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March Medium Range Discussion

nzucker

By nzucker,
in New York City Metro

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Weathergun

Weathergun

Posted
Posted

This is the best look we have seen on the modeling since 2010. It doesn't seem real.

 

The GFS finds a weakness between the main PV lobe and the one that gets phased into it...thus bridges the SE ridge between that weakness and into the block. The GFS always likes to find rogue weaknesses during big blocking patterns...Sandy is a prime example of that. 

 

The Euro has pretty much all of Canada as a PV. :lol: It kinda seems more likely, though, considering the block is in Greenland and the Davis Straights, and not so far south. This is a way we can get our block and our cold air. Considering how strong this block is, I don't really see said weakness occurring. This helps keep the storm track to our south. 

 

The GFS is opening up a weakness in the PV, with the 16-18th wave, over the Upper Mid-West. I think it's likely too amplified with that wave.The 6z GFS was weaker and further south.

 

0z GFS

 

post-187-0-29976400-1363001873_thumb.gif

 

6z GFS:

 

post-187-0-57690700-1363002033_thumb.gif

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Weathergun

Weathergun

Posted
Posted

The ECMWF has the 16-18th wave flatter over the Upper-Midwest/Great Lakes and moving faster into New England by 144hr. This allows both lobes of the PV to phase into one stronger PV over Ontario/Hudson Bay. So that forces the Pacific s/w with the 19-20th storm, to dive further SE. Given how fast the flow has been this year out the Pacific, I think this solution is more likely to occur.
 

 

0z GFS :

k0n0nd.jpg

 

 

 

0z ECMWF:

 

6s9kao.jpg

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jm1220

jm1220

Posted
Posted

Amazing run. We just need to see the storm still there for a few runs and we are in business.

I'm more interested in the overall 500mb pattern and teleconnectors which would favor a storm at this point. If the strong west -NAO and favorable MJO are in place, getting the big storm is far more likely. And given how hard this last storm was to predict even 24-48 hrs out, a storm 200 hours out should be taken with a grain of salt. There's an indication that this time frame would favor a storm, that's really how I would look at it.

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SnoSki14

SnoSki14

Posted
Posted

When the Euro shows a huge storm in longer range for several runs then you have to take it seriously.

The potential is def there and hopefully the Euro continues this solution, the gfs is still very different and probably wrong as it tries to ram storms into the intense block. The MJO signal is what stands out to me most since it's what sparked the Feb 8 blizzard despite unfavorable blocking.

Now if you add strong blocking with a favorable MJO and we could be talking a longer lasting storm that occurs further south. The amount of cold air available for this time of year on the Euro is also very impressive.

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pazzo83

pazzo83

Posted
Posted

Not to pour water on all of this (but that's what I'm going to do), but daily snowfall 5" or greater in NYC (proper) after 3/14 is quite rare.  Rare as in it has only happened 22 times since just after the Civil War ended.

 

Looking at records going back to the mid 1870s, it seemed to be about a decadal (+/- a few years) occurrence during the late 19th Century:

April 13, 1875: 10"

March 19, 1890: 6"

March 18, 1892: 7.2"

March 15-16, 1896: 6.5" and 5.5" respectively

 

During the early 1900s, a few times every decade seemed to be the norm:

March 15, 1900: 5"

March 15 and 19, 1906: 6" and 5" respectively

April 9, 1907: 5"

April 3, 1915: 10"

April 9, 1917: 6.4"

 

After this point, there are extremely wide gaps in time between events this late in the season.  After an 8.5" snowfall in April of 1924, NYC would have to wait 20 years for another 5"+ snowfall in this period (April 1944, 6.5").  

 

The mid-late 1950s were great in this area for snowfall in late March.  The blizzard of 1956 combined with a storm right before combined to create three days with 5"+ snowfall  on 3/16, 3/18, and 3/19.  The March 1958 blizzard brought 7.1" of snow to the city on 3/21 of that year.  

 

However, after this great period, accumulating snowfall of this magnitude becomes extremely infrequent.  There have been only FIVE recorded instances of 5"+ snowfall from 3/15 after 1960.  There have been three in the past 30 years, with the last being on March 16, 2007 (5.5").  Accordingly, a 5" snowfall in this period appears to be a one in 10 year event, or 10% probability of occurring in any given year.

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pazzo83

pazzo83

Posted
Posted

And greater than 4 inches never happened In the first week of November. Oh and nothing more than an inch and a half or so had ever fallen in October for the entire month. Tell that to oct 2011 and nov 2012

The chance of those two events occurring again in our lifetimes is close to 0.  We are talking about a multiple sigma event in both cases.  5" snowfall in late March is far more common, but still extremely unlikely. 

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Kaner587

Kaner587

Posted
Posted

The chance of those two events occurring again in our lifetimes is close to 0. We are talking about a multiple sigma event in both cases. 5" snowfall in late March is far more common, but still extremely unlikely.

I know I'm just playing around really. But also pointing out that in the right circumstance what has already happened and what has not, is irrelevant. We all know late season significant/major snows are rare, though.

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pazzo83

pazzo83

Posted
Posted

I know I'm just playing around really. But also pointing out that in the right circumstance what had already happened and what has not, is irrelevant. We all know late season significant/major snows are rare, though.

 

If we want late season snow, this seems to be the setup we'd need.  I'm just saying I'd bet on it not occurring, given history.  Also I am flying to Miami next Thursday so if this messes up my flight I will NOT be happy.

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ag3

ag3

Posted
Posted

Not to pour water on all of this (but that's what I'm going to do), but daily snowfall 5" or greater in NYC (proper) after 3/14 is quite rare.  Rare as in it has only happened 22 times since just after the Civil War ended.

 

Looking at records going back to the mid 1870s, it seemed to be about a decadal (+/- a few years) occurrence during the late 19th Century:

April 13, 1875: 10"

March 19, 1890: 6"

March 18, 1892: 7.2"

March 15-16, 1896: 6.5" and 5.5" respectively

 

During the early 1900s, a few times every decade seemed to be the norm:

March 15, 1900: 5"

March 15 and 19, 1906: 6" and 5" respectively

April 9, 1907: 5"

April 3, 1915: 10"

April 9, 1917: 6.4"

 

After this point, there are extremely wide gaps in time between events this late in the season.  After an 8.5" snowfall in April of 1924, NYC would have to wait 20 years for another 5"+ snowfall in this period (April 1944, 6.5").  

 

The mid-late 1950s were great in this area for snowfall in late March.  The blizzard of 1956 combined with a storm right before combined to create three days with 5"+ snowfall  on 3/16, 3/18, and 3/19.  The March 1958 blizzard brought 7.1" of snow to the city on 3/21 of that year.  

 

However, after this great period, accumulating snowfall of this magnitude becomes extremely infrequent.  There have been only FIVE recorded instances of 5"+ snowfall from 3/15 after 1960.  There have been three in the past 30 years, with the last being on March 16, 2007 (5.5").  Accordingly, a 5" snowfall in this period appears to be a one in 10 year event, or 10% probability of occurring in any given year.

 

 

So basically, based on this, we are due for one.

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WintersGrasp

WintersGrasp

Posted
Posted

I have to say....getting a huge late season snowfall in mid-late march would not at all surprising for us, would it ? Following a major October snowfall a couple years ago, a major November snowfall a few months ago which followed a hurricane landfall in NJ, and a Norlun trough that rarely gets our area spread a blanket of 5-30" from here to New England....A foot of snow in mid-late march would not be at all surprising

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Stormlover74

Stormlover74

Posted
Posted

I have to say....getting a huge late season snowfall in mid-late march would not at all surprising for us, would it ? Following a major October snowfall a couple years ago, a major November snowfall a few months ago which followed a hurricane landfall in NJ, and a Norlun trough that rarely gets our area spread a blanket of 5-30" from here to New England....A foot of snow in mid-late march would not be at all surprising

Its definitely been a while since we've seen one. While not huge storms we had back to back events in 92 after the 17th. About 85% of our winter's total came that one week.

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Kaner587

Kaner587

Posted
Posted

So basically, based on this, we are due for one.

Individually given Pazzos states, it's a 10% chance of a significant march snow after 3mod month every yr. it is this 90% that if wont happen. So if we use this as our basic probabilities, the odds of 6 straight years of no significant post mid march snow would be a cumulative probability of every single year's odds. Given this, the odds of there not being a post mid march significant snow for a 6th yr in a row would be (0.9x0.9x0.9x0.9x0.9x0.9) or 53.1%.

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pazzo83

pazzo83

Posted
Posted

Individually given Pazzos states, it's a 10% chance of a significant march snow after 3mod month every yr. it is this 90% that if wont happen. So if we use this as our basic probabilities, the odds of 6 straight years of no significant post mid march snow would be a cumulative probability of every single year's odds. Given this, the odds of there not being a post mid march significant snow for a 6th yr in a row would be (0.9x0.9x0.9x0.9x0.9x0.9) or 53.1%.

 

Yep, now if we look from 3/20 on, there have been 3 occurrences of post 3/20 snow >= 5" since 1960:

3/22/1967: 9"

4/6/1982: 9.6"

3/22/1998: 5"

 

This appears to be an approx one in 15 year event, so probability in any given year is 6.67%, or a 93.33% chance of not occurring.  Given that the last occurrence was in 1998, we have the prob of it not occurring for 15 straight years (e.g. it doesn't happen this year) as 0.9333^15 or 0.355, 35.5%.

 

I guess it does look like we're due...

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