Sey-Mour Snow

Still Heavy snow and low vis live cam in DC right now.. That 700mb warm layer has met some resistance already

What is the board clearing rules for a storm of this duration? How many hours in? Do I do it when I change to sleet?

First flakes 6:45am 7.7 degrees . Hoping for 12-15" here .

@ORH_wxman how big is the scope of the 10"+ compared to some of the other big ones? An area from Texas to Maine 300-600 miles wide seems insanse.

ya hard to tell exactly where it is based on obs and CC, it should be a few hours ahead as the accumulating snow is about 2-3 hours ahead up here..

CC looks close to where guidance had it at this time..

Widespread 2-3" rates in DC area

not down here, I'd imagine so the further north you go. However, White Plains was 10/-7 at 5am and by 6am moderate snow.. Already 1"+ reports in North Jersey

Everyone head over to the obs thread as the first flakes are minutes away from New England. Heavy snow during the day just hits different, enjoy everyone.

it is coming down hard in jersey already, good 4 hours ahead of schedule for that intensity.. as I said earlier in the week, these always come in earlier than modeled - 20-30:1 ratios being reported in Mid-Atlantic

All guidance now 20-30” almost the entire state of MASS, besides cape and island, cant recall that before

Snow is 2-4 hours head of schedule over Jersey with instant moderate snow

Hrrr giveth NAM taketh away

Yikes, bad typo lol I'm going back to laying down, this cold is killing me.

00z HRRR looks exactly like RGEM cold and snow output

it wasn't done yet, I'll post the full run when I have it, it's goods for all , very juicy

Negligible sleet on HRRR , we take and pray it has a clue

Ya that's what I meant, we'd have to wait until meso 00z's finish for the next one to come out.

Isn't that the HREF from 18z? we'd have to wait til 00z finishes

Interesting, that's too cold I think, southern outlier, kinda of like the old rap runs

Band rotting over EMASS at 02z

HRRR trending thumpier.. Eric Webb also reporting from the Carolina's that the HRRR verifying better than the NAM early on for ptype there. Hrrr is unbelievably cold for the NYC Metro tomorrow with a massive thump wow.. Good news for the rest of New England on the thump if that verifies

We are 12 hours away from what promises to be the most widespread New England snowstorm in several years. Around a foot of snow is a lock for many, however some questions remain. Nowcasting will be important as we track the following: 1. 700mb warm layer which may cut down accumulations along the south shore and cape possibly up to I-84. NAM and GFS are now the warmest. While HRRR and RGEM and RAP are the coldest. An extra hour or two in the "thump" can be the difference between 8" or 12"+ along the south shore. 2. Snow growth and snow rates. How many hours can the zone of greatest uncertainty (south coast) maintain great snow growth. I will be following the snow rates down to our SW to see if we have an overperformer on our hands. 3. Extent of heavy accumulations into NNE? 4. Wrap around snows on Monday, will there be accumulating snow? How far SW will it extend?