A better look at H5 if the Friday storm was still a thing, worse for a cold front.
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Pattern The Great December Dump
- Thread starter Rain Cold
- Start date
Icon just a nice cold rain Friday
Yes it is actually, that prediction map that I posted days ago is off with the overrunning. The overrunning that I predicted is likely to come true, even though I predicted the snowfall sector too far south in area's of MS, AL and GA. Overall, my prediction of the overrunning snow sector wasn't that far off at all, margin of error does happen with predictions. I do not think the 2nd wave system should *NOT be written off at this time. Also, on that prediction map that I posted days ago, the timing was obviously off on it with the freezing rain, but I still have confidence that a significant ice storm could occur.
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Shortwave is now over the US btw, so if there’s any trends that occur, it’s cuz of that
NoSnowJoe
Member
Can you do a new map for us with your current prediction?
Jessy89
Member
Wow high in perfect position on gfs. With no moisture.
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Sure, I can work on a prediction map. I'll try to have it posted soon as possible.
Blue_Ridge_Escarpment
Member
Hour 108 GFS ice in WNC.
Quicker arrival leads to ice, even with less seperation
FWIW GFS did trend heavier snow pack with first system. Can’t imagine rain there in Virginia after that...maybe more changes folks.
I wouldn’t rule out a damaging ice storm for Virginia. Unlikely it’s mostly rain after all that snow and cold air prior. Something seems off.
A rich tongue of snow from the NC mountains into DC prior to possible CAD. I know wrong thread but huge fly in the ointment here for second storm IMO. 
The 0z GFS is a better run regarding the track of low versus it's 18z run. The reason why the CAD erodes away quickly is because the surface low is too far north, the low amplifies slightly and the high slides away too quick. The CAD would not erode away if there is a much weaker devloping low further south pushing moisture inland (like what the 12z CMC showed from today) and while the high holds it's position. If this was the case on the 0z GFS, there would have been significant amounts of ice for the CAD regions.
Almost comical the GFS trends to the (textbook track south of current snow cover theory) by bringing winter weather down further south with the second system. Very CMC like. Better hope snowpack is actually there or north the track will go resulting in rain for all.
CMC looking pretty much the same maybe some minor changes through hr 60 but after this energy goes more positive tilt resulting in less precip
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GFS at 18z Friday after lots of precip. Somewhat alarming since this global model won’t be able to pick out the micro-climates within the CAD regime. That 32 could be more like 27 degrees for a good chunk of north-west NC. I’ve noticed the GFS has been consistent on heavy rates..idk about that but I do know it always warms up too quickly. EURO/NAM usually handle the erosion of CAD better. 
At hr 96 CMC starting to build in precip with a 1044 hp over eastern NY CAD signal is pretty strong
Significant ice storm on the CMC, lol
Blue_Ridge_Escarpment
Member
Yikes, CMC.
This is the most consistent model run I’ve seen all day it looks to mostly follow the 12z run. Weird since it’s the CMC ?
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.
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