USCAPEWEATHERAF

One factor we have to continue to watch on the coastline is the potential for dynamic cooling if the NAM and mesomodels are correct. They cool the 850mv to 925mb temps rapidly as the low begins to move eastward south of Long Island. We should stay all snow even if they winds change to the northeast and stay that way, unless they change to the east or southeast, we should stay snow.

Congrats everyone northwest of I-95 corridor. I hope you enjoy the sight of a foot of snow, while I bask in 45F rain and winds Thursday!

Snow Map! This is the map for the nor'easter. Cape and Islands will see a few inches and turn to rain, the upper Cape west of Hyannis can see up to 6" or more, while HYA east sees less!

December 16-18th, 2020 Nor'easter Final Call Snow Prediction Map

Damn, do you really see the low moving that far northwest?

No powderfreak, you already got your snow somewhat, let the coastline have our fun. I am going to be upset if the majority of this system is rain!

awesome, love it when Will is making the defense for snow on the Cape!

lift should help cool the surface as 850mb temps near -10C and 925mb near -6C

its north of the H7 low up to 100 miles.

What was the UKMET for Cape Cod?

Even if the larger bands move inland, this seems like a storm that will keep producing snow bands from the south or southeast, someone will receive the pivot point for this system and where that monster death band/deformation band sits and pivots will determine the final snow jackpot location. My bet right now, is that the zones of highest amounts are elevated locations just in from the coast in CT, NE RI, SE Interior MA and the Cape. From Provincetown to Hyannis. That corridor on the Cape should see amazing amounts. my top five includes 17" from NEMO and 24 inches from the Feb 25th, 1999 storm.

I think what is leading to the large amount of QPF and moisture is the development of the strong warm front that every model run produces coming northward off the Carolina Coast. There is a large temperature gradient on the north side of the front from 925mb to 850mb of almost 10C+ within a fifty mile distance. That front never passes Nantucket on a majority of the models. I could definitely see QPF amounts increase throughout the next 36 hours. HI-Resolution models like the 3km NAM and the ARW 2 both show the onset of snow beginning much earlier tomorrow with the OES bands in the northeast winds as 850mb temps cool to nearly -10C.

The trough is a beauty

January 2015 had one

That map is not accurate for Cape Cod, Harwich got 15.5"

latitude is worse then longitude

18z GFS made a big correction. Remember that iffy trailing shortwave, well it phases with the lead shortwave, however near 40N: 65W. Again too far for anything meaningful, but if the trend is real, it will phase quicker in the next few cycles.

Oh the 3km NAM is now showing OES developing right after sunset WED for coastal SE MA

Watches now extend to 48 hours not the previous 36 hours!

I am not Chatham

The gradient is getting more extreme as the models keen in on the track of the SFC-H7 lows and their intensities as well as the final location and track of the Deformation band, which lies 100 miles north of the H7 low track or from the low to the north by 100 miles.

Just because the goal posts are narrowing, has no implications that the GFS is right! In fact, the GFS is bound to come back to reality. A consensus towards a CMC-EURO-UKMET combination seems most reasonable. 18z NAM does not rain at all for me, and I am west of CHH, I am more Mid-Cape then outer Cape!

Yeah I reached 54 hours now and it has significantly deamplified!

That was uncalled for!

Really, I see a diverging pattern to the confluence over Quebec and east, I just see more space in the isopleths.