psuhoffman

We tend to get a lot of our snow in epic runs that happen sporadically once in a blue moon. This pattern has that kind of upside potential. I wouldn't put any qualifiers on it. Sure we need to get some luck, it could go sideways if things don't fall our way...(but by sideways I mean we just get some snow not epic totals) but this is the type of pattern we could score multiple big hits.

The flow that drives the surface low up to our west is happening at the mid levels in response to what is happening to our west, the surface and the strength of the MSLP isn't really the issue. Take a look at the mid level wind flow as the trough is phasing to our west...that is the issue on the runs that drive the primary further north.

This UKMET run is somewhat similar to the Feb 2014 storm...but colder and without that upper low part 2. Big heavy thump up front before a huge dry slot. And the thump wouldn't end with temps in the upper 30s and melting...temps would stay well below freezing...the dry slot would be light sleet and freezing rain.

I don't think this pattern is one and done. But I'd sure love to get the big hit out of the way right up front.

The wall of high pressure is still there. The difference is the trend has been towards more energy ejecting and a more phased amplified system which will attack that thermal boundary with WAA and press it north more...how far is the question. Before guidance was showing a less energetic phased system which wasn't going to really move the thermal boundary much and just slide along it. This has more upside but more fail potential also.

What did the UKMET show last night?

Not sure it will...but on that particular GGEM run the 50/50 exits a little too quickly allowing more ridging to penetrate further north head of the trough axis, with more phasing to "flip" the whole thermal profile on its axis, pinwheel effect so to speak. The greenland block is north of perfect, the 50/50 isn't locked in like we see in true suppressive patterns, but there is a crazy EPO ridge and crazy blocking with a 50/50 and an arctic high in place, there is plenty good here...but is it technically possible if we get a full phase like the GGEM for this to over amp a little and the HECS snow ends up NW of us...yes. But there are plenty of ways for us to win...slightly less phasing, the 50/50 hangs on 12 hours longer, the phasing happens but is centered a little further southeast...there are more win paths than fail ones here, and even the fail path is not a full fail just a failure to maximize potential.

ratios will be slightly higher NW of 95, and that zone that gets a little less snow also gets more sleet after the flip, in the end it evens out...everyone ends up with like 8-10" OTG probably...area's NW do it with more sleet, along 95 with a quick heavy snow thump before a flip and more dryslot.

I know this is anecdotal but might be relevant, at about this range ahead of the 2016 storm, the GGEM was the most amped consistently showing crazy ridiculous snowfall totals further north than the other models. It has also been over amped a few times over the last few years when I was rooting for a more amped solution in systems where I was getting fringed...and I got fringed so... All of that to say, if the GGEM ends up on its own with an over amped solution I would not worry too much...if other guidance ends up going that way...then I would worry some.

It's a 6-12" snowstorm across our area followed by sleet. What adjective people use to describe that is up to them. It is pretty close to the worst case scenario given the setup, so to be fair in that way it is a disaster because we would underachieve in a rare big potential setup. But by most objective standards that kind of storm affecting our whole area would still be very rare, a once every 5 years type event, so calling it a disaster is kinda harsh...but depends by what lens you're viewing it.

This GGEM run is pretty close to what I see as the worst case scenario, but yes it's a realistic option...it's also showing 6"+ of snow followed by a lot of sleet which is not a bad event, if we don't start expecting HECS level snow when were still 4 days away.

BTW I wonder if it's not a coincadence that all the major guidance systems come out in inverse of their verification scores ICON, GFS, GGEM, UKMET, EC I know there used to be something to the delay in the euro and its accuracy, they used an initialization process that took longer but was significantly better. I have not kept up to date with the details of the various guidance over the last 10 years so I can't say for sure this is still true, but it seems odd that basically the longer the model takes to generate, the more accurate it is. ETA: Odd meaning maybe not a coincidence

Of course I still stand by my wish that the GFS either didn't exist or was run AFTER the other globals so it didn't get more attention than it deserves (which in my opinion is about NONE). But if we are going to look at it, it might as well be awesome!

The thermal boundary quickly collapses back south as the coastal takes over on the GFS. That run was pretty close to perfect for 95 NW in terms of track and speed.

LOL Let Randy cook

The last few days have been crazy busy for me and I have not had time to scroll through 75 pages to get caught up so I apologize if any of this is redundant but some thoughts on where we are right now after looking at everything 1) I was never concerned with suppression, and frankly I never thought anything actually showed that...the runs that were south were because the energy got stuck out west and only weak waves ejected which of course would slide east under the cold dome. That's not suppression. There was never anything showing some wall of immovable confluence with the typical sharp northern cutoff of precip you see in true suppression. The greenland block is centered north of ideal actually, up over northern Greenland...not Baffin, and the 50/50 is ideal...and relaxing as the wave approaches not some vortex over Maine like we see when a storm gets suppressed. This never looked like that was the issue. 2) However, I am also not overly concerned this turns into some non event from a north trend. While the greenland block is north of ideal, there is one of the most impressive ridge bridges to a poleward EPO ridge that I have ever seen and a strong 50/50 feature. There is an arctic high in the way. And the low and mid level cold starts out really far south. This system has a lot of similarities to the February 2007 storm but the mid level cold is penetrating about 100 miles further south in this storm. That system I was always worried leading in because the cold really wasn't set up far enough to our south as the WAA started. This time...there is a limit IMO to how far north this can go because the low and mid level cold is really pressing ahead of it. I do think we might mix, but the worst case scenario would be a result for DC and Baltimore similar to 2007 but displaced about 75-100 miles south...meaning DC could experience what Harrisburg PA got during that 2007 storm, which was about 4-6" of snow followed by 4-5" of sleet and freezing rain and in the end had 10" of a concrete glacier OTG and a major impact event. I know everyone would prefer 2 feet of cold smoke powder, and a ton of snow is still possible, I'm just saying I don't think this can turn into some predominantly rain event...this is either a huge snowstorm, or at worst a decent snow turning into a prolific sleet/ice event. Right now I would lean somewhere in between, with the most likely outcome being a big snow before mixing with sleet in the cities.

Who’s got the cigarettes?

Tonight is the first time we’ve been in range where I felt it was worth paying much attention other than to say the pattern looks great which I’ve said multiple times. WRT analysis I’ll add when I think it’s necessary but y’all have been all over it. The next generation is stepping up. And good for ya. I’m tired.

Damn UK at 120 looks like

For reference

@Ji you probably didn’t notice because it was during the dry slot and not much was happening. We didn’t lose much precip to sleet. Maybe it cost us 1”. But it was off and on light sleet for a while. We did lose 6” or so to the dry slot which is why we had about 24” and not the 30”+ further west and north did. And the sleet was a function of the same thing that caused the dry slot so related. I’m certainly not complaining about the 24” we got. It was an awesome storm but remember they had us in the 30”+ zone for a bit but the warm mid levels pushed further NW than expected.

No 1996. Sunday afternoon. During the dry slot. Light sleet for 2-3 hours. While the cowboys were kicking the snot out of the Eagles in the playoffs in what was Randall’s last game in Philly. I remember.

I was in Herndon VA and it did sleet for a few hours but it was during the lull so it didn’t really cost us much accumulation.

Sleet got all the way into central MD in the 1996 storm too. Not saying that happens. Just saying this ggem run reminds me of that storm.