Likely due to the large increase in snow amounts from Arkansas to Virginia. Almost laughable change and I’m not sure if I believe that much...may be a bit too much if you go back compare the change in snow maps with the first system.
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Pattern The Great December Dump
- Thread starter Rain Cold
- Start date
Blue_Ridge_Escarpment
Member
No change from 12Z. Almost carbon copy.
Hmm CMC with a consistent ice storm now for something coming up on 3-4 days out ... Gfs slowly begins to show some sort of ice for CAD regions .. euro has great high pressure placement for CAD but no precip around... maybe with this new modeling of better sampling of the system plus the thump of snow soon to be covering us to the north... maybe models are under doing CAD like usual ... Gfs warm bias .. euro dry precip bias ... and icon both biases .. should be interesting to continue monitoring .. I’m sure some will be staying up for the EURO
Could this be due to it being sampled now that it’s over land
Well, this is actually Wave number 2 that the CMC is showing, very similar to the miller B composite @Webberweather53 made, tad stronger “confluence” this run, ridge axis extending into the GLs, nice closed low in south Texas completely closed off, don’t really have to worry about separation with that, only issue is if we’re gonna see a winter storm with this energy, your threading a microscopic needle Becuase there’s barely any confluence, just got that high pressure to your north sliding along, 00z CMC makes it work 
WxBlue
Meteorologist
Northerners never like using ICON for their winter events anyway... so I wouldn't put too much weight on that model.
Not according to tropical tidbits. I didn’t look into the fine details but there is a HUGE difference.
Yeah it’s warm biased at times to, and just is flat out weird, remember last winter in showed what looked like a hurricane in the gulf in the winter, lmfao
WxBlue
Meteorologist
Exactly.
RGEM turned out to be a decent model... but it's only out to 48 hours. That's too bad.
Blue_Ridge_Escarpment
Member
If you’re looking at snow accumulation maps, don’t. For a mixed event, it will be worthless.
Yeah, RGEM can sniff out things, just sometimes over here in CAD areas it shows insane ice storms that don’t verify, but other than that it’s decent
GEFS looks like it might have had another uptick in totals in some places. I’ll post when it gets a little farther out
I doubt it this is the CMC after all which I use to nick name consistently wrong or consistently making cyclones. I’m only using it to spot any trends and to kill time until the euro. I think to some degree it’s right and wrong at the same time. Probably overkill on amounts but trending to a better onset mix.
It will be interesting to verify the CMC with short range models once it gets within 84 hours. I'm going to save the model images from the CMC to work off of to help of the creation of my predictions.
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GEFS looks a little more bullish with ice, but every single member still changes it to rain, but every single member now shows onset icing, and some look more aggressive with it 
I’m only comparing the snowpack prior to CAD setup. Which is snow to our west and north. Not ice or mix.
WxBlue
Meteorologist
I'm really curious to see how RGEM will handle a southern event. It did pretty well with northern events when I was in New Hampshire last couple winters. Sadly, we'll have to wait until it's inside 48 hours to use it.
18z
00z
00z
Guys.. about that CMC...
Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1134 PM EST Sun Dec 08 2019
Valid Dec 09/0000 UTC thru Dec 12/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
12Z Model Evaluation with Preferences and Forecast Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...Eastern CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-CMC blend favoring ECWMF then GFS in blend
Confidence: Slightly above average
The global scale deep latitude trof is taking a more phased shape
currently as presented by GOES-WV suite. The model guidance
appears to have come into stronger consensus with respect to the
timing of the northern stream shortwave and point where the
southern stream shortwave decouple late Monday into Tues...and
show strong timing/amplitude agreement aloft which translates to
solid agreement in the depth/track of the surface wave and cold
front. By late Tuesday, though the 12z CMC starts to fall out of
tolerance in both the northern and southern stream. The southern
stream, it is a bit stronger but also evolves into a more
compact/deeper solution while the remaining sheared energy slides
through the Appalachians into the Northeast in the other
solutions. The 00z GFS and 12z ECMWF are in fairly solid
agreement with only moderate differences noted in QPF. The 00z
NAM shows a bit stronger inflection in this energy lifting through
the Mid-Atlantic into the Northeast by end of Day 3 which is
solid, but may be too wet, especially given the likely dynamic
cooling, and potentially producing a bit too much snow...so a
GFS/ECMWF solution is generally more favored but some localized
inclusion of the UKMET/NAM may be employed if desired.
Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1134 PM EST Sun Dec 08 2019
Valid Dec 09/0000 UTC thru Dec 12/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
12Z Model Evaluation with Preferences and Forecast Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...Eastern CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-CMC blend favoring ECWMF then GFS in blend
Confidence: Slightly above average
The global scale deep latitude trof is taking a more phased shape
currently as presented by GOES-WV suite. The model guidance
appears to have come into stronger consensus with respect to the
timing of the northern stream shortwave and point where the
southern stream shortwave decouple late Monday into Tues...and
show strong timing/amplitude agreement aloft which translates to
solid agreement in the depth/track of the surface wave and cold
front. By late Tuesday, though the 12z CMC starts to fall out of
tolerance in both the northern and southern stream. The southern
stream, it is a bit stronger but also evolves into a more
compact/deeper solution while the remaining sheared energy slides
through the Appalachians into the Northeast in the other
solutions. The 00z GFS and 12z ECMWF are in fairly solid
agreement with only moderate differences noted in QPF. The 00z
NAM shows a bit stronger inflection in this energy lifting through
the Mid-Atlantic into the Northeast by end of Day 3 which is
solid, but may be too wet, especially given the likely dynamic
cooling, and potentially producing a bit too much snow...so a
GFS/ECMWF solution is generally more favored but some localized
inclusion of the UKMET/NAM may be employed if desired.
GFS has statistically been worse than the CMC, but it’s likely wayyyyy out to lunch showing a all out ice storm, and it has issues with CAD, but anyways light/moderate ice to rain for CAD areas seems likely right now