Alfoman

Looks like the heaviest snow producer could be the overnight 5 AM band as the LP shifts towards the coast. The path towards success is a stronger more organized LP off the NC coast. This would make temps slightly more marginal but I think it would be a worth it trade off for I-95

Never doubt Papa Euro

I believe this is what Heisy was mentioning on a previous page, but increased separation between these NS SWs is evident on the GFS the past few runs - this leads to a flatter evolution of our southern stream interaction for the 16th. While it is not a significant amount, the 12Z Euro moved towards more separation here as well (like it had yesterday at 12Z actually). I've been noticing this so far with the GFS this winter, it seems to be the first to sniff out how far energy will pull back in general. It lead the charge for a flatter and weaker 500 mb vort evolution for our last storm in the Day 3-5 range which ended up being the correct forecast compared to more progressive CMC and Euro solutions. Something to keep in mind.

My god that cold push at hour 168 is insane - 0's and below down to Arkansas

Still new to what's favorable for the MA region but should have known better than the B-word.

What would it take to bring this south and maybe turn it into a Miller B transfer in a favorable spot for the MA for next weekend?

Interesting to watch the evolution of the blocking pattern on the last few runs of the CMC Ens - can't say I don't enjoy it

Won't ever take Hours 60+ on the NAM with any sort of seriousness - but on that note, there was better confluence and slightly lower surface temps this run.

At this point we're really looking for baby step progressions for overall synoptic setup as we move into the 100 hour window tonight - increased confluence in accordance with a stronger LP and less movement of the High to our North. To me, it all starts by looking at the energy interaction out West as the shortwave off the NW Pac moves in much faster the last few runs leading to a much flatter evolution of our SW. Just about every model has trended in this direction the past 12 hours - need the separation to increase here

Looks like that shortwave up in Canada also translating down towards the surface and not allowing the High to flex a little further south - interesting detail in the northern stream evolution.

Lots of vorticity flying around is going to make this a "noisy" look this far out - these interactions are delicate and will probably cause a significant amount of variability. Nino makes things more difficult to track in the 5-7 day range for this reason. Looks like on the 12Z GFS the NS energy interaction from behind shears the hell out of it as it hugs the coast versus the CMC with a more ideal look if we can slow down the NS overhead and better time any sort of interaction.

Stronger energy off the NW coast doesn't allow that ridge to build out west and drive out the TPV earlier. Don't think the weak 1030 High in Canada as the 12z GFS shows will be enough for the interior regions, but an improvement nonetheless.

No Ji, it's that when you get choosey with run-to-run Week 4/5 ENS Mean outputs, you're going to drive yourself up a damn wall. Just moved up to the DMV from the Southeast...somehow ya'll are more pessimistic than them down there

13/5/1

Hey ya'll! I truly think I only have myelf to blame for the misfortune of wave 1 and wave 2. I am currently moving up to DC from Atlanta and I will absolutely be bringing the snow curse I've faced for the last 8 years with me. I just wanted to apoligize in advance! It is crazy to me how the GFS has slowly brought the mon/tues low farther and farther west/inland. The ridging over Nova Scotia is ticking stronger and stronger each run while the ULL is being pulled almost off the coast now on 12z.

You guys all need to understand that a hurricane's strength is not simply defined by the storm's sustained winds it has but rather the accumulated kinetic energy it holds and how deep its pressure is. Katrina only made landfall as a category 3 but the immense amount of energy it had retained produced storm surge well above that threshold. The danger with Ida is having her make landfall while still strengthening as a major rather than producing Katrina-level surge. This will not be Katrina but it can be its own disaster.

NAM finally in range for Monday's system (take with a grain of salt because it is the long range NAM). GFS is still much flatter with the h5 vort with little northern stream interaction. LA/TN/MS/AL could score in the morning hours (if the NAM is correct) but that warm air advection ahead of the surface low + daytime heating is going to be a killer combo for the piedmont with no good source of cold air. Still time with this one though

I agree with you and the 12z GFS just essentially lost the system at the surface. The combination of just too many pieces of energy flying around and the northern stream confluence is causing these models to struggle immensely. But the cold just is not there for us to tap into

18Z GFS similar to 12Z but a tad bit slower with the progression of the shortwave as it interacts with the northern energy. Also a few degrees colder at the surface for the Piedmont, but obviously still too warm for most. It is unfortunate this seems like a daytime event too

Yup, broad SLP straight through GA 500 vort is a damn mess...the H5 evolution has been different every single run the past few days on most every model

Wondering how much snow cover over the foothills into VA could factor into forecasted temps for next Monday's system. The 12Z suite was interesting to say the least, with the storm signal still very much there. It is going to be a delicate balance for how the shortwave progresses as it digs south, which will determine how this plays out. 12Z CMC has too much early interaction with some northern stream energy causing NE cyclonic rotation of our wave around it while also placing a 1038 mb HP over the Midwest. GFS has the interaction happening later, so the system isn't driven as much northward but which a much weaker 1028 surface HP over the northeast.

It is looking more and more likely that we are heading towards an interesting start to 2021. Nothing for the Southeast is ever a guarantee and even in the best patterns we could end up in disappointment, but the long range set up is one of the best I’ve ever seen. As Grit and other have mentioned, the west based –NAO is fairly important for us and it seems as if it could be here to stay. The new EPS weeklies have it staying to some degree through early February. It could take some time for arctic air to funnel its way southward in accordance with our block too (probably mid-January if it does). We have been incredibly fixated on mess in the Pacific, which should slowly improve over the next two weeks. It seems like the Pacific jet extension is retracting going into week 2 of Jan which could lead finally lend us to some ridging on the west coast. But the jet does not disappear (but rather slightly pulls back), so I would not expect a sustained –EPO… a manageable pacific with a more neutral/slight negative look to it works too. As hinted on the GEFS and Euro Ens, the large scale pattern begins to retrograde once ridging takes over the pole. This moves the EPO domain west (helping us move more toward a more neutral EPO look) and shifts ridging in Asia which helps stop the Pac Jet influence. As CustomWX mentioned though, we do not need this necessarily to get some good opportunities. By day 8-15 on the Euro Ens, the PV shifted west in the Bering Sea, allowing the incoming pieces of energy to rotate farther west as well which helps pump heights in western Canada in conjugation with the west based –NAO. Lastly, it looks like we finally have some general agreement with the starto warming event as well into the first two weeks of Jan (Euro is still quickest with the reverse). However, do not expect immediate changes with this, as it is common for the synoptic effects to materialize a few weeks after the event. Things looking up from here and I have hope! Happy New Years Everybody!

Disclaimer: Depending on changeovers along frontal boundaries hardly ever works in our favor in AL/GA, but the more robust trough helps our chances. Also the CMC looks nice with some backside snow showers into the morning of the 25th

It is going to be frustrating watching all this energy constantly feed in from the pacific just to see cutters and clippers, but patience is key. Also, I would really not pay too much attention to the details in the long range GFS, because it has a hard time adjusting to the impending SSW event in accordance with good high lat blocking. Even with the best pattern we can ask for, a well positioned system can be tough to come by in the south.

It seems like this Christmas storm is a pattern-breaking type of system, so I'm hopeful the models start to adjust as we get closer to the 25th. I am keeping an eye out on the potential system on the 28/29th. 12z GFS has our Baja wave finally north enough to interact with the energy propagating in from the Pacific, but we would need it to dig deeper and sharper. 12z CMC and Euro have the energy too far south+ dissipating over the Gulf, resulting in a clipper over the NE. Could be interesting!