NYC/PHL Jan 25-28 Potential Threat Part 2

[Bilas]

It would only take a 25-50 mile shift east on the Euro with the high holding on a little longer to give the NW suburbs of NYC/PHL a HECS.

You are right about that and like others have stated including me this storm is not done moving around. As we get closer we will get a better idea should be fun to watch!

[NJwinter23]

By the way, I don't want to come off as the storm hater on this. The threat, from the H5 depiction being shown, amount of QPF, and the potential pressure gradient involved with the departing high alone, makes this really interesting and potentially awesome. I'm excited for it, and I vision a good deal of snow in the coastal locations is still possible at the onset given the current models, before a change to rain. It was just baffling me when people were screaming this is a HECS setup for I95 corridor with our arctic high sailing away offshore as the storm comes up the coast. Y'all need to open up your KU books to find what 95% of I95 HECS are made of. I'm getting excited for our inland folks.

[eduggs]

I've never quite seen this before on the Euro text data..but EWR gets 1.20" QPF in 6 hours...0.62" QPF in the 6 hours before that too.

Wow. Prompted me to take a closer look and the Euro is a crippling snowstorm for C/NEPA, NWNJ, Catskills, possibly elevated SENY.

[TheTrials]

A very dangerous situation coming up with the potential for close to 3 inches of liquid in a very short period of time for some areas with some good snow pack and frozen rivers. This could get real ugly for a lot of folks in river plains and there is definately a strong coastal flood situation here.

[A-L-E-X]

By the way, I don't want to come off as the storm hater on this. The threat, from the H5 depiction being shown, amount of QPF, and the potential pressure gradient involved with the departing high alone, makes this really interesting and potentially awesome. I'm excited for it, and I vision a good deal of snow in the coastal locations is still possible at the onset given the current models, before a change to rain. It was just baffling me when people were screaming this is a HECS setup for I95 corridor with our arctic high sailing away offshore as the storm comes up the coast. Y'all need to open up your KU books to find what 99% of I95 HECS are made of. I'm getting excited for our inland folks.

Actually with the way the EURO looks this could still be a MECS for the coast. 1 inch of rain and a foot of snow? A distinct possibility. And who can ask for anything more than that with the way this winter has gone? I see youre at 40" for the winter already, as am I..... this could easily get you to 50" and with a potentially historic February coming up, I would say its at least 50/50 that we exceed 60 inches of snowfall this season. So it's pretty crazy to see people down about one storm lol.

[gibson16]

Actually with the way the EURO looks this could still be a MECS for the coast. 1 inch of rain and a foot of snow? A distinct possibility. And who can ask for anything more than that with the way this winter has gone? I see youre at 40" for the winter already, as am I..... this could easily get you to 50" and with a potentially historic February coming up, I would say its at least 50/50 that we exceed 60 inches of snowfall this season. So it's pretty crazy to see people down about one storm lol.

What makes you think an historic February?

[A-L-E-X]

What makes you think an historic February?

Based on the well prognosticated AO dive coming up, the major stratospheric event about to begin and the usual very conservative Don S being gung ho about it of course

[famartin]

Actually with the way the EURO looks this could still be a MECS for the coast. 1 inch of rain and a foot of snow?

I don't think the EC shows that. The way thicknesses rise suggests that warm air gets shoved in pretty fast... I'd say the EC says 6-10" *AT MOST* before the changeover.

[ace0927]

By the way, I don't want to come off as the storm hater on this. The threat, from the H5 depiction being shown, amount of QPF, and the potential pressure gradient involved with the departing high alone, makes this really interesting and potentially awesome. I'm excited for it, and I vision a good deal of snow in the coastal locations is still possible at the onset given the current models, before a change to rain. It was just baffling me when people were screaming this is a HECS setup for I95 corridor with our arctic high sailing away offshore as the storm comes up the coast. Y'all need to open up your KU books to find what 95% of I95 HECS are made of. I'm getting excited for our inland folks.

i just went thru EVERY storm in the KU book--- NOT ONE has this setup...not one....BUT, there hasnt been a La Nina winter like this and the ocean temps are really cold...

[ag3]

Who's to say the high will slide off the coast like the Euro is showing? Euro has been all over the place this winter.

We are still in model fantasy range, as far as Im concerned.

Models will change a dozen more times, including High position.

[gibson16]

Based on the well prognosticated AO dive coming up, the major stratospheric event about to begin and the usual very conservative Don S being gung ho about it of course

Thanks for the reply I haven't really been following things lately next weeks storm brought me back

[TheTrials]

Who's to say the high will slide off the coast like the Euro is showing? Euro has been all over the place this winter.

We are still in model fantasy range, as far as Im concerned.

Models will change a dozen more times, including High position.

its all about timing. Faster solution allows the 50/50 to do its work. Slower allows the 50/50 to move out. You are 100% correct, this will change a lot.

[Ericjcrash]

By the way, I don't want to come off as the storm hater on this. The threat, from the H5 depiction being shown, amount of QPF, and the potential pressure gradient involved with the departing high alone, makes this really interesting and potentially awesome. I'm excited for it, and I vision a good deal of snow in the coastal locations is still possible at the onset given the current models, before a change to rain. It was just baffling me when people were screaming this is a HECS setup for I95 corridor with our arctic high sailing away offshore as the storm comes up the coast. Y'all need to open up your KU books to find what 95% of I95 HECS are made of. I'm getting excited for our inland folks.

I'm not they historically get a lot more snow then us on the coast, so what if they have a few lesser years. This one storm could easily put us on a level playing field total wise so I don't wish them anything and I'm not saying this to battle the NW folk either IDC they fact that we are wishing them more snow is crazy. How many times have we had a snow to rain scenario where they have stayed all snow and got crushed? This storm has great potential and I hope we all get a HECS,

[A-L-E-X]

Thanks for the reply I haven't really been following things lately next weeks storm brought me back

You'll find a very interesting read in the main forum where we've been throwing some analogs around. I mean all you can really say at this point is that a very wintry month of February is "likely" but normal February snowfall for this area is around 10" so even just a slightly better than average month would mean the third straight month of double digit snows.

[ace0927]

Who's to say the high will slide off the coast like the Euro is showing? Euro has been all over the place this winter.

We are still in model fantasy range, as far as Im concerned.

Models will change a dozen more times, including High position.

its been made very clear why the high slides east....go back and read what the red taggers and some of the more educated posters have explained...

i have asked, but of course got no response ( i only get a response from the usual wastes about my negative posts), if the very low ocean temps would offset a strong easterly fetch....so if anyone has a real idea wants to speak up...im listening.

[A-L-E-X]

I don't think the EC shows that. The way thicknesses rise suggests that warm air gets shoved in pretty fast... I'd say the EC says 6-10" *AT MOST* before the changeover.

What about the change back as the storm winds up east of LI? I heard it was a snow-rain-snow scenario Ray?

[Noreaster07]

Does anyone have the H5 track as per the 12z Euro?

[ag3]

its all about timing. Faster solution allows the 50/50 to do its work. Slower allows the 50/50 to move out. You are 100% correct, this will change a lot.

By tonight, euro can be back to a weak 1008, slow moving low, with a high parked over NY State. We are in fantasy range.

People are acting like the storm is 48 hours out.

Positions of highs, lows, 50/50, SW's, troughs and everything else will change dozens of more times.

[Ed Lizard]

Ignoring p-type for a second, the Euro 850 mb winds are 40 m/s+ at the height of this, or about 90 mph, and GFS near surface winds are 20m/s over Long Island, about 40 knots. My AccuWx Euro graphics hasn't updated for the 12Z run, but I suspect if anything it'll show stronger surface winds than the GFS. The Canadian with its inland solution has 50 knot 850 mb winds at hour 133 over Suffolk County. Rain or snow, this could be a major coastal event.

[NJwinter23]

i just went thru EVERY storm in the KU book--- NOT ONE has this setup...not one....BUT, there hasnt been a La Nina winter like this and the ocean temps are really cold...

We do have a gulf stream with 40-50 degree water temps well offshore you know. Don't think for a second a storm like this cant bring in this type of marine influence with a strong, prolonged easterly fetch and a departing arctic high. Doesnt really matter if water temps are 35 degree for the first few miles on the coast. And yes, the euro has a lot more low level warmth, or at least would imply it, and does not mean MECS totals verbatim.

Then again in this historic winter en route, who the hell knows what will happen. You get the feeling If it can snow, it will find a way in these winters.

[nzucker]

What about the change back as the storm winds up east of LI? I heard it was a snow-rain-snow scenario Ray?

It would probably change back to snow there as the low bombs to the east and winds shift. You're not very far from all snow on the ECM either, as the warmest panel has the 0C 850 line just a hair north of NYC.

[famartin]

What about the change back as the storm winds up east of LI? I heard it was a snow-rain-snow scenario Ray?

Sort-of... Based on how much rain falls most of the snow that fell already would probably be gone anyway by then. Its uncertain just how fast it goes back to snow... 850's don't fall that fast and neither do thicknesses, and on the backside of storms it seems you need them to really drop off to get a real effective changeover. Plus, lets remember climo on these "rain to snow" wraparound events I wouldn't bank on the wraparound being a good snowfall...

[Ed Lizard]

What about the change back as the storm winds up east of LI? I heard it was a snow-rain-snow scenario Ray?

Looking at raw numbers for FRG, with the 6 hour data points, it looks a touch too warm at the surface for snow-rain-snow, but there is a lot of guess work as the phase changes would happen between the 6 hour points. At 39ºF and 850s above freezing, there is definitely a good period of rain. Over an inch. Then 850s go back below freezing, but surface temps fall slowly to about 36ºF by the time precip ends. Even 36ºF is marginal for snow, really. If the Euro was perfect, I'd guess a quick change to rain, a little snow at the end, but maybe not sticking, and a lot of rain in between. Just picking FRG as a decent place in Nassau County.

The true snow that accumulates, rain, then more snow that accumulates, looks like Queens (LGA) and points North and West. If one wants to accept a global model as verbatim beyond 5 days.

Or, Readers Digest version, big storm, p-type issues likely, but no real way of guessing amounts this far out. But lots of something, and high winds, looks like a real problem.

[NJwinter23]

I'm not they historically get a lot more snow then us on the coast, so what if they have a few lesser years. This one storm could easily put us on a level playing field total wise so I don't wish them anything and I'm not saying this to battle the NW folk either IDC they fact that we are wishing them more snow is crazy. How many times have we had a snow to rain scenario where they have stayed all snow and got crushed? This storm has great potential and I hope we all get a HECS,

We have our favorable major/historic snow setups (which we have seen well more than enough of this winter, last winter and the whole decade to be honest) on the coast, and they have their own setups inland. Being inland allows them more leeway to hold onto cold, deal with it.

[A-L-E-X]

We have our favorable major/historic snow setups (which we have seen well more than enough of this winter, last winter and the whole decade to be honest) on the coast, and they have their own setups inland. Being inland allows them more leeway to hold onto cold, deal with it.

Haha it sounds like you dont want a historic February

You would have hated the early part of the twentieth century lol.

[A-L-E-X]

Looking at raw numbers for FRG, with the 6 hour data points, it looks a touch too warm at the surface for snow-rain-snow, but there is a lot of guess work as the phase changes would happen between the 6 hour points. At 39ºF and 850s above freezing, there is definitely a good period of rain. Over an inch. Then 850s go back below freezing, but surface temps fall slowly to about 36ºF by the time precip ends. Even 36ºF is marginal for snow, really. If the Euro was perfect, I'd guess a quick change to rain, a little snow at the end, but maybe not sticking, and a lot of rain in between. Just picking FRG as a decent place in Nassau County.

The true snow that accumulates, rain, then more snow that accumulates, looks like Queens (LGA) and points North and West. If one wants to accept a global model as verbatim beyond 5 days.

Or, Readers Digest version, big storm, p-type issues likely, but no real way of guessing amounts this far out. But lots of something, and high winds, looks like a real problem.

Youre right, based on my experience, wet snow scenarios dont work out well above 36 F. In these kinds of set ups, 38 F is usually rain, 37 F a mix and 36 F or lower a wet snow. BTW Im 5 miles east of the Queens line near JFK.

[Stormlover74]

Yeah that almost never works out, Usually by the time the cold air rushes back in most of the precip has cut off. We did get 2 to 3" of snow on the backside in 93 after several hours of sleet and rain and then Christmas '02 but of course that was somewhat localized.

Sort-of... Based on how much rain falls most of the snow that fell already would probably be gone anyway by then. Its uncertain just how fast it goes back to snow... 850's don't fall that fast and neither do thicknesses, and on the backside of storms it seems you need them to really drop off to get a real effective changeover. Plus, lets remember climo on these "rain to snow" wraparound events I wouldn't bank on the wraparound being a good snowfall...

[A-L-E-X]

Sort-of... Based on how much rain falls most of the snow that fell already would probably be gone anyway by then. Its uncertain just how fast it goes back to snow... 850's don't fall that fast and neither do thicknesses, and on the backside of storms it seems you need them to really drop off to get a real effective changeover. Plus, lets remember climo on these "rain to snow" wraparound events I wouldn't bank on the wraparound being a good snowfall...

Only a few really worked out-- one that comes to mind was Xmas 2002.

[ag3]

Coastal is saying that euro ensemble has similar low track as operational but faster.

I would think that its better that its faster.

Waiting to see the mean precip maps from a friend who has access.

[famartin]

It would probably change back to snow there as the low bombs to the east and winds shift. You're not very far from all snow on the ECM either, as the warmest panel has the 0C 850 line just a hair north of NYC.

There are several problems with your analysis.

1) The low doesn't bomb out to the east. Its more or less steady state from Virginia on northeastward.

2) 540dm thickness moves just north of LI at 126 hours. It then crosses back at 138 hours. All the real heavy precip is in between those two times.

3) The real key here is the temps closer to the ground, not 850 mb. 925 mb temps are also above freezing during 126-138. There's a tight gradient to the north, but A-L-E-X is clearly on the warm side of that gradient. They only fall back to -2C at 144 hours... which is a better bet of when it'll go back to accumulating snow at the ground. Of course by then the precip is mostly over.