wxsniss

0z RGEM cut back but not terrible... burst of better dynamics from like 3pm-9pm Friday for eastern SNE Looks like another 3-6" ORH east

0z RGEM will be telling... along with GFS, UK, was really robust at 18z.

So cool: look closely between Weymouth and Plymouth... you can see the OES echoes moving inland while the storm echoes move eastward. Probably some under the beam stuff impacting coastal locales further north.

MV was probably seeing 2-3"/hr for a bit today. Personally, I would have loved to see photos and video of 54 dBz rates from an iconic SNE locale that rarely sees that.

Agree... best support for those higher amounts from 18z RGEM, 18z HRRR long range, 18z GFS, and 12z UK... not our most reliable guidance. Stakes are not the highest. We're talking a prolonged 3-6" vs. 4-8" for eastern SNE.

For Boston metro... the irony is we are whitening surfaces more efficiently than the 2/1 storm where we had heavy rates for hours and nothing to show for it.

Counting on enough mechanics with the last pulse Friday...

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.