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potential for a few (million) mangled flakes part 2


Alpha5

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the 700 low actually is centered over western PA now before it contracts and moves east. That is pretty big shift. Forget the SLP, the mid levels are not favorable for snow until the very end.

Also, the SLP track is west, its inside the BM and goes over the cape.

On the GFS it appears roughly 0.4-0.5 falls as frozen precip in NYC. Would probably still add up to a slushy inch. It seems like the best bet at this point is to blend the temp profiles of the NAM and GFS (with maybe more credence to the NAM since it has some euro support, at least at 00z). I think no matter what happens, there is a very small chance any of the airports measure more than 2 inches with the greatest chance being at EWR and NYC. I think these small differences in resolving the temp profiles will have the GREATEST impact on the people who live in the burbs immediately outside NYC, because in the colder NAM solution it is entirely plausible you could end up with 6+ while NYC measures a sloppy 1-3in, while in the warmer scenario it might be more of a region wide (ie NYC and immediate burbs) 1-3in with a steep increase N and W of 287.

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12Z GFS is slightly to the east of its prior runs and slightly to the west of NAM, but GFS' temp profiles are still considerably warmer than the NAM. They almost agree on the track of the low, seem to be trending toward the NAM, except for temperature profile. We may learn something about the recently upgraded NAM from these differences.

WX/PT

We'll probably turn out a little colder than the GFS, but not as cold as the NAM, in that case. The NAM's higher res is allowing it to pick up on dynamic cooling. However, the NAM is also probably overdoing precip intensity.

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I said 850 line was under NYC, and it is before it crashes, first time its been that far north. And the surface low track at 6z was east of the cape, now its over it.

Over the Cape sucks for Boston but it's fine for NYC. We just need the SLP to move east of the southern tip of NJ so the low level winds stay out of the north. If that happens and the storm deepens rapidly, it could make a really close pass and still switch to snow almost to the coast. Thereafter, if the mid-levels really wrap up and the storm makes landfall over EMa, that's actually good for us. It would allow a comma head type snow to linger a bit longer over us.

A closely tucked track is only bad if the storm approaches from EPa or NJ... or if you live south or east of NYC.

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The GFS track looks classic.

Right-if anything we should be breathing a sigh of relief here. It definitely ticked a bit east from 6z, and maybe now we'll see models even out or head a little east as the final track. Given all other guidance mostly backing the NAM's temp profile, I would buy it over the GFS especially given its superior resolution.

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We'll probably turn out a little colder than the GFS, but not as cold as the NAM, in that case. The NAM's higher res is allowing it to pick up on dynamic cooling. However, the NAM is also probably overdoing precip intensity.

That would make the updated NAM similar to the prior NAM in this respect. If it's not overdoing precip intensity, this event would be incredibly historic. Otherwise, it will, probably,.....just be historic.

WX/PT

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That would make the updated NAM similar to the prior NAM in this respect. If it's not overdoing precip intensity, this event would be incredibly historic. Otherwise, it will, probably,.....just be historic.

WX/PT

I'm not going to discount the NAM overdoing precip until I see that it no longer does that.

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This is a forecasting nightmare for the meteorologists.

In more ways than one. Elevation is a challenge, but at least you know where the higher elevated places are and they do not change. The more difficult aspect is determining where the heavy bands of precip sets up. Someone at a lower elevation that gets heavier bands of precip training over them could very well get more snow than a higher elevated place that does not cash in on the banding.

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Its all about where the heavy CCB sets up.

The heavier it is, the more snow for the coast and NYC.

If its weak, like the GFS, NYC only sees slushy accumulations.

If its strong like the euro or NAM, NYC sees over 4" of snow.

We wont have the heavy banding pinned down until we see it on radar tomorrow afternoon.

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I believe I recall someone saying earlier that if we can drop temps rapidly tonight, we won't be able to moderate much tomorrow. I think this is important, and if a majority of precip falls after 2pm this could also really help out.

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Its all about where the heavy CCB sets up.

The heavier it is, the more snow for the coast and NYC.

If its weak, like the GFS, NYC only sees slushy accumulations.

If its strong like the euro or NAM, NYC sees over 4" of snow.

We wont have the heavy banding pinned down until we see it on radar tomorrow afternoon.

And THAT is what makes this forecast so tricky.

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Its all about where the heavy CCB sets up.

The heavier it is, the more snow for the coast and NYC.

If its weak, like the GFS, NYC only sees slushy accumulations.

If its strong like the euro or NAM, NYC sees over 4" of snow.

We wont have the heavy banding pinned down until we see it on radar tomorrow afternoon.

All i know is if the changeover is as abrupt as 12/25/02 on long island we can still pile up quickly. That intensity really made the snow stick fast and it accumulate fast
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Some very severe over reactions in this thread initially.

The posts by eduggs and jm are spot on. This is not going to be all snow. It's October. However, the track is absolutely classic. We have some warm boundary layer temps to fight off initially but you can't deny what's going on here.

Although the GFS is warmer, it's still showing the rapidly deepening low pressure offshore and very impressive frontogenic forcing and the potential for instability in banding and very impressive dynamic cooling.

The westward tilt with height and the tuck northwest as the low is kicked by the h5 pva is classic. It's going to be a rain/snow transition event, but once it flips..it's going to feel like mid-winter.

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Someone already mentioned it, but, for emphasis--

Central Park is at 44 degrees, at noon on October 28th under clear skies. 44 degrees!!!!

The forecast high (NWS) for today was 53; while we will still likely climb a few degrees, we will likely stay sub-50 today, which is extremely impressive for the time of year (especially under clear skies). Look at models all you like, but the early indications today are certainly not bad for the BL temps into tonight and tomorrow. The progged low tonight per the NWS is 41, and I would think that is too high... wait and see, but if we drop into the 30s tonight, I will feel much more confident that the city proper sees at least 2-3" of snow (obviously not in Times Square, but the park, etc).

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Some very severe over reactions in this thread initially.

The posts by eduggs and jm are spot on. This is not going to be all snow. It's October. However, the track is absolutely classic. We have some warm boundary layer temps to fight off initially but you can't deny what's going on here.

Although the GFS is warmer, it's still showing the rapidly deepening low pressure offshore and very impressive frontogenic forcing and the potential for instability in banding and very impressive dynamic cooling.

The westward tilt with height and the tuck northwest as the low is kicked by the h5 pva is classic. It's going to be a rain/snow transition event, but once it flips..it's going to feel like mid-winter.

I think the nrn hills of NJ ene into se NY just nw of NYC and western ct are in for something special. The mid level low track is classic. Just classic.

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