psuhoffman

No it’s not gonna do it. Wave is weaker. And faster which is no good because it’s coming across before ridging can really get going behind the Tuesday wave. That’s the biggest difference the last 2 euro runs v the one that had a good outcome yesterday 12z. Weaker wave and faster so less ridging in between it and the departing wave.

The latitude the wave is coming across, the amount of ridging, where the confluence is, and history of these setups. That doesn’t mean it cannot happen. There was a storm in 1980 in a somewhat similar look that fringed us. But that’s pretty rare. The gfs jumps the upper low southeast to phase with the coastal. That part looks overdone. If the wave is amplifying my guess is that process happens without as much of a sink south among the coast and that tucks the low in a little further north. The threat of it going south is a weaker wave that’s de amplifying and in that case given the flow it’s likely to get crushed way south. I think the in between option is less likely.

The GEFS might already be seeing that a bit. The last few runs the very sharp northern edge of the precip has not moved much...running through central NJ and PA...but the precip is increasing south of that line tightening the gradient. That seems right to me.

Notice...the GEFS have not shifted that NE wall to the precip running through central NJ at all the last few runs...but are tightening up the precip south of that line. That is about what I expect in the end. Somewhere between Philly and NYC is going to be a very very sharp cutoff and south of that gets a good snow and north is smokin cirrus

@stormtracker You're gonna LUV the GEFS.

True...but those factors can often time lead to there being a very heavy banding along the northern fringe as the lift meets the resistance in the flow. Globals often miss that and its why a lot of times you get a "shift north" at the last minute. The storm didnt actually shift north the models simply didnt see that feature.

GEFS coming in way more amplified with the trough ejecting from the Rockies and way more ridging ahead of it so far...lets see...

The CMC was close to a complete monster had it phased that tpv lobe in a little more....OMG

no that is VERY rare... I think this goes one of two ways...if the wave is weak and not washing out it ends up a NC "event". If the wave is amplifying I think from Philly south is good.

still looks kinda fringy for us but we have a LOT of time for that last minute north adjustment. It still happens its just only 50/100 miles not 500 miles like in the past.

I know this sounds contradictory...but imo its all about the health of that upper level system in the Ohio valley. If that is amplified enough I do expect some north adjustment towards gametime. But I bet it goes one way or the other. If the upper level wave is too weak and starts to shear out this will trend south...and end up not even that close. If it is healthy enough to pump ridging in front it will amplify enough that it will trend north SLIGHTLY. So long as its not a shearing out mess as it comes across my bet is it trends slightly north...but this isn't a setup that argues way north...if DC is being fringed we are good...if richmond is being fringed...uh oh. But I don't see a close south miss with an amplified wave to be a high risk...this is either going to wash out and be a weak NC system or amplify and we are good.

GFS run was perfect in every way except slightly too far south with the upper level track. We need to get the primary up into northern KY or southern Ohio and transfer to off VA beach...its simply a little too far south on this run. But the setup is all there...and I would rather need a slight north adjustment to the upper level feature (assuming it is healthy) then a south one. But I do agree with HM this is NOT a setup that argues for some huge north trend. If we need it to trend north 50/100 miles the last 72 hours we are good. If we get to 72 hours and its targetting NC its over.

@PivotPoint I am sorry I was harsh with you earlier. Something happened that has nothing to do with weather and I took my frustration out on you. You didn't deserve that and I am sorry. I should have explained my meteorological points without the unwarranted personal attack. IMO the representation of the high is an effect of the amplitude and latitude of the trough not a cause.

Yea I’ve noticed a tendency to linger the Early week wave in the western Atlantic. Not thrilled with that. Was it always this difficult? Lol

yea everything is complicated when the base state temps of the northern hemisphere are this warm. Truth is we've had several perfect track upper level features this year to produce some snow and a lot of them just did not. Sometimes the problem isnt that we arent getting some 40" historic winter...those were always rare. But its that winters with a pattern that should at least have produced like 10" are producing next to nothing.

We have had plenty of snowstorms from a banana high! The issue here is where the upper feature ejects out west It will generally move west to east in this pattern...so if it ejects too far south...ugh, and how strong...it needs to be amplified enough to pump ridging in front. The runs that had a really good snowstorm for our area had a very similar high pressure representation up top. That wasn't the difference in the sudden weaker/souther trend. You do this with every long range threat. And most of the time you are right because we live somewhere with a horrible snow climo and 99% of anything we identify at range will fail. So 99% of the time you look really smart. But you also have done this with storms that ended up hitting. No one is saying this is going to hit for sure. But the high pressure is the least of our issues right now.

He said in other comments for our area we need the western system to eject at a higher latitude...I would argue stronger is the more important factor but both matter... a weaker wave is more easily squashed south in the flow...can't pump the ridging in front so its a symbiotic relationship.

Because the upper level energy trended weaker coming across out west. One of two things will happen...if that upper level energy is too weak to amplify the system into the TN/OH valleys...this will be a weak southern wave with some rain/snow in NC and SC. If the upper levels are strong enough to produce an amplifying primary and upper low into the OH valley to create the strong boundary/trough pressing against the confluence to the northeast...this will end up a storm like last nights GGEM or the Euro from the other day and come north. The in between solution with a big snowstorm for central VA is actually the least likely outcome imo.

it makes me feel awesome that we need to rely on dynamic cooling to get snow in the mountains from a blocking regime on January 26th!

West to east waves really only work when there is good cold in front of them. Two things working in conjunction made this harder then it looked from range. One is that even though the airmass coming in ahead of this is polar in origin its simply not that cold. It gets easily bullied out of the way by that very weak washing out northern stream wave. The second is that NS wave. Even though its weak...the flow around it still wrecks the thermal profile ahead of the southern wave. So it took both...the cold is pathetic for a polar airmass on Jan 25...but it still would have been good enough had that NS wave not come across ahead of the southern wave. On the other hand....had there been a truly cold by normal Jan 25 polar airmass standards...the thermals probably could have survived that weak NS wave. But both those factors together...womp womp

yes but once the wave clears the cold presses behind it on the NAM some...not so much here but in the midwest which suppresses the next wave. On the GFS there is no separation so the ridging goes up before the cold can press at all.

I know but I was pointing out why it was different. It trended towards the globals a little but its still by far the furthest south of all guidance. What's hilarious is if the NAM is right it might be a total non event anywhere in the east because its so suppressed with the wave I doubt heavy precip makes it much further north then the PA line but the cold is further north...it might be another perfect track rainstorm on January 26 in a blocking regime with a polar airmass. LOL

The real issue with this...is we need the upper low and associated surface system in the TN and OH valleys to be stronger. This is not an amplifying up the coast coastal setup. These can be nice storms...but the mechanism is a strong upper low and surface system to our west into the Ohio valley pressing WAA against the compressed confluent flow over the northeast. That ends up creating a really strong inverted trough to focus moisture transport and lift along as the secondary forms off the coast. But that secondary will not gain much latitude. If the system in the midwest is weak and not amplified enough to create that strong inverted trough feature this is a non event. The coastal itself will not affect us. This is 100% about the strength of the upper level wave that ejects out west. Stronger and further north...we have a storm. The trend the last 24 hours was suddenly weaker on average across all guidance after it had been a very healthy wave...even on the GEFS in prior days. All I want to see today is trend back towards an amplified closed upper level low coming across.

weren't you complaining there was no high like that for the last storm...and now this one that is the reason it wont hit. Guess you are consistent with your character at least.

The NAM is much slower with getting the wave organized and moving east...and that allows cold to press in behind the northern stream low that comes across Sunday. That suppresses the wave as it finally gets its act together to come across. The GFS is the most extreme in the other direction where it organizes the wave so fast that by the time the NS wave clears the ridging in front is already blasting up the ohio valley and the cold comes down behind that wave not in front and on top of it. A pretty major difference when it shows up at only about 50 hours now on the NAM.