psuhoffman

This probability map also shows it. You had about a 45% chance of getting 3”+ at 12z and you still do at 18z. The difference was at 12z the 55% choice you didn’t was almost exclusively from a miss south. Now your equally likely for it to miss north. 18z 12z there is more spread now due to a cluster of north track members.

Not for the reason you think. Gefs shifted north quite a bit. This captures most of the event. Look where the max is centered now. Mean qpf did drop slightly in central VA but because there is slightly more spread where members place the max precip. And the nature of this setup with the extreme compressed flow to the NE but with the upper low causing the system coming west to east pretty far north means it’s a fairly narrow zone of high impact. Not like a typical climbing the coast event. But the spread increased to the north. There are now several members that get good snow north of Philly when almost none did before. And the snow mean decreased in VA for the opposite reason as the euro. RAIN lol. Its hard with timing differences to catch them all in one panel but there are a cluster of members that are so amped it in most or all of VA. There are even a couple members that give me rain. And some that come across so far north it miller b’s us and we’re pretty dry. I count 11 flush hit members for the DC area. I count 9 members that are either south or weak but I count 10 members where snow is limited because it’s too far north and rains or simply jumps over us because the upper low comes across too north to hook up with the southern wave until too late for us. So the threat of a miss to the north is now the greater probability on the gefs. So it may have decreased snow totals in VA but not for the same reason as the eps. It trended a little too amped in some members!

The euro isn’t flawless. You realize we’re still at the range when it was giving DC 20” of snow back in December. One of the storms in 2018 it was giving me 8” of snow literally 12 hours from the storm and I got NOTHING lol. What’s odd is they are both opposite their biases right now. But this isn’t a typical gulf wave to coastal setup. The upper low is coming across pretty far north and it’s interacting with the NS flow some on the way across and that’s the driver here not the southern stream wave it links up with in the southeast. I wonder if that has to do with why they are opposite their tendencies. I also wonder if the NS interaction matters more here and if that might not favor the gfs some.

Better imo

I was just thinking about that comparison earlier today.

This is classic. After the gefs and geps have their best runs in years following the EPS being lit up like a Christmas tree the last few days ....the eps decides to take a huge DUMP on us. so did we feel better yesterday when the EPS was honking and the GFS and GEPS were like nah?

Which model shows the lakes cutter? You know what’s crazy about this crusade of yours...you set an impossible standard so you can complain about the guidance. And yes we don’t know exactly where the rain snow line will set up for the overrunning wave Monday night. Could be somewhere between DC and Harrisburg. But if we didn’t have NWP we would have no freaking idea what Monday was even going to look like yet!!! And next Thursday...maybe it ends up a NC event and Maybe DC but before NWP we wouldn’t have any clue there was even a threat of ANYTHING on the east coast that day. Before satellite and NWP when some of the smartest meteorologists applied only your techniques a 48 hour forecast was like a 7 day one today. There were huge busts back then with no lead time. But instead of focusing on the amazing advancement we’ve made...the fact we even know there will be two waves next week...you want to go all Paul Bunyan and rail against the evil chainsaw. Why don’t you learn how to use the new technology and supplement your old school methods instead of complaining incessantly about it! Btw still waiting for you to ever contribute a day 5-10 forecast that beats the ones generating with the aid of guidance.

We need some good news. Cmc ensembles. biggest difference I see compared with the euro is a slower progression. Cmc ensembles even hints the initial wave in the south might escape and the storm forms along a second wave as the upper low slowly advances. The euro races it across before the flow has a chance to relax behind the early week system

The biggest change in the euro from 3 runs ago when it had that very nice solution is it sped up the wave each of the last 2 runs tightening the spacing in front of it. The gfs and cmc ensembles (which both bullseye our area) have a slower progression so they are able to get more ridging ahead of the wave as it crosses the Midwest.

Debatable as I’m looking at it more. That track was north. It didn’t miss is south it just died. But the wave was a bit weaker and faster which offset. Those trends need to stop though.

It was an improvement from 0z. The track of the upper feature is perfect. It dies but follow the precip associated with that and it’s headed right for us. Problem is it was too weak. But that’s not some huge change. It needs to be slightly more amplified with that exact track. The surface low is a response to arhat upper low do don’t worry about that. If that upper feature was stronger you get a stronger more tucked surface low and that precip coming from the west doesn’t die. There is a critical mass type level of amplitude the wave has to reach and this run was just a bit under it.

You can tell with this very early when it ejects to the plains. This is not a system that will amplify at the upper levels on the east coast. It needs to be amplifying and pumping ridging with a healthy surface low in the Midwest. If it’s a weak wave coming off the Rockies it’s game over.

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.