BufordWX
Member
By the way, NAM is showing temperatures in the upper 20s across North GA as the precipitation moves in.
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Wintry 1/9-12 Winter Potential Great Dane or Yorkie
- Thread starter SD
- Start date
Are you crazy? Of course I do.
As always, gotta be cautious of mixing on the southern edge with these, but mainly use them for trends
ICON coming in with the heat this morning 
packfan98
Moderator
packfan98
Moderator
Found the Kuchera on pivotal. Nice!
You, Grit and others dedication to this thread is amazing. Couldn’t sleep and knew you guys would still have pbp for the morning data
Back to lurking …
AI Euro 850 temps. You don't want to be bumping up close to this 0 deg line for all snow. But 1) these have been trending a little colder save maybe parts of E NC, and 2) it looks like a situation where most of the meaningful precip is done before the temps rise to danger levels along that transition line
rburrel2
Member
For the upstate, the danger zone of flipping to sleet is from the 650-750mb level temps Friday night.that will only occur after the front end thump happens though, if it does at all… but it certainly will somewhere… maybe i85 south in sc
Normally pick niece up at 3pm on Fridays in Durham for weekends in Concord. Should I change that time to earlier?
Woke up for work at 3:45. Just taking a look at everything. Wow. 
I was confused on the Morristown update. They have increased their confidence with heavier snow it would seem. In the same paragraph they mention less QPF reaching the area showing on models.They were touting more snow, as in 2-6" a good possibility, but with less QPF, talking it down in the next sentence. I'm guessing they're counting on higher ratios but less QPF with their wording.
Sent from my SM-S916U using Tapatalk
I was confused on the Morristown update. They have increased their confidence with heavier snow it would seem. In the same paragraph they mention less QPF reaching the area showing on models.They were touting more snow, as in 2-6" a good possibility, but with less QPF, talking it down in the next sentence. I'm guessing they're counting on higher ratios but less QPF with their wording.
Sent from my SM-S916U using Tapatalk
Yeah, I just know that if you are getting close at 850, the levels above that are probably warmer.
One thing I've noticed is that the Euro AI soundings on Pivotal have some issues. At 00z Sat, the temp in Charlotte is 25 on the Euro AI sounding on Pivotal, but 28 on the Pivotal map and 29 on the WBell map. So, be leary with some of the sounding data / double check it
For the AI, on the last 3 run trend here, we can see that the trough has bumped a little less positive tilt, but it makes up for it with more energy falling into the trough (stronger, deeper trough) which lowers the height lines....along with that, the 50/50 low is bumping west - so that combo counteracts the less positive tilt action. You can see that the height lines thru GA to NC really don't change, so temps aren't climbing in this trend - and the stronger, deeper wave with less positive tilt yields more precip
This is the Euro Graphcast AI Ensemble Mean for precip totals to Sunday morning. There are very limited maps for the ensemble on SV - this is probably the best info we have on that model on SV for viewing. But you can see the increasing totals overall
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Gfs is slowly caving at H5. Very slowly 
packfan98
Moderator
The low track on this run was about 50 miles further east. Quite a bit drier though so the winter weather doesn’t look as impressive. Take a blend of all the models right now, and a lot of us would be happy.
rburrel2
Member
The Euro AI has been consistent for like 4 days now starting this event around 6-7am at my house. The GFS is the only one close to that with a start time of around 8am. Every other model starts precips between 2-5pm Friday afternoon. Wonder who's going to win here?
I'm rooting for a 6am start time b/c the temp/dews would be like 32/15 then... Just feel like we'd wetbulb down to the mid 20's quickly in that scenario which would be dreamy. If it doesn't start until 3pm I could see us at like 42/15 and only wetbulbing down to 29 or 30.
I'm rooting for a 6am start time b/c the temp/dews would be like 32/15 then... Just feel like we'd wetbulb down to the mid 20's quickly in that scenario which would be dreamy. If it doesn't start until 3pm I could see us at like 42/15 and only wetbulbing down to 29 or 30.
| Model | Run Cycle | precip start |
| icon | 12z jan6 | 4pm friday |
| gfs | 12z jan6 | 9am friday |
| CMC | 12z jan6 | 5pm friday |
| ukmet | 12z jan6 | 5pm friday |
| euro | 12z jan6 | 3pm friday |
| euro ai | 12z jan6 | 5am friday |
| icon | 18z jan6 | 11am friday |
| gfs | 18z jan6 | 9am friday |
| euro | 18z jan6 | 1pm friday |
| euro ai | 18z jan6 | 6am friday |
| icon | 00z jan7 | 2pm friday |
| gfs | 00z jan7 | 9am friday |
| cmc | 00z jan7 | 2pm friday |
| euro | 00z jan7 | 2pm friday |
| euro ai | 00z jan7 | 6am friday |
| icon | 06z jan7 | 2pm friday |
| gfs | 06z jan7 | 8am friday |
iGRXY
Member
It’s still hilarious to me that the Icon is the middle ground between the more positively tilted and more negatively tilted troughs and you see the result. I promise if we luck into another 6-10” storm I will sthu about no snow once every 3 years going forward lol
Flo
Member
Everyone but CAE. Good thing I have to go to charlotte Friday anyway.
rburrel2
Member
Dude i'm so stoked. I can't sleep. I'm just waiting for something to go wrong at this point. This is easily the best 4 day threat of my lifetime for my backyard. February 2014 was probably the next best and that one went horribly horribly wrong for me. January 2011 didn't have this much high end potential, imo.
It feels like the only uncertain thing at this point is if we change over to sleet, and if we do, how much front end snow do we get. Seems like realistically we should get 4-6 before a changeover even if the most extreme amped solutions verify.
iGRXY
Member
What’s nice is most of the models are at or near barely above freezing most of the day regardless of start time. The airmass is getting colder and colder in response to snow pack to the north (shout out to Webber) and a stronger 50/50 trending further west
Good for you for remaining rock solid with the positivity. Not saying we can’t trend to a disaster, but you’ve been probably the most consistent as far as vibes since tracking this storm. Respect.
Bigedd09
Member
Loving the trends overnight! Honestly would be nice to get the GFS on our side though lol
Forevertothee
Member
Peachtree City (ATL)
An Arctic surface high will have settled over the Southeast at
the start of the period. As such, the coldest temperatures of the
week ahead will likely be seen on Thursday morning with upper
teens across much of north Georgia and low 20s elsewhere. Highs on
Thursday will struggle to rebound, reaching the upper 30s to low
40s in north Georgia to near 50 in the far southern tier.
Moving into the late week, the elephant in the room remains the
increasing likelihood of wintry precipitation across portions of
the area by Friday. As an upper trough deepens over the center of
the country, it will phase with an upper cutoff low over the Baja
of California and push eastward, leading to the development of a
surface low over the northern Gulf of Mexico. This low will lift
northeastward Thursday night into Friday, and moisture will begin
to overspread the CWA during the day Friday. With antecedent cold
temperatures in place, frozen precipitation is likely to occur. At
onset, light snow is most likely to be the ptype across north
Georgia with rain/snow mix more likely farther south. Through the
day Friday into Friday night, the ptype will become more of a
mixed bag as WAA advection aloft intensifies. Some degree of
transition in ptype is likely as the event progresses, with rain
becoming more likely farther south with a transition to some mix
of snow, sleet, and/or freezing rain across north Georgia. Thus,
accumulation details remain fuzzy at this time, though
accumulating snow is likely across north Georgia with at least a
glaze (or more) of freezing rain within the transition zone also
appearing more likely as well. Prepare now for the increasing
likelihood of a messy winter weather scenario Friday through
Saturday morning that would affect travel, especially along and
north of I-20, though some impacts will be possible farther south.
Additionally, should more freezing rain become dominant, an
increased impact to utilities could become more of a concern.
Impactful precipitation will come to an end by midday Saturday as
the system exits eastward. Temperatures will, however, be slow to
warm, with highs likely struggling to warm into the mid to upper
30s by Saturday afternoon. Transportation issues could linger,
particularly again Saturday night when subfreezing temperatures
will lead to refreezing. Below normal temperatures will then
continue into next week with highs largely in the 40s in north
Georgia to 50s in central Georgia and lows remaining well below
freezing.
An Arctic surface high will have settled over the Southeast at
the start of the period. As such, the coldest temperatures of the
week ahead will likely be seen on Thursday morning with upper
teens across much of north Georgia and low 20s elsewhere. Highs on
Thursday will struggle to rebound, reaching the upper 30s to low
40s in north Georgia to near 50 in the far southern tier.
Moving into the late week, the elephant in the room remains the
increasing likelihood of wintry precipitation across portions of
the area by Friday. As an upper trough deepens over the center of
the country, it will phase with an upper cutoff low over the Baja
of California and push eastward, leading to the development of a
surface low over the northern Gulf of Mexico. This low will lift
northeastward Thursday night into Friday, and moisture will begin
to overspread the CWA during the day Friday. With antecedent cold
temperatures in place, frozen precipitation is likely to occur. At
onset, light snow is most likely to be the ptype across north
Georgia with rain/snow mix more likely farther south. Through the
day Friday into Friday night, the ptype will become more of a
mixed bag as WAA advection aloft intensifies. Some degree of
transition in ptype is likely as the event progresses, with rain
becoming more likely farther south with a transition to some mix
of snow, sleet, and/or freezing rain across north Georgia. Thus,
accumulation details remain fuzzy at this time, though
accumulating snow is likely across north Georgia with at least a
glaze (or more) of freezing rain within the transition zone also
appearing more likely as well. Prepare now for the increasing
likelihood of a messy winter weather scenario Friday through
Saturday morning that would affect travel, especially along and
north of I-20, though some impacts will be possible farther south.
Additionally, should more freezing rain become dominant, an
increased impact to utilities could become more of a concern.
Impactful precipitation will come to an end by midday Saturday as
the system exits eastward. Temperatures will, however, be slow to
warm, with highs likely struggling to warm into the mid to upper
30s by Saturday afternoon. Transportation issues could linger,
particularly again Saturday night when subfreezing temperatures
will lead to refreezing. Below normal temperatures will then
continue into next week with highs largely in the 40s in north
Georgia to 50s in central Georgia and lows remaining well below
freezing.
rburrel2
Member
Somebody pinch me...
Clemson, SC
2.7 inch ECMWF Ens mean
3.9 inch GEFS mean(increased from 00z run)
2.6 inch CMC Ens mean
Clemson, SC
2.7 inch ECMWF Ens mean
3.9 inch GEFS mean(increased from 00z run)
2.6 inch CMC Ens mean
Forevertothee
Member
GSP (Greenville-Spartanburg) NWS
As of 315 am Tuesday: A positively tilted short wave trough is
forecast to sweep across the Southeast early in the period. As a
consequence, cyclogenesis is expected along the Texas Coast Thu
night, which will then progress along the rest of the Gulf Coast
Friday through early Saturday before moving into the western
Atlantic in "Miller-A" cyclone fashion. Confidence continues to
increase that this feature will pass close enough to our forecast
area for moisture and frontogenesis to impact the CWA...with wintry
weather likely for at least a portion of the area. The ECMWF remains
the weaker/more suppressed solution...and therefore stingiest with
precip. Meanwhile, the latest versions of the Canadian and GFS are
actually remarkably similar in their solutions...suggesting at least
some wintry weather for virtually the entire CWA...with significant
accumulations possible. Enough cold/dry/low wet bulb surface air
will likely be in place for precip to begin as light snow Friday
afternoon, with a transition to rain/freezing rain possible as warm
advection pushes a warm nose into the area toward the end of the
event Fri night. The most likely locations to see significant wintry
weather will be along/north of the I-85 corridor, but to repeat:
some wintry weather is likely in all areas, and significant accums
can`t be ruled out anywhere.
Otherwise, dry and cold weather will return for the latter half of
the weekend, as temperatures remain around 10 degrees below normal.
Some modification of the air mass may result in a warming trend by
Monday, but temps are still expected to be around 5 degrees below
climo Mon afternoon.
As of 315 am Tuesday: A positively tilted short wave trough is
forecast to sweep across the Southeast early in the period. As a
consequence, cyclogenesis is expected along the Texas Coast Thu
night, which will then progress along the rest of the Gulf Coast
Friday through early Saturday before moving into the western
Atlantic in "Miller-A" cyclone fashion. Confidence continues to
increase that this feature will pass close enough to our forecast
area for moisture and frontogenesis to impact the CWA...with wintry
weather likely for at least a portion of the area. The ECMWF remains
the weaker/more suppressed solution...and therefore stingiest with
precip. Meanwhile, the latest versions of the Canadian and GFS are
actually remarkably similar in their solutions...suggesting at least
some wintry weather for virtually the entire CWA...with significant
accumulations possible. Enough cold/dry/low wet bulb surface air
will likely be in place for precip to begin as light snow Friday
afternoon, with a transition to rain/freezing rain possible as warm
advection pushes a warm nose into the area toward the end of the
event Fri night. The most likely locations to see significant wintry
weather will be along/north of the I-85 corridor, but to repeat:
some wintry weather is likely in all areas, and significant accums
can`t be ruled out anywhere.
Otherwise, dry and cold weather will return for the latter half of
the weekend, as temperatures remain around 10 degrees below normal.
Some modification of the air mass may result in a warming trend by
Monday, but temps are still expected to be around 5 degrees below
climo Mon afternoon.
Forevertothee
Member
CAE (Columbia)
High confidence in a storm system impacting the region Friday
into early Saturday.
- Low but increasing confidence in a period of wintry
precipitation for portions of forecast area Friday Night.
- Cold and dry weather resumes Sunday and Monday.
Confidence remains high that an area of low pressure will
develop in the GOMEX and track northeast towards the forecast
area on Friday as the system gets picked up by a potent trough
emerging from the Central CONUS. Friday begins cold and dry with
PWATs ranging from 0.25 to 0.75 inches at daybreak. While rain
chances will increase as the day goes on, it will likely take
some time for the entire column to saturate and precipitation
to reach the ground. Current thinking is that it will be rain at
the onset of the event but temperatures will decrease in the
evening opening up the possibility of frozen precipitation
types.
The exact track of the surface cyclone, the strength of the
upper trough, and the depth of the cold air in place over the
area during the event are all factors that will determine the
precipitation type or types that a location sees. So while the
probability of precipitation Friday Night is high, 70 to 80
percent, it is too early to determine what, if any, type of
frozen precipitation (snow, sleet, or freezing rain) will fall.
The most concerning possibility resembles the 00Z Canadian
where the storm tracks to our south and shallow cold air near
the surface is difficult to erode, resulting in freezing rain
in areas that have temperatures at or below 32 degrees. Due to
the level of uncertainty, opted for a wintry mix (in areas with
subfreezing temperatures) where rain could mix with or change
over to snow and/or freezing rain depending on the storm track.
As is typical with these events, confidence in mixed
precipitation is highest north and west of I-20, with a sharp
cutoff possible to the south and east.
The storm quickly pulls away from the region on Saturday, being
replaced by high pressure building in from the west. However, this
air mass does not appear to have the origins as the one
currently settling in. This combined with southwesterly flow
aloft, should result in slightly warmer temperatures on Sunday
and Monday under sunny to mostly sunny skies.
High confidence in a storm system impacting the region Friday
into early Saturday.
- Low but increasing confidence in a period of wintry
precipitation for portions of forecast area Friday Night.
- Cold and dry weather resumes Sunday and Monday.
Confidence remains high that an area of low pressure will
develop in the GOMEX and track northeast towards the forecast
area on Friday as the system gets picked up by a potent trough
emerging from the Central CONUS. Friday begins cold and dry with
PWATs ranging from 0.25 to 0.75 inches at daybreak. While rain
chances will increase as the day goes on, it will likely take
some time for the entire column to saturate and precipitation
to reach the ground. Current thinking is that it will be rain at
the onset of the event but temperatures will decrease in the
evening opening up the possibility of frozen precipitation
types.
The exact track of the surface cyclone, the strength of the
upper trough, and the depth of the cold air in place over the
area during the event are all factors that will determine the
precipitation type or types that a location sees. So while the
probability of precipitation Friday Night is high, 70 to 80
percent, it is too early to determine what, if any, type of
frozen precipitation (snow, sleet, or freezing rain) will fall.
The most concerning possibility resembles the 00Z Canadian
where the storm tracks to our south and shallow cold air near
the surface is difficult to erode, resulting in freezing rain
in areas that have temperatures at or below 32 degrees. Due to
the level of uncertainty, opted for a wintry mix (in areas with
subfreezing temperatures) where rain could mix with or change
over to snow and/or freezing rain depending on the storm track.
As is typical with these events, confidence in mixed
precipitation is highest north and west of I-20, with a sharp
cutoff possible to the south and east.
The storm quickly pulls away from the region on Saturday, being
replaced by high pressure building in from the west. However, this
air mass does not appear to have the origins as the one
currently settling in. This combined with southwesterly flow
aloft, should result in slightly warmer temperatures on Sunday
and Monday under sunny to mostly sunny skies.
rburrel2
Member
I'm glad I don't live in Texas. They keep losing the storm jackpot inch by inch. Looking like Southern Arkansas or possibly somewhere in NGA/SW NC/upstate SC is the place to be.
packfan98
Moderator
Very interesting thoughts about less potential ice amounts from the NWS office in Raleigh. Leaning on the more traditional Miller A "snow or NO" guidelines backed up with looking at current soundings it sounds like:
Leaning on cluster analysis from 12z grand ensemble highlights the
most likely scenario accounting for nearly half of EPS, GEFS, and
GEPS members, which is a very high percentage at this time range.
This most likely scenario features a positively tilted trough axis
stretching from the Great Lakes to the ArkLaTex region that slides
eastward with the trough axis approaching the East Coast through Sat
evening. This mid/upper pattern would support a Miller A low
developing over the northern GOM Fri evening and moving ENE through
the Southeast and off the NC coast into the western Atlantic by Sat
evening. Typically with Miller A surface low tracks, p-type
distribution is mostly rain/snow with a narrow corridor of mixed p-
type separating the two regimes. Point soundings analysis from the
deterministic 00z GFS and ECMWF confirm this p-type configuration.
Planer plots of p-type on deterministic guidance have been too
aggressive with the freezing rain area as point soundings in these
regions show mostly isothermal layer around 0C that would still be
capable of producing wet snow aggregates and fleeting sleet. The
biggest question mark, and one most people would like to know, is
where the rain/snow line will set up, and there are still too many
uncertainties with the finer details of the forecast to say with any
reasonable/responsible sense of certainty. Latest forecast leans on
climatology based on the forecast low track and highlights an
initial period of snow areawide with the rain/snow line migrating
northward towards the climatologically favored I-85 corridor with
precipitation coming to and end from west to east from 18z Sat to
00z Sun.
Leaning on cluster analysis from 12z grand ensemble highlights the
most likely scenario accounting for nearly half of EPS, GEFS, and
GEPS members, which is a very high percentage at this time range.
This most likely scenario features a positively tilted trough axis
stretching from the Great Lakes to the ArkLaTex region that slides
eastward with the trough axis approaching the East Coast through Sat
evening. This mid/upper pattern would support a Miller A low
developing over the northern GOM Fri evening and moving ENE through
the Southeast and off the NC coast into the western Atlantic by Sat
evening. Typically with Miller A surface low tracks, p-type
distribution is mostly rain/snow with a narrow corridor of mixed p-
type separating the two regimes. Point soundings analysis from the
deterministic 00z GFS and ECMWF confirm this p-type configuration.
Planer plots of p-type on deterministic guidance have been too
aggressive with the freezing rain area as point soundings in these
regions show mostly isothermal layer around 0C that would still be
capable of producing wet snow aggregates and fleeting sleet. The
biggest question mark, and one most people would like to know, is
where the rain/snow line will set up, and there are still too many
uncertainties with the finer details of the forecast to say with any
reasonable/responsible sense of certainty. Latest forecast leans on
climatology based on the forecast low track and highlights an
initial period of snow areawide with the rain/snow line migrating
northward towards the climatologically favored I-85 corridor with
precipitation coming to and end from west to east from 18z Sat to
00z Sun.
06z ukmet looked even better. More suppressed height field in the SE, stronger northern stream dropping down into the northern tier of the U.S. 
iGRXY
Member
One thing I really am liking what I’m seeing here is you can really see the higher resolution model like the ICON picking up on that front end thump that looks a lot more realistic to Jan 2022 while your surface low is still down in Florida. The entire column is very safe from WAA at this point.
It is worth noting that those temps are during near-peak daytime heating too.
tennessee storm
Member
Like my area sw Tennessee
rburrel2
Member
This airmass is really dry and really cold in the mid-levels. The front end thump will over perform I think. I'm expecting places like Atlanta/Augusta and maybe even columbia to get in on the front end before transitioning.
iGRXY
Member
The S/W in the south west was their jackpot H5 association with the storm. Now that you’re pushing that back further east they’re losing the the natural cold production and the orientation of the trough is allowing warmer air to pump in from the south before it gets a fresh injection of cold air from the N/S. Those of us further east have more time to allow that injection of colder air to happen and we have the luck of being closer to the confluence and snowpack with CAD.
rburrel2
Member
Yep... They've paid the price for our good trends over the last day or so.
CNCsnwfan1210
Member
Snowman63
Member
Yep, Global Ensembles and NBM have the highest mean totals in South Central AR, West/Middle TN, and North Miss.
The precip maps do not show it, but the Icon is extremely close to an absolute sleet storm across the CAD areas of east AL into GA.
tennessee storm
Member
Atlanta going have some mixing issue as most north Georgia