wxsniss

Wasn't long duration, but would've been an awesome spot for today! Axiom this season: whenever family visits from Philly area, Philly overperforms and Boston region vomits on itself. N=3. Added frustration that they get the impression New England winters are not much different from mid-Atlantic.

that's really impressive

Great post. Some thoughts to add, correct me if I have anything wrong. The fast flow at 250mb could serve as a vent to enhance rather than shear cyclogenesis... Ginx yesterday made an interesting comparison to 2/11/1994 where the jet enhanced rather than sheared mechanics. In contrast, the fast flow and compression at H5/H7 is shearing the WAA component seaward. Other things to look for when thinking about shearing vs. venting in this specific scenario? Too fast? Orientation more west to east rather than northeast?

A definite tick northwest, but still nowhere close to GFS Verbatim a protracted advisory event for most of SNE. The better dynamics still developing too late for eastern SNE and didn't improve much on Euro.

So far sizable tick north on Euro for WAA portion compared to 12z

From SPC: "Conceptually, PMM (probability-matched mean) is a variation of the ensemble mean with the original ensemble amplitude restored. At each grid point, the ensemble mean value is replaced with a value from the full distribution of individual member forecasts whose rank matches the point's rank within the ensemble mean distribution."

Thanks Don I've never used PMM before. Anyone know how probability-matched mean is calculated and when to use it compared to the regular mean?

That signal for northeast MA again on 0z HREF

Decent bump NW with best rates into eastern CT, RI, MA.. compare 9z Fri People can see it here before other vendors: https://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

Nice find. Resemblance at H5 and surface too

This will be another good test of old vs. v16 GFS... both have been really consistent yet different

About what I'm expecting... I posted earlier 2-4" north of pike / 3-6" south of pike, spots 7-8" south coast, maybe some enhancement east Still think there is time to inject more shortwave energy to reinvigorate the low for eastern areas

CMC/RGEM had been the most robust with the reinvigoration and CCB portion for eastern SNE... 12z old GFS now on its own. Still can't completely rule it out, but the trend is not good and we need that well-timed infusion of shortwave energy to reappear. Otherwise, mechanics are just not there for more than 2-4" north of pike / 3-6" south, spots 7-8" along southcoast, and maybe a little enhancement east.

Interestingly, father GFS has been more consistent (and robust) than v16 son

Like 10-14" southeast MA on Pivotal, and that's an improvement over 12z GEM. In any case, I think there's room to trend better. Interesting how this evolved from predominantly a WAA thump yesterday, and now those dynamics look weak and instead we're hoping for CCB of a reinvigorated low.

This is a good Euro run... a tick towards the CMC. The WAA portion is garbage, but the CCB portion is better.

Molasses... apparently on all vendors

Yeah I commented earlier... CMC and RGEM both are slower with arrival of the surface low. I suspect that allows the surface low to be reinvigorated by the lagging shortwave energy more. They both have better closing of midlevels, and eSNE actually gets a bit of a CCB. I think there's still room for improvement in the WAA portion too. But the 10"+ amounts will need to see the CCB portion like the Canadians do it. CMC was ahead of all guidance for Tuesday's turd. Let's hope for whatever reasons the Canadians do better than other guidance in this fast flow regime.

Yeah. The best runs for eSNE --- last night's 0z CMC and tonights 0z RGEM + CMC --- do the same: vorticity is close enough / the system is slow enough that it reinvigorates it, we actually have closing mid-level lows, and eSNE gets a bit of a CCB. The models that have weak sauce have this system running way ahead of the best shortwave energy further southwest, and most of our snowfall is from the weak WAA. Another way to see this is timing: if the surface system arrives later, it has better chance to be impacted by vorticity behind it. If the surface system arrives faster, it fizzles out seaward / we get a smeared multi-weak-low system. Compare at 6z Sat CMC/RGEM (eSNE is getting a CCB) vs. NAM/GFS (system is long gone).

Most guidance has relatively progressive H5 flow, midlevel centers materializing too late... so there's a ceiling with this one. 12z CMC has best indication of closing midlevel centers and a CCB impacting at least eSNE. It saw Tuesday's debacle before the rest, so let's hope it again has a clue. NWS:

37 F Brookline, MA 3 F Arlington, TX

What a turn of events on this 0z suite... redemption Friday in the making for SNE GFS, v16, CMC, and now Euro... Tuesday's debacle may do the trick as anticipated... drags in better antecedent cold, heights and the southeast ridge are pushed further out

Would happily trade Tuesday for a solid snow thump Friday, and end the week 1 for 3. 0z Mon Euro depicts a better antecedent airmass Friday for NNE, but SNE still looking borderline. Plenty of time to improve if a more amped Tuesday system advects more cold behind it.

Not considering whatever happens after this week... I can't remember the last time SNE had such a devolution of high-ceiling, multiple event potential... Just 4 days ago it looked like Feb 94 redux, at least 2-3 events, on track for widespread foot+ of snow SNE by the end of this week on guidance as recently as Euro Feb 12 0z!... and now large parts of SNE are looking at a nuisance kitchen sink / rainstorm. Live and die by the gradient.

Euro 12zFri - 0zSat - 12zSat... all progressive ticks southeast... that's a good trend for lots of folks in Pike region Subtle but maybe trend is for northern stream energy and confluence a little slower to move out?