Thanksgiving Eve SECS/MECS Discussion II

[NorthShoreWx]

Did you see my post with the sounding, not looking good for nyc right now. Maybe 1 - 3 tops.

 

That sounding was for Long Branch, NJ.  Not NYC.  But I do agree it looks hideous.

[JC-CT]

at the end of the run (hr 15) it shows the rain snow line collapsing and is moisture loaded

 

Did you happen to catch what the 18z GFS showed at hour 384?

[LongBeachSurfFreak]

It's very unlikely in this setup the entire thing feels weird as I don't recall off hand a storm tracking east of us which was as dynamic as this where we didn't go over to a decent period of snow but in this case the 700 low tracks inland, this could potentially bust even worse than we think to the extent even inland areas see very little

I don't understand what mechanism causes the mid level low to do that. Just because the models show it doesn't mean it's going to happen. All the good forcing should be shooting towards the Gulf Stream with all the convection . That's the big thing here this is a super moist amped miller A. I think if anything it actually ends up dryer then modeled west and wetter east

[Zelocita Weather]

Temps really crashing in n interior jersey...40 in Somerville already and 41 Morristown

[WintersGrasp]

Temps really crashing in n interior jersey...40 in Somerville already and 41 Morristown

A few areas are at 33 degrees including Walpack. I'm at 50 here

[Guest Pamela]

In my experience, when the mid range models forecast cyclogenesis along the East Coast 4 to 7 days out, the thermal profiles forecast are almost always going to seem unusually cold.  Then, as the storm approaches (from a time perspective) all the models concurrently feature solutions that get gradually warmer...until about 24 hours prior to the actual onset of the snow or rain...which would probably be where we are now...or at least the 12z or 18z runs were today.  Then, at the last moment, the process reverses ever so slightly and the models start to show ever so slightly colder solutions right before the precip moves in...and the actual result is usually a bit colder that those very warm models showed 24 hours before.  Assuming arguendo that there is an element of validity to this take on the matter, I would think that the 0z runs may trend a fraction colder and the worst (i.e. furthest NW) modeled rain / snow lines will likely be displaced a bit to the SE of those extreme solutions. 

[Heisy]

PS. Remember the RGEM weatherbell map is using 10:1 ratios (it'll likely be worst)....plus places would likely waste a lot of snow on non-accumulating snow. 

[SnowGoose69]

In my experience, when the mid range models forecast cyclogenesis along the East Coast 4 to 7 days out, the thermal profiles forecast are almost always going to seem unusually cold. Then, as the storm approaches (from a time perspective) all the models concurrently feature solutions that get gradually warmer...until about 24 hours prior to the actual onset of the snow or rain...which would probably be where we are now...or at least the 12z or 18z runs were today. Then, at the last moment, the process reverses ever so slightly and the models start to show ever so slightly colder solutions right before the precip moves in...and the actual result is usually a bit colder that those very warm models showed 24 hours before. Assuming arguendo that there is an element of validity to this take on the matter, I would think that the 0z runs may trend a fraction colder and the worst (i.e. furthest NW) modeled rain / snow lines will likely be displaced a bit to the SE of those extreme solutions.

Sometimes the case, models always underdo midlevel warm advection when the 700 or 850 lows track over or to your west up until 24-36 hours before, in this case though models really didn't have the 700 low west or over us til close in. This is why southwest flow or WAA winter events in the southern us often are forecast too snowy, models may show 850s of -1c with SW winds of 75 knots, the end result there will be 850 verifying at +2c and sleet most times

[Guest Pamela]

Sometimes the case, models always underdo midlevel warm advection when the 700 or 850 lows track over or to your west up until 24-36 hours before, in this case though models really didn't have the 700 low west or over us til close in. This is why southwest flow or WAA winter events in the southern us often are forecast too snowy, models may show 850s of -1c with SW winds of 75 knots, the end result there will be 850 verifying at +2c and sleet most times

 

I recall that February 2008 one did turn out all right though...but point taken.

[Zelocita Weather]

A few areas are at 33 degrees including Walpack. I'm at 50 here

Yeah, temps are all over the place, NYC is 52 and parts of somerset, hunterdon, Morris, and Sussex well into the 30s....interesting

[NEG NAO]

Temps really crashing in n interior jersey...40 in Somerville already and 41 Morristown

if you are looking for a quick change to frozen tomorrow you would want your temps below 40 when your precip starts with DP's below 25 and wind direction from the N or N-NE and heavier precip to start sooner then later to help cool down the layers faster - thats why don't be surprised if it is frozen first to the southwest of here similar to the November 2012 storm

 

http://kamala.cod.edu/nj/latest.asus41.OKX.KOKX.html

[Guest Pamela]

There are times when the amount of WAA is actually overdone...I've seen times when the Low is oh say near Ohio / West Virginia...its raining in Pittsburgh and even Cleveland...but with cold air building down from New England and the Maritime Provinces (*especially* in February & March)...forecast changeovers to rain are delayed considerably...several inches of snow accumulates...and by the time the warm air arrives...its too late. 

[NEG NAO]

Yeah, temps are all over the place, NYC is 52 and parts of somerset, hunterdon, Morris, and Sussex well into the 30s....interesting

and I would assume all of these areas are mostly cloudy ? First thing I was thinking was there was some clearing in the area causing some radiational cooling

[rgwp96]

Yeah, temps are all over the place, NYC is 52 and parts of somerset, hunterdon, Morris, and Sussex well into the 30s....interesting

clear skies =rad cooling

[Guest Pamela]

All the radiational cooling in the world isn't going to make any difference along the coastal plain once the wind resumes blowing...

[alwaysready126]

All the radiational cooling in the world isn't going to make any difference along the coastal plain once the wind resumes blowing...

will the winds come from the east?  I thought that the winds would be coming down from the north?

[Guest Pamela]

Can't be much cold air advection as most of N. Jersey was calm or light out of the SW at last observation...

[Guest Pamela]

will the winds come from the east?  I thought that the winds would be coming down from the north?

 

They should veer to northeast / 45 degrees.

[NorthShoreWx]

and I would assume all of these areas are mostly cloudy ? First thing I was thinking was there was some clearing in the area causing some radiational cooling

 Definitely the case here.  Temp is down to 43 and I expect it might rise a little for a while later this evening.  It is not clear clear,,,but just enough.

 

You can visualize this very well by plotting the 2 meter and 85 meter temps on the tower at OKX:

 

http://wx1.bnl.gov/graph.html

 

It is about 8 degrees warmer at 85 meters height than at the surface (50 vs. 42). 

 

You can also plot the difference in wind between the 10 meter standard surface observation level and 85 meters.  The winds at the surface are nearly calm while they are blowing a steady 15 mph from the southwest at 85 meters.  If any of those winds mix down, the surface temperature will rise to 50.

[alwaysready126]

They should veer to northeast / 45 degrees.

if this storm occurred in January, is it fair to say that the entire coastal plain would see snow, down to VA?

[Guest Pamela]

Its about 44 F in Scranton / Avoca and 38 F at Albany...two not terribly encouraging numbers 12 hours from a storm.  On the bright side, dewpoints at both those airports have fallen off into the mid-20's...so there might be *something* to work with. 

[TWCCraig]

Think it will be more of a sleet/rain mix. While 700mb is above freezing, lower levels are still below freezing (except surface). I think most of us on the island will see snow at some point tomorrow, definitely early on before mid level warming arrives and after the mid level warmth escapes though majority of precip may be done by then. A potential for a C-1" exists.

[Wxoutlooksblog]

This storm is going to disappoint alot of folks. But there could also be some nice surprises. It will be interesting to watch this unfold. 

WX/PT

[Guest Pamela]

if this storm occurred in January, is it fair to say that the entire coastal plain would see snow, down to VA?

 

The coastal plain near Virginia (Norfolk  / Portsmouth) only averages six inches of snow per year....its always iffy down there...Atlantic City averages about 15 inches...maybe...but too many other variables....NYC averages almost 30 inches...so if there was a good cold anticyclone parked over Quebec, the upper air pattern was favorable, and the track progged today for the surface feature was the same...yes, I think there is a good chance NYC would see a pretty fair snowstorm. 

[KEITH L.I]

if this storm occurred in January, is it fair to say that the entire coastal plain would see snow, down to VA?

Without a doubt

[Guest Pamela]

I know people discount the warm ground...but face it...the ground is pretty warm after today & yesterday and has very little time to chill.  Especially in urban settings. With current temperatures close to 50 F in NYC...that process is not even underway.

[WintersGrasp]

I know people discount the warm ground...but face it...the ground is pretty warm after today & yesterday and has very little time to chill. Especially in urban settings.

Yeah, to really accumulate it's going to have to come down very hard since we won't have a rapid drop off in temperature dipping below freezing

[mob1]

Its about 44 F in Scranton / Avoca and 38 F at Albany...two not terribly encouraging numbers 12 hours from a storm. On the bright side, dewpoints at both those airports have fallen off into the mid-20's...so there might be *something* to work with.

The 850 line was shown on all models to retreat north a bit before crashing back south towards the morning, this isn't exactly a gradient pattern it's a stale airmass with the lowest temperatures still well west northwest.

[jm1220]

The coastal plain near Virginia (Norfolk  / Portsmouth) only averages six inches of snow per year....its always iffy down there...Atlantic City averages about 15 inches...maybe...but too many other variables....NYC averages almost 30 inches...so if there was a good cold anticyclone parked over Quebec, the upper air pattern was favorable, and the track progged today for the surface feature was the same...yes, I think there is a good chance NYC would see a pretty fair snowstorm. 

If the airmass behind this front was just a little colder many people would receive a good bit more snow. At the surface at least most of us will have a good wind direction and the low should track far enough east that it should stay that way. Only problem is that it's a putrid airmass. The mid level low tracks though aren't great. A significant snow event usually has the 500mb vort pass southeast of us, so I think there would be a changeover eventually but would have to fight through more cold air to get there.

[Guest Pamela]

So overall, my take, at least for NYC / urban NJ would be that I've seen more favorable setups than this one fail to deliver much snow.  However, each & every storm is unique and can surprise...so with a little luck, you never know.