Potential Clipper Jan 21st 2015

[SleetStormNJ]

GFS is cooking something up similar to the NAM Wednesday evening into the overnight (Hrs 72 and 78 on the current run).  Showing coastal development off Virginia.

[nyblizz44]

GFS is cooking something up similar to the NAM Wednesday evening into the overnight (Hrs 72 and 78 on the current run).  Showing coastal development off Virginia.

Bingo......hold your breaths....Ladies & gents.

[rcad1]

Nws is back to a rain/snow mix on Wednesday for western Long Island.... they changed that forcast fast first it was rain then all snow now it's back to a mix!!!!

[WintersGrasp]

While the GFS came in a bit better than its previous run, let's not let the NAM get us excited here. Rather than think of the 18z GFS as "trending toward the NAM solution", think of it as the GFS a looking a bit better than the 12z run (giving us 1-3" and more for eastern LI) and the NAM exaggerating it's solution as it usually does (4-8"). Just because the NAM comes out before the GFS does not mean it is more accurate or "on to something". It has been proven time and time again that is not true. until more model support comes in and this idea is carried through in subsequent runs, we shouldn't be expecting this to be more than a 2-4" system, if that. The likelihood is that this either doesn't get its act together, or does turn the corner too late.

[SleetStormNJ]

While the GFS came in a bit better than its previous run, let's not let the NAM get us excited here. Rather than think of the 18z GFS as "trending toward the NAM solution", think of it as the GFS a looking a bit better than the 12z run (giving us 1-3" and more for eastern LI) and the NAM exaggerating it's solution as it usually does (4-8"). Just because the NAM comes out before the GFS does not mean it is more accurate or "on to something". It has been proven time and time again that is not true. until more model support comes in and this idea is carried through in subsequent runs, we shouldn't be expecting this to be more than a 2-4" system, if that. The likelihood is that this either doesn't get its act together, or does turn the corner too late.

 

Right now, there really isn't a "likelihood" of anything.  Too soon to tell either way.

 

I think the GFS and NAM are suggestive now of the idea of coastal development.  But there's been too much of a lack of model run to model run on continuity or progression (48 hrs ago, several models were strong on a light-significant event, then dramatically backed off to dry just 24hrs ago).  We need to see the idea of a coastal development and NE track hold water so to speak tonight and tomorrow.

 

What is interesting is they are keying in on the second low and s/w to come down out of Canada.  They dry out/shear off the first one. Something to watch for in the next few runs.  I was surprised when the GFS introduced and trended stronger with the second one in this 18z run before it finally does weaken and transfer to a new low off of Virginia.

[jbenedet]

Key here was the trailing shortwave was dampened quite a bit, which is the difference between flurries and a moderate snow event. As a result the leading shortwave (our storm) was able to amplify the downstream ridge and intensify.

As was said earlier, keying in on the NAM itself isn't important. It can be viewed as a leading indicator in the sense that the latest data becomes visible with it first, as it is the first to run. This can give us clues about the upcoming gfs run...

[WintersGrasp]

Right now, there really isn't a "likelihood" of anything. Too soon to tell either way.

I think the GFS and NAM are suggestive now of the idea of coastal development. But there's been too much of a lack of model run to model run on continuity or progression (48 hrs ago, several models were strong on a light-significant event, then dramatically backed off to dry just 24hrs ago). We need to see the idea of a coastal development and NE track hold water so to speak tonight and tomorrow.

What is interesting is they are keying in on the second low and s/w to come down out of Canada. They dry out/shear off the first one. Something to watch for in the next few runs. I was surprised when the GFS introduced and trended stronger with the second one in this 18z run before it finally does weaken and transfer to a new low off of Virginia.

I definitely agree here that this one is one to watch. I'm saying that this is more likely to not develop into something too significant for a couple reasons. First and and foremost is that despite what models have seemed to show 3-4 days out, the outcomes have usually seemed to favor more progressive solutions. The fast flow has been pushing the ridge quickly eastward and causing the positively tilted trough with cold air present to push systems out to sea. While this could change, similar setups 3-4+ days out have not yielded significant snowstorms. I think 4-8" snowstorms have become so common and have been overshadowed by 10-20"+ storms over the past several years that we've forgotten that rather than them just being bigger storms that have failed to come together too well.....4-8" snowstorms occur when the weather goes "against the grain". In other words, it is usually unlikely that they will happen for us, even in pretty good patterns. Given that our areas accumulate only 20-30" per season on average, but we feel the effects of many storm systems per winter, the likelihood truly is that they will miss us, for one reason or another. The other reason is just for our own sanity, it is best to expect the worst and hope for the best (especially given the countless times we were "almost there" this season so far)

[SnowGoose69]

Key here was the trailing shortwave was dampened quite a bit, which is the difference between flurries and a moderate snow event. As a result the leading shortwave (our storm) was able to amplify the downstream ridge and intensify.

As was said earlier, keying in on the NAM itself isn't important. It can be viewed as a leading indicator in the sense that the latest data becomes visible with it first, as it is the first to run. This can give us clues about the upcoming gfs run...

 

Its not just the trailing shortwave but also the lobe of energy in SRN Canada is now not as strong and was not that strong on the 12Z runs either, but definitely that trailing vort over Minnesota isn't as strong which is what killed this thing on last night's runs and the 12z runs...part of the reason the trailing vort is weakened I think is due to this one being slower and stronger so it almost absorbs the trailing piece into itself.

[Guest Pamela]

Both American models hinting at some pretty good potential for a significant snowstorm...especially out over Long Island for Wednesday afternoon...given that we are within 72 hours...some credence must be given.

[Guest Pamela]

All the reactions tossing the favorable runs at 18z are not unexpected...when you have not had a snowfall of more than 2 inches in almost a year...you will have a tendency to adopt a "believe it when I see it approach". Very common conditioned mindset.

[SnowGoose69]

Both American models hinting at some pretty good potential for a significant snowstorm...especially out over Long Island for Wednesday afternoon...given that we are within 72 hours...some credence must be given.

 

Its possible it could just be 18z runs toying with us but there is definitely a physical reason visible for why they made the change...the RGEM through 54 did look like the NAM too

[Guest Pamela]

Also, this may be an event that misses (or mostly misses) central New Jersey (i.e. Monmouth & Middlesex Counties)...but really goes to town off to the northeast...L.I. & SNE...the last couple of years have caused some to forget that there are more of those than one would think...since central Jersey has been hit unusually hard by most events since about Boxing Day...maybe even back to the 12/19/2009 storm. 

[Guest Pamela]

Also, this may be an event that misses (or mostly misses) central New Jersey (i.e. Monmouth & Middlesex Counties)...but really goes to town off to the northeast...L.I. & SNE...the last couple of years have caused some to forget that there are more of those than one would think...since central Jersey has been hit unusually hard by most events since about Boxing Day...maybe even back to the 12/19/2009 storm. 

 

2004-05...now that was a classic winter illustrating the quoted concept...

*image courtesy of board member NorthShoreWx*

[WintersGrasp]

2004-05...now that was a classic winter illustrating the quoted concept...

*image courtesy of board member NorthShoreWx*

Definitely! I almost forgot how well Long Island did then. As you said, even if most of us in an around NYC as well as the NW burbs do miss out on this next one, it is possible that Long Island gets hit hard. Just how sometimes we can all get almost no snow while the NW burbs get hit hard, Long Island can sometimes get hammered while many of us watch it explode for the island on radar. LI, especially eastern, often does well from the coastal SNE systems that develop too late for us. Hopefully this one pans out well for the island, at the very least

[Guest Pamela]

Definitely! I almost forgot how well Long Island did then. As you said, even if most of us in an around NYC as well as the NW burbs do miss out on this next one, it is possible that Long Island gets hit hard. Just how sometimes we can all get almost no snow while the NW burbs get hit hard, Long Island can sometimes get hammered while many of us watch it explode for the island on radar. LI, especially eastern, often does well from the coastal SNE systems that develop too late for us. Hopefully this one pans out well for the island, at the very least

There was also a big difference during 2003-04...the winter before:

[Guest Pamela]

Or the winter before that...2002-03:

 

[Guest Pamela]

These statistics clearly demonstrate how much snowier it has been out over sections of Long Island than most of the rest of the mid-Atlantic region over the last 14 years...

Total Snowfall
2000-01 through 2013-14 (Last 14 Years)

Boston / Logan Airport: 679.8 inches / average 48.56 inches
Brookhaven Lab, L.I. / Upton: 596.1 inches / average 42.58 inches
New York City / Central Park: 467.5 inches / average 33.39 inches
Philadelphia / International Airport: 389.9 inches / average 27.85 inches
Baltimore / BWI Airport: 292.0 inches / average 20.86 inches
Washington / Reagan Airport: 214.7 inches / average 15.34 inches

 

Snowfall chart WSO Upton:

 

http://www.bnl.gov/weather/4cast/MonthlySnowfall.htm

 

[Guest Pamela]

Even the winter of 2008-09...a winter that is seldom discussed because of its unremarkable snow totals (though it was rather cold)...produced a decent snow season around these parts...

 

 

[WintersGrasp]

Or the winter before that...2002-03:

Yeah the differences in the totals are pretty extreme. I wonder what the snowfall averages the past several years have been for areas around Wading River, or Rocky Point. Those areas seem to be hit even harder than Brookhaven south of them

[Guest Pamela]

Yeah the differences in the totals are pretty extreme. I wonder what the snowfall averages the past several years have been for areas around Wading River, or Rocky Point. Those areas seem to be hit even harder than Brookhaven south of them

 

Couple things factor in to help them...close to the 41st parallel (i.e. north...which *always* helps*...area is not too developed...at best suburban...some parts semi rural...the slightest bit of altitude relative to the S. Shore (highest spot is 401 feet...much of N. Shore is above the 200' contour)...the open waters of the Sound do enhance snowfall just a bit...sticking out to the east allows the area to catch these late developing cyclones...while for areas to the SW...by the time the cyclone gets its act going, it is too late. 

[nyblizz44]

Or the winter before that...2002-03:

I remember those seasons when LI outperformed all areas to the west but the level of outperformance is mindnumbing. 2nd behind BOS and well over a 100 inches more than CPK. thats a wow. In winter 1990 In experienced it with a storm that dumped about 8 inches in Stonybrook and then headed back to Rutgers that same day to find barely 2 inches on the ground. It can and does happen with more frequency than many think. In fact the current scenario can easilyspell 6-9 out by the forks and barely 3 in CPK. we shall see.

[NEG NAO]

18Z GEFS has the heaviest precip across central/southern  NJ up through LI with between 0.25 and 0.50 qpf - ensembles showed more precip then the OP on the 12z runs and is leading the way for this event

 

http://www.tropicaltidbits.com/analysis/models/navm.html?model=gfs-ens&region=us&pkg=apcpn24&runtime=2015011818&fh=90&xpos=0&ypos=1100

[Guest Pamela]

I remember those seasons when LI outperformed all areas to the west but the level of outperformance is mindnumbing. 2nd behind BOS and well over a 100 inches more than CPK. thats a wow. In winter 1990 In experienced it with a storm that dumped about 8 inches in Stonybrook and then headed back to Rutgers that same day to find barely 2 inches on the ground. It can and does happen with more frequency than many think. In fact the current scenario can easilyspell 6-9 out by the forks and barely 3 in CPK. we shall see.

 

1989-90 was notable for the severe cold that enveloped the region during November and December. On 11/23/1989 a coastal storm developed and brought the first substantial November snowfall the region had seen in decades. While the event could be deemed "plowable" in the five boroughs of NYC, out on the Twin Forks and closer to the Atlantic Low, it was a major storm.

Snowfall 11/23/1989:

Bridgehampton: 10.0"

NYC Central Park: 4.7"

JFK Airport: 3.7"

As the New Year arrived, the rubberband snapped and the NY area was flooded with mild air. January was fairly inactive, but on 2/25/1990, the area came under the influence of a developing Norlun Trough. This feature produced some prodigious snow totals over the East End, but managed to just brush the NYC area with some light snows.

Snowfall 2/25/1990:

East Hampton 14.0"

Bridgehampton: 13.0"

Cutchogue 13.0"

Greenport: 12.0"

NYC Central Park: 1.8"

JFK Airport: 1.3"

That was basically it for the winter, but when the bookeeping was complete the snow totals showed what has to be deemed a passable / perhaps even good winter on the East End, but an unimpressive one for NYC.

Snowfall 1989-90:

Bridgehampton: 35.2"

NYC Central Park: 13.4"

JFK Airport: 9.6"

[donsutherland1]

Its possible it could just be 18z runs toying with us but there is definitely a physical reason visible for why they made the change...the RGEM through 54 did look like the NAM too

The 0z runs will be interesting. With the AO having gone ever so weakly negative and forecast to fall while the PNA ridge generally holds through this event, there might be some opportunity for something a little bigger than the typical clipper. I'll have more confidence after tomorrow's runs, but at least there are some things that are more favorable than they have been for most of the month. Long Island probably has the best chance of seeing the largest accumulations.

[NEG NAO]

The 0z runs will be interesting. With the AO having gone ever so weakly negative and forecast to fall while the PNA ridge generally holds through this event, there might be some opportunity for something a little bigger than the typical clipper. I'll have more confidence after tomorrow's runs, but at least there are some things that are more favorable than they have been for most of the month. Long Island probably has the best chance of seeing the largest accumulations.

I think by looking at the ensembles the highest snowfall amounts will be across north central NJ route 1 corridor - east - northeast through SI and LI - areas from Monmouth County below the Raritan Bay / River and points south may have mixing issues

 

http://www.tropicaltidbits.com/analysis/models/navm.html?model=gfs-ens&region=us&pkg=apcpn24&runtime=2015011818&fh=90&xpos=0&ypos=1100

[Mophstymeo]

What do the models say about temps? The NWS has the area at about 37 degrees.

[Guest Pamela]

I remember those seasons when LI outperformed all areas to the west but the level of outperformance is mindnumbing. 2nd behind BOS and well over a 100 inches more than CPK. thats a wow. In winter 1990 In experienced it with a storm that dumped about 8 inches in Stonybrook and then headed back to Rutgers that same day to find barely 2 inches on the ground. It can and does happen with more frequency than many think. In fact the current scenario can easilyspell 6-9 out by the forks and barely 3 in CPK. we shall see.

 

Or even look at 1998-99, which didn't start much better, but in a year of eerie symmetry, nine years to the day after the aforementioned Norlun Trough (2/25/1999), a major Atlantic storm developed. Even as late as the night before the storm, there was considerable uncertainty as to the precise track, though the consensus was that the farther east you went, the better your chances for seeing significant snow. When the dust cleared, over a foot fell over parts of the East End (and much more over Cape Cod), but NYC was basically spared, as both NYC and JFK recorded under 2 inches.

Snowfall 2/25/1999:

Montauk: 13.5"

East Hampton: 10.0"

Shinecock: 8.5"

Bridgehampton: 8.5"

Central Park: 1.5"

Kennedy Airport: 1.0"

After the excitement died down the consensus out east was that a good March could conceivably salvage the winter. On 3/14/1999 a winter storm began to bear down on the area. Though the highest totals with this event were generally over central L.I., (Kings Park recorded just under a foot), the East End again did very well, while the urbanization factor may have been a factor in reducing this storm's impact in NYC:

Snowfall 3/15/1999:

Bridgehampton: 9.0"

NYC Central Park: 4.5"

JFK Airport: 4.3"

When things were tabulated a few weeks later, a passable winter, snow wise, had been witnessed by the Bridgehampton observer, but it was a third consecutive sub-par one for NYC.

Snowfall 1998-99:

Bridgehampton: 30.7"

NYC Central Park: 12.7"

JFK Airport: 12.3"

           

[PB GFI]

What do the models say about temps? The NWS has the area at about 37 degrees.

GFS and it's ensembles are below freezing.

Don't worry about temps this far out. . If it deepens the BL will take care of itself .

If the SW does not deepen than the BL will be irrelevant

[nyblizz44]

Or even look at 1998-99, which didn't start much better, but in a year of eerie symmetry, nine years to the day after the aforementioned Norlun Trough (2/25/1999), a major Atlantic storm developed. Even as late as the night before the storm, there was considerable uncertainty as to the precise track, though the consensus was that the farther east you went, the better your chances for seeing significant snow. When the dust cleared, over a foot fell over parts of the East End (and much more over Cape Cod), but NYC was basically spared, as both NYC and JFK recorded under 2 inches.

Snowfall 2/25/1999:

Montauk: 13.5"

East Hampton: 10.0"

Shinecock: 8.5"

Bridgehampton: 8.5"

Central Park: 1.5"

Kennedy Airport: 1.0"

After the excitement died down the consensus out east was that a good March could conceivably salvage the winter. On 3/14/1999 a winter storm began to bear down on the area. Though the highest totals with this event were generally over central L.I., (Kings Park recorded just under a foot), the East End again did very well, while the urbanization factor may have been a factor in reducing this storm's impact in NYC:

Snowfall 3/15/1999:

Bridgehampton: 9.0"

NYC Central Park: 4.5"

JFK Airport: 4.3"

When things were tabulated a few weeks later, a passable winter, snow wise, had been witnessed by the Bridgehampton observer, but it was a third consecutive sub-par one for NYC.

Snowfall 1998-99:

Bridgehampton: 30.7"

NYC Central Park: 12.7"

JFK Airport: 12.3"

           

As a writer I can tell you Pamela you should very seriously consider beginning a weather blog. Style is reticent, informed, accurate.In short, your credibility will attract an audience. Thank you for sharing the knowledge.

[MJO812]

Cips has feb 15,1996 as number 1analog