December 18-20 Talking Points - Part 2

[goombatommy]

Coastal areas should not give up. However if you are inland by about 50 miles then it is time to move on.

Well, things are definitely looking more interesting come Christmas weekend . And its not just DC South and east either.

[benfica356]

is Roselle Park still in the game lol

[Riptide]

is Roselle Park still in the game lol

Cape Cod FTW.

[mitchnick]

Cape Cod FTW.

maybe on the GFS, but the Euro gave the cape around .03" on the 12z run

[mattinpa]

All those who are saying they are giving up are sure to be watching the 00z runs like everyone else. It's until 12z tomorrow for me - at that point I'll look more towards the next threat if no good trends.

[whiteoutwx1796]

All those who are saying they are giving up are sure to be watching the 00z runs like everyone else. It's until 12z tomorrow for me - at that point I'll look more towards the next threat if no good trends.

Next threat? Get ready for cold and dry.

[Quincy]

Re: two lows

It's just an elongated area of low pressure, the resolution blips out what appears to be two separate lows.

[Riptide]

Next threat? Get ready for cold and dry.

Don't forget about the occasional clipper.

[Voyager]

Well, things are definitely looking more interesting come Christmas weekend . And its not just DC South and east either.

And that's what......10 days away???

[jm1220]

I'm not throwing in any towels until all features are initialized on land. If this weak/no wave situation still exists then, it's obviously all over.

In probably even an ENSO neutral year the southern stream wouldn't be so dead like this lol.

[greg ralls]

This thread makes a good case for the forums to have special "read-only" threads that can only feature posts from professional meteorologists. I loathe having to sort through all of the garbage to find the valid points made by the experts on the forums.

[Yorkpa25]

When will the gfs ensembles be out?

[earthlight]

When will the gfs ensembles be out?

Just initialized

[earthlight]

18z GFS Ensemble mean has shifted south and east a good bit. Not a whiff, but a definite shift.

[earthlight]

The mean brings about 0.75" QPF to NYC by 120 hours--but we all know how uninformative the mean QPF can be.

[redbanknjandbigbasslakepa]

I have to admit I never really was enthused about this threat. 500mb pattern just is not amplified enough and too progressive to get a storm up the coast. I think that has been pretty clear using the Euro for days now. This one is over guys. The Euro is hundreds of miles east of even being considered a threat to this region. There is no way in hell it is wrong by that much. In fact it is probably dead on close at this point.

I really think we should not even take serious any threat unless it is on the Euro within say 4 days. You'll save yourself a lot of heartache. I mean it doesn't have to be a direct blow on the Euro, but at least somethng of a hit at the surface. In fact, if the NWS and US weather outlets wanted to be more accurate in their forecasts they would talk to the Euro folks, run it four times a day to establish more output and identify any trends and scrap the rest of the numerical output because it is all garbage. If you followed the Euro, maybe ran it every six hours and forgot about the rest you would have a lot more accurate picture of the weather without the wild swings in emotion and hope.

[_AR_]

This thread makes a good case for the forums to have special "read-only" threads that can only feature posts from professional meteorologists. I loathe having to sort through all of the garbage to find the valid points made by the experts on the forums.

model huggers

[WeatherX]

Spaghetti plot on the 18Z GEFS is impressive, to say the least

[earthlight]

Here's the 18z GFS ensemble spread..all of the red lines indicate 990 or lower surface pressure and those are really the ones you want to pay attention to. The heavy black line I outlined is the OP GFS. Heavy disagreement and heavy hope on these ensembles.

[Riptide]

Thank you GFS ensembles, I almost killed myself.

[SACRUS]

How were the euro ensembles?

[earthlight]

[SACRUS]

3/12 nice hits, 2/12 grazers and 7/12 total misses

[SBUWX23]

3/12 nice hits, 2/12 grazers and 7/12 total misses

Too early to give up but I am begging to think this might be the start of a hedging toward the ECMF and UKMet idea of a flatter southern stream. Obviously there is still plenty of time, but I am for one concerned at the overall consistency of the Euro being a miss for several days now and also has been showing the flatter southern stream now for a few runs.

[Riptide]

The good thing about weather is that if you don't like what you see now, you can just wait six hours and maybe find something you like.

I still believe the euro and GFS will merge in the middle with a near-miss for the coast and MECS for parts of the SNE. Mabye that southern shortwave will become more potent again.

[rossi]

Nick Gregory on Fox 5 NY just indicated that the Atlantic is very favorable for the storm to come more west.

I respect Nick alot as I am sure most of you in NY/NJ do.

Rossi

[WeatherX]

Nice disco from Upton

Long term /Saturday night through Tuesday/... 
there are two camps in the extended...the La-Nina/fast Pacific flow 
dominated ECMWF/UKMET...and the negative nao dominated GFS/CMC/gefs 
mean. Noting that the negative nao has been a dominate player so 
far...and there is no clear signal that it will abate...have used 
the gefs mean as the basis for the extended forecast...as it is not 
the extreme of either the operational GFS or CMC global. This also 
fits in with the idea that when you are in an aclimatological 
pattern...as we are...that you go with the aclimatological solution 
- which the GFS/CMC/gefs mean are for a La Nina pattern. 


Ultimately either one of the two solutions will play out...there is 
no middle ground...as if the nao yields...then the fast Pacific flow 
will win out...with a flatter less amplified solution bearing out. 
However...this is not the most likely solution at this time. 


The net result is that the mean trough is most likely to continue to 
linger over the NE US...with below normal temperatures. This trough 
will interact with Pacific energy...currently forecast to reach the 
Pacific northwest Friday night...and reach the middle Atlantic coast by Sunday 
morning. This should yield a storm off the middle Atlantic 
coast...which at this time likely will track to the southeast of the 40/70 
benchmark. For now bring in chance probability of precipitation across southern areas 
Saturday night...then chance probability of precipitation throughout Sunday and Sunday 
night. For now it appears that most areas will be all snow...though 
without a strong high to the north...enough warm air could work its 
way in for the Twin Forks to see a rain/snow mix at times. 


Based on the expected low track...the best chance for accumulating 
snows is over the southeast 2/3 of the County Warning Area...with the highest probability 
over eastern CT/Long Island (depending on mixing there). Since there 
is still at least a 30 percent chance of warning level snows across 
the County Warning Area...will continue to mention in the severe weather potential statement...though will 
highlight that eastern areas have the best chance for significant 
snow. The lack of a strong overrunning high is somewhat 
problematic...as dynamical/frontogenetic forcing will be the key for 
significant snows...as the isentropic lift should be weak with this 
storm. Unfortunately...model skill at placing frontogenetic/dynamic 
forcing is not great...especially this far out. As a result...not a 
high confidence forecast in the details. 


In the wake of the storm...should have disturbances coming around 
the base of the trough to warrant slight chance probability of precipitation for snow 
showers Monday-Wednesday (except for now Tuesday night...as it 
appears we should be in between shortwaves then). 


For temperatures...used a blend of mex/mex ensemble mean/low mex 
ensemble mean member and subtracted a degree to counteract typical 
warm GFS bias in this pattern for highs...and a mex/mex ensemble 
mean blend for lows. 

[LetItSnowInPhilly]

Nick Gregory on Fox 5 NY just indicated that the Atlantic is very favorable for the storm to come more west.

I respect Nick alot as I am sure most of you in NY/NJ do.

Rossi

Atlantic:

Pacific:

[Ridingtime]

Nice disco from Upton

Long term /Saturday night through Tuesday/... 
there are two camps in the extended...the La-Nina/fast Pacific flow 
dominated ECMWF/UKMET...and the negative nao dominated GFS/CMC/gefs 
mean. Noting that the negative nao has been a dominate player so 
far...and there is no clear signal that it will abate...have used 
the gefs mean as the basis for the extended forecast...as it is not 
the extreme of either the operational GFS or CMC global. This also 
fits in with the idea that when you are in an aclimatological 
pattern...as we are...that you go with the aclimatological solution 
- which the GFS/CMC/gefs mean are for a La Nina pattern. 


Ultimately either one of the two solutions will play out...there is 
no middle ground...as if the nao yields...then the fast Pacific flow 
will win out...with a flatter less amplified solution bearing out. 
However...this is not the most likely solution at this time. 


The net result is that the mean trough is most likely to continue to 
linger over the NE US...with below normal temperatures. This trough 
will interact with Pacific energy...currently forecast to reach the 
Pacific northwest Friday night...and reach the middle Atlantic coast by Sunday 
morning. This should yield a storm off the middle Atlantic 
coast...which at this time likely will track to the southeast of the 40/70 
benchmark. For now bring in chance probability of precipitation across southern areas 
Saturday night...then chance probability of precipitation throughout Sunday and Sunday 
night. For now it appears that most areas will be all snow...though 
without a strong high to the north...enough warm air could work its 
way in for the Twin Forks to see a rain/snow mix at times. 


Based on the expected low track...the best chance for accumulating 
snows is over the southeast 2/3 of the County Warning Area...with the highest probability 
over eastern CT/Long Island (depending on mixing there). Since there 
is still at least a 30 percent chance of warning level snows across 
the County Warning Area...will continue to mention in the severe weather potential statement...though will 
highlight that eastern areas have the best chance for significant 
snow. The lack of a strong overrunning high is somewhat 
problematic...as dynamical/frontogenetic forcing will be the key for 
significant snows...as the isentropic lift should be weak with this 
storm. Unfortunately...model skill at placing frontogenetic/dynamic 
forcing is not great...especially this far out. As a result...not a 
high confidence forecast in the details. 


In the wake of the storm...should have disturbances coming around 
the base of the trough to warrant slight chance probability of precipitation for snow 
showers Monday-Wednesday (except for now Tuesday night...as it 
appears we should be in between shortwaves then). 


For temperatures...used a blend of mex/mex ensemble mean/low mex 
ensemble mean member and subtracted a degree to counteract typical 
warm GFS bias in this pattern for highs...and a mex/mex ensemble 
mean blend for lows. 

Wow, that is extremely positive. Lets hope their expertise wins out with this one and they get it right.

[CTWeatherFreak]

Re that fine Upton discussion, what, pray tell, is this 'County Warning Area'?