NYC/PHL 12/21-12/27 Forecast Threats

[tombo82685]

anyone have the ukmet? Still hasn't come out on my maps

[Feb]

anyone have the ukmet? Still hasn't come out on my maps

They probably all froze to death over there.

[CooL]

storm cancel

seriously though i really like what i see, the consistency on the GFS is astounding

what i like more is the euro agrees to a certain extent with the GFS, rather than the cmc...Euro and GFS are showing a snowstorm for xmas as of right now with awesome potential when you look at the upper level setup. Thats as good as it gets this far out.

[earthlight]

Big time upper air pattern trend towards the GFS on the Euro the last two runs. Still a whole lot of time to go.

[WeatherX]

anyone have the ukmet? Still hasn't come out on my maps

[LocoAko]

12z GFS gives 18-25" throughout area.... lol

http://www.meteor.ia...s/gfs3_kswf.dat

http://www.meteor.ia...s/gfs3_klga.dat

http://www.meteor.ia...s/gfs3_kewr.dat

http://www.meteor.ia...s/gfs3_khpn.dat

http://www.meteor.ia...s/gfs3_kisp.dat

Not that it matters much at this point, but I find those estimates to be grossly overestimated. I just peeked at the BUFKIT data for the 12Z GFS for Central NJ and it shows 13.0". For LGA, 12.0". I don't know where it is getting these estimates from. They both show the same QPF (1.22" and 1.23") so I would have no idea why it would estimate 20+ in a case like this. I'm using the new release of BUFKIT which has a "Snowfall Accumulation" option, although I am not entirely sure what goes into the algorithm.

[_AR_]

Not that it matters much at this point, but I find those estimates to be grossly overestimated. I just peeked at the BUFKIT data for the 12Z GFS for Central NJ and it shows 13.0". For LGA, 12.0". I don't know where it is getting these estimates from. They both show the same QPF (1.22" and 1.23") so I would have no idea why it would estimate 20+ in a case like this.

It uses a formula to take into account air temperature and what not for higher ratios. Usually those estimates seem to come out way too high.

[BxEngine]

Not that it matters much at this point, but I find those estimates to be grossly overestimated. I just peeked at the BUFKIT data for the 12Z GFS for Central NJ and it shows 13.0". For LGA, 12.0". I don't know where it is getting these estimates from. They both show the same QPF (1.22" and 1.23") so I would have no idea why it would estimate 20+ in a case like this.

Im not 100% sure but I think it uses that same odd algorithm that those clown maps use? Something about omega values...definitely nowhere near a normal 10-1 type deal. I think theyve come close to being right in some really dynamic events...but for the most part I think youre right, they have been usually way off.

This was all stuff posted on Eastern years ago though so Im more than likely completely screwing up that explanation I think i remember lol....

[NittanyWx]

And how do those things look to you, when comparing the GFS and Euro?

This far out, both have trended towards significant amplification of the western ridge at H5. Something which was sorely lacking with this past event.

[SACRUS]

ggem/uk vs gfs/ecm

[Analog96]

Not that it matters much at this point, but I find those estimates to be grossly overestimated. I just peeked at the BUFKIT data for the 12Z GFS for Central NJ and it shows 13.0". For LGA, 12.0". I don't know where it is getting these estimates from. They both show the same QPF (1.22" and 1.23") so I would have no idea why it would estimate 20+ in a case like this. I'm using the new release of BUFKIT which has a "Snowfall Accumulation" option, although I am not entirely sure what goes into the algorithm.

Those seem a little low based on QPF. Ratios would be a bit higher, still the BUFKIT numbers are too high too. Something like 12-20 would be better, not that it matters this far out.

[Stormlover74]

Because it has 23:1 ratios for part of it. It also has 7:1 at one point as well.

Not that it matters much at this point, but I find those estimates to be grossly overestimated. I just peeked at the BUFKIT data for the 12Z GFS for Central NJ and it shows 13.0". For LGA, 12.0". I don't know where it is getting these estimates from. They both show the same QPF (1.22" and 1.23") so I would have no idea why it would estimate 20+ in a case like this. I'm using the new release of BUFKIT which has a "Snowfall Accumulation" option, although I am not entirely sure what goes into the algorithm.

[Analog96]

Because it has 23:1 ratios for part of it. It also has 7:1 at one point as well.

That's ridiculous. Seems like 12:1- 14:1 would be pretty good,.

[CooL]

Not yet, ukmet is painting a similar solution to the CMC.

[bluewave]

Which site did you find that forecast on?Those look like the FSU graphics but they took the UK down a while ago.

[WeatherX]

ggem/uk vs gfs/ecm

I think the UK is on board, judging by the SLP map.......we shall see

[WeatherX]

Which site did you find that forecast on?Those look like the FSU graphics but they took the UK down a while ago.

http://moe.met.fsu.edu/tcgengifs/ukm/

[SACRUS]

Not yet, ukmet is painting a similar solution to the CMC.

I'd bet byt tonights runs we'll have all models converging on a solution closer to the ecm

[SnoSki14]

All I know is based on the setup aloft, I'd be shocked if we didn't see a few inches for Christmas day. It probably won't look any better for the rest of the season than it does now.

[Analog96]

I'd bet we have all models converging on a solution closer to the ecm

Maybe something BETWEEN the EC and GFS? The Euro has been trending toward the GFS, and it didn't do well with the last storm threat (today).

[Analog96]

All I know is based on the setup aloft, I'd be shocked if we didn't see a few inches for Christmas day. It probably won't look any better for the rest of the season than it does now.

And I think we would all happily take an accumulating snowfall on Christmas Day.

[bluewave]

http://moe.met.fsu.edu/tcgengifs/ukm/

Cool..thanks.

[SACRUS]

Maybe something BETWEEN the EC and GFS? The Euro has been trending toward the GFS, and it didn't do well with the last storm threat (today).

At least converging on something closer to the ECM with a more robust storm further north. The UK and GGEM are conistently ugly on this one.

[Zelocita Weather]

Maybe something BETWEEN the EC and GFS? The Euro has been trending toward the GFS, and it didn't do well with the last storm threat (today).

When the two big models (EURO & GFS) are in very good agreement about the overall set-up/upper air pattern and even very similar at the surface with low placement/strenght AND one of the models (GFS) has been remarkebly consistent over the past few days with the other model moving in the direction AND both give NJ/NYC between 4" - 12"+ of snow, chances are pretty good some snow will fly on Christmas...

Details will be sorted out later, but looking good for 5-6 days out...

[LocoAko]

Those seem a little low based on QPF. Ratios would be a bit higher, still the BUFKIT numbers are too high too. Something like 12-20 would be better, not that it matters this far out.

BUFKIT ratios are too high?

Anyway, pouring through BUFKIT, there are a few things. For KLGA specifically... there is 1.23" of QPF.

In terms of snow ratios, algorithms using Profile Temperatures as well as Surface Temperatures argue for a 10:1-15:1 ratio (increasing as the storm goes on). Using a Zone Omega algorithm, these spike to 20:1-25:1, which is likely where those absurd totals come from. I guess those ratios are accurate IF the dynamics played out exactly how they are being presented but the chances of that happening are slim to none, so I think 10:1-15:1 is a better bet.

When I was using in BUFKIT was actually the "Snow Accumulation" function. That is what I was confused about what went into it.

When I do "Snow Totals" and sum them, I get "11.3 (16.1)". I am not sure what the number in parenthesis is (it is new to this version of BUFKIT). Anyone??? Perhaps it takes into account surface temperatures and other factors so that the number in parenthesis is the actual snowfall total but the outside number would be what was left over on the ground?

Also, there is a new function called "Add Hourly Snowfall". When that is performed, it comes up with exactly 16.1" which sounds both accurate for the given set up and may be what that number in parenthesis is for. In the future I think I will "Add Hourly Snowfall" but I'd be curious as to an explanation for the differences between all of these functions.

[Analog96]

BUFKIT ratios are too high?

Anyway, pouring through BUFKIT, there are a few things. For KLGA specifically... there is 1.23" of QPF.

In terms of snow ratios, algorithms using Profile Temperatures as well as Surface Temperatures argue for a 10:1-15:1 ratio (increasing as the storm goes on). Using a Zone Omega algorithm, these spike to 20:1-25:1, which is likely where those absurd totals come from. I guess those ratios are accurate IF the dynamics played out exactly how they are being presented but the chances of that happening are slim to none, so I think 10:1-15:1 is a better bet.

When I was using in BUFKIT was actually the "Snow Accumulation" function. That is what I was confused about what went into it.

When I do "Snow Totals" and sum them, I get "11.3 (16.1)". I am not sure what the number in parenthesis is (it is new to this version of BUFKIT). Anyone??? Perhaps it takes into account surface temperatures and other factors so that the number in parenthesis is the actual snowfall total but the outside number would be what was left over on the ground?

Also, there is a new function called "Add Hourly Snowfall". When that is performed, it comes up with exactly 16.1" which sounds both accurate for the given set up and may be what that number in parenthesis is for. In the future I think I will "Add Hourly Snowfall" but I'd be curious as to an explanation for the differences between all of these functions.

Where is that 16.1" number for? If it's for EWR, it's about perfect, based on GFS gridded data. 1.28" of liquid with a 13-14:1 ratio= 16.1"

[LocoAko]

Where is that 16.1" number for? If it's for EWR, it's about perfect, based on GFS gridded data. 1.28" of liquid with a 13-14:1 ratio= 16.1"

It is for KLGA.

What I really need to do is just find documentation for the new version of BUFKIT and clarify these things for myself.

[famartin]

Arguing about ratios on a storm 6 days out... :lol:Anyway, just remember that the GFS has a slight wet bias and the EC has a slight dry bias, QPF-wise.

[LocoAko]

Arguing about ratios on a storm 6 days out... :lol:Anyway, just remember that the GFS has a slight wet bias and the EC has a slight dry bias, QPF-wise.

It isn't so much about this storm so much as I've seen that link before and it always seems grossly overdone. And when it is overdone and people take them at face value, others make think the model performed much worse than it did.

[A-L-E-X]

Arguing about ratios on a storm 6 days out... :lol:Anyway, just remember that the GFS has a slight wet bias and the EC has a slight dry bias, QPF-wise.

Youre coming home for xmas regardless, correct?