weatherwiz

H7-H5 fronto starting to strengthen! I still think the best banding may occur a bit southeast of guidance...at least per mesoanalysis that HP seems farther south

Forget model snowfall maps right now (in a perfect world they would be forgotten all together)...focus on mesoanalysis and how the system evolves over the next several hours. You'll be able to tell from this much more clearly what to expect than from a stupid snowfall map.

If I talked about severe wx in here I'd be yelled at

This is something I really need to utilize more.

I always misjudge that I think. I'm always inclined to think they are coincident, but in reality it's typically just northwest of where the best fronto is, right? Or does the slope influence the actual placement too?

Very cute 18z HRR bufkit for BDL. what is really going to help with verifying higher range of totals will be the much higher ratios under the band. Should see ratios push 18:1 - 20:1. I would wager many are recording like 8-10'' in a 3/hr span...maybe even 11-12'' for the slant stickers

I don't see a situation like that either. If I remember correctly, that was a product of the banded nature of the storm due to it being "too intense". But you do make a point...even in subsidence snow could still come down heavy.

good point

I am a bit concerned down here though about busting too high. I also find it quite intriguing there is such an intense fronto band shown without the pleasure of a more compact closed H7 low but the profile certainly favors it

Would be better as a gif but the NAM pivots the band right through central MA it appears but it rots. Even probably clips NW CT

Also, I don't think the wind direction is very favorable for valley shadow or downsloping. what would get us is any subsidence if we are on wrong end of the band.

Be fun to watch how quickly we can moisten up the llvls. That is one significant gradient between very dry air and more saturated air.

Awesome info, thanks. gotcha...I think I see where the disconnect is coming from. I'm just talking about the potential in general while the focus was on that specific example.

We saw this exact same situation with the storm last December...or maybe it was the year before. HRRR started indicating mixing and every single person dismissed it and it was over the same argument. I wish I had the brain power to remember specific events but I recall several over the past few years where this happened, especially during these early season events; 1) when precipitation intensity is light and 2) when best lift falls below the DGZ it doesn't matter how thin that warm layer (even if barely boerderline)...now perhaps it will be as cold as indicated in the cloud layer as dendrite mentioned but I don't get why everyone is so quick to dismiss these things when we've seen them happen so many times before.

I'm not talking about the algorithm...obviously it is picking up on some warmer layer somewhere if it's showing IP precip type. Unless thermals aren't built into the algorithm which would be pretty stupid and I'm sure the developers are a bit more smart than that. Perhaps the forecast sounding is not properly addressing the warm layer. I mean we've seen this happen dozens of times in the past. Everyone dismisses the mixing it shows and dismisses the HRRR everytime it shows something that isn't favorable. I mean how many times have people dismissed the HRRR when it's going all out and other models are opposite? If this was forecast to be a 3-6'' storm and the HRRR was spitting out 10-15'' would people be dismissing it, probably not.

Certainly based on the sounding you would expect all snow but even in times past...we have seen forecast soundings in similar situations which would completely nix mixing only for it to happen. The issue I think is the warm layer is so subtle that even a model with a resolution like the HRRR doesn't pick up on it, When precipitation is heavy you would certainly get snow but in those lulls...mixing is possible. Not saying this happens but we've seen it happen too many times in the past.

One thing to kinda consider here is there could certainly be some wonky thin warmer layers in here...I think the HRRR is very sensitive to thermal profiles, isn't it? Anyways, I think it's something we should certainly not toss...we have seen in similar set ups where we toss the mixing and it happens. There could be a crap ton of latent heat release too. given the forecast track of H7/H85 I wouldn't be shocked to see some sneaky warmth aloft...especially given where H85 is closing off. Maybe some warmth around 780-800?

Comparing mesoanalysis to models the high looks a bit farther south based on observations. Now this could strictly be a resolution type issue but where mesoanalysis has the closed 108 contour is noticeably farther south

Hoping we can pivot that through but looks like the whole system starts to occlude and the band will start to weaken. Looks very close though. And as Ryan just said...700 low coming a bit north on NAM which is a bit of a concern too for sure.

How do you keep clothes on when you see this?

Agreed...there will be some 20''+ reports

I can't believe 60 units of omega into the DGZ...on both models too. Could see ratios perhaps up around 18:1 if that verifies. Could snow 3''+ per hour for a good 3 hours

Let's go!!!! 60 units of omega in the DGZ WOOOOHOOOOO!!!! Whip it out

there is no bufkit for DXR but it will dump. Going to increase totals a bit!!!

The 6z GFS/NAM bufkit is ridiculous at BDL!!!! 60 units of omega into the DGZ....HOLY SHIT!!!! Def could see a swath of 18-24'' I think