18z Models 2/11/2014 | Potential Major Coastal Storm

[WeatherFox]

Forecasters that separate themselves from the rest of the pack with respect to a very challenging "snowstorm forecast" use their knowledge of climatology, meteorology and ensemble forecasting.  They shy away from MOS or the single model of the day.   Something I learned while at Certificate in Weather Forecasting at Penn State University.  

[UlsterCountySnowZ]

Don't forget a lot of times models tend to overcorrect themselves when playing catch up then adjust properly in this case a western trend was inevitable...and models may have come too far west... It's also the 18z, I think the 00z will bring it back east a bit

[IsentropicLift]

The 18z GEFS mean is very similar to the op. The surface freezing line ends up way inland while the 850mb lags southeast.

[snowNAO]

Is it me or wouldn't that RGEM latest run be rain for most? Its 980 inland. Hopefully too amped.

[NickD2011]

RGEM is trying to phase the kicker. I doubt that happens

[IsentropicLift]

It's not unusual for models to over correct west inside of 48 hours.

[bluewave]

Looking like a really rough go with the potentially historic icestorm over the Southeast.

 

 

 

 

[WintersGrasp]

Forecasters that separate themselves from the rest of the pack with respect to a very challenging "snowstorm forecast" use their knowledge of climatology, meteorology and ensemble forecasting. They shy away from MOS or the single model of the day. Something I learned while at Certificate in Weather Forecasting at Penn State University.

So true ! Despite all the drama lol....I've always respected DT's forecasts and he seemed to have an idea about this one well ahead of time. It is so easy to follow certain model runs especially when all of them are trending a certain way. My gut feeling for this storm is that for the NENJ/NYC area, we see 3-5" of snow followed by a quick switch to rain ending as an inch or two of snow. As much as the models can easily trend the other way, when we're this close to an event and they are trending the opposite direction and it seems to make sense (no blocking, high sliding off the coast, kicker slowed down, marginal temps, strong area of low pressure)....we have a lot going against us and not as much going for us. Hopefully I'm wrong

[SleetStormNJ]

Is it me or wouldn't that RGEM latest run be rain for most? Its 980 inland. Hopefully too amped.

Yup.

[IsentropicLift]

This doesn't look like its phasing the kicker to me at all. I think someone probably posted that somewhere and people are running with it like they know what they are talking about. It's more just a product of being very amplified at 500mb. This would likely track northeast from here.

 

[earthlight]

The trends are strongly towards a less snowy scenario along the coast. I understand why some people are defaulting to the "dynamics will cool things off" idea, but that doesn't apply when the mid level warm air advection is so strong.

What needs to be understood is that the damage is done prior to the H5 and mid level centers taking a favorable track. In essence, the shortwave being so ramped up initially forces positive vorticity advection to be especially impressive near OBX. The developing surface low can tuck northwestward amidst an explosive jet structure. And the result is a southeasterly fetch to the north of it. Warm air advection in the mid levels will be simply surging northwest from the Western Atlantic into the Northern Mid Atlantic and there is no mechanism to stop that as currently modeled.

This is not to say that there won't be a thump of moderate snow initially, because all guidance indicates that. There is very impressive lift surging northward into the area at the start of the storm. Many areas are going to see very heavy snow and I suspect some convective snow as well. But right behind this comes the warming mid levels.

The surface low then pulls northeast to a position presumably east of ACY. But at that point we have to cool the column again. I like that models are hinting at a redeveloping CCB underneath a favorable jet structure at that time. But hanging my hat on back end snows is never something I indulge in.

This is not to say that all hope is lost. We can still benefit from a tick east and southeast. The mid level low being a little less amped up initially could benefit us greatly with a solution similar to the GGEM. But right now it is looking more and more likely that many areas will see a moderate amount of snow followed by a change to rain. What happens thereafter is still up in the air.

[nyblizz44]

The trends are strongly towards a less snowy scenario along the coast. I understand why some people are defaulting to the "dynamics will cool things off" idea, but that doesn't apply when the mid level warm air advection is so strong.

What needs to be understood is that the damage is done prior to the H5 and mid level centers taking a favorable track. In essence, the shortwave being so ramped up initially forces positive vorticity advection to be especially impressive near OBX. The developing surface low can tuck northwestward amidst an explosive jet structure. And the result is a southeasterly fetch to the north of it. Warm air advection in the mid levels will be simply surging northwest from the Western Atlantic into the Northern Mid Atlantic and there is no mechanism to stop that as currently modeled.

This is not to say that there won't be a thump of moderate snow initially, because all guidance indicates that. There is very impressive lift surging northward into the area at the start of the storm. Many areas are going to see very heavy snow and I suspect some convective snow as well. But right behind this comes the warming mid levels.

The surface low then pulls northeast to a position presumably east of ACY. But at that point we have to cool the column again. I like that models are hinting at a redeveloping CCB underneath a favorable jet structure at that time. But hanging my hat on back end snows is never something I indulge in.

This is not to say that all hope is lost. We can still benefit from a tick east and southeast. The mid level low being a little less amped up initially could benefit us greatly with a solution similar to the GGEM. But right now it is looking more and more likely that many areas will see a moderate amount of snow followed by a change to rain. What happens thereafter is still up in the air.

and the room goes silent.

[USCG RS]

This doesn't look like its phasing the kicker to me at all. I think someone probably posted that somewhere and people are running with it like they know what they are talking about. It's more just a product of being very amplified at 500mb. This would likely track northeast from here.

I'll take responsibility for that blunder. I edited it immediately but obviously the damage was done and for that I apologize. Those graphics, imo, do not show the kicker phasing in. As I said in my edit, the kicker is likely too late and allows the storm to completely phase to a point that it gets drawn further NW. Again my apologies for causing confusion.

[IsentropicLift]

I'll take responsibility for that blunder. I edited it immediately but obviously the damage was done and for that I apologize. Those graphics, imo, do not show the kicker phasing in. As I said in my edit, the kicker is likely too late and allows the storm to completely phase to a point that it gets drawn further NW. Again my apologies for causing confusion.

Don't sweat it. Regardless the 18z RGEM is still likely a good front end dump followed by a switch to rain and then back to snow. Places well inland would jackpot immensely.

[snowNAO]

at least I am in York Pa..So I am way safer than most on this sub forum. Sorry NYC, its not over yet for you, but trends aren't looking good neither for me .

[BoulderWX]

The trends are strongly towards a less snowy scenario along the coast. I understand why some people are defaulting to the "dynamics will cool things off" idea, but that doesn't apply when the mid level warm air advection is so strong.

What needs to be understood is that the damage is done prior to the H5 and mid level centers taking a favorable track. In essence, the shortwave being so ramped up initially forces positive vorticity advection to be especially impressive near OBX. The developing surface low can tuck northwestward amidst an explosive jet structure. And the result is a southeasterly fetch to the north of it. Warm air advection in the mid levels will be simply surging northwest from the Western Atlantic into the Northern Mid Atlantic and there is no mechanism to stop that as currently modeled.

This is not to say that there won't be a thump of moderate snow initially, because all guidance indicates that. There is very impressive lift surging northward into the area at the start of the storm. Many areas are going to see very heavy snow and I suspect some convective snow as well. But right behind this comes the warming mid levels.

The surface low then pulls northeast to a position presumably east of ACY. But at that point we have to cool the column again. I like that models are hinting at a redeveloping CCB underneath a favorable jet structure at that time. But hanging my hat on back end snows is never something I indulge in.

This is not to say that all hope is lost. We can still benefit from a tick east and southeast. The mid level low being a little less amped up initially could benefit us greatly with a solution similar to the GGEM. But right now it is looking more and more likely that many areas will see a moderate amount of snow followed by a change to rain. What happens thereafter is still up in the air.

 

very well said.. unfortunately... would you be leaning more towards an Eastern PA/Western NJ jack pot based on latest guidance?

[REDMK6GLI]

Don't sweat it. Regardless the 18z RGEM is still likely a good front end dump followed by a switch to rain and then back to snow. Places well inland would jackpot immensely.

ive substantially lowered my expectations for SW Suffolk where I am. Im thinking that I may get like maybe 6" total. backend snows I never hang my hat on as they may happen but intensity is usually nowhere near it was forecasted to be. purely an inland storm at this point, congrats to the EURO

[JetsPens87]

and the room goes silent.

 

The trends are strongly towards a less snowy scenario along the coast. I understand why some people are defaulting to the "dynamics will cool things off" idea, but that doesn't apply when the mid level warm air advection is so strong.

What needs to be understood is that the damage is done prior to the H5 and mid level centers taking a favorable track. In essence, the shortwave being so ramped up initially forces positive vorticity advection to be especially impressive near OBX. The developing surface low can tuck northwestward amidst an explosive jet structure. And the result is a southeasterly fetch to the north of it. Warm air advection in the mid levels will be simply surging northwest from the Western Atlantic into the Northern Mid Atlantic and there is no mechanism to stop that as currently modeled.

This is not to say that there won't be a thump of moderate snow initially, because all guidance indicates that. There is very impressive lift surging northward into the area at the start of the storm. Many areas are going to see very heavy snow and I suspect some convective snow as well. But right behind this comes the warming mid levels.

The surface low then pulls northeast to a position presumably east of ACY. But at that point we have to cool the column again. I like that models are hinting at a redeveloping CCB underneath a favorable jet structure at that time. But hanging my hat on back end snows is never something I indulge in.

This is not to say that all hope is lost. We can still benefit from a tick east and southeast. The mid level low being a little less amped up initially could benefit us greatly with a solution similar to the GGEM. But right now it is looking more and more likely that many areas will see a moderate amount of snow followed by a change to rain. What happens thereafter is still up in the air.

 

Great post John. The writing may be on the wall here. With no block, an H5 low closing off that early would surely spell disaster along the coast. I still believe in the end that as long as the kicker does not phase in it will ultimately act as a repellant to the coastal low and hopefully not allow it to close off so early. However, as I was speaking to before, with so much energy rounding the base of the trough, it may spin itself up into exactly that kind of situation. Also, a departing HP with the coastal riding up the eroding back side of it does not a HECS make.

 

I will wait until 00z tonight to make my forecast though, as that is when we should have all players on the field as well as the Recon data ingested. At that point we may begin to see some more consensus amongst data.

 

If you were to ask me where the heaviest snows were going to be right now I would say from interior SEPA-up past ABE into NWNJ(Sussex,Warren) and into SNY (lower and mid Hudson valley). SE from there I would be seriously concerned.

[USCG RS]

ive substantially lowered my expectations for SW Suffolk where I am. Im thinking that I may get like maybe 6" total. backend snows I never hang my hat on as they may happen but intensity is usually nowhere near it was forecasted to be. purely an inland storm at this point, congrats to the EURO

with all due respect, I would not congratulate the Euro quite yet. This is a very complicated storm with a plethora of components to it. Additionally, the s/W is incredibly energetic. So while the Euro looks like it has a good handle on this storm, I don't think it's perfect yet. I also want to remind those that the kicker is not yet onshore, thus it has not been sampled and just a minor change in this leads to huge implications for our area (take for example the storm that was showing Sunday and then when the northern stream shortwave was sampled, models lost the storm).

[LongBeachSurfFreak]

The Euro keeps winds NE to NNE so I think most of the warming will be aloft before temps drop again at night.

That's great news with those winds we never never go above mid 30s with very very minimal melting

[DiehardFF]

No one worried about ZR? Sure, the Mid Lvls torch but perhaps the low levels hold on longer...

[USCG RS]

No one worried about ZR? Sure, the Mid Lvls torch but perhaps the low levels hold on longer...

Imho, no. Without that HP in place, there's no cool air being funneled in and thus we need dynamics to keep us relatively cold.

[bluewave]

That's great news with those winds we never never go above mid 30s with very very minimal melting

 

Hopefully, we can get into some of the wraparound snows Thursday night after the front end thump and change to rain

during the day.

[SnoSki14]

Hopefully, we can get into some of the wraparound snows Thursday night after the front end thump and change to rain

during the day.

So how warm will the surface get, will the rain get absorbed or will it melt all the snow. Most wraparound snows don't produce much though last Feb was a pleasant surprise so who knows if we get anything after though the 18z gfs shows it too so that's something I guess.

[ILoveWinter]

Its not a complete disaster (so far), I mean we do get an initial thump.  Also, John did leave at least some possibility for a slight improvement.

[jm1220]

So how warm will the surface get, will the rain get absorbed or will it melt all the snow. Most wraparound snows don't produce much though last Feb was a pleasant surprise so who knows if we get anything after though the 18z gfs shows it too so that's something I guess.

If it stays around 35 or below, little will melt. The rain will just be absorbed by the snow and then freeze later.

[JetsPens87]

I truly think the models have over corrected in their 18z suites... U guys gotta stop getting so worked up over each run like the latest model run is what's gonna happen.. Plenty of time for change...

 

The models have played this game all winter long, yes the trend has been NW, but only up until about 24-36 hours before the event starts when they correct back SE a bit. That correction SE a bit(as long as we don't come too far NW) could really help still. Too many people giving up hope when in meteorological terms we still have lots of time.

[UlsterCountySnowZ]

The models have played this game all winter long, yes the trend has been NW, but only up until about 24-36 hours before the event starts when they correct back SE a bit. That correction SE a bit(as long as we don't come too far NW) could really help still. Too many people giving up hope when in meteorological terms we still have lots of time.

Which was all I was suggesting.. That we don't take an over corrected 18z suite so serious especially over 24hr out...

[JetsPens87]

No one worried about ZR? Sure, the Mid Lvls torch but perhaps the low levels hold on longer...

 

This is not really a good ZR setup. If any areas of mixing it would predominantly be IP due to mid levels warming.

[SnoSki14]

The models have played this game all winter long, yes the trend has been NW, but only up until about 24-36 hours before the event starts when they correct back SE a bit. That correction SE a bit(as long as we don't come too far NW) could really help still. Too many people giving up hope when in meteorological terms we still have lots of time.

What comes to mind is the Monday storm when the Nam and other models had the very heavy snow up in NW NJ, Eastern PA extending to NE NJ when in reality it was considerably further south by nearly 100 miles or so. So I guess anything is possible and hopefully it is an over-correction as I can't really imagine it going any further west than it is now.