RU848789

Personally I'm good with the NWS going with the "average" model camp (8-12" NW of 95, 12-16" near/along 95 and 16-20" for the coast) from a public safety/trust perspective, since going with the low end model average and having something near the high end verify would have people not quite ready for an historic storm. They can easily bump down from the average camp if things trend that way before the storm starts and easily bump up towards something historic (the 10% high case) if the low end models bump up significantly. I am a bit surprised their 10% low end case is so low - that implies they still think there's a worst credible case for the system to go back to the Euro 2 days ago. That would kind of suck.

Nothing is tougher to remove than sleet, especially when it falls at 15F and freezes solid if people didn't remove it soon enough (I did, but many friends didn't). This won't be a picnic though, either.

AIGFS 18Z snow map? TIA. And has there been a WN2 lately?

We still have 2-3" of heavy snow/sleet on our entire property (over 1" since 1/17), although it's no longer topped off with a hard frozen sleetcrete layer anymore as that has softened up from the rain/warmth. Should still be >1" on Sunday and then boom!

They updated that but not the main map yet - actually they just did update, but it's only through 7 am Monday - was wondering why the numbers looked low. I wish they'd only ever issue maps for full events - these partial maps are misleading.

That's an HECS like the GFS. Wow! Thanks for posting the AIGFS/Weathernext models which TT/Pivotal don't have.

Thanks. Ignore the point and click when they're at odds with the issued snowfall maps. They'll update soon. Also if you go in to the hourly weather graphic it shows 4.3" of snow for Perth Amboy.

More pretty pictures...

As I mentioned earlier, the NWS said in their AFDs that they were closely following the NBM, so given that the NBM has taken a decent bump upwards (maybe included the NAM already) at 07Z, I'd expect watches to go up for anywhere that is at at least 6" on that map, which includes this entire subforum basically and the Philly subforum too (note that this map includes previous snow from the Catskills northward).

Yes, we've been NAM-ed. Huge to see even if it's a bit out of its range (the important changes were mostly earlier).

That's incorrect. NWS forecast for NB through NYC is 4-6" through 7 am Monday, which would be 5-7" through the end of the storm at 1 pm Monday, assuming use of the NBM (which they said they followed closely). See my other post with the maps and such.

I'd argue that the NAM at the end of its range shouldn't be used to inform snowfall forecasts. Also most of the 6Z models showed decent increases in snowfall for this subforum and the immediate NYC metro, as per below. Based on the models and the NWS forecast of 6.5" for CPK assuming they'd follow the NBM through 1 pm Monday as per my other post, I'd maybe say 4-8" is a better call for NYC Metro, although I an also see 3-6" being a good starting point with the high uncertainty and huge range we have over the models, as per the NWS 10% low and high cases being <1" for CPK to ~10" for CPK Just my thoughts. 6Z ICON shows 6-12" for NYC metro and 9" for CPK (big increase from 0Z) 6Z GFS shows 12-18" for NYC metro with 15" for CPK (decent increase from 0Z) 6Z AIGFS shows 10-14" for NYC metro and 12" for CPK (a big increase from 0Z) 6Z Euro-AIFS shows 4-6" for NYC metro with 5.5" for CPK (same as 0Z) 6Z Euro shows 3-5" for NYC metro and 3.1" for CPK (a bit of a decrease from 0Z) 7Z NBM shows 6-8" for NYC metro and 7.8" for CPK (slightly more than 01Z). The 0Z CMC/UK both only showed 2-3" for NYC, but I'd argue these are outdated

Keep this in mind when looking at Mt. Holly's forecast and snowfall map. Both are only through 7 am Sunday (they only project out 72 hours) and in thier AFD they said, "Given the uncertainty, our latest forecast stuck closely to the NBM," which should mean the 01Z NBM (the AFD came out at 3 am and would've been based on the 01Z NBM) through 7 am Monday, which is the first graphic, which is fairly close to their forecast map.And if they were forecasting for the whole storm, it would've been the 01Z NBM in the 3rd graphic, which is a respectable starting point, IMO, given the still pretty high uncertainty facing them. I'd expect watches to go up at 4 pm, unless we see some unexpected significant model backtracking on snowfall. And there's plenty of room for them to bump totals up should it come to that, looking at their 10% high probability case showing 12-24" - but they also might have the biggest spread from high to low I've ever seen with their 10% low probability case being for <1" for all. Strap in folks.

And the cherry on top might be the AIGFS trend in precip/snow (it's cold enough). And even though I know there's not a lot of love for the AIGFS, the fact that it's arriving at a pretty good snowfall for 95 to the coast, via a totally different model algorithm (AI vs. physics) is encouraging, meaning the GFS solution can't just be some weird data initialization or model physics error. I guess we have to keep tracking, lol.

PTTD (Post-Traumatic Tracking Disorder) Prediction: GFS caves most publicly at 12Z tomorrow, then when nobody is watching at 6Z Saturday all the models jump to the GFS blizzard solution, then everyone celebrates - for about 12 hours - when the NAM sends us all an FU goodbye, by showing that that blizzard is going to become a snow to sleet to rainfest and all the models slowly follow. 2" of snow, then 2" of sleet then 1" of rain to wash it all away. Curtain comes up, NAM bows and waves goodbye.