108 replies to this topic

[Stormchaser]

Becoming more likely, particularly for the I-95 corridor northeast of PHL. Nothing set in stone just yet; however, model consensus is very good for 3 days in advance. The breakdown:

Still two seperate camps, although the one camp is fading:

1) GFS, JMA, Euro, UKMET, CMC, GFS and Euro ensembles, SREF members -- all depict a major to historic snowstorm for the Northeast. Blizzard conditions are also being hinted at on a number of models. Pressure gradient is impressive with a rapidly intensifying low to sub 980mb near the benchmark, HP up to the north. Fairly slow moving system as well. The Euro at 00z (taken verbatim) is all snow NW of I-95 with around 1 1/2 to 2ft, mainly snow with a brief period of sleet for the coast, still 1-2ft of the white stuff.

2) NAM and MM5. Although these two models are the warmest and furthest north with the energy transfer to the secondary low -- both are in the correction stage. NAM is no longer a driving rainstorm, it's a driving sleet storm -- that's an improvement. As it continues to detect the stronger low-level cold drainage from the north, it will trend towards the other data. I'm confident this will occur over the next couple NAM/MM5 runs.

Let's begin with the 06z GFS ensembles -- decent consensus:

http://www.meteo.psu...PRS_6z/f84.html

Total QPF anywhere from 1 to 2":

http://www.meteo.psu...2NE_6z/f96.html

With rain:snow ratios of 10:1 and 15:1 for most, we're talking a widespread 1-2 feet.

Euro:



The synoptic-scale evolution is one that continues to favor a partial phase -- a piece of the Polar Vortex phasing with the sub-tropical jet system; however, not a complete capture, aka the mid-west low being dominant. What this implies is a very dynamic solution with the associated upper low closing off at 500mb -- the surface reflection is a 1978 type situation with bombogenesis occuring east of the tristate. I believe the heaviest snow amounts will accumulate from central New Jersey northeastward, NNJ, through NYC, and into southern new england. These totals will likely surpass 12" -- and that's all I'm going to say right now. There's potential for much more than 12" in regions that receive >1.25" of QPF. Some models printing out 3" for inland southern new england! Coupled with a 40-50knot wind we're talking a crippling blizzard for some locations.

The bottom line here folks is this WILL BE signficant to major snowstorm for the entire region -- it's no longer IF, but HOW MUCH.

As far as rain/sleet issues -- I believe this is all snow west of I-95, and probably all snow for NYC and central NJ although I cannot rule out a period of sleet prior to when heights crash over the region. This "explosion" offshore will allow temperatures to drop through the 20's by Wednesday morning so that everyone, even SE NJ is all snow. I do see some sleet/freezing rain for the coast of NJ and LI, could limit totals there.

More to come -- not putting out totals yet -- too early. But I think one can conclude from the above, at the very least, I'm expecting a major snowstorm.

[rgwp96]

storm, hate to bash your thread but the 12z gfs hugs the coast and most are rain.

[monmouthcoweather]

storm, latest trends are starting to worry me. wouldn't be so worried if i was nw of nyc, but being in monmouth the models are starting taking the low too close to the coast and it looks like mixing will be an issue

[Stormchaser]

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storm, hate to bash your thread but the 12z gfs hugs the coast and most are rain.

It's one run, and it contradicts all other guidance. In the trash.

[Stormchaser]

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storm, latest trends are starting to worry me. wouldn't be so worried if i was nw of nyc, but being in monmouth the models are starting taking the low too close to the coast and it looks like mixing will be an issue

Yes, there will probably be a period of mixing for the coast, but it should be mainly snow. I don't buy the GFS as the NAM/MM5 have been shifting SE the past couple runs.

[roughsurf]

Thanks for write up Storm. Great as usual. Just a quick question for NW Jersey. How fast does the heavy precip line cutoff?  Does it seem, at least at this point in time, that we are also in the heavy precip or just on the fringes ?  Also, what is the timeframe of it starting and possibly ending ? :)

Thanks for any info..

[Stormchaser]

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storm, hate to bash your thread but the 12z gfs hugs the coast and most are rain.

You are just one big downer on this winter aren't you? LOL.

[LongIslandWthr]

Oh my, oh my, this suspense is killing me! I cannot wait until Tuesday!

[Stormchaser]

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Thanks for write up Storm. Great as usual. Just a quick question for NW Jersey. How fast does the heavy precip line cutoff?  Does it seem, at least at this point in time, that we are also in the heavy precip or just on the fringes ?  Also, what is the timeframe of it starting and possibly ending ? :)

Thanks for any info..

Roughsurf, you're definitely not on the fringes. Take a look at the QPF maps I posted above -- you're clearly in the >1.00" range on virtually all members. As of right now -- you might actually be in the sweet spot with this storm -- all snow -- and higher ratios. NW NJ up through interior southern new england will probably be the jackpot, although I can't say for sure. Any shifting of the track south and NYC and the coast are the sweet spots.

[weatherbowl]

At least there is a major storm finally coming. The issue may be mixing but that usually is in our area. I say enjoy the moment, it's about time.  :)

[roughsurf]

Thanks Storm. I saw that, but reading your post I thought maybe was more of the Lower Hudson valley up through BOS was going to be the sweet spot, but I was hoping you would say NW Jersey too !  ;D  Again, thanks for posting your thoughts, always appreciated.

[Stormchaser]

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At least there is a major storm finally coming. The issue may be mixing but that usually is in our area. I say enjoy the moment, it's about time.  :)

Most big time storms do have mixing of sleet at the height. In the Jan 2005 blizzard I was literally 5 miles west of heavy sleet in southern Monmouth county. In PD II Washington changed over to sleet as well as south coast NJ. You're going to have mixing issues for a brief period NYC south and east as this storm looks to be a monster, dynamically speaking.

[weathergeek87]

Excellent analysis storm.

[weatherbowl]

That's very true Storm, even with temps well below freezing some mixing usually accurs near the coast. I have seen sleet mixed in here on Long Island with temperatures well down into the 20s. I guess it is the intensity of the low bring in warm air aloft.

[Snow15]

storm...what your saying is to not trust the 12zgfs and the nam.....these two models have trended to rain... and philly MET Rob Guarino is also becoming a little worried by these two runs!

[Stormchaser]

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storm...what your saying is to not trust the 12zgfs and the nam.....these two models have trended to rain... and philly MET Rob Guarino is also becoming a little worried by these two runs!

Let's wait for the rest of the 12z data before we get worried. It's one run of the GFS.

[njblizzard]

guys, how about dynamic cooling. It should come hard and produce its own cold air. what are the chances of that? We only need 50 miles shift to east and we are back.

[Pstar3182]

Ice pointed out the same thing Strom trying to get across. Most Mets rely on the NAM, however because it had errors and is still correcting, the Mets are either ignoring it or freaking out about the inconsistencies and going with what they know. The large majority have ignored those runs an like Strom just posted....more runs are needed.

[Stormchaser]

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Wow - If that GFS verifies than the Nam pulls off the coup of the century and we should stop wasting our time with these models. Last night it was the Nam against the world now we have a serious problem.

Start saying prayers that the GFS has the same initialization problems as the Nam.

Look at this massive change in the GFS from 0Z to 12Z:

0Z:

http://www.meteo.psu...N_0z/avn84.html

12Z:

http://www.meteo.psu..._12z/avn72.html

12Z @ 84 hours:

http://www.meteo.psu..._12z/avn84.html

I've never seen two storms in the atlantic that close to each other. It has me questioning if this GFS is even possible. Also though the solution is similar to the Nam in the storm placement everything else about the solution is different than the Nam including where the second storm in the Atlantic is and the placement of the arctic high. In fact the arctic high is hardly displaced from the runs that give us an all out blizzard and in this solution I'd expect it should have been moved to where the Nam has it. This could be a bad run and I'm interested to see how the pros on Eastern play it. If the map was more identical to the Nam I'd say the trend just killed us. But I'm going to wait and see the 18Z run and the 0Z run before thinking that. That second Atlantic storm due east of our coastal hugger seems to be the only real change and again I've never seen two lows that strong so close together.

Here's the Nam by comparison:

http://www.meteo.psu..._12z/wrf84.html

Storm, Robbbs - your thoughts.

Ice,

There are initialization erros on the 12z GFS as per a couple meteorologists on eastern. The solution doesn't make sense compared to it's past several runs -- that's a HUGE flip. Appears to be a blip, however, we won't know for sure until 18z.

Remember the GFS 00z run a couple nights back -- also a "hiccup". I think this is such a dynamic, complex system, the models are haivng a difficult time figuring out the timing of northern branch short-waves. If full phase occurs -- we're dead meat. Adios.