December 18-20 Talking Points - Part 2

[yoda]

Let's see what the GEM Ens say. Maybe the Op was a fluke.

I am pretty sure this is the correct ensemble run

72 -- http://www.weatheroffice.gc.ca/ensemble/charts_e.html?Hour=72&Day=0&RunTime=12&Type=pnm

84 -- http://www.weatheroffice.gc.ca/ensemble/charts_e.html?Hour=084&Day=0&RunTime=12&Type=pnm

[Rainshadow]

through hr 90 there is no sruface reflection at all, the trof is pretty neg tilted, but no surface reflection, also its not as amplified in my eyes as 0z

FWIW the FIM had a New Jersey coast scrape.

[Rainshadow]

I am pretty sure this is the correct ensemble run

72 -- http://www.weatherof...ime=12&Type=pnm

84 -- http://www.weatherof...ime=12&Type=pnm

Yeah glancing at all of the members it looks like the op is toward the western edge of its ensemble solutions.

[am19psu]

Let's get back to discussing the weather and not bashing each other. Thanks.

[IsentropicLift]

The Euro was a step in the right direction, on this run the PV shifted west just as we wanted but the shortwave is very weak. I think that the strength was way underestimated with this run. Both are a change in continuity. If you take the location of the PV along with a stronger shortwave you get a solution closer to the GFS. I'm putting my faith in the GFS here. I'm not saying that its going to be a hit but I think its idea of a very close miss is much more accurate. I still think once we get more inside the NAM's range that will be the key. If the NAM says no storm, then this thing is offically dead. Some people put way too much credit in the Euro. Instead of looking and saying its a miss. Look and see why is it a miss. Not sure if their was an initialization error also that may have had some effect.

[atownwxwatcher]

Last time i had checked the verification models all the models had taken a downhill turn and it looked like the GGEM was actually at the top as far as best performing at day 5.

When it comes to this storm i do not think that any model is going to have a proper handle on the situation until 24 hours out and under. The ECM was the first one that showed this and it was literally burying the east coast...So if this is suppose to be the best model that there is it got off to a atrocious start with this storm system because at that point and time the GFS was not even showing it.

Then it was four runs in a row where the ECM had a huge East Coast storm of which delivered anywhere from 6 inches to a foot plus. There after it had backed off... However...last night it was considered an outlier because of the way it handled a low pressure area across SE Canada...

I am not saying the ECM is not a superior model because it is..however it becomes superior and deadly at 48 hrs and out. Until then it is open to and subjected to any other flaws like any other model

[KEITH L.I]

The Euro was a step in the right direction, on this run the PV shifted west just as we wanted but the shortwave is very weak. I think that the strength was way underestimated with this run. Both are a change in continuity. If you take the location of the PV along with a stronger shortwave you get a solution closer to the GFS. I'm putting my faith in the GFS here. I'm not saying that its going to be a hit but I think its idea of a very close miss is much more accurate. I still think once we get more inside the NAM's range that will be the key. If the NAM says no storm, then this thing is offically dead. Some people put way too much credit in the Euro. Instead of looking and saying its a miss. Look and see why is it a miss. Not sure if their was an initialization error also that may have had some effect.

Euro had no snow for the Island Monday night..I got 2 inches..it's a good model..but it's just a computer..It's not god

[Rainshadow]

yes, op seems to be an outlier.

Relative to its ensemble members today, yes. What this has to do with the final outcome, I'm not sure yet. Its still four days away and all of the players are not being as accurately sampled as possible at initialization time.

[blizzardof09]

Euro had no snow for the Island Monday night..I got 2 inches..it's a good model..but it's just a computer..It's not god

Not god but some call it king lol....but it does look a step in the right direction though alteast

[Rainshadow]

Last time i had checked the verification models all the models had taken a downhill turn and it looked like the GGEM was actually at the top as far as best performing at day 5.

When it comes to this storm i do not think that any model is going to have a proper handle on the situation until 24 hours out and under. The ECM was the first one that showed this and it was literally burying the east coast...So if this is suppose to be the best model that there is it got off to a atrocious start with this storm system because at that point and time the GFS was not even showing it.

Then it was four runs in a row where the ECM had a huge East Coast storm of which delivered anywhere from 6 inches to a foot plus. There after it had backed off... However...last night it was considered an outlier because of the way it handled a low pressure area across SE Canada...

I am not saying the ECM is not a superior model because it is..however it becomes superior and deadly at 48 hrs and out. Until then it is open to and subjected to any other flaws like any other model

Maybe I wasn't looking at the whole east coast but my recollection of the Euro runs were that all of its 00z runs did not have a hit, well in our area this post I believe is true.

[greg ralls]

Final nail in coffin. Euro at this timeframe is normally locking in things.

Disagree. I'd wait until 12Z tomorrow before putting any nails in any coffin.

[IsentropicLift]

Disagree. I'd wait until 12Z tomorrow before putting any nails in any coffin.

let's see what the ensembles bring, they seem to hint which direction things are going for the next run. For example it seemed to pick up on the westward movement of the PV before the OP.

[Yorkpa25]

When are the ensembles?

[Porsche]

When are the ensembles?

I believe they come out around 3:30

[psv88]

http://www.weather.com/weather/tenday/11747

Not that weather.com is ever accurate, but they have snow chance at 40% for sunday...seem to be going with GFS? Also looks pretty damn cold next 10 days

[Kmlwx]

http://www.weather.c...er/tenday/11747

Not that weather.com is ever accurate, but they have snow chance at 40% for sunday...seem to be going with GFS? Also looks pretty damn cold next 10 days

I don't think weather.com uses ANY human input, quite frankly. It's probably straight up GFS derived. Not exactly an accurate source. I'd pick the NWS any day.

[am19psu]

Rosenstein at HPC is actually buying the 12z GFS. Wow. Here is Day 5.

[tmagan]

I'm still sticking with my call for a big warm up toward New Year's Eve/Day.

[gkrangers]

So why is the Euro a fail? Is it PV related or shortwave related? Or both?

[A-L-E-X]

Disagree.  I'd wait until 12Z tomorrow before putting any nails in any coffin.

Correct, proper data sampling doesnt occur until 12z tomorrow so all outcomes are on the table.

[A-L-E-X]

So why is the Euro a fail?  Is it PV related or shortwave related?  Or both?

According to DT, the Euro has developed a bias with holding the s/w too far to the SW

[IsentropicLift]

http://www.weather.c...er/tenday/11747

Not that weather.com is ever accurate, but they have snow chance at 40% for sunday...seem to be going with GFS? Also looks pretty damn cold next 10 days

The chance of snow is rather high at this time, especially for Long Island where your located. The bigger question is, does just the coast get brushed? or alot less likely atm, are we dealing with a major event for the entire east coast?

[tmagan]

By the way, the 12Z KMA is way out to sea with the Sunday storm.

[am19psu]

According to DT, the Euro has developed a bias with holding the s/w too far to the SW

The Euro has that problem with cutoffs in the SW. I don't necessarily think that is the problem here. The GFS is already more amplified at T+24 over SoCal. My guess is that is a few meters difference at initialization.

[IsentropicLift]

HPC says...don't dismiss the GFS!

12Z GFS REMAINS THE MOST AGGRESSIVE MODEL WITH ITS STRONGER

SHORTWAVE AMPLIFICATION AS IT APPROACHES THE EAST COAST SATURDAY.

ITS MID LEVEL CONFIGURATION BY DAYS 4-5 FITS THE 00Z ECMWF ENS

MEAN PATTERN. ITS EXACT TRACK IS CRITICAL TO PCPN CHANCES AND

AMOUNTS ALONG THE NORTHEAST COAST ESPECIALLY NEW ENGLAND. GOOD

AGREEMENT BY THE 12 GFS ENS MEAN AND 12Z CMC BUT CONTINUED FLAT

AND WELL AT SEA BY THE UKMET AND 12Z ECMWF. UNCERTAINTY CONTINUES

WITH TWO SEPERATE CAMPS. RAPID OFFSHORE DEEPENING SCENARIO BY THE

GFS RUNS SEEMS MORE LIKELY AS THE SHORTWAVE AND DEVELOPING SFC LOW

ENCOUNTER AN UNSTABLE MARINE ENVIRONMENT WITH INCREASED

BAROCLINICITY FROM THE CURRENT STRONG COLD ADVECTION FLOW OVER

RELATIVELY WARM OCEAN WATERS.

[SACRUS]

I had tried posting these 12z GGEM images before, but my pc crashed. Anyway it looks like 0.10 - 0.25 qpf south of for the area 0.25 (+) for the area and 0.50 just north and east of NYC.

[Colin]

just to summarize...we have the following:

gfs - hit (for eastern sections)

ggem - hit (for eastern sections)

ukmet - out to sea

euro - out to sea

kma - out to sea

jma - out to sea

being west of the cities, i've thrown in the towel but i guess for those along i-95 and east (especially coastal sections) still have a shot at a few inches.

[jm1220]

It could be the Euro's bias of holding the energy back too much, or the GFS could be overemphasizing the southern stream wave (which I find to be unusual since the GFS' cold bias often underemphasizes the southern stream). The GFS ensembles lurching west and the NAM's apparent agreement show that there's probably something to this west trend today. I would've liked the Euro coming on board but there's time for it to change. The polar vortex looks like it won't be a problem now for amplification, and may even help it along. The key is how much of a wave moves into the Miss. Valley and sharpens the trough. The GFS and Euro still appear to be in alternate universes with regards to that wave, and one or the other will likely be very wrong. Euro ensembles later today could be telling.

[RutgersWx92]

just to summarize...we have the following:

gfs - hit (for eastern sections)

ggem - hit (for eastern sections)

ukmet - out to sea

euro - out to sea

kma - out to sea

jma - out to sea

being west of the cities, i've thrown in the towel but i guess for those along i-95 and east (especially coastal sections) still have a shot at a few inches.

Keep in mind that the NAM would also likely be a hit if it continued past 84 hours. GFS ensembles are also in agreement with the OP's shift west.

[Kaner587]

SREF's out to 72 look a lot like 12z nam and gfs