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Stumbling into a wintry pattern, weenies confused; still shaken from last winter

earthlight

By earthlight,
in New York City Metro

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IsentropicLift

IsentropicLift

Posted
Posted

With a big PNA ridge out west and the position of the PV big potential is in play. To be fair, my comparisons to PDII ended with a weak low pressure system and duration. I haven't done enough research on the evolution of PDII to make a proper comparison regarding storm eveolution. I just remember a long duration event and if I remember correctly, the low wasn't sub 1000 mb at our latitude. This could be another scenario where the mid-atlantic gets hammered and the PV is just too far south for us. Similar to two winters ago when the DC area had two KU events like a week apart.

 

Some changes on the 18z GFS, it never closes off the shortwave over the SW. instead it remains fairly weak. What a pig of a PV. It takes up almost all of Southern Canada from coast to coast.

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SnowGoose69

SnowGoose69

Posted
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With a big PNA ridge out west and the position of the PV big potential is in play. To be fair, my comparisons to PDII ended with a weak low pressure system and duration. I haven't done enough research on the evolution of PDII to make a proper comparison regarding storm eveolution. I just remember a long duration event and if I remember correctly, the low wasn't sub 1000 mb at our latitude. This could be another scenario where the mid-atlantic gets hammered and the PV is just too far south for us. Similar to two winters ago when the DC area had two KU events like a week apart.

 

Some changes on the 18z GFS, it never closes off the shortwave over the SW. instead it remains fairly weak. What a pig of a PV. It takes up almost all of Southern Canada from coast to coast.

PDII was basically 2/11/94 on steroids, it was a weak southern stream disturbance in a split flow pattern slamming into a 1040MB arctic high over SERN Canada, the precip was all overrunning generated.

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Snow_Miser

Snow_Miser

Posted
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On my phone so it's a PITA, but can someone please start a thread devoted to the upcoming cold pattern and possible threats. Let's leave this one for banter so people can let off some steam. A more focused thread will have better moderation. This one was originally created for banter anyway.

 

Yes. I can start that up. Good idea.

 

Here's the thread:

 

http://www.americanwx.com/bb/index.php/topic/38789-possible-snow-threats-and-upcoming-cold-spell/

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IntenseBlizzard2014

IntenseBlizzard2014

Posted
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With a big PNA ridge out west and the position of the PV big potential is in play. To be fair, my comparisons to PDII ended with a weak low pressure system and duration. I haven't done enough research on the evolution of PDII to make a proper comparison regarding storm eveolution. I just remember a long duration event and if I remember correctly, the low wasn't sub 1000 mb at our latitude. This could be another scenario where the mid-atlantic gets hammered and the PV is just too far south for us. Similar to two winters ago when the DC area had two KU events like a week apart.

 

Some changes on the 18z GFS, it never closes off the shortwave over the SW. instead it remains fairly weak. What a pig of a PV. It takes up almost all of Southern Canada from coast to coast.

 

Need some help to find out about PDII?

 

Here you go:

 

http://www.raymondcmartinjr.com/weather/2003/17-Feb-03.html

 

Very helpful link. :)

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IntenseBlizzard2014

IntenseBlizzard2014

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PDII was basically 2/11/94 on steroids, it was a weak southern stream disturbance in a split flow pattern slamming into a 1040MB arctic high over SERN Canada, the precip was all overrunning generated.

 

Funny thing is that there was a Neutral ENSO during that time, along with a -NAO to +NAO and a -AO. lol

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SnowGoose69

SnowGoose69

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Funny thing is that there was a Neutral ENSO during that time, along with a -NAO to +NAO and a -AO. lol

The NAO was positive most of the 02-03 winter, it was the AO/EPO/PNA that just overwhelmed the pattern.  It was the closest thing to 93-94 we've had for a good part of the eastern US.  The difference was that unlike 93-94 the PNA was raging positive which helped the MA/southern US get in on it too.

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IntenseBlizzard2014

IntenseBlizzard2014

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The NAO was positive most of the 02-03 winter, it was the AO/EPO/PNA that just overwhelmed the pattern.  It was the closest thing to 93-94 we've had for a good part of the eastern US.  The difference was that unlike 93-94 the PNA was raging positive which helped the MA/southern US get in on it too.

 

That'll be nice to have at least half the raging PNA of that season with the upcoming Arctic Outbreak.

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PB GFI

PB GFI

Posted
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The cold coming may just come in waves. The mjo is rallying to get thru phase 7 in the coming week and will more likely in the coming days to get progged into 8. Neg epo pos pna and u will see a neg nao will develop. So even if a one off model run doesnt see the cold. The ensembles and weeklies hav it i will follow them. They caught the warmth from early jan and now they see the cold. Ths is not a one ans done pattern

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PB GFI

PB GFI

Posted
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Ever wonder why the Euro and GFS are usually worlds apart .
 

"This computational bottleneck limits the US model in two key ways. First, it runs at a coarser spatial resolution (about 25 kilometers, as opposed to 15 in the ECMWF model). Anything in the atmosphere that takes place at a smaller scale has to be approximated. In general, finer resolution models can directly simulate more processes, especially once you reach the scale of an individual storm cell.

Second, the way in which measurements are fed into the models differs. The US model takes “snapshots” of data, builds a global picture (the initial conditions), and then begins the forecast simulation. The ECMWF model, on the other hand, takes continuous observations spanning half a day, runs the model with that real data, and then sets it loose on the future. While computationally expensive, this can result in more realistic initial conditions, and is part of the reason why the ECMWF model is usually reliable a couple days further into the future then the US model."       

 

 

This is why the Euro skill score trounces the GFS and one has to wonder why NOAA keeps leaning on the GFS for day 10 -15 temps

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PB GFI

PB GFI

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All true, however, currently the GFS accuracy is higher days 8 & 10 than the Euro, and it did re_catch the Boxing Day storm before the Euro.

I like to think the Euro ensembles have the  highest skill score  .The GFS operational has at times been better than the Euro operational recently , But I would think  the Euro ensembles have a higher skill score than the GFS and all the other global models and there ensembles  .

Can we get those scores ?

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Edge Weather

Edge Weather

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I like to think the Euro ensembles have the  highest skill score  .The GFS operational has at times been better than the Euro operational recently , But I would think  the Euro ensembles have a higher skill score than the GFS and all the other global models and there ensembles  .

Can we get those scores ?

I have never seen them. My wife has a Phd in Mathematical Physics and she tells me that sometimes there would be a benefit to the lower resolution because the higher resolution can actually magnify a problem when there is a mistake in a calculation, which might explain Boxing Day, but surely typically the higher resolution will yield a better result in the shorter term anyway. It is interesting though how that advantage appears to be lost by around 8-10 days.
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WEATHER53

WEATHER53

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I have never seen them. My wife has a Phd in Mathematical Physics and she tells me that sometimes there would be a benefit to the lower resolution because the higher resolution can actually magnify a problem when there is a mistake in a calculation, which might explain Boxing Day, but surely typically the higher resolution will yield a better result in the shorter term anyway. It is interesting though how that advantage appears to be lost by around 8-10 days.

I believe in this also.  Too fine of a grid is not as good 5+ days.  Looking at Statue of Liberty with binoculars does provide finer detail but you lose the bigger picture.

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