psuhoffman

+NAO

984 TUCKED off Delmarva

I know I'm probably behind, been actually working lol but if the surface looks anything like the h5 I just saw....HOLY FING SHIT!!!

GEM ens

Who has the UKMET ensembles?

Logically yes...but have you noticed this year whenever the op is not so good and we wait for the ensembles and take joy that they were better....the op has won! Talking about when were inside 150 hours not the crazy unicorn range stuff.

LOL at 6-12" being the floor for significant for DC. watch the news...6-12 flakes is significant. 6-12" is Armageddon

So far the ICON is SECS, GGEM and UKMET are MECS across our area. I expect the Euro to fall in line. Last night's run might have been overdone but maybe it repeats...remember the euro does tend to be the most amplified in this range.

I don't know what the official amounts for each are but this is what they mean and what I've always thought in my head as the range in the "meat" of such storms HECS Historic East Coast Storm 18" plus MECS Major 8-18" SECS Significant 4-8"

Damn we got some old cars up in here

sure but if so far the GFS showed a big snowstorm and then the GGEM and UKMET came in with a miss and the last euro was a miss...we would be feeling pretty bad right now. As long as the euro holds I feel good tossing the GFS.

Since I brought up 1996 I think I should point something out, which most of you know, but we have some in here who maybe do not.... Yes we have the potential for a BIG 12"+ event here...potential though. The reason I said a few days ago I would bet against a 12"+ event was simply playing the odds...they are very rare and require everything to come together perfectly. I think its good to root for the HECS or MECS+ (depending on what your bar for HECS is) type solutions...but don't but your bar at some crazy we need everything to go perfectly result just to be happy. 1996 could have ended up a 8-12" storm had it not phased perfectly and the arctic wave and STJ wave had stayed more disconnected which is what models showed all week leading in. That can happen. Messy phase, front runner escapes, dry slot... a 18" snowstorm takes more than just a perfect pattern (which I do think we have here) but it also takes all the details and variables to go absolutely perfect. That just doesn't happen often. All that to say...if we end up with a 6-10" snowstorm because all the 10 million things that need to come together to get a 20" snow didn't I am not going to let it ruin my enjoyment of this storm. When I dreamed up this period the analogs I was looking at had a lot of very nice snowstorms, but almost all of them were 6-12" type deals...not a lot of HECS, that was never actually on my mind. The fact maybe we have the upside of something like that if all goes well is awesome but I'm not raising my bar just to be let down.

It's basically a 8-14" snowstorm area wide. @Ji will be along to tell us why its awful and the biggest disaster in the history of of the world.

These are the most recent verification scores I found for day 5 H5 verification. ECMWF: .946 UKMET: .928 GGEM: .924 GFS: .919 The euro and UK have been 1 and 2 since about 2006 consistently. The GFS used to run 3rd but was overtaken by the GGEM after its major upgrade in 2022 and since the GGEM has been running consistently ahead (if only by a small margin) the GFS.

1983 was about 1002 MB as it crossed the VA Tidewater but it had great upper level support and arctic air in the way, we don't need a 980 low to get "beast" snow results. Also the pressure is relative, with a 1060 high lurking around and a much higher pressure base state you don't need as low of a surface pressure to get the same effect as when you have 1020 pressures over the top as we have become used to lately. This is a throwback kinda.

It's better than the GFS so... take it seriously in what way?

That is the axis I want to see!

Agreed, l not sure I like the orientation of the TPV there. It’s stretched E-W we want to N-S that’s what the better runs have so energy can dive down around it (dig in) and phase. An E-W orientation directs the flow w-e under it instead of amplifying the trough. But…it can still work like this run did IF the western tail rotates around and amplifies and tilts the whole thing on its axis. That’s actually a more upside idea. But if it doesn’t pull that off the way it’s oriented can just shove the whole thing off like the GFS. This is a boom or bust setup kinda.

ehh I spoke too soon saying it was "better than 6z" the upper energy is way weaker and we get no "part 2" with this, its just a quick WAA wave which that part was better then nothing else and its a lot further from actually being a big storm. The only good was the location of the upper low, but it was way less amplified and positively tilted with offset that one good trend. Let's see what the better models have to say. As long as the GGEM and Euro don't go this way I'm not worried...gfs is bouncing around.

The upper low is further NW but its also more positively tilted with a flatter flow over the top which offsets. In the end similar but slightly better result than 6z but worse than 12z. I still think its focusing too much on the southern piece and killing off the northern one too much but this run with the positively tilted upper low that would make more sense.

About 96... the upper low isn't as amplified and isn't digging quite as far south...those things limit the top end potential here...also its late Feb not early January although we have an arctic airmass to work with so not sure that matters too much.... BUT...in terms of the storm type and evolution they are similar in other ways...with a STJ wave timing up with an arctic front above it and a TPV lobe breaking off and diving down behind the wave. If you look at the surfact map at 114 hours and compare it to the day before 1996 they look very similar. Not predicting the same outcome...just identifying similar storm progressions in the past. Models struggled with the phasing between the waves in that system also but that was 30 years ago so they should do better now you would think. That might mean catching on at 100 hours instead of 36 hours out.

Gfs is hard to judge because it jumped from being the furthest SE (other than Gem) to way NW then over corrected SE again and has been correcting back NW. icon was consistently SE. not as much as the furthest SE gfs runs but it never adjusted NW until recently.

This

Something I've noticed guidance doing on some runs which limits the outcome but I think might be a common error...as the wave approaches there is a duel wave structure with a wave along the arctic boundary associated with the upper low and a wave down along the gulf coast with the STJ. As the whole system progresses east some runs (this latest ICON and last GFS) are focusing too much on the STJ wave and having that wave amplify and race out ahead of the real energy which is along the arctic front. I think that is wrong. I think the main wave is the one along the arctic front which has much better mid and upper level support and that one takes over, amplifies, transfers to the coast and we have a more connected phased system not the strung out disconnected one some runs are showing. I think famously this was the error in 1996 which was why guidance was too far south with that system all week leading up.