psuhoffman

Winchester was such a nice place...shame...real shame.

yea I actually have something REALLY important to do that day...and I have no problem driving in snow. I have driven through actual blizzards out west where I could only see 10 feet in front of the car. I have absolutely no issue with snow. But ICE....no thank you.

The 0z NAM is painful up here...I get almost no snow but 20 miles north of me gets 10" lol. Probably too much to ask to get that to start to shift south when the overall bleed is the other way the last 72 hours.

The secondary yes...but its ALL about the primary to our west...we need that to hold on longer...and this ICON run kills the primary a little quicker further south then the 12z run. That is the key because the flow becomes more compressed the further east you get. Once the storm transfers I expect absolutely no northward component and the precip will actually likely start to sink southeast from there. We need the primary to hold on and create that "inverted" trough feature to train moisture along from as the secondary forms. That inverted trough banking up against the compressed flow to the northeast creates a really strong focus for lift. That is the mechanism to get the precip NW. If the primary dies too soon the secondary will wrap up like that ICON run did to our south. Ideally we want to get the primary to hold on into WV or southern Ohio. Yes I know that sounds like blasphemy to some who equate a west track to rain...but once the transfer happens there is likely to be no further northward component to the precip shield so we need the primary to hold until AFTER we get the inverted trough up through our area and the heavy precip is overhead. Then it can make the jump. If it jumps to our south...we get that icon solution.

Before I say this let me preface that I am still optimistic for this storm. I think we are in a pretty good spot. I think this will work out. But I wanted to highlight the double bind we are in right now and why we keep failing despite what has been one of the better longwave patterns we have had in many years all winter long. Look at this from the 18z EPS. Now...that was a pretty good run...but we still need a north adjustment. The target was still just a little south of DC on that run. There were some nice hits but too many misses still. So we need a little more ridging or relaxing of the suppressive flow over the northeast to get the storm to trend north some...but look at where the "cold" boundary is as the storm approaches there! How much can we even afford to "give"? And yes the temps crash after once the storm secondary's and bombs to our southeast...but because of the suppressive flow to our north we need to get the primary up into southern Ohio or WV before it transfers to get heavy snow here. But what if that ridging does shift north say 50/100 miles? How much further before that primary maybe holds on into western PA and the transfer ends up to off NJ instead of off VA Beach and we get a miller b jump over us solution? And about 9 members of the 18z GEFS had just that. We're walking a razor edge on EVERY possible snow solution right now because of "THIS" double bind. Right there...on that run...we have barely enough suppression to prevent warmth from surging north of us ahead of the wave...but its slightly too much suppression for a storm to amplify enough to "crush" us. We have absolutely no margin of error because the cold is so freaking pathetic that to resist warmth from surging north of us ahead of any wave we need such a suppressive flow that it prevents any storms from amplifying. If the suppression relaxes we can get a storm but its rain. I debated not posting this... but I think we can keep this from becoming an out of control debate about "you know what". I am not going to even say its all "THAT". There are some factors that maybe aren't permanent. The PV got sent to the other side of the globe, the pac torched north america all fall and early winter and so perhaps the base state is even warmer now then just due to AGW. But regardless of all that...this is the bind we are in right now trying to get snow regardless of the pattern. The same exact equation is playing out Monday also. That storm is suppressed so much it becomes a strung out mess that barely gets heavy precip to the mason dixon line...and NYC is on the northern fringes. Yet DC can't get any snow??? If the storm was suppressed much more there would be no heavy precip anyways...this keeps playing out time and again all winter long.

Me too. Thing is...it is getting suppressed. NYC is on the northeast fringe! The real heavy precip stays south of PA. But even with the suppression the cold is too pathetic to hold. Here is the scary double bind that puts us in. If the thermal base state is so warm that to get cold we need more suppression then this...well look at Thursday. It’s not even that cold. It’s barely cold enough to snow really. And it’s taking such a suppressive flow to get even that, that there is a serious risk the storm gets squashed. So what’s our path to a win if the cold is so weak that to prevent warmth from surging north in front of any wave we need such a suppressive flow that nothing can amplify?

it’s a little too soon to make definitive projections when it ends at 90. EPS goes to 144 but not out yet. the energy that will become the storm along the UT AZ border is closed and more consolidated that’s good Imo. The wave in the Ohio valley is a little more progressive creating more space. Slightly more ridging ahead. That’s good. I have no idea what to make of the TPV being further south in Canada. If the euro still rotates it north like previous runs it’s irrelevant. If it gets in behind it could help. If it comes across on top it would hurt. Overall I would take the 18z over the 12z look but it’s hard to say that early. Anyone else wanna chime in?

Another tick north on 18z euro. 12z seemed to have stopped the bleeding but 18z feels like it started again. Not sure how much more we have to give at this point.

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.