wxsniss

It's probably too late and overwhelmed by guidance at this point, but if we're looking potential of a positive bust (at least for eastern SNE), we want the IVT feature to weaken faster and shut off warming midlevel temps... I'm looking at 850 winds here... the less westerly, the weaker the feature: Tues 6z off Euro:

Most relevant portions of 446pm AFD: ...There still remains some uncertainty on exact snow amounts across the lower elevations, including eastern MA and Boston... Still dealing with lots of critical differences in the latest guidance suite. While gaining confidence in some aspects of the forecast, still some lingering questions with the precise details. Among the guidance, we discounted the 12Z NAM, which looked to be a far western outlier with its track. This forecast was based more on the idea of the storm staying just offshore of eastern MA. All the guidance had a little pinwheel effect with the surface low pressure at some point tomorrow into tomorrow night. The critical question is where this happens. The main concern for this will be related to temperatures, which are rather marginal already. A more westward jog to this low pressure will mean armer air and less snow towards the coast. Another complicating factor to the snowfall forecast will be the timing and track of a dry slot in the dendritic growth zone. This looks like it will impact southeast MA and portions of RI. This will limit snowfall simply because the snowflakes themselves will not be as large or well formed.

Ha that's actually not a terrible run for eastern SNE... 925s are like -2C after 15z, that would be something like 36-37˚C heavy snow

High stakes for eastern SNE (among CT and other places with this storm). "non-linear" changes as you put it is so appropriate. It really wouldn't take much for a widespread 8-12" for eastern SNE, but we need that IVT lobe to fade faster. As is, we're now biting nails to see how quickly the main surface low takes over and where it slings up. Trying to figure out things we can pay attention to nowcast... one thing might be 925mb winds over LI pre-dawn Tues... if they have a more easterly component than southeasterly, the bigger scenarios are on the table. If they still have a strong southerly component, not good.

15z Tues actually looks like a big hit once it cools eastern SNE

For eastern areas, actually not bad consensus emerging between 12z GFS / Euro / NAM (more so 3k). RGEM and CMC look on their own with torching the mid levels and looping system inland.

18z Tues that's all snow for much of eastern SNE... 925mb 0C down to maybe Plymouth to Cape

I have so little confidence in any forecast at the moment. The goalposts have drastic changes to forecast. 0z runs NAM-Euro-GFS just 12 hours ago were probably the best solutions in days for your area and a good chunk of eastern SNE... here's hoping we trend back to that later today. 3k NAM and GFS hint that it's still on the table. Not sure what to make of the 6z-Euro-12z RGEM running this so far inland with mostly rain for us. That's a pretty discontinuous jump, but not totally unrealistic.

Reasons to "curb your enthusiasm" are shrinking... You could see since last night that momentum was east, and models just struggled to sort out low consolidation until converging on tonight's consensus among EPS, Euro, CMC, UK. GFS the clear outlier. Verbatim, the B word is warranted.

18z Tues: 925mb winds: Surface:

For eSNE, BEST Euro solution yet!!!! Now a consolidated low by Tues 12z The dual low / disorganized solutions on guidance earlier today were steps in an evolution towards what we're now seeing on CMC / Euro... GFS is the clear outlier

Synoptically and at H5 thru 48h much more like CMC than GFS

Any experience/thoughts on how the potential counterclockwise backing-in would impact snowfall rates? Akin to surge impacted by approach of hurricanes, I'm guessing the west/southwest-ward approach (vs. the more typical northeast-ward approach) might enhance snowfall, but not sure if there's any truth to that.

Agree not sure where the need (?expectation) of precise numbers this far out. Should be perfectly acceptable to put a region-wide alert for potential of heavy snow + winds, stay tuned for detailed TBD. Unnecessarily setting themselves up for criticism.

I’d have more confidence northcentral CT up to ORH than depicted… that area pretty consistently hit

Agree this will likely change… unless anticipating further east all happens after 8pm Tuesday, and guidance has trended later with the further east captures

Actually fairly decent <100 mile consensus for low track, furthest NW tracks into SE SNE, most tracks seem to be around islands / elbow / east of the Cape Quick glance looks like 12z Euro only one with dual low / 12z UK with nipple, but otherwise NAM/GFS/CMC look consolidated Momentum seems to be east with a more dominating SRN shortwave that gets boosted but not stretched by infusion of NRN energy... for ESNE, good trend to see given that SRN shortwave was sampled this morning

Discussed this yesterday SRN stream vorticity getting better sampling this morning and if more robust expected a tic east Major power issues, 925mb winds:

For QPF mean, note this is 24hr so some far west QPF is cut off:

Contrast to 12z when most members went inland: 0z 90hr: 0z 96hr: Several 966 members in there.

Euro definitely could be wrong. But the trend towards a more eastern solution over 12z-18z-0z today makes me think improved sampling of NRN stream (which is now mostly over land) played a role. SRN stream I believe will be fully sampled over land Saturday, so we'll see how the 12z suite plays out tomorrow. IF SRN stream samples more robust, I think there's potential for more southeast tics. In any case, good to see the whiffs are completely off the table tonight.

After so many rug pulls this winter, it's hard to believe this is within 96 hours Still a relatively fragile setup but great to see some consensus emerge tonight. I would not be shocked to see this trend a bit further southeast if sampling of the southern stream Saturday proves it to be more stout

Would be widespread power issues 925mb winds at 90hr:

hours 90-96 absolutely crushed in much of SNE low grazes Cape, captures at elbow for eastern folks, exactly what we wanted to see at 0z... all the big leagues Euro, GFS, CMC with a widespread big hit, and Euro arguably the best of them

early trend was ridge out west slightly more stout along Tip's x-axis Tues blizzard in much of SNE