CAPE

I wonder if WW has ever deleted a post.

Dude..

6z NAM and GFS are a bit north of their previous runs. Not a good move for those of us living on the southern/eastern edge. Really need to see continued slight adjustments south.

Somewhat interesting discussion from Mount Holly. Nothing earth shattering, and pretty much agrees with my assessment that the front end is everything here.. Changes...Guidance overall has shifting southward some with the surface low track and therefore is colder. Given enough consensus, shifted some higher snowfall amounts farther south and east. If this colder trend holds, then there may be less freezing rain and just snow/sleet. Still maintained a zone of freezing rain however late Thursday afternoon and evening. Despite some increase in the snow/sleet totals south and eastward some, no changes were made to the Winter Storm Watch. In addition, after collaborating with our neighboring offices we opted to remain with the Watch at this point with no upgrades just yet. Expect all snow at the onset over most of the area due to the cold/dry airmass and the enhanced lift/dynamic cooling in the frontogenesis zone. Given a robust 850-700 MB jet, would expect that we will start to see a transition to sleet from south to north Thursday afternoon. How fast this warm layer aloft progresses north is still a question as guidance continues to wrestle with this. The 00z NAM and some other guidance is a little colder and trended south some with the surface low track. The forecast soundings, especially from the NAM show a decent sleet potential into portions of the I-95 corridor later Thursday afternoon and evening. We continued with a blended approach which gets sleet mixing in across the I-95 corridor. Since the consensus was a little colder, did not bring the mixed precipitation as far northwest as previously. The warm layer aloft may not be well pronounced which may result in more snow, although lighter precipitation intensity could tip that more toward some sleet. Snow and ice amounts...Total were increased some a bit farther south and east based colder trend. The thinking is that a zone of quick accumulations (rates up to 1 inch per hour) occurs with the initial burst but totals then will likely be cut down by mixing later in the event. As of now, the timeframe from about 6 AM to 2 PM Thursday looks to feature heavier snow intensities and when the road conditions should tend to deteriorate quickly. Over the New Jersey coastal plain and southern Delmarva, amounts will be highly dependent upon how well the dynamic cooling with the initial precipitation overcomes the encroaching warm layer aloft. Generally expect 1-3 inches at this time, but amounts further northwest in this zone could get 3-5 inches if the progression continues slightly south. Regarding ice amounts, confidence is rather low at this time, stemming from uncertainty in the positioning of the freezing rain/sleet transition zone. But currently have some areas in the vicinity of I-95 with up to a tenth of an inch of ice Thursday evening.

Para was the first model to hint at some additional action on the backside. I noticed it several runs ago- during the brief time when WB offered it lol.

NAM has 2" of sleet here and a half inch of zr lol. Building an iceberg.

Yeah it has been clear since this first began trending back from what looked a rain event, that the best possible outcome would include quite a bit of non-snow p-types for the coastal plain. But now that we are here, the way to maximize the snow part is to get it to come in hot and heavy on the front end. Maybe the precip 'fork' look will morph into something different in the next few runs.

None of these maps are ever good lol. Just looking at the thermals I know what I need here. Precip needs to come in fast and fall hard, and even then 2-4" is probably the best outcome before mixing. That has seemed like a reasonable expectation, but with these latest solutions implying an initial dry area, that wont work. Now we are seeing some potential on the backside on some guidance, but I don't trust that a bit given how the coastal looks to evolve. That will end up being little to nothing at this latitude.

These things always seem to go from something simple and workable to convoluted. The good front end thump is perfect for this set up with the legit cold/dry air in place initially. That idea seems all but gone. The regular GFS still has it though. I will probably have to kick it out of bed in a couple hours.

This is what it looked like at 12z lol.

Yep that is a hell of a betrayal. Matches everything else though.

It never came out on WB at 18z. What does it look like? It was my baby, but I am sure it betrayed me.

Did the 18z Para have a malfunction?

Looks like it. I just hope I can get in on the goods of one or both. Kind of looking betwixt and between here for the snowy parts.

I think we have an evolving situation with the back end. Euro now has 4"for southern DE. That dead zone is kind of brutal, but will probably change.

I just noticed my rain gauge says 1.25" I forgot about the snow/sleet/ice caked on there that melted in the last 2 days. I think I probably got 0.6" or so last night. It poured for a while.

Getting the good front end isn't as critical up where you are as the warming aloft occurs slower and doesn't last as long, outside of maybe the NAM.

I'm blaming the alcohol.

Dammit you quoted my post before I fixed my homophone abuse.

Absolutely. But we need the precip to come in quick and heavy for some decent snow, because there is no denying the warming aloft.

Eh its frozen in the end. I hate it when I am expecting all snow and I start to hear the pingers. In this setup, I would take it over freezing rain, and given the uncertainty, even up your way I would be prepared to see more than you expect or want.

Given the advertised strong LLJ and the likely warming from 850-700mb, imo 2-4" is a win along/east of I95 before a flip to sleet/zr. This is far from an ideal set up for the lowlands.

Wait, the other day you said you weren't picky.

Nice thump for DC-Balt and over this way on the 18z GFS.

Yeah this has trended colder at the surface, at least. The warm nose aloft is one issue, and that is a beast on the NAMs, the other is how this storm is morphing from a nice front end thump to a one-two punch sort of a deal. There will likely be an area that largely misses out on both if that verifies. The front end is where it is at for places further south/east because there will be legit cold/dry air in place. Just need the goddamn precip to come in hot and heavy to mitigate the warming aloft for a few hours. If it is delayed or light, forget it.