eduggs

The radar already appears to be showing where the sharp gradient will set up right along I-95.

Such glorious looking runs for LI to ECT to BOS. Gonna be some serious banding in there somewhere. There are also hints of an outer deform band from coastal NJ through NYC to WCT. If this materializes, it could kind of pivot in place on Saturday.

NAM, EC, UK, CMC actually all in pretty good agreement at this point. With a large QPF gradient, small shifts in the precipitation shield will have a big impact on totals.

So true. I think of it as being tucked into the armpit between NJ and LI. But like you say it's relative to location of interest and also previous runs. Funny thing is we use the SLP as a reference point for model shifts, but the SLP doesn't even generate precipitation. The track and evolution of lift and moisture (e.g, PVA and 700mb RH) determine precipitation. But we barely look at those other features.

Yeah it's all relative. No model runs have been tucked. Even the furthest NW ens member isn't really tucked (well maybe one or two EPS members over the past several runs). This is an offshore low. Fortunately the mid level lows get going early enough and the trof takes on a significant enough tilt to wrap moisture and lift mechanisms pretty far west of the SLP. That's a good thing for most of the coastal plane since it keeps everyone snow.

The EC has been steadily ramping up the QPF... into the 2"+ range that we've been expecting. That's big for approx. 24 hr duration. And the EC won't truly capture banding at the mesoscale. Whoever gets into the mega bands - get outside and experience it. These events don't come around very often... especially daytime weekends.

Even on the 0z UK and CMC, the SLP is pretty far offshore. Synoptically, these usually impact primarily coastal regions and LI.

The UK doesn't spit out those kinds of QPF totals in a snow column at our lat lon very often.

That's the kind of shift on the UK that makes you take notice.

OMG coastal NJ to LI crushed on the UK. NYC in the western edge of the really heavy stuff. Big pivot and deform banding potential there.

We pray it's true. The UK and GFS rarely stay in separate coastal storm camps for long.

LI, and eastern SNE are buried on the CMC!

Big one NYC east, solid west. Out on B&W... but we pretty much knew how it would look from the RGEM.

We have to proceed with extreme caution until the GFS gets on board. It remains a huge caution flag. The background tug will want to pull this east, so that is the default here. I guess we should consider ourselves lucky that the NAM, RGEM, ICON, and JMA threw us a bone this cycle. I'm very wary that this might have been a brief head fake west.

The RGEM barely phases... just in time. This trof is so sensitive to the timing of little pieces of energy. This could easily shift mostly OTS or a big hit for all. High drama!

Hell yeah so far with 0z! We live for another day... or at least another model cycle. The RGEM, NAM, and ICON confirm the threat is still legit. A convincing shift west from the GFS would confirm that we're still in the game for significant snow. But will we bounce back east at 6z like a wobbling hurricane eye?

People jump the gun and get overexcited. But in fairness H5 was worthy of excitement considering previous runs even though the surface didn't work out very well.

Great run on the 0z NAM. It's not quite what we want - still needs work - but it was the kind of run we needed to stay in the game. There's a good chance the 700mb low shifts north on future runs if that basic upper level evolution holds. That could end up looking very Euro-like. If everything else at 0z stays the same or shifts further east, this was probably a blip run and we're probably toast. It would be huge to see meaningful shifts west from the rest of 0z.

Huge 0z tonight. If we get movement back west we're still in the game. If not, time is probably running out outside of eastern LI. The EC works as is, but barely. We need model support.

It's a very minor shift west. And the improvement is partially offset by a slightly shallower mean trof and worse upstream height field orientation.

The NYC area got one decent event for those lucky enough to have been awake to witness it. Some areas have seen no events of significance.

Suffolk County LI is still a decent spot, but NYC west is in trouble... approaching longshot territory.

It looks like we're pretty much cooked except maybe parts of LI. Bummer that guidance universally trended away from us. We're getting to the point where we would need major models errors just as we approach the short term when those errors become unlikely. Late phase and offshore low was the clear risk with a super fragile trof setup. Obviously with such a sensitive setup, this could always come roaring back. I was hoping we would at least stay within striking distance today so small shifts west would get it done. But now unfortunately we need pretty big shifts. The season of tracking frustration continues...

The UK is far enough east that it almost fringes Boston. Not quite though. H5 still looked salvageable for us. No precipitation west of NYC. Totally plausible... just to keep us from getting greedy with high expectations. From here we need to avoid any major shifts or seeing multiple runs in a row shift east.

I don't think it matters too much whether the EC shifts one way or the other tonight as long as the changes are relatively minor. I'd guess a shift east is slightly more likely than west just based on it being on the western edge of consensus, but who knows. Either way, the outcome won't be decided tonight. All of the 0z runs are close enough where modest changes could lead to a widespread major snowstorm.