weatherwiz

Once the storm passes

We have very similar thoughts on this. But you’ve been consistent since multiple days ago…took me a few days to catch on

Updated map and even a blog post https://weatherwiz.blogspot.com/2025/12/friday-december-26-2025-southern-new.html

It's very possible. If there is any setup that the NAM is going to outperform other guidance it is going to be this. The globals aren't particularly skillful when it comes to banding. In terms of other mesos, I don't even think the HRRR handles that well. The best thing I think to do is forget QPF amounts and QPF trends and using those to define the storm trends. The focus and assessment should be on the mid-levels and particularly that mid-level warm front. Often, models will produce the heaviest QPF right under directly under where the best dynamics or fronto or gradient is but more time than not the heaviest QPF is going to be displaced a bit north of this.

If you look at where models (NAM, GFS, Euro) have the 700mb warm front...the NAM actually I think makes sense with how far north and east it has the banding. I think the area of strongest frontogenesis on the 12z RGEM would be northeast of where it has it

do you know how well historically the RGEM handles banding?

I am so torn on this. Dry air races in aloft. Here is simulated reflectivity for 3z. I choose this over QPF because that's 3hr QPF up until that hour. anyways...looks pretty good but look at 500mb RH (80-85% but dropping quickly) This heavy snow is going to be so brief and I have to suspect this will have some impact on ratios, except for directly under the banding. You could see something like Danbury get 7" and Waterbury barely 3" (just using those two locations to illustrate the tight gradient)

Humpy dumpy came in like a wall

Not sure. I usually don't really look around at maps until I've made one...unless I don't feel like making one lol.

Time to work on an updated snow map

Interesting...advisory for Hartford County

snow ratios are definitely going to be hefty under the banding...certainly upwards of 15:1, if not maybe even upwards of 18:1. Certainly leading to some potential that could even some 8-12" totals, even with the speed. The 10-15" I don't know about...those models were also pegging snowfall rates4-5"/hour. If that happened then we would see those totals I think but 4-5"/hr might be a bit high

Hopefully when you flush your phone goes down with it

The good news is I think everyone here who is in line to potentially be impacted by the band has realistic expectations. I think there is solid agreement on the max swath somewhere in the 4-8/6-10 range.

I would do it right at the table. Hell, I may bring my laptop and an additional monitor and toss the food onto the floor and setup shop on the table

Weakens a bit crossing CT but this would lead to a helluva dump. It just sucks this is going to be in and out. But I am feeling confident much of the state will get 4-8 inches. My map yesterday looks very stupid now. I think the ranges with this will have to be a bit larger than usual because of the cutoff that will occur

Euro may be a bit more northeast too...tough to tell but regardless looks pretty solid for much of CT with a quick glance

No disagreement there. The uncertainty is definitely there, particularly moving northeast of Fairfield County. Here is HREF probability for 1"+ per hour rates. Right on the border getting into Hartford and eastern half of New Haven County. I guess it may just come down to how confident the forecaster is in meeting warning criteria.

We should saturate quickly but this will be a concern along the fringes of the precipitation shield. The bigger concern with dry air IMO is how quickly does dry air filter in aloft...that is going to cut down the banding very quickly. This is one of the reasons I think its just a 3 hour or so period of very heavy snowfall and why I think max totals will be 6-8" versus something like 9-10" or 9-12"

I'm also factoring in holiday travel. Winter Storm Watches certainly raises awareness but you figure alot of people will probably be wanting to adjust plans today. In a normal scenario I think it would be watches then warnings tonight but holiday travel may factor into the decision making.

Depending on how the euro swings, I wonder if we could even go straight to Winter Storm Warnings

I would certainly hold off traveling Saturday morning, where to in PA?

any changes/adjustments would mostly likely come with the afternoon package and I doubt any significant changes would be made until after assessing the Euro too. This is a very delicate situation, we've been burned before shooting the moon with these amped solutions only for things to trend down a bit as we got closer. The trends have been great for our region, but there are still lots of uncertainties and flags to consider, particularly when determining what and where the max swath will be. This is probably something we can't even pin down until nowcasting time. @Sey-Mour Snow thoughts several posts up I think sum this up extremely well with a sharp cutoff away from the strip

meh get your shit together

these certainly typically have two max areas. I like your idea of BGM to BDR for the main max zone. Hell, you can even see that on the GFS too