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Potential Winter Storm March 6-7


NEG NAO

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I don't think there will be too much of a warm layer, only at the beginning. Surface is also warm verbatim. Precip will help cool though. If this is trending north, I expect the precip field to come north as well. There's mixing problems on the models, but trends further north and more cooling will occur for this to change over.

 

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A pure coastal low ( no annoying midwest/lakes primary)with marginal temps in March would yield snow even if it starts as rain, we underestimated events in early Nov and late Oct when we got more snow than anticipated.

Now if its a pure pacific like cutoff than ok but I don't see that. I think this will be a more classic coasting that slows down and cuts off due to the block.

The northern extent will be key but these events do tend to go north as we get closer unless there's major confluence.

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agreed - unless this thing tracks perfectly and bombs out creating its own cold and or dragging it in during a phase job from the north its rain in NYC immediate metro

I would agree if the amount of precip is low, if its higher than I strongly disagree, it's not April or May, there's still cold air around. If we can get snow in late Oct/early Nov than we could def get it now.

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Guest Pamela

agreed - unless this thing tracks perfectly and bombs out creating its own cold and or dragging it in during a phase job from the north its rain in NYC immediate metro

 

Not sure if you misinterpreted what I wrote...by 45 degree wind...I meant at an angle of 45 degrees, i.e., true NE.

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Euro and the ensembles did trend north but not enough. There is a northern trend today on all the models except for the Ukie. The confluence on the GFS moved out faster on this run.

 

All the models basically exit the low east off SE VA or NC under the very strong block to the north. If the Euro weakens the blocking

over the next day or two then the low would be able to track a little further north over the Southern Delmarva and we would get

a shot a the heavier precip. Even if the models hold course on today's tracks, they still may push the northern edge of the precip

shield farther north than they are showing now. But the best UVV's would end up just to our south.

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Not sure if you misinterpreted what I wrote...by 45 degree wind...I meant at an angle of 45 degrees, i.e., true NE.

well from what I just looked at on that run NYC is right on the border between rain and snow and I still say you will need intensity in the precip with the borderline temps especially during daylight hours to have a chance of frozen - thats why it has to bomb out and phase with a perfect track  - where is the cold enough air temps will be above 32 during the daytime ????

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Guest Pamela

well from what I just looked at on that run NYC is right on the border between rain and snow and I still say you will need intensity in the precip with the borderline temps especially during daylight hours to have a chance of frozen - thats why it has to bomb out and phase with a perfect track  - where is the cold enough air temps will be above 32 during the daytime ????

 

Probably is a pretty close call...especially in urban areas...once the sun gets low in the sky late Wednesday afternoon...around 4:00 PM...chances for accumulations should be better....and I think the bulk of the precip will likely fall Wednesday evening into early Thursday...which would work in this area's favor.  But I agree, it is pretty borderline. 

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Guest Pamela

Probably is a pretty close call...especially in urban areas...once the sun gets low in the sky late Wednesday afternoon...around 4:00 PM...chances for accumulations should be better....and I think the bulk of the precip will likely fall Wednesday evening into early Thursday...which would work in this area's favor.  But I agree, it is pretty borderline. 

 

On the good side...the anticyclone over eastern Canada is looking more robust and even though it is not arctic in nature...it should provide a steady source of reasonably cold air that just might be able to turn the trick down here. 

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On the good side...the anticyclone over eastern Canada is looking more robust and even though it is not arctic in nature...it should provide a steady source of reasonably cold air that just might be able to turn the trick down here. 

 

I think people are once again exaggerating the "it's March" argument against snowfall. It's amazing how some posters don't learn that BL warmth is unimportant when you have sufficient dynamics and a proper track of the coastal low. We snowed on 10/29/11 and 11/7/12; average highs at that time period are 56-58F in the NYC metro area. Average highs on March 6th are around 44-45F, so climo isn't nearly as big of an obstacle this time. Most of the week looks slightly below normal anyway with highs in the 41-42F range. 

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I think people are once again exaggerating the "it's March" argument against snowfall. It's amazing how some posters don't learn that BL warmth is unimportant when you have sufficient dynamics and a proper track of the coastal low. We snowed on 10/29/11 and 11/7/12; average highs at that time period are 56-58F in the NYC metro area. Average highs on March 6th are around 44-45F, so climo isn't nearly as big of an obstacle this time. Most of the week looks slightly below normal anyway with highs in the 41-42F range. 

The best dynamics are south of NYC. Also the low itself is in a position that would allow easterly winds to warm the BL.

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The best dynamics are south of NYC. Also the low itself is in a position that would allow easterly winds to warm the BL.

guys once the energy is sampled i truly believe it will trend north up to 100 miles! It could also trend south a 100 miles! My guess right now is that it could go 100 miles either way from the 18z suite!
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Guest Pamela

I think people are once again exaggerating the "it's March" argument against snowfall. It's amazing how some posters don't learn that BL warmth is unimportant when you have sufficient dynamics and a proper track of the coastal low. We snowed on 10/29/11 and 11/7/12; average highs at that time period are 56-58F in the NYC metro area. Average highs on March 6th are around 44-45F, so climo isn't nearly as big of an obstacle this time. Most of the week looks slightly below normal anyway with highs in the 41-42F range. 

 

Solar angle on March 5th at this latitude is not an enormous factor...but it is also not one to be entirely dismissed...it is the same angle as we see at roughly October 7th.  Unless it is exceptionally cold and the overcast is very thick, it does have somewhat of a deleterious effect upon accumulations...even if snow is falling at at good clip...especially between 10:00 AM and 2:00 PM. 

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Guest Pamela

The best dynamics are south of NYC. Also the low itself is in a position that would allow easterly winds to warm the BL.

 

To get surface wind direction...one does not follow the isobars absolutely & precisely.....although the isobars make it look like a screaming easterly wind would be over the region...this type of setup invariably produces northeasterly winds at 10 m around here. 

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On the good side...the anticyclone over eastern Canada is looking more robust and even though it is not arctic in nature...it should provide a steady source of reasonably cold air that just might be able to turn the trick down here.

I think people are once again exaggerating the "it's March" argument against snowfall. It's amazing how some posters don't learn that BL warmth is unimportant when you have sufficient dynamics and a proper track of the coastal low. We snowed on 10/29/11 and 11/7/12; average highs at that time period are 56-58F in the NYC metro area. Average highs on March 6th are around 44-45F, so climo isn't nearly as big of an obstacle this time. Most of the week looks slightly below normal anyway with highs in the 41-42F range.

Agreed! It can easily overcome with heavy snow

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To get surface wind direction...one does not follow the isobars absolutely & precisely.....although the isobars make it look like a screaming easterly wind would be over the region...this type of setup invariably produces northeasterly winds at 10 m around here. 

The gfs has an ene wind for nyc at the surface. So some northerly component, but majority from the east.

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guys once the energy is sampled i truly believe it will trend north up to 100 miles! It could also trend south a 100 miles! My guess right now is that it could go 100 miles either way from the 18z suite!

The energy sample is not the issue with this. Its the confluence, which has nothing to do with the energy being sampled out west. It all depends on how strong and how far south that confluence is. The reason why the 18z gfs trended north was cause the confluence shifted north a little, not because the energy was any different. This is a case where the further northeast you live the stronger the confluence is compared to areas northwest or west.

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The energy sample is not the issue with this. Its the confluence, which has nothing to do with the energy being sampled out west. It all depends on how strong and how far south that confluence is. The reason why the 18z gfs trended north was cause the confluence shifted north a little, not because the energy was any different. This is a case where the further northeast you live the stronger the confluence is compared to areas northwest or west.

Yeah most of it has to do with the confluence. But if the shortwave is somehow sampled somewhat stronger it will help pump heights ahead of it  and will help tick it north a bit . 

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The best dynamics are south of NYC. Also the low itself is in a position that would allow easterly winds to warm the BL.

 

The best dynamics are currently south as the upper low develops over the Arlatex, but they are slowly trending north. 

 

Also, the warmer models like the 12z GGEM still have thicknesses right around 540m in NYC, so it's not exactly a torch. It would probably be a non-accumulating rain/snow mix down by JFK during the day while the suburbs picked up light accumulations, and then everyone would score a few inches of wet snow overnight, if the wetter scenarios played out.

 

Also, the 18z GFS went back to showing very cold air entering the region around 3/14, which makes sense with the PNA spike and redeveloping NAO showed on the ECM Ensembles. It has another snowstorm in fantasy range. While -15C 850mb temperatures and 12+" snow may be an exaggeration, it's safe to say that the warm-up after this storm should be brief (and trending briefer as the low bombs further north and brings more cold air down), and that we will have one more window for accumulating snow certainly, probably from 3/15-3/20, but potentially going out even later. I could see snow threats continuing until 3/25 or so with this pattern as they did in 2011 when the -NAO recovered. Definitely a very different look for March than 2012 and 2010 offered. 

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Again we have nothing to worry about with this storm yet, and I like where we are right now. I believe it will come north we are still 4- 5 days out. I actually wouldn't want to be in the jackpot zone at this time frame especially this winter.

 

- 0z Monday is when I would start to worry if this wasn't trending north.

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Washington's National Airport with just 8.7 inches of snow over the last 13 March's combined (2000 - 2012).  Tells you one of two things...either they are overdue or the climatological probabilities of major snow down there in March are pretty slim.   

 

Pshaw William.  Stop cherry picking only the data that supports your point.  The National Arboretum, 6 miles to the northeast of Regan National had a whopping cumulative March snowfall of 11.6 inches for that same period. 

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Guest Pamela

Pshaw William.  Stop cherry picking only the data that supports your point.  The National Arboretum, 6 miles to the northeast of Regan National had a whopping cumulative March snowfall of 11.6 inches for that same period. 

 

Must have taken measurements in the flower beds...

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Again we have nothing to worry about with this storm yet, and I like where we are right now. I believe it will come north we are still 4- 5 days out. I actually wouldn't want to be in the jackpot zone at this time frame especially this winter.

 

- 0z Monday is when I would start to worry if this wasn't trending north.

you mean 3.5-4 days, precip starts getting into nyc around noon wednesday or just there after.

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At HR 42 the shortwave is slightly more positive than HR 48 on the 18znam! Same position. Edit; hr 45 on the 0Z name shows the ULL moving out a bit quicker and keeps the shortwave a little more positively tilted soo far but more amped! Same position EDIT: HR 54 looks very similar to HR 60 on 18z nam! Some minor changes ! Shortwave looks. A bit stronger south

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