wxsniss

18z AI-GFS (I have no idea if this is worth anything) is also ticking better than 12z

If there's any takeaway from 18z suite, it's that this is not continuing to slip away into nothing (which was a distinct possibility on yesterday's guidance). It will be meager, but there will be accumulation.

On this 18z NAM: some decent fronto scrapes the south coast... could see upwards of 3-5" right at the water if that occurs. Let's hold or continue these ticks in the next 12 hours...

Yeah it's been a tough stretch for the region and this hobby. I posted last night... I remember the forum days of all-hands-on-deck war-room analysis for an impending KU, and now I'm micro-dissecting 1-2" vs. 2-3". We're famished for a region-wide larger event. Dec 20 2024 was the last positive bust for MBY (Boston suburbs) in years, and it was ~5.5". But easy to forget (maybe because the unseasonal cold) that it's very early and there's lots of winter to go.

Box update As noted above, upside potential at this point IF the vort comes in stronger, could add 1-2" south and east zones, with maybe spots 4-5" total in outer Cape...

Do you know how often the AIFS is re-trained? Would be amazing if in fact it gets better over the course of each event and each idiosyncratic setup. I came across this indicating an updated training schedule, but does not detail: https://arxiv.org/abs/2509.18994 (before I get misconstrued... I would hate losing the joy and suspense of forecasting to a perfect AI)

Brace yourselves... Let's at least get some Foxboro snow mojo in the air Sunday

18z NAM was an example... on that run, more energy was able to compensate a little for the worse tilt and southeast squash To echo what CoastalWx and others have said... I remember the occasions, felt like a few times every season, when we were micro-analyzing such details with huge stakes on the eve of classic KUs. Now the stakes are a few inches and it's tiring. 0z Euro continued to tick the trough more positive and outcome more southeast... maybe 1-3" south coast, 3-4" outer Cape. 0z AIFS a hair better.

Not liking NAM trend at 18z, fwiw... 18z Saturday/0z Sunday is a key litmus I've been using on all guidance... all about pin-the-PV-center-on-the-lake... the further northwest that lobe center is, the better the downstream heights and tilt of our trough for our storm a day later: Over Lake Superior, high-end advisory. East of Lake Huron, it's a scraper.

Maybe the most negative steady trend today is both Euro-AIFS and EPS incrementally pulling away for 4 cycles since 6z today

0z EC: can see the worse outcome well before... at 72h 0z Sunday the PV center ticked slightly east over Lake Huron instead of Lake Michigan... that slight tick is enough to smush heights downstream and keep the trough more positive... Models are vacillating between SNE graze vs. 1-3/2-5... (and though hard to explain, it does strangely seem to correlate with 6z/18z vs. 0z/12z). Probably won't lock in for another 24 hours or so. I'm still favoring at least advisory in southeast areas.

Definitely better tilt, orientation of TPV, and upstream ridging by 0z Sunday compared to EC 0z... at moment a light event for southeast areas, but just minor tweaks will get significant improvement at surface on future runs

vs. 6z, EC significantly improved western ridge, not sure energy will dig and tilt enough to deliver on this specific run, but 14th a definite contender

Always a thrill to see opening best rates of the season, though only for about 3 minutes… We’ll have our chances… this alone looks like it should bring much better results at surface than it actually has, and can tweak significantly better with time:

Messenger's back yard (may he RIP) in Plymouth must be pushing 8" at this point That coastal front / area of convergence has been nearly stationary for >24 hours Let's repeat late January