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Pattern The Great December Dump

^ That looks like a good trend for the DC area where our cold source will filter in through CAD. Would be interesting to compare the CMC snowfall mean map for Virginia with the first system.
 
Myfrotho704_ said:
now I know what birdman is saying, he saying the more snowfall to our north they get with that anafront, the more refrigeration of the air and colder the air is gonna be on top of that, which would help out our CAD, ok ok
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And I thought it was known in most research that low pressure tracks tend to trend south of snow cover. The caveat being the snow cover is not there yet and models will be wishy washy until storm #1 completes.
 
WxWatch said:
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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Whatever you do don’t use the ice or sleet accumulations it’s utter garbage 100% of the time. The only thing interesting is the euro/nam combo from time to time for most in the Carolinas. CMC can be useful if Ptype onset is within question...which it seems to be so far. Beyond that it’s really hard to include it in a forecast I’ve noticed..sometimes temps are ok but not great on that model.
 
It’s funny that there’s a 1041 over PA, then 48 hours later the rain/snow line is in southeastern Canada. I forgot the recipe for frozen precip around here. It just ain’t like it used to be. That’s for sure
 
Euro says cold rain and the gfs mostly agrees except for some ice in nw NC.


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Taking the Euro bias so far this year into consideration, dont sleep on a threat in the 16-17th time frame. Starting the get really block happy in this time frame and if it is once again under modeling the Pac ridge, the threat may be significant.
 
Arcc said:
Taking the Euro bias so far this year into consideration, dont sleep on a threat in the 16-17th time frame. Starting the get really block happy in this time frame and if it is once again under modeling the Pac ridge, the threat may be significant.
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yeah, weak -NAO, tropospheric PV lobe in northern Canada, 50/50 low in NE Canada, blocking around northern AK, Aleutian low, only issue is that WAR trend E16E2F85-2262-4CCB-8F2D-82EE89EB6BF9.jpeg
 
Worth mentioning that about 10/50 of the 0z EPS suite had significant freezing rain over the western piedmont of NC w/ wave #2 mainly from GSO-CLT and points NW. Potential for a light glaze late Thursday night into early Friday certainly doesn't seem too far fetched atm. However, the EPS has been trending drier around this period fairly consistently for several runs. The odds of decent ZR actually occurring w/ wave 2 over NC are probably no greater than 15-20% as it currently stands.
 
crecre9 said:
Is there public access to this data? I'd like to try to see composites for storms in my area.
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These composites were created in python & I attained the NCEP Reanalysis data from NOAA ESRL. You can make composites yourself using NOAA ESRL's NCEP Reanalysis daily compositing page but you can only do up to 20 days at a time. Here w/ python, I'm able to do several hundred simultaneously & change the region, color table, etc. as I wish.
 
Webberweather53 said:
Worth mentioning that about 10/50 of the 0z EPS suite had significant freezing rain over the western piedmont of NC w/ wave #2 mainly from GSO-CLT and points NW. Potential for a light glaze late Thursday night into early Friday certainly doesn't seem too far fetched atm. However, the EPS has been trending drier around this period fairly consistently for several runs. The odds of decent ZR actually occurring w/ wave 2 over NC are probably no greater than 15-20% as it currently stands.
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I wonder if those 10 members have better snowfall on the ground to our north with the first system. Seems like the OP is quiet low compared to the GFS/CMC.
 
BirdManDoomW said:
It’s well documented low pressure systems tend to tick or trend south of snow cover in terms of track. This can sometimes leave gaps or a snow hole (ask someone in DC) as new snow cover is developed even further south.
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Huh? You need to show some proof when making such posts. And not random storm tracks that happened to do so.
 
BirdManDoomW said:
I wonder if those 10 members have better snowfall on the ground to our north with the first system. Seems like the OP is quiet low compared to the GFS/CMC.
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The operational ECMWF was pretty representative of the ensemble mean on this most recent run. Enhanced snow cover over VA could certainly help areas immediately downstream in western NC on Friday morning & late thursday night if a few other large-scale pieces move in our favor.
 
Blue_Ridge_Escarpment said:
Verbatim that’s cold rain, but numerous times I’ve seen CAD undermodeled especially by the global models. Really need the NAM/RGEM to get into range.
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The canadian is the only model showing a significant ZR event in the western piedmont & its surface temps are way out in left field to say the least & not just over CAD regions of the Carolinas & NE GA. There's certainly some potential for this to be under modeled but we definitely need to see surface temps at least get down to ~30F or in the upper 20s to really be a concern.

gfs_T2m_seus_18 (1).png

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Webberweather53 said:
The canadian is the only model showing a significant ZR event in the western piedmont & its surface temps are way out in left field to say the least & not just over CAD regions of the Carolinas & NE GA. There's certainly some potential for this to be under modeled but we definitely need to see surface temps at least get down to ~30F or in the upper 20s to really be a concern.

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I could be totally off base and completely wrong but to me, with a 1040+ HP parked over PA/NY the CMC has the most realistic 2m temps. We’ll see!
 
We should get within range of the 12km NAM by tonight for folks worried about ZR late thursday into Friday.

Fwiw (not much atm), the CAD high placement is much better on the NAM vs the GFS at 84 hr.

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Blue_Ridge_Escarpment said:
I could be totally off base and completely wrong but to me, with a 1040+ HP parked over PA/NY the CMC has the most realistic 2m temps. We’ll see!
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My prior experience says if the CMC actually has the right large-scale pattern being forecast, it's the most realistic of the global models in its depiction of CAD although low-level cold is usually overdone in this model.

The potential for us to build a snow pack down into VA and this kind of high being in play in this pattern does suggest some bust potential here by the global models. I'd feel a lot more confident about a solution once the NAM & RGEM provide their respective opinions tomorrow & Wednesday. It's also not like this is 6-7+ days out, we're only ~4 days or so away from this occurring, so as crazy as the CMC is atm vs other globals we're definitely not in la-la land. I'm personally leaning 20/80 for/against an ice storm here for now, it's hard to feel any confidence in this solution when the only model in your camp is the "crazy uncle".

Fwiw, the 6z CMC basically continues to hold serve, delivering a legit ice storm to GSP-CLT-GSO

I_nw_EST_2019120900_105.png
 
Webberweather53 said:
My prior experience says if the CMC actually has the right large-scale pattern being forecast, it's the most realistic of the global models in its depiction of CAD although low-level cold is usually overdone in this model.

The potential for us to build a snow pack down into VA and this kind of high being in play in this pattern does suggest some bust potential here by the global models. I'd feel a lot more confident about a solution once the NAM & RGEM provide their respective opinions tomorrow & Wednesday. It's also not like this is 6-7+ days out, we're only ~4 days or so away from this occurring, so as crazy as the CMC is atm vs other globals we're definitely not in la-la land. I'm personally leaning 20/80 for/against an ice storm here for now, it's hard to feel any confidence in this solution when the only model in your camp is the "crazy uncle".

Fwiw, the 6z CMC basically continues to hold serve, delivering a legit ice storm to GSP-CLT-GSO

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Thanks for you input, always valuable. And as always around here, 1 or 2 degrees makes all the difference.
 
Webberweather53 said:
My prior experience says if the CMC actually has the right large-scale pattern being forecast, it's the most realistic of the global models in its depiction of CAD although low-level cold is usually overdone in this model.

The potential for us to build a snow pack down into VA and this kind of high being in play in this pattern does suggest some bust potential here by the global models. I'd feel a lot more confident about a solution once the NAM & RGEM provide their respective opinions tomorrow & Wednesday. It's also not like this is 6-7+ days out, we're only ~4 days or so away from this occurring, so as crazy as the CMC is atm vs other globals we're definitely not in la-la land. I'm personally leaning 20/80 for/against an ice storm here for now, it's hard to feel any confidence in this solution when the only model in your camp is the "crazy uncle".

Fwiw, the 6z CMC basically continues to hold serve, delivering a legit ice storm to GSP-CLT-GSO

View attachment 27560
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Are there any instances that you can that the CMC was on to something like this while the other modeling wasn’t. If my memory serves correct there was a major sleet/ice event in I want to say February 1994 that wasn’t forecasted at all locally in Charlotte until literally 24 hours before. I was in high school at the time and can remember watching the forecast at 5pm with temperatures at that time well into the 70s and the local mets saying that temps were going to be 45-50 degrees colder 24 hours later and that we would be seeing significant sleet/freezing rain... that was pretty much dead on too
 
Chazwin said:
Are there any instances that you can that the CMC was on to something like this while the other modeling wasn’t. If my memory serves correct there was a major sleet/ice event in I want to say February 1994 that wasn’t forecasted at all locally in Charlotte until literally 24 hours before. I was in high school at the time and can remember watching the forecast at 5pm with temperatures at that time well into the 70s and the local mets saying that temps were going to be 45-50 degrees colder 24 hours later and that we would be seeing significant sleet/freezing rain... that was pretty much dead on too
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February 12-13 2014 definitely immediately comes to mind as a recent instance where the cmc beat most other globally to the punch
 
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