Bust of the Century January 26-27 2015 model suites and discussions

[SleetStormNJ]

Yes this is typical convective feedback issues for the NAM. It looks beautiful at h5 and again h3 with the jet streaks are just mouth watering. The convection feedback at the surface pulls it east and elongates it.

 

I don't understand how the NCEP models (GFS does this all the time too) can struggle so mightily with this type of issue and do it over and over to boot in lead ups to major storms.  I mean is it algorithmic?  Data ingestion?  Resolution?  

I'd love a MET to chime in on this.

[danstorm]

Steady folks, steady...

The NAM is a clown model, its solutions oftentimes look more like toddler fingerpaintings than atmospheric reality. I'd toss it even if it had 4' for all...

[SnoSki14]

Go with the Euro simple as that. It has the best track record, it's the best model, it's had the most continuity, and it caught this storm initially. I really would be shocked if tonight's Euro was that different otherwise there was some serious corrupted data in its previous runs. 

 

If all the other models are similar to the Nam then I'll bite. Keep in mind the Nam went from very little at 06z this morning to a massive hit in one run at 12z and 18z. 

[Morch Madness]

The 0z NAM is Exhibit A in why it is an awful model. Throw it directly out of your nearest window.

[+SNfreak21]

Look at the double barrel low at 54hrs after it closes off at 500mb, trash model

[Mitchel Volk]

Looks like the NAM cuts totals for most everyone. I wish I could see the NCEP data but it stops at 27 hours. I need to see the GFS and RGEM before I make any assistment.

BTW did I hear that Bill Evens went for 36" that is insane to forecast until you see where the heavier bands form and develop.

[Nygmen]

people have to realize this...the euro is so far west with precip it would take a huge jump east just to screw the western part of this sub forum...we are 24 hours out...the euro making that big of a jump east after 3 runs holding steady in a row would be a fail of biblical proportions for it

[WintersGrasp]

The NAM does do the loopy, just much further NE

[BL03]

Everything looks nice in the beginning of the run... the tailing s/w that will phase is coming in a little quicker but then the NAM just seems like it can't handle/get a grasp of things and fires convection all over before organizing the storm...   

[The_Global_Warmer]

Look at those height contours bend from that intense lift.  Don't want to see that.

 

 

 

 

 

[ScottB]

The NAM does do the loopy, just much further NE

Probably because it spends 6-8 hours determining where to place the damn surface lp on its way up. Would like to see the 4k res and the rest of the 0z suites before figuring out how to handle reading the nam's solution

[jm1220]

Look at those height contours bend from that intense lift.  Don't want to see that.

 

 

 

 

 

 

 

Very likely overdone, and that's what pulls the low east. Aloft, it's a great setup with the 500mb low closed south of NYC.

[RU848789]

I've been talking about it all day, and JB as well as JC and a few others believe many will see 20:1/30:1 ratios overnight Monday into Tuesday.. Even someone at 1.0qpf could end up at 18-20"

 

 

billgwx explained the reasoning, strong winds tend to break the crystals up into smaller pieces thereby reducing the ratios.

 

Just to amplify on Bill's comments, which I agree with, what's going on, fundamentally is that high winds lead to much more horizontal and vertical movement of the falling snowflakes, which are relatively brittle.  But it's not the wind, per se, that "breaks" the dendrites, it's the wind causing far more particle-particle (i.e., snowflakes colliding) collisions, leading to breakage.  This is a very common process with pharmaceutical crystalline solids slurried in a solvent and recirculating through a high shear rotor-stator "wet mill" in which particle-particle collisions break the particles, not the mill itself.  

[WintersGrasp]

Hi-res NAM looks the same really.....Has NE NJ in the 6" area, NYC in the 6-10", 15-20" on the island and 25-30" around BOS

[NEXtreme]

DT doesn't care for the NAM ... Says its incorrect and it does this sometimes before an event .

[+SNfreak21]

Slight alteration of the 500mb and where the low closes off once transferred to the coast reminds me of Dec 2010, where the models were really causing mass hysteria run to run, I think that makes a major difference on the snow totals (especially west of the city), so it is a "fragile" storm, but the Euro is very consistent and the ULL over Kentucky looks nice and its ready to dig the trough into a neutral/neg tilt as expected (not an expert, mets chime in)

[The_Global_Warmer]

The backside of the trough is so much better as well you would think the nam would have come in crushing from the NE Philly burbs threw the Hudson Valley, NYC, to Worcester. 

 

If the nam tones down that convection over the gulf stream I'd expect to see it explode closer to Delaware and drop a 3" qpf band from NNJ to Worcester

 

 

 

 

[WintersGrasp]

RGEM is running.....Light snow overspreading the area in the early morning hours....

[The_Global_Warmer]

Very likely overdone, and that's what pulls the low east. Aloft, it's a great setup with the 500mb low closed south of NYC.

 

 

Exactly.  And the backside has a nice piece of energy coming down as well.

 

 

 

 

[UlsterCountySnowZ]

The backside of the trough is so much better as well you would think the nam would have come in crushing from the NE Philly burbs threw the Hudson Valley, NYC, to Worcester.

If the nam tones down that convection over the gulf stream I'd expect to see it explode closer to Delaware and drop a 3" qpf band from NNJ to Worcester

 

Exactly why I had thought jumping the gun thinking it would explod much sooner... Shouldn't have posted an opinion till the run played out lol

[SACRUS]

1/26 00Z Summary

 

NYC : QPF (snowfall)

 

SREF: 1.10 - 1.40  (>18")

NAM:  0.85 - 1.15  (>12")

[RU848789]

DT doesn't care for the NAM ... Says its incorrect and it does this sometimes before an event .

We've all seen the NAM hiccup with a run before a big event, but given that the NWS based its forecast accumulations on a blend of the Euro and NAM, as per the AFD and Billgwx's comments on this thread, I don't think it's quite right to say, "toss the NAM."  It has to at least give one pause.  Let's see if it's an outlier or a trendsetter - hopefully the former (at least the SREFs were still good).  

[Sophisticated Skeptic]

NAM has been pretty much consistent with that same track though... 3 runs in a row. 

 

along with a slight eastward shift each run. 

 

can't just say 'throw it out' because it's what u want. 

[HailMan06]

NAM vs. the world.

[WintersGrasp]

RGEM at 25 hours compared to it's last run looks bit east...Hitting long island and southern new england hard at that time, but being pulled east quicker than its last run

[SnoSki14]

It would be a major bust but there are indication of a capture further east. 

[Rjay]

NAM vs. the world.

More like the Euro/Euro ensembles vs the world.

[Superstorm93]

RGEM

 

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

[WintersGrasp]

The serious banding on the RGEM is further east. Considering that its last run was also far east (of the euro), we would have liked it to trend west, not the opposite. Hoping for the best with the euro, but expecting the worst. Kinda gets to a point where you can't toss out every other model....Or can you ? lol

[ScottB]

Guys the 12z suite was essentially the same damn thing. Nam east. Rgem east. Wait for the full 0z suite to run and we'll go from there.