SnowGoose69

This will be a test for the RRFS to see if its idea of the line pushing back SE is right.

Its unlikely I think they'd add more than 1-2 more inches anyway, though they probably did get an inch from 1-2pm

Yeah the good news is it seems the RRFS is close to as good as the NAM and better than the HRRR on this. The HRRR actually picked up on it this event, probably because it was such strong warm advection

They had 7.2 at 1pm

Yeah based on measurement of 7.2 and EWR 8.0 I think we know those are off unless ratios came down so far the last 3 hours they averaged out 9 or 10:1 in the end

I have heard EWR was 7.7 as of 1pm, not official, it may be near that

The liquid equivalent at NYC of .73 seems high relative to LGA/EWR/JFK unless they just have been under heavy banding.

Yes. I think even LGA/JFK have some freezing rain like 01-04z maybe as things really lighten up

The Central Park cam at 72nd street you can see the plow go by and within 10 minutes its covered up

JFK now at 5, EWR 7, NYC had .17 liquid this hour! I think JFK may be undermeasuring a bit, they do often times in windy events.

PHL over to SNPL. EWR on their SPECI just now has had .09 liquid this hour already so maybe 2-3 inches again

EWR 2/5 now .09 last hour...JFK reported .06 but no snow remark total for the hour. NYC had .13 liquid

Looking outside I swear 2 inches has fallen in past 30 minutes

The ratios will begin to fall to like 8 or 9:1 by 18Z probably but you'd think there will be amounts now of 10-12 in some spots before it changes

LGA and NYC had .12 and .10 liquid past hour. LGA now reporting 3 on the ground 2 last hour

I think there will be many 7s-8s-9s but getting over that unless rates go to 2-3 inches an hour after 15Z will be hard

I think they may get saved a bit by sleet but I’m not highly optimistic

Does now look like NE side of ATL metro will get hit hard. Didn’t think they’d do it a few hours ago but even think down to the airport now makes 31-32 by 4-5am but those areas may benefit from the dryslot more once they are under the threshold

Looks like across Maryland and south snow began when cloud decks reached around 7,000 ft. Across PA it’s been 4,000ft. Up here it may take til they get down to 2500-3000ft. I’d say it could begin as early as 10Z but meaningful accumulations won’t be til 12-13Z. In these setups too the immediate NYC area as well as western LI always pulls down more dry air from the Connecticut river valley and can take longer to saturate than NW NJ and central and eastern LI

This looks pretty close. 7-9 or 8-10 for LI/NYC area unless little mixing happens https://www.spc.noaa.gov/exper/href/?model=href&product=snowfall_024h_mean&sector=ne

I prefer the high to be situated a bit more SE and the approach of the storm to be more due south than it is in this case but both are close. I’ve mentioned before the center of the high over or slightly east of PWM and the core of the system approaching from along the VA/NC coast due north vs more from the SW is ideal. January 87 2014 and November 2018 are examples of that. It tends to result in more severe lifting and crazy snow rates but can also slow the changeover

I’d be more worried honestly this comes pretty far back north. The trof while deep in the east it’s not an exceptionally cold air mass anymore by late week and it’s not like January 20 last year screaming suppression to me. I’m not saying it’s a Tennessee snow event but it may be the classic north of a Montgomery Macon Charleston line event where Birmingham to Atlanta and on east gets the snow

The one reason I can argue the NAM may be wrong is almost every other model shows insane snow rates ahead of the changeover line. If that happens it’s likely the NAM is too fast on the changeover to sleet

The oddest thing about the NAM to me is it does not even have crazy rates ahead of the changeover line. The frontogenesis is semi dislodged from the area where that would occur which may be why. But every other model shows insane rates 2-3 hours before that change occurs...so if the NAM is wrong on that idea the changeover may be delayed

The 3KM NAM does bear some similarities to the RAP as far as precip but the RAP seems to not even see the wedge. At least the 3km NAM has the wedge back well south and west of ATL 10-15Z tomorrow. The scary thing for the ATL metro is how far back the NAM has wanted to push the wedge as far as lateness into Sunday, if that verifies and IF significant ZR happens there will be way less time or chance to melt things off before winds pick up. But the fact now it has things so mild til 10Z is concerning on the bust end. I am not confident at all in any forecast I have out, even NYC it may be mainly sleet after 20Z tomorrow