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2/19 East Coast Winter Storm Threat (Part 2)


OKpowdah

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Must be me but I think the NAM looks pretty nice.

It's nowhere near the 12z/18z solutions of the GFS, that's out the window early, but that's not bad either as the GFS was not the best for me here on the CP anyway. It has a speed change down deep which helps to still keep us on the edge of the game, but it'll be tough in the NAM depicted pattern to get much more than a Cape scrapper. (again based on the NAM).

We'd need the energy in the northern stream to dig/be slower...otherwise the flow over us is the W/SW to ENE that's been advertised on the miss models.

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A few things, major timing differences with southern stream energy, GFS is about 12+hours quicker than NAM, EURO. Around 00z Sunday GFS really speeds up Southern energy while Euro holds it back.

Also how often does the NAM nail down a solution 84 hours out? One thing is for sure, this storm will be well north or well south of where the Nam now predicts for 12z Sunday.

Another interesting thing to look at is hour 84 on NAM isn't as bad as you would think from a surface perspective if you look at sim radar, the precipitation shield is moving North East with heavy precipitation getting into south central jersey by 12z Sunday, so a much closer call than it looks on this "lousy" Nam run.

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A few things, major timing differences with southern stream energy, GFS is about 12+hours quicker than NAM, EURO. Around 00z Sunday GFS really speeds up Southern energy while Euro holds it back.

Also how often does the NAM nail down a solution 84 hours out? One thing is for sure, this storm will be well north or well south of where the Nam now predicts for 12z Sunday.

Another interesting thing to look at is hour 84 on NAM isn't as bad as you would think from a surface perspective if you look at sim radar, the precipitation shield is moving North East with heavy precipitation getting into south central jersey by 12z Sunday, so a much closer call than it looks on this "lousy" Nam run.

Those two statements though don't follow the same logic. At 5h it's not the best, it's either too fast in the north or not fast enough in the south to get this all the way up the coast. So the surface/sim radar is cool, but meaningless.

If the NAM nails the 5h features at 84 hours to within 100 miles it'll be the first time.

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A few things, major timing differences with southern stream energy, GFS is about 12+hours quicker than NAM, EURO. Around 00z Sunday GFS really speeds up Southern energy while Euro holds it back.

Also how often does the NAM nail down a solution 84 hours out? One thing is for sure, this storm will be well north or well south of where the Nam now predicts for 12z Sunday.

Another interesting thing to look at is hour 84 on NAM isn't as bad as you would think from a surface perspective if you look at sim radar, the precipitation shield is moving North East with heavy precipitation getting into south central jersey by 12z Sunday, so a much closer call than it looks on this "lousy" Nam run.

Yea and looking at 300 mb and how 8 H is not scooting east, this is not a done OTS run by any means but alas it is the NAM which yesterday had tomorrows vort max on LI , that's off the Delmarva now.

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Those two statements though don't follow the same logic. At 5h it's not the best, it's either too fast in the north or not fast enough in the south to get this all the way up the coast. So the surface/sim radar is cool, but meaningless.

If the NAM nails the 5h features at 84 hours to within 100 miles it'll be the first time.

Exactly. What I'm saying is that the 5h features are not great, but with 84 hours to go who's to say that this won't change. Maybe speed up (better for us) or even slow down (not good).

But what I'm saying is even with this poor 5h set up look at the precip shield it spits out.

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Exactly. What I'm saying is that the 5h features are not great, but with 84 hours to go who's to say that this won't change. Maybe speed up (better for us) or even slow down (not good).

But what I'm saying is even with this poor 5h set up look at the precip shield it spits out.

NAMs attrocious at 500mb beyond about 24 or so hours. The only significant thing I took from it was the change towards the Euro handling north of ND in the early stages. Beyond that, it's toast and meaningless, JMHO.

There will be a time when it nails one of these, I don't think this is that time.

I'm interested to see what the GFS does in the next 12-18 hours.

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Compared to earlier GFS runs the 0z does two things:

1. faster with the energy coming into BC overnight

2. Not as impressive with the system diving towards ND (less ridging between the s/ws...so there's no opportunity for the s/w coming towards ND to tighten up...it'll be faster this run)

Those two changes, speaking specifically of just those two features is a move towards the Euro. I'll let the rest of the run play out as those are the two features I was most interested in..back to watching TV as that drama is more interesting.

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Compared to earlier GFS runs the 0z does two things:

1. faster with the energy coming into BC overnight

2. Not as impressive with the system diving towards ND (less ridging between the s/ws...so there's no opportunity for the s/w coming towards ND to tighten up...it'll be faster this run)

Those two changes, speaking specifically of just those two features is a move towards the Euro. I'll let the rest of the run play out as those are the two features I was most interested in..back to watching TV as that drama is more interesting.

Lol, what?

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Not sure if anyone from the 1st topic on this storm posted this, don't have the time to go through that. From the HPC after all the 12z models came in:

..SHORTWAVE TROUGH ENTERING THE PLAINS/MIDWEST FRI-SAT...

PREFERENCE: ECMWF

THE GFS APPEARS TO HAVE WORSE INITIALIZATION OF THE TROUGH'S

PLACEMENT OVER BRITISH COLUMBIA AND NUNAVUT THIS MORNING COMPARED

TO THE NAM/ECMWF. MEANWHILE...THE GFS IS MOST AGGRESSIVE IN

ALLOWING AN UPSTREAM PERTURBATION CURRENTLY OVER THE PACIFIC TO

CUT THROUGH THE SHORTWAVE RIDGE OVER THE CANADIAN ROCKIES ON

THURSDAY...WHICH THEN PHASES WITH THE NORTHERN STREAM AND SLOWS

THE ENTIRE GFS SOLUTION. THE COMBINATION OF WORSE INITIALIZATION

AND QUESTIONABLE AND EVEN SUSPICIOUS PHASING OF THE SEPARATE

STREAMS IS SUFFICIENT TO DISCARD THE GFS PARTICULARLY LATE IN THE

PERIOD. AMONG THE REMAINING SOLUTIONS...THE NAM BECOMES SLIGHTLY

FASTER THAN THE CANADIAN/ECMWF...WHILE THE UKMET IS SLOW AND

AMPLIFIED...WITH ITS GREATER AMPLIFICATION POSSIBLY AN INDICATION

OF ITS STRONG BIAS AT LATER TIME FRAMES. THUS...THE UKMET IS

DISCOUNTED. MEANWHILE...THE NAM...WHILE PLAUSIBLE...IS CONSIDERED

LESS LIKELY THAN THE ECMWF DUE TO ITS NARROWER DATA ASSIMILATION

WINDOW AND ULTIMATELY QUESTIONABLE INITIALIZATION PARTICULARLY AT

THE HIGHER LATITUDES.

(http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdhmd)

In my advanced forecasting class, my professor discussed this storm, one main issue with the 12z GFS was the longwave and how short and funky it was, he claims that the atmosphere is uncomfortable when you have a short/funky longwave. He also discussed the issues concerning the cut off low in the southwest and how bad the models do trying to predict the energy coming out of it. After over 30 years of experience, he is not sold on this storm. To him too many issues. To me, the GFS is trying to phase, when it is not phase until later. Not buying it, and until otherwise (aka, a high pressure is in Southern Canada - Ontario or Quebec), no big storm for us.

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