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Jan 23/24 Major Coastal Storm Discussion


Zelocita Weather

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The NAM is practically stalled, and then loops, loops again and then takes off. In the time that it stalls and loops, it dumps 2ft+ of snow on the area. The movement, unfortunately, is ridiculous and unlike any other model. The RGEM looks great, similar to the NAM. Unfortunately, the CMC looks great as well at that point(and to a lesser degree, even the GFS), but past that point is where it just does not match the NAM. Extrapolated, who knows what the RGEM shows, but I doubt it would be anything like the NAM unless it stalls and loops. Although the GFS and CMC could both be "missing something", clearly the NAM is the outlier here. We have all been "NAM'd" by 25-35"+ snow amounts more than once or twice before. When it "changes it's mind", it doesn't gradually work away from the former solution; it leaves it behind like it never happened. I think we all know to toss the long range NAM, but aren't ready to give it up ;)

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I'd say the "safe" forecast at this point is 8-12" for NYC, with the possibility for more if there is a more consolidated front end that does not mix, and the CCB develops the way the NAM shows. I think warning criteria shouldn't be a problem for NYC, but this subforum still has quite a ways to go before getting the obscene totals that west and SW of Philly are looking at. The problem continues to be how deeply the upper low digs, closes off and maxes out dynamics. It could be feedback-related, but what arrives at NYC still looks subpar on most guidance compared to near DC where dynamics are better. 

 

The 6" line looks to be setting up from around Morristown ENE to White Plains, and then south of Danbury towards Middletown, CT. North of I-84 I still think has 4" or less, possibly 2" or less if the sharp cutoff happens. 

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I'd say the "safe" forecast at this point is 8-12" for NYC, with the possibility for more if there is a more consolidated front end that does not mix, and the CCB develops the way the NAM shows. I think warning criteria shouldn't be a problem for NYC, but this subforum still has quite a ways to go before getting the obscene totals that west and SW of Philly are looking at. The problem continues to be how deeply the upper low digs, closes off and maxes out dynamics. It could be feedback-related, but what arrives at NYC still looks subpar on most guidance compared to near DC where dynamics are better.

The 6" line looks to be setting up from around Morristown ENE to White Plains, and then south of Danbury towards Middletown, CT. North of I-84 I still think has 4" or less, possibly 2" or less if the sharp cutoff happens.

8-12 is exactly what I'm going with right now but I've emphasized chances are much better it ends up higher than that vs lower

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I'd say the "safe" forecast at this point is 8-12" for NYC, with the possibility for more if there is a more consolidated front end that does not mix, and the CCB develops the way the NAM shows. I think warning criteria shouldn't be a problem for NYC, but this subforum still has quite a ways to go before getting the obscene totals that west and SW of Philly are looking at. The problem continues to be how deeply the upper low digs, closes off and maxes out dynamics. It could be feedback-related, but what arrives at NYC still looks subpar on most guidance compared to near DC where dynamics are better.

The 6" line looks to be setting up from around Morristown ENE to White Plains, and then south of Danbury towards Middletown, CT. North of I-84 I still think has 4" or less, possibly 2" or less if the sharp cutoff happens.

It's looking less likely this storm has as an extreme cutoff of 2/10. And another big take home is we will not know where the best banding sets up until Friday when the short term models get in range. So somewhere in our subforum there could be a 20" lollipop most likely in north central jersey away from the coast. Overall 8-10" as an average is my call in NYC

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The NAM is practically stalled, and then loops, loops again and then takes off. In the time that it stalls and loops, it dumps 2ft+ of snow on the area. The movement, unfortunately, is ridiculous and unlike any other model. The RGEM looks great, similar to the NAM. Unfortunately, the CMC looks great as well at that point(and to a lesser degree, even the GFS), but past that point is where it just does not match the NAM. Extrapolated, who knows what the RGEM shows, but I doubt it would be anything like the NAM unless it stalls and loops. Although the GFS and CMC could both be "missing something", clearly the NAM is the outlier here. We have all been "NAM'd" by 25-35"+ snow amounts more than once or twice before. When it "changes it's mind", it doesn't gradually work away from the former solution; it leaves it behind like it never happened. I think we all know to toss the long range NAM, but aren't ready to give it up ;)

But all of that 45" is suppose to fall in just the last 27hrs of the run, like the other models storm time frames, so how does it have time to be going in circles?  It shows multiple 1 hour periods with a record 4" rate.   Seems like convection on steroids to me.

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8-12 is exactly what I'm going with right now but I've emphasized chances are much better it ends up higher than that vs lower

I know-frustrating how the GFS/GGEM still show these issues with warm layers and mystery lows popping up offshore, along with nudging the upper low east. The mid levels look pretty decent, and I remember issues popping up before with this, like 12/19/09, that turned into blizzards for NYC and east. But I guess it can't be discounted that there's interference like that. 

 

Call this the moment the models finally go in, but I'll be watching this from Austin. May the odds be ever in your favor. 

 

I'm actually rooting for the digging S/W for my backyard-it might spark up some T-storms tomorrow when it comes through. 70 and sunny here when y'all are digging out.  :snowman:

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Yeah it absolutely is IMO. I think the CMC was actually going to be better than prior runs til it did that

But can the same be said of the GFS?with upper air dynamics and positioning that seems to support for more in the way of QPF it certainly begs the question. I don't want to be self-serving by tossing the model thats not sexy but....

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But all of that 45" is suppose to fall in just the last 27hrs of the run, like the other models storm time frames, so how does it have time to be going in circles? It shows multiple 1 hour periods with a record 4" rate. Seems like convection on steroids to me.

You're right. The NAM's frames every 3 hours, along with the visible low placement off the coast still past midnight Sunday threw me off, and make the low appear to circle around while the GFS does not. The NAM quite simply blows up the precipitation and takes aim at the NJ/NYC area

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But can the same be said of the GFS?with upper air dynamics and positioning that seems to support for more in the way of QPF it certainly begs the question. I don't want to be self-serving by tossing the model thats not sexy but....

I'm less inclined to say the GFS was convective related issues. I didn't completely agree with the QPF though based on upper levels

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I am not smart enough to weed through the various model outputs and their algorithms and pre-post processing techniques, so I will end the day with a    SD of 5"    and a mean of 13" for NYC.          So   8"-18"   70%

                                                                                            3" -23"   90%      23"+  less than 3%

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Why is the NAM "extremely overdone" or a "severe outlier" with 45" yet the GFS depicting 50" for some is perfectly acceptable and "more likely to verify" because its "more realistic"? Just sayin.

The amounts down in the MA aside from higher terrain are probably too high. The Euro definitely was more realistic on high end amounts today. I bet someone sees a 35 or 36 there but it'll be higher elevations somewhere

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i'm going out on a limb and saying this thing exits between ocean city and acy,just looking at the current water vapor and satellite loops you can clearly see how far north it is currently off it's modeled forecast.in the scheme of things n.y.c looks pretty good for a heavy amount of snow. :snowing:

Looks pretty spot on to me. We'll see.

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The amounts down in the MA aside from higher terrain are probably too high. The Euro definitely was more realistic on high end amounts today. I bet someone sees a 35 or 36 there but it'll be higher elevations somewhere

The place I'd want to be for this would be something like Hagerstown, MD down to Harrisonburg, VA. This is going to be one for the record books on I-81 down that stretch, maybe even coming close to Jan 1996. I could see Dulles coming in with over 24", but DCA somehow always comes in on the low end ("low" meaning maybe 18"). 

 

I drove I-81 that way coming down to Texas, that's a gorgeous stretch down the Blue Ridge. 

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The place I'd want to be for this would be something like Hagerstown, MD down to Harrisonburg, VA. This is going to be one for the record books on I-81 down that stretch, maybe even coming close to Jan 1996. I could see Dulles coming in with over 24", but DCA somehow always comes in on the low end ("low" meaning maybe 18").

I drove I-81 that way coming down to Texas, that's a gorgeous stretch down the Blue Ridge.

I drove through it overnight 2 winters ago and it is beautiful even at night

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The place I'd want to be for this would be something like Hagerstown, MD down to Harrisonburg, VA. This is going to be one for the record books on I-81 down that stretch, maybe even coming close to Jan 1996. I could see Dulles coming in with over 24", but DCA somehow always comes in on the low end ("low" meaning maybe 18"). 

 

I drove I-81 that way coming down to Texas, that's a gorgeous stretch down the Blue Ridge. 

 

That's my home!

 

Yea, we got about 36" in 1996, looks like this'll be close.

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