this post


Link to post
Share on other sites

Those in the NE corner of Georgia, especially the following counties:

  • Rabun
  • Towns
  • Union
  • White
  • Habersham
  • Lumpkin

You my friends,  are going to have a mess. All modes of winter weather will be possible and for an extended length of time. For that matter, those of you within that purple line better be prepared as well, this is a very dicey winter setup  that can surprise people VERY quickly. Power outages due to downed trees as well as icy roads will be a major impact.

Ice will be the biggest impact, and it doesn't take much to cause issues. There are pros and cons to the heavy and lengthy precip that's coming... the pro is that heavy warm rain is more difficult to accumulate. The bad part is that there is that much more to accumulate, and over a long period of time, it could start to add up. 

This is a quickly changing forecast, so please check back for the most recent updates. And now, with the low on a more southerly track, the forecast could and probably will change again. 

image1-07.png.ee45d0839a08262eda12cb2e226715ed.png

  • Thanks 1

Share this post


Link to post
Share on other sites
Quote

...FLOOD WATCH IN EFFECT FROM SATURDAY MORNING THROUGH SUNDAY
EVENING...

The National Weather Service in Peachtree City has issued a

* Flood Watch for North and Central Georgia.

* From Saturday morning through Sunday evening

* A strong storm system will spread rain across north and central
  Georgia tonight and continuing into Sunday. Some of the rain
  could be heavy late Saturday and Saturday night. Total rainfall
  of 2 to 3 inches is expected across the watch area with isolated
  higher amounts.

* The ground across north and central Georgia remains saturated
  from recent rains. Some rivers and creeks are already running
  high. Any additional heavy rain will result in high runoff,
  potentially causing some rivers and creeks to rise above flood
  stage. High water may not recede until well after the rains end.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Watch means there is a potential for flooding based on
current forecasts.

You should monitor later forecasts and be alert for possible
Flood Warnings. Those living in areas prone to flooding should be
prepared to take action should flooding develop.

 

Snap34564-07.thumb.jpg.2dbd0f2e9c933ef523ea3858997fe26f.jpg

Share this post


Link to post
Share on other sites
6 minutes ago, NorthGeorgiaWX said:

Those in the NE corner of Georgia, especially the following counties:

  • Rabun
  • Towns
  • Union
  • White
  • Habersham
  • Lumpkin

You my friends,  are going to have a mess. All modes of winter weather will be possible and for an extended length of time. For that matter, those of you within that purple line better be prepared as well, this is a very dicey winter setup  that can surprise people VERY quickly.

Ice will be the biggest impact, and it doesn't take much to cause issues. There are pros and cons to the heavy and lengthy precip that's coming... the pro is that heavy warm rain is more difficult to accumulate. The bad part is that there is that much more to accumulate, and over a long period of time, it could start to add up. 

This is a quickly changing forecast, so please check back for the most recent updates. And now, with the low on a more southerly track, the forecast could and probably will change again. 

image1-07.png.ee45d0839a08262eda12cb2e226715ed.png

So begins MessWatch 2018. 

Since this is my first post, I should say hello. Lumpkin County resident here who's...well, watching.

:)

  • Like 2

Share this post


Link to post
Share on other sites

Tennessee is now getting in on the Winter Storm Watches

Quote

MRX WATCHES/WARNINGS/ADVISORIES...
NC...Winter Storm Watch from Saturday evening through Monday morning
     for Clay.

TN...Winter Storm Watch from Saturday evening through Monday morning
     for Blount Smoky Mountains-Claiborne-Cocke Smoky Mountains-
     Hancock-Hawkins-Johnson-Northwest Carter-Northwest Greene-
     Sevier Smoky Mountains-Southeast Carter-Southeast Greene-
     Southeast Monroe-Sullivan-Unicoi-Washington TN.

VA...Winter Storm Watch from Saturday evening through Monday morning
     for Lee-Russell-Scott-Washington-Wise.

 

  • Like 1

Share this post


Link to post
Share on other sites
1 minute ago, Tanith said:

So begins MessWatch 2018. 

Since this is my first post, I should say hello. Lumpkin County resident here who's...well, watching.

🙂

And WELCOME! 🙂 You're going to have some great nasty weather!  I even have a link where you can post all of those great winter weather pictures when it starts falling! 🙂

 

 

  • Like 5

Share this post


Link to post
Share on other sites
53 minutes ago, SlicNic13 said:

I'm spending waaay too much time on this feed lol Scouring the internet for information and updates. 

I'm running two monitors at work. One is dedicated to being productive, the other is 5 tabs of weather related nonsense 🤣

  • Like 4
  • Haha 2

Share this post


Link to post
Share on other sites
5 minutes ago, Tanith said:

So begins MessWatch 2018. 

Since this is my first post, I should say hello. Lumpkin County resident here who's...well, watching.

🙂

Welcome! I think there's a few of us in here. I'm in the SE corner by Chestatee Ford. 

  • Like 3

Share this post


Link to post
Share on other sites
23 minutes ago, kshields8426 said:

I just don't see the temps playing along. I expect we will see 2-4 inches fall, but by Sunday 6-8:00 PM, I think much will have washed away depending on how much actually does stick to begin with. And the NAM has a consistent history of overdoing moisture and types. I think we will transition to snow at some point early sunday morning (and that greatly depends on your definition of early morning) but will then transition back and forth between sleet and snow by mid morning before taking a turn towards rain. Right now, the temps that we are looking at do not support a dumping.

I would agree but until the Euro is not in our corner I am expecting more. Euro is trending colder again as I type this. Yes late sunday pm it shows us going above freezing just barely but by then the heavy precip is gone, its a drizzle at best. That is not going to wash away the amounts of snow and sleet that falls before it. And a lot of times those warm ups on the back side of storm are overdone as snowpack can help hold you a few degrees colder. If it was only the NAM I'd agree, but the GFS is frankly a warm outlier at this point. Euro, CMC, Fv3 GFS, NAM, and UKMET all have much more wintry precip. There's still time for that to change as more high resolution models get closer but until then I don't see lots of above freezing rain other than on the front end. Some mixture of snow, sleet, freezing drizzle and above freezing drizzle. How long we hold snow instead of sleet determining the amounts. More warm nose, then more sleet zr and drizzle, and vice versa.

  • Like 1

Share this post


Link to post
Share on other sites

It looks like we better get ready for a “big one” in Sky Valley with the latest projections from the NWS, not that we weren’t anyway. Crazy stuff though, 18” land may not be out of the question. 

6E6DB968-BB89-40F3-A34F-52A7B1B47EC4.png

Share this post


Link to post
Share on other sites

It's a real nail-biter. I'll be driving home to Pickens County from Callaway Sunday afternoon. Sounds like the ride could get interesting...

  • Like 1

Share this post


Link to post
Share on other sites
4 minutes ago, KingOfTheMountains said:

I would agree but until the Euro is not in our corner I am expecting more. Euro is trending colder again as I type this. Yes late sunday pm it shows us going above freezing just barely but by then the heavy precip is gone, its a drizzle at best. That is not going to wash away the amounts of snow and sleet that falls before it. And a lot of times those warm ups on the back side of storm are overdone as snowpack can help hold you a few degrees colder. If it was only the NAM I'd agree, but the GFS is frankly a warm outlier at this point. Euro, CMC, Fv3 GFS, NAM, and UKMET all have much more wintry precip. There's still time for that to change as more high resolution models get closer but until then I don't see lots of above freezing rain other than on the front end. Some mixture of snow, sleet, freezing drizzle and above freezing drizzle. How long we hold snow instead of sleet determining the amounts. More warm nose, then more sleet zr and drizzle, and vice versa.

I just think you are underestimating the warm rain that will keep us above freezing longer than it seems you give it credit for. Right now, even the NWS and others have us just barely flirting with freezing until Monday PM. I happen to agree with them. Unless something really changes, this doesn't have the making of a high water mark of wintery accumulation. Ground still not cold enough, but that could be overcome., temperatures not really diving to hard, but that could be overcome...but both? We will have to see a change. And I cannot tell you how many times I've seen people go with the Euro here and on his facebook page...only to realize that it seems to want to give us blizzards. And as we all know, the models with what they say and what hits the ground differ...a lot.

Share this post


Link to post
Share on other sites
5 minutes ago, Preston said:

It looks like we better get ready for a “big one” in Sky Valley with the latest projections from the NWS, not that we weren’t anyway. Crazy stuff though, 18” land may not be out of the question. 

6E6DB968-BB89-40F3-A34F-52A7B1B47EC4.png

Get a picture...you may be the only one with pretty snow weather. That said, 18" is probably a large stretch, but not unheard of up there.

Share this post


Link to post
Share on other sites
1 minute ago, kshields8426 said:

I just think you are underestimating the warm rain that will keep us above freezing longer than it seems you give it credit for. Right now, even the NWS and others have us just barely flirting with freezing until Monday PM. I happen to agree with them. Unless something really changes, this doesn't have the making of a high water mark of wintery accumulation. Ground still not cold enough, but that could be overcome., temperatures not really diving to hard, but that could be overcome...but both? We will have to see a change. And I cannot tell you how many times I've seen people go with the Euro here and on his facebook page...only to realize that it seems to want to give us blizzards. And as we all know, the models with what they say and what hits the ground differ...a lot.

Ground temperatures are not actually that much of a limiting factor. There is plenty of scholarly writing that all but disproves it having a substantial impact on snow totals unless they are very very warm. The initial rain falling into dry air is not a warming process, the exact opposite. It is what drives the temps down with evaporational cooling. Its not the surface temps we need to worry about so much, but the mid level temperatures. This is what will change our snow back over to sleet or rain, and the NWS has said they are expecting less of a warm nose than modeled becasue of the flat suppressed flow allowing less of a southerly flow into the region. We can still have snow and sleet with temps at 33-35, yes that will limit accumulations some. Temps don't need to dive too hard, most of our winter events happen hovering around or just below freezing anyway. I'm not saying the amounts will be much higher than what you're saying, only that once we flip over to heavy wintry precip, odds are against getting much plain rain after that, exept for drizzle once the moisture is no longer deep enough to saturate the dendritic growth zone on the back side of the storm. I'd say 4-6 snow most of the county, an inch or 2 of sleet, and a glaze of ice. Now Sky Valley, I think the NWS is right on. They should see similar conditions as the Blue Ridge Escarpment in NC, and that is going to be the bulls eye for this storm.

  • Like 1

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.

  • Who's Online   0 Members, 0 Anonymous, 8 Guests (See full list)

    There are no registered users currently online



×
×
  • Create New...