February 12-13 Storm, Part III: Trilogy ends and then Obs thread soon!

[Scarlet Pimpernel]

its not drier. Those are 6 hour panels... I was thrown as well

Yeah, I also had to do a double-take because the plot didn't say 6-hour amount...had to go by what Yoda said.

[vinylfreak89]

The GFS has implied a bigger bit than the sfc shows for days. I guess it really sucks or is the best ever.

 

not really. the h5 was not supportive of a big hit until tonights run

[winterymix]

When Kocin posted his maps yesterday, that was his nod and wink.

He saw a pattern with excellent potential.

I think we all need to adjust our expectations to match climatology.

If most get 4" to 8" with some mixing, be happy.  If it overperforms,

be happy but realize we may wait another year or three before it happens again.

[vinylfreak89]

UKIE is lockstep with 12Z for those confused. Not drier

[Grothar of Herndon]

UKIE is lockstep with 12Z for those confused. Not drier

Thanks

[Scarlet Pimpernel]

UKIE is lockstep with 12Z for those confused. Not drier

 

Yes, looks remarkably similar including bombing the low out.

[yoda]

Yes, looks remarkably similar including bombing the low out.

 

Yes, UKIE should be same as 12z... maybe slightly better QPF wise

[dtk]

agree 100 % that strong convection can rob moisture from a system. What I have a problem with is not how the QPF field is screwed with, but the emergence of strong convection in the first place. None of the dynamics support it.

 

Here is 30 hours h5, for when that panel I posted is valid starting QPF time, where do you see any lifting mechanism to support strong convection off the coast like that? UL support is way down in GA

Convective precipitation isn't necessarily driven by the main (upper level) large scale dynamic forcing.  I would have to look at profiles, cap, and then find the trigger(s).  The convection looks to be driven from the bottom, since at hour 30 there is strong low level warm advection, some frontogenetical forcing, and perhaps some low level convergence.  With the correct profiles, the model has no choice but to trigger convection in the warm sector to adjust.

[mitchnick]

UKIE is lockstep with 12Z for those confused. Not drier

and CBB still at work at 48 hrs too

700mb RH

http://vortex.plymouth.edu/cgi-bin/gen_grbcalc2.cgi?re=us&id=&zoom=.6&ti=0≥=1280x1024&mo=ukmet≤=700&va=rhum&in=5&pl=cf&ft=h48&cu=latest&overlay=no&mo=≤=&va=&in=&pl=ln&ft=h24&cu=latest

850mb RH

http://vortex.plymouth.edu/cgi-bin/gen_grbcalc2.cgi?re=us&id=&zoom=.6&ti=0≥=1280x1024&mo=ukmet≤=850&va=rhum&in=5&pl=cf&ft=h48&cu=latest&overlay=no&mo=≤=&va=&in=&pl=ln&ft=h24&cu=latest

[StudentOfClimatology]

Ukie is *not* drier...though correct that it's west and colder than the GFS. Very similar from what I can tell to its 12Z.

I need to remember not to post when sleep deprived. It's a wonder I haven't flunked out of school yet.

[Ian]

not really. the h5 was not supportive of a big hit until tonights run

not sure how you come to that conclusion but here's 6z and 12z. CIPS has been spitting out big hits for days from the GFS even though it's looked pretty meh.

 

 

[WxMan1]

If you had to pick one model that has been pretty consistent with this system, beginning on FRIDAY (6 days out)...

 

I think it would have to be the UKMet.  Actually for a while, the UK and CMC were steady as she goes until the CMC went farther west with the SLP track 12Z today.

[Scarlet Pimpernel]

It's truly hard to know what to make of the last 2 GFS cycles.  Quite a conundrum.  I hope it's off the rails in some manner.

[yoda]

and CBB still at work at 48 hrs too

700mb RH

http://vortex.plymouth.edu/cgi-bin/gen_grbcalc2.cgi?re=us&id=&zoom=.6&ti=0≥=1280x1024&mo=ukmet≤=700&va=rhum&in=5&pl=cf&ft=h48&cu=latest&overlay=no&mo=≤=&va=&in=&pl=ln&ft=h24&cu=latest

850mb RH

http://vortex.plymouth.edu/cgi-bin/gen_grbcalc2.cgi?re=us&id=&zoom=.6&ti=0≥=1280x1024&mo=ukmet≤=850&va=rhum&in=5&pl=cf&ft=h48&cu=latest&overlay=no&mo=≤=&va=&in=&pl=ln&ft=h24&cu=latest

Not much QPF after I would surmise though IMO... prob 2-3mm more

[mitchnick]

If you had to pick one model that has been pretty consistent with this system, beginning on FRIDAY (6 days out)...

 

I think it would have to be the UKMet.  Actually for a while, the UK and CMC were steady as she goes until the CMC went farther west with the SLP track 12Z today.

RGEM came back east some tonight so CMC will "probably" do the same

[Scarlet Pimpernel]

I need to remember not to post when sleep deprived. It's a wonder I haven't flunked out of school yet.

 

LOL!  Apologies if that came off harsh how I said it, not my intent.

[ohleary]

I don't think we need a reason to throw out the GFS QPF....It is an outlier...that is reason enough...I don't think anyone who has followed the model evolution of this storm can say much positive about the GFS or put any faith in it at all....I am looking forward to the upgrades...

 

Agree with the first bolded.  Regarding the second bolded, anyone who isn't just forecasting on a forum is looking seriously at it.  It's now not showing much that other models aren't save for low qpf.  At this point take from it what is helpful and leave the details to the mesoscale models..this system the devil is in the details, not something a lower res model will necessarily handle well within 24 h.

[winterymix]

Convective precipitation isn't necessarily driven by the main (upper level) large scale dynamic forcing.  I would have to look at profiles, cap, and then find the trigger(s).  The convection looks to be driven from the bottom, since at hour 30 there is strong low level warm advection, some frontogenetical forcing, and perhaps some low level convergence.  With the correct profiles, the model has no choice but to trigger convection in the warm sector to adjust.

So why are the precipitation maps so different for the NAM compared to the GFS?

I thought the NAM was skillful with modeling temperature as well as warm and cool convection.

Which model is more believable for this storm?

[Ian]

this appears to be more than a trilogy -- prob can get thru another whole model thread still

[mitchnick]

Not much QPF after I would surmise though IMO... prob 2-3mm more

Euro gave BWI .27" after 0Z Friday, so maybe closer to 4-6mm if it's similar to Euro

[dtk]

I don't think we need a reason to throw out the GFS QPF....It is an outlier...that is reason enough...I don't think anyone who has followed the model evolution of this storm can say much positive about the GFS or put any faith in it at all....I am looking forward to the upgrades...

Yeah, it hasn't performed particularly well.  My commentary on DA, model physics, interpretation of "convective feedback", etc., is only to help get rid of some commonly overused (and misused) justification for tossing model integrations that people don't like.

[vinylfreak89]

not sure how you come to that conclusion but here's 6z and 12z. CIPS has been spitting out big hits for days from the GFS even though it's looked pretty meh.

 

gfs_namer_063_500_vort_ht.gif

 

gfs_namer_057_500_vort_ht.gif

 

analog packages don't take in to account whether a low is closed of vs open... its how many Standard Deviations at spot x and y and alignment of the height pattern (but mostly departures I think... someone with more info can chime in)...and those maps you posted to me do not scream rapid deepening/strong frontogenesis. Tonights run does.

 

ETA: They mostly say "moderate hit" to me

[wxmeddler]

Just loaded up all the H5 maps I could on the accuwx pro "animator" main difference I am seeing is the evolution of the GL system.

[Ian]

analog packages don't take in to account whether a low is closed of vs open... its how many Standard Deviations at spot x and y and alignment of the height pattern (but mostly departures I think... someone with more info can chime in)...and those maps you posted to me do not scream rapid deepening/strong frontogenesis. Tonights run does.

ok. i'll disagree with your assessment but you make good pts. this may be a better run but your original comment was incorrect imo.

[Scarlet Pimpernel]

Agree with the first bolded.  Regarding the second bolded, anyone who isn't just forecasting on a forum is looking seriously at it.  It's now not showing much that other models aren't save for low qpf.  At this point take from it what is helpful and leave the details to the mesoscale models..this system the devil is in the details, not something a lower res model will necessarily handle well within 24 h.

I'm not sure I'd even say it's much of an outlier per se.  Maybe a bit more east, but in terms of 500-mb and surface track it's pretty similar to others.  But the temperatures and precip are clearly far different.

[Deck Pic]

Yeah, it hasn't performed particularly well.  My commentary on DA, model physics, interpretation of "convective feedback", etc., is only to help get rid of some commonly overused (and misused) justification for tossing model integrations that people don't like.

 

I appreciate your comments about this stuff

[k94]

If you had to pick one model that has been pretty consistent with this system, beginning on FRIDAY (6 days out)...

 

I think it would have to be the UKMet.  Actually for a while, the UK and CMC were steady as she goes until the CMC went farther west with the SLP track 12Z today.

 

Include the EURO too, until what went down @12z today.

[dtk]

So why are the precipitation maps so different for the NAM compared to the GFS?

I thought the NAM was skillful with modeling temperature as well as warm and cool convection.

Which model is more believable for this storm?

Neither?  To be honest, I'm not sure.  One certainly wouldn't normally want to rely on a coarser resolution model for a short range, dynamic forecast like this.  However, the GFS is generally decent guidance (with weaknesses and biases in certain regimes/regions/situations not being forgotten about) and I don't think it can simply be ignored.

[yoda]

00z GGEM at 24 -- http://weather.gc.ca/data/model_forecast/528_100.gif

 

Snow moving into region... 1007mb L Big Bend of FL

 

36 --http://weather.gc.ca/data/model_forecast/530_100.gif

 

Heavy snow... 999mb L off SE NC coast by ~50 miles or so

 

48 -- http://weather.gc.ca/data/model_forecast/531_100.gif

 

Looks close to a capture... snow winding down... 982mb L just SW of 40/70 BM

[nj2va]

Hires:  4kNAM, RGEM, RAP, HRRR, NAM?, Euro?

Globals:  GGEM, GFS, UKIE

 

I thought I previously read that the Euro is a hires model but I can't remember.  Just trying to get a handle on which models are the higher res vs. the others.