40/70 Benchmark

H7 warm front stagnates out there as it runs into resistance from the confluence and the system decays.

Final https://easternmassweather.blogspot.com/2025/12/final-call-for-saturday-snows.html

Final Call For Saturday Snows More Significant Impact Region-wide Synoptic Overview There have been subtle changes from First Call issued on Monday that will have fairly significant impacts across the region. The general evolution remains the same, as the northern steam disturbance approaching from the west will encounter confluence over northern New England and weaken while being deflected to the southeast. However, it now appears that said confluence will be slightly weaker and further to the northeast, meaning that the approaching system makes it slightly further north and remains coherent enough for sizable impacts into the region. Note that by 4pm this afternoon, the system has closed over the eastern Great Lakes. After midnight, the mid level low makes it into New York State, at which point it begins to encounter the confluence from the block to the north east, and in response weakens and veers more to the southeast. Expected Storm Evolution Snowfall should begin to break out across southwestern Connecticut this evening. Overspreading central Massachusetts by midnight. And the balance of southern New England by shortly thereafter, although it may struggle to reach the ground initially due to the antecedent dry air. During the predawn hours, a heavy burst of snow moving northeast in association with the 700mb warm front will begin to slow over Connecticut river valley of Massachusetts into the far northeastern corner of Connecticut, as the warm push aloft meets resistance from the confluence stationed over Maine. This will prolong a few hour stretch of up to 1-2"/hr snowfall rates in this area. It is at this point that the system will begin to weaken, and the dynamics will before more diffuse as the storm progresses eastward. This is evidenced by the disparity in the forecast soundings across the state of Massachusetts, as the profile is much more conducive for a period of heavy snow at Westfield, for instance, than it is at Lawrence. Westfield, MA Lawrence, MA It is around mid morning that the focus of the storm will shift to the north and south shore of the Boston area, as ocean effect and enhanced snow becomes the predominate low level forcing mechanism as the mid level dynamics decay. Snowfall will taper off across the region of the region during midday hours. and ultimately during the afternoon across the north and south shore. FINAL CALL:

You can see that on the soundings...cross hair sig out in Westfield, but it get smore diffuse further east.

Well, it's not coming up from the south and running west of us....it's a northern stream storm that rides east through the lakes, closes off, and then hits the confluence, turns se and begins to fall apart.

This is why some of the same SWFE rules in terms of limitations are applicable here...we get there a bit differently, but this is essentially a SWFE in which the cold ultimately winds....usually in those the warmth does in a relative sense.

Right's...it's attenuating....closing lows over NYS and antecedent dry air doesn't scream S+ to me.

My counter to that is that while closed mid level lows are good, having them over NYS isn't.

Right....these are qualitative changes, though...not quantitative. The storm is getting further north, but the mechanics of it are the same, thus we have the same limitations....all I meant. Hey, I hope you are right and there are widespread 10"+ amounts...I just don't see it right now.

No, I hear that....I get the limitations, as I was just saying to Wolfie, but I do think a 5" cap is a bit stringent...EURO is a hair light on QPF IMHO, but yea...toss the GFS 12" clown-kuchie to Mars.

All of JD's booze and food on me at the next GTG if anyone in SNE gets 12".

Confluence backed off a bit and it's coming further north, but the characterization of the storm hasn't changed....it's a moderate system abutting strong confluence...if anything, it's attenuating on approach.

Irrelevant.

Even there, very isolated if so...but I was referring to SNE.

No one is getting 12".

IDK...10:1 on the EURO has no one over 5"...I feel like a bit of a blend is in order, at least.....I am fine with the EURO Kuchie, but ignore the GFS product.

We always see a few rouge OP runs trying to up the ante on these deals, but we know that they are.....dynamics are really limited to a relatively short window. 10"+ amounts are very isolated if they do occur.

Yea, I just think it's wise to modulate expectations based on past experiences with systems of this ilk, rather than every permutation of model consensus. I'm annoyed that I caved on first call and had everything so far SW instead of sticking to my guns it would move north.

Wow....man, that is far north-

I still wouldn't pin hopes to many double-digit totals....

Probably bands from ORH to you...a rough rule of thumb is that the bending tends to follow the QPG gradient...

Can already see it this year...one west on 12/2, north last one, even though I got the white xmas, and now southwest...every direction. Next one rainer (north)...

Well, I didn't last year...just a dusting.