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Wintry December 28-29th Possible Winter Storm

12Z Euro is dangerously close to a significant ZR along the SE coast but there is no ZR on it. Whenever there is a sfc low such as this run shows that forms as far SE as E of central FL, the SE coast needs to be wary based on wx maps of SE coast wintry events going back to the 1870s. The main question as Stormsfury suggested for near the coast for these very rare cases is actually moisture rather than it being cold enough.
 
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Looking similar to the most recent CMC isn't a step in the right direction I don't think.

Well I would do a priceisrightfailhorn.gif or say that's it, but considering how things have gone this year I still think we don't really know what's going to happen. This is bad, within a week and still no clue.
 
CentralGAColdFront said:
GaWx, do you know how far inland the precipitation occurred during the 1922 Savannah ice storm? I'm roughly 150 miles due east of Savannah and ever so slightly latitudinally north and was wondering if this was simply confined to the coast or all of the lower half of Georgia.
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Your area likely had a significant ZR and possibly IP though probably not as hard a hit. Augusta for example had much less liquid equivalent precip than CHS-SAV.
 
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There's the difference maker, the trough over New England at day 3 is deeper than the GFS >>> more confluence >>> stretched/sheared s/w >>> more suppression
ecmwf_gfs_z500_conus_15.png
 
EURO 35° with a TD below 10° in KCHS at hour 90. Seems to want to kick up the 1st wave a little bit too but failed. May also produce some NVA behind wave 1 on Wednesday.

Sure as hell looked squashed. Much more confluence and even WNW flow ay 500mb...
 
SimeonNC said:
Any significant difference between the 12z and the 00z Euro you've seen?
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Stormsfury said:
EURO 35° with a TD below 10° in KCHS at hour 90. Seems to want to kick up the 1st wave a little bit too but failed. May also produce some NVA behind wave 1 on Wednesday.

Sure as hell looked squashed. Much more confluence and even WNW flow ay 500mb...
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The Euro didn't increase the confluence near the eastern seaboard around day 3, so this is still clearly game on. Notice the heights are actually higher over Atlantic Canada out to 78 hours which argues for a tad less confluence and less shearing on our wave.
Here's the dz500/dt plot vs the 0z run for the Euro at 78 hours.
ecmwf_z500_dt_noram_14.png
 
Webberweather53 said:
The Euro didn't increase the confluence near the eastern seaboard around day 3, so this is still clearly game on. Notice the heights are actually higher over Atlantic Canada out to 78 hours which argues for a tad less confluence and less shearing on our wave.
Here's the dz500/dt plot vs the 0z run for the Euro at 78 hours.
View attachment 2284
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We need a few more runs like this to keep us in the game, another run or two with a deeper trough over New England at day 3 would seal the deal against us and we'd have no storm. It's a tad encouraging to see that we've at least put a momentary halt to the deepening trend w/ the trough over New England on the operational Euro
 
The largest problem I see for people, is the air mass will be cold. ZR, doesn't take much to cause major problems. If we have less shearing of the wave, and we get more precipitation than expected with current runs, people are in trouble without a whole lot of warning.
 
Webberweather53 said:
We need a few more runs like this to keep us in the game, another run or two with a deeper trough over New England at day 3 would seal the deal against us and we'd have no storm. It's a tad encouraging to see that we've at least put a momentary halt to the deepening trend w/ the trough over New England on the operational Euro
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Won't take much of a lessening of the push. Just a subtle difference, totally different ball game.
 
Webberweather53 said:
We need a few more runs like this to keep us in the game, another run or two with a deeper trough over New England at day 3 would seal the deal against us and we'd have no storm. It's a tad encouraging to see that we've at least put a momentary halt to the deepening trend w/ the trough over New England on the operational Euro
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I have a feeling that this will be the trend, every other model has been showing improvement except for the CMC.
 
I know we say this on a regular basis just to keep hope alive but the reality is the next 2-3 model suites are going to be very critical to fleshing out the fate of this system. Once our s/w gets close enough to the Pacific NW and our s/w in the northern branch over central Canada gets into the dense RAOB coverage in the northern US I think we'll begin to find a solution. The spread in the models is pretty substantial for day 3-4 and just a few minor tweaks at the synoptic scale could take this from 0 to 100 & vis versa...
 
Webberweather53 said:
I know we say this on a regular basis just to keep hope alive but the reality is the next 2-3 model suites are going to be very critical to fleshing out the fate of this system. Once our s/w gets close enough to the Pacific NW and our s/w in the northern branch over central Canada gets into the dense RAOB coverage in the northern US I think we'll begin to find a solution. The spread in the models is pretty substantial for day 3-4 and just a few minor tweaks at the synoptic scale could take this from 0 to 100 & vis versa...
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It's quite scary how easy this could be a nightmare with little warning. Icon vs Euro is a ridiculous spread with precipitation totals.
 
Shawn said:
And the Euro. The Euro was a bit better initially with our wave (not great); and then went down hill... but still no precipitation.
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It's good that the confluence situation stopped getting stronger. If it continued then you could likely toss the rest of the model suite.
 
Seems like if you placed all models together, I'd say the trend was slightly better for today. I definitely wouldn't say the trend got "worse"
 
For what it's worth, the JMA was really wet.
We essentially have the GFS, it's eventually successor the FV3, the DWD-ICON (german model), GFS Ensemble, CMC Ensemble, NAM, and the JMA completely on board, the UKMET is awkwardly riding the fence but certainly looked no worse than yesterday, and the Euro is a big no but it again looked no worse than yesterday, if anything slightly better at the synoptic scale w/ less confluence near the eastern seaboard. Really need to see the EPS
 
Webberweather53 said:
For what it's worth, the JMA was really wet.
We essentially have the GFS, it's eventually successor the FV3, the DWD-ICON (german model), GFS Ensemble, CMC Ensemble, NAM, and the JMA completely on board, the UKMET is awkwardly riding the fence but certainly looked no worse than yesterday, and the Euro is a big no but it again looked no worse than yesterday, if anything slightly better at the synoptic scale w/ less confluence near the eastern seaboard. Really need to see the EPS
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Yeah I was wondering if the EPS had come out yet.
 
Webberweather53 said:
For what it's worth, the JMA was really wet.
We essentially have the GFS, it's eventually successor the FV3, the DWD-ICON (german model), GFS Ensemble, CMC Ensemble, NAM, and the JMA completely on board, the UKMET is awkwardly riding the fence but certainly looked no worse than yesterday, and the Euro is a big no but it again looked no worse than yesterday, if anything slightly better at the synoptic scale w/ less confluence near the eastern seaboard. Really need to see the EPS
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The Euro did a really poor job on the early December storm, I think only catching on about 2 days out!? And on the confluence, it's usually never as strong as modeled when we need it, hopefully it doesn't crap the bed on this storm!
 
There’s so many things in play here, you could always argue that the GFS is clueless. Is it? We don’t know yet. We can also say that the European is the best mid range model but what do you consider mid range? I say days three through seven is its wheel house so can you say well, maybe that we’re just not in its wheel house anymore at GFS might actually win. LOL I doubt it ha ha Ha ha ha. AnyWho, I think the chances are certainly lowered that I have in the last couple of days and many just maybe left out cold and dry. We don’t know that yet. I will say we should start seeing some changes in the Nam and the GFS Since they are geared to more short term Rangers versus the European
 
FFC looking more confident in wintry precip here. However, their discussion is not as confident due to the Euro drying out.
Plotter.php
 
What do yall think about the NAM this far out? I know it shows a mix over parts of SC and GA towards the 78-84hr time frame. Is it worth looking at that far out?
 
Bryce- @Midlands_Wx said:
What do yall think about the NAM this far out? I know it shows a mix over parts of SC and GA towards the 78-84hr time frame. Is it worth looking at that far out?
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For temps and thermal profiles, yes! Moisture, I'm not sure!
 
CAE says:

Area Forecast Discussion
National Weather Service Columbia SC
106 PM EST Mon Dec 25 2017

Little change in the thought that there could be some potential
wintry weather impacting the forecast area late this week due
to an arctic airmass and developing cold air damming regime.
However, uncertainty remains regarding the amount of moisture
available, the timing of precipitation onset and QPF amounts
due to inconsistencies among the medium range models handling
shortwave energy moving through the base of the upper trough.
The latest ECWMF has come in much drier for the Thur-Fri time
frame with more northwesterly 500mb flow keeping moisture to
our south while the GFS/Canadian continue to show overrunning
precipitation through the cold surface layer.

Relatively high confidence in a very cold airmass spreading
over the forecast area starting Wednesday night emanating from
a 1040mb arctic high pressure centered over southeastern Canada
and New England. Persistent northeasterly flow into the area
will usher in colder and drier air through Thursday. The ECMWF
and Canadian continue to be a bit colder than the GFS with the
near surface arctic air. Increasing clouds and light
overrunning precipitation expected to begin sometime Thursday
afternoon into Thursday evening and continue into the day on
Friday as moist southwesterly flow increases atop the near
shallow surface cold layer, in response to shortwave energy
moving through the base of an amplifying upper trough. The
operational GFS is a bit more progressive and less amplified
with this feature compared to the slightly more amplified
EC/Canadian solutions and therefore move end precipitation
earlier on the day Friday. The resulting coastal surface low
development from the GFS is weaker and further offshore than
the EC/Canadian resulting in less QPF over the forecast area.
It should be noted though that the GEFS mean QPF is about
double the operational run and more in line with the other
medium range models.
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12Z EPS is a little drier well inland than the 0Z EPS but it is about same near the SE coast as the 0Z EPS with a respectable 0.25" of what would largely be wintry. Also, it is wetter than the 12Z Euro, which had only 0.05" right along the SE coast and almost nothing further inland.
 
Has there been a situation where all the models were on board with something except the Euro and then the models dropped everything and followed the Euro?
 
RollTide18 said:
Has there been a situation where all the models were on board with something except the Euro and then the models dropped everything and followed the Euro?
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Euro ain't what it used to be! I'm glad to see some of Webbs and Larrys positive posts on how close this is to being a decent storm and how small changes in the players , can make big differences in the outcome!
 
Yeah I agree Larry the EPS actually looked better for the lowlands of SC and southern GA, virtually unchanged for areas like Macon GA, Columbia SC, & Fayetteville NC. EPS mean precip decreased in the upstate and towards RDU but there's still a considerable amount on the suite verbatim, enough to where these areas are clearly still in the game
 
deltadog03 said:
View attachment 2286 View attachment 2287 View attachment 2288 I know it only goes out 48 hours but here is the rgem
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RGEM's thermal profile for parts of the Atlanta metro actually looks good for snow/sleet. 850s are either at or slightly above 0c. Not sure if future frames will push the 850mb 0c isotherm back north as the precip moves in, but it looks a lot like what the CMC did before it lost all of it's precip, at least temperature wise. RGEM is pretty solid when it comes to warm noses and the thermal profile of the column.
 
Webberweather53 said:
Yeah I agree Larry the EPS actually looked better for the lowlands of SC and southern GA, virtually unchanged for areas like Macon GA, Columbia SC, & Fayetteville NC. EPS mean precip decreased in the upstate and towards RDU but there's still a considerable amount on the suite verbatim, enough to where these areas are clearly still in the game
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I haven't looked but what is the mean amount near MCN? And that corridor
 
Webberweather53 said:
Yeah I agree Larry the EPS actually looked better for the lowlands of SC and southern GA, virtually unchanged for areas like Macon GA, Columbia SC, & Fayetteville NC. EPS mean precip decreased in the upstate and towards RDU but there's still a considerable amount on the suite verbatim, enough to where these areas are clearly still in the game
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Any maps?
 
Well, from all I have read today, looks like for here it's riding the fine line between nothing or a big deal. That seems to be it always goes here lately.
 
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