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Mid-Atlantic winter storm patterns and analogs


Ian

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btrwx suggested this and it seems like a good idea.

 

Here's snowy and non snowy strong nino 500mb anomaly composites. Up for some debate on certain years, but think it checks out overall. 

 

 

 

YX4Dnef.png

 

5c0AQZy.png

 

More

 

Would prob be good to get some more general stuff up on first page but since strong Nino sure people may want to chat Nino.

 

Add your knowledge or ask your questions.

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Ah, I was just going to suggest that somebody start a thread on this topic! I'm quite interested in seeing what made the super ninos of 57-58, 65-66, and 82-83 all end up having abovr average snow by season's end...And whether or not we have similar patterns potentially setting up here! Thanks for starting the thread!

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The frustrating thing is that there isn't as much difference in the placement of the h5 anomalies as you would expect between the snowy and non snowy outcomes.  Subtle differences in the strength of the low and high heights and exact placements seem to make a huge difference.  That will make it even more difficult to clearly identify which way we are headed (73/98) vs (58/66/83).  On top of that is the fact that some of those months could have been flukes.  Take away the one big storm Feb 83 and we probably remember that year like 98, at least up here, I think DC got one decent snow earlier that year that missed this area.  I would almost rather group 83 with 73 and 98 in the "less snow" group just to see if that gives a clearer pattern, then group 58 and 66 together as the "snowier" outcomes.  Even though 58 had that good snowfall in early Dec if you take that out it was mostly a warm start until late winter.  Snowfall alone is such a fluke thing I would rather group them by overall pattern to see what happens.  Either way the differences seem too subtle to be able to clearly say were heading right or left at this point.    

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Here's a top 10 DC snowstorms composite. Tho it's a mix of northern stream and STJ dominated still shows good generalities. That mix probably reason for no notable ridge thru the Rockies even if can envision axis.

 

5 DAYS PRIOR

 

JiJIioV.gif

 

4 DAYS PRIOR

 

QiNIkVw.gif

 

3 DAYS PRIOR

 

fDXTfzv.gif

 

2 DAYS PRIOR

 

EMrxWeL.gif

 

DAY PRIOR

 

8iZaI4t.gif

 

DAY OF (MOST SNOW IN DC)

 

Cm6MMbI.gif

DAY AFTER

 

0gnx1BA.gif

 

Includes:

 

1/27-28/1922    28.0
2/11-13/1899    20.5
2/18-19/1979    18.7
2/5-6/2010    17.8
1/6-8/1996    17.1
2/15-18/2003    16.7
2/11-12/1983    16.6
12/18-19/2009    16.4
2/7/1936    14.4
2/15-16/1958    14.4
 

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Ian, since we often focus on things several days in advance of a threat, would you mind posting the same composite 3 days prior to the snowfall dates? I was going to do it earlier but I've been busy. I was up after midnight working and and back up at 5am doing the same. I know you guys think I don't work much. LOL. But my job is not a 9-5er. 

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Ian, since we often focus on things several days in advance of a threat, would you mind posting the same composite 3 days prior to the snowfall dates? I was going to do it earlier but I've been busy. I was up after midnight working and and back up at 5am doing the same. I know you guys think I don't work much. LOL. But my job is not a 9-5er. 

Ha funny just added day prior and after. Can also add in earlier. Working on a project that does this more in depth.. may put it up unfinished today or tomorrow.

 

edit: added a few more in. really should probably break them into dominant stream but still shows some ideas I think.

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Here's a top 10 DC snowstorms composite. Tho it's a mix of northern stream and STJ dominated still shows good generalities. That mix probably reason for no notable ridge thru the Rockies even if can envision axis.

 

*snip*

 

hmm, never would have thought that days before the event there's Low Pressure at the NP (relatively speaking)

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hmm, never would have thought that days before the event there's Low Pressure at the NP (relatively speaking)

Not sure where or if daily numbers of AO/NAO are... but phase change even if brief of -AO is a sign, no? May also act to shift -NAO block into 'proper' region?

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btrwx suggested this and it seems like a good idea.

 

Here's snowy and non snowy strong nino 500mb anomaly composites. Up for some debate on certain years, but think it checks out overall. 

 

 

 

YX4Dnef.png

 

5c0AQZy.png

 

More

 

Would prob be good to get some more general stuff up on first page but since strong Nino sure people may want to chat Nino.

 

Add your knowledge or ask your questions.

Thank you Ian! Wow do we think alike. Before seeing this I had this comment in the long-range thread. :)

Ignoring all models, ask yourselves the following. Relative to past nino years is the current (early January) pattern more conducive for a boom or bust season? I don't have an immediate answer.

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Pretty cool Ian. If I only knew what I was looking at, lol.

Unfortunately their sfc pressure plots aren't the greatest or I'd do more of them to show as comparison. I think overall, the 500mb patterns are the ones to watch at any range during any season. If you learn how to read the 500mb you can figure  out the surface at least relative to the 500 location or 500 anomaly location.

 

Above mainly you see the various features like the Greenland block/-NAO ridge in orange, the idea of a 50/50ish and east anomaly also partly related to the -NAO. Here as mitchnick pointed out the leadup seems to show low heights develop over the north pole as well, indicative of lessing high pressure or increasing low pressure. Warm colors are higher than normal heights, blue are lower than normal. The sfc is not generally fully colocated.

 

From day 2 thru storm in particular you can see the idea of activity coming out of the southwest US/northwest depending on storm source.

 

One day out you see a pretty strong tendancy for low heights over the southern Plains. There's probably a sfc low off to the east of that area.. where exactly is dependent on things like the trough axis etc.  Day of, the lowest heights sort of over the mid-South/TN area tend to argue for a sfc low tracking from the GOM area toward the East Coast still on its eastern height periphary more or less. Day after would have a sfc low moving offshore or off the NE coast or so depending on individual trough orientation..  I think the top 10 has just about every type of event. 

 

One thing you see from both northern and southern stream beasts is they tend to "meet" in path somewhere west of/near the Missisippi (including its mouth!). Not a hard rule, but from that point on the general low pressure paths are more similar than prior.   

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Anyone else have an opinion? I like the fact that most of the U.S. + western Europe to an extent has low heights (lowest over great lakes + just off northwest pacific coast) + ne of Hawaii over Pacific + similar trough over open Atlantic, high heights north of Alaska + southern Greenland blocking high height maximum

eta: differences (seem minor to me) Newfoundland + nw of Alaska + Afghanistan

The ridge in western NA and the much higher heights off Newfoundland stood out to me. Wes has often talked about the area off Newfoundland and if I remember we don't want those heights high there. Of course, memory ....

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The ridge in western NA and the much higher heights off Newfoundland stood out to me. Wes has often talked about the area off Newfoundland and if I remember we don't want those heights high there. Of course, memory ....

Very true. What I like about that is I believe that would be pretty easy to correct with coming runs. Though that could also backfire.

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Anyone else have an opinion? I like the fact that most of the U.S. + western Europe to an extent has low heights (lowest over great lakes + just off northwest pacific coast) + ne of Hawaii over Pacific + similar trough over open Atlantic, high heights north of Alaska + southern Greenland blocking high height maximum

 

eta: differences (seem minor to me) Newfoundland + nw of Alaska + Afghanistan

 

There's similarities but the placement of the blocking and the lack of a 50/50 low stood out the most to me. 

 

Really great thread Ian, BTR, etc.  I need to start doing this more (plotting composites and comparing the forecasted looks, etc).  This is a great learning thread for us. 

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There's similarities but the placement of the blocking and the lack of a 50/50 low stood out the most to me. 

 

Really great thread Ian, BTR, etc.  I need to start doing this more (plotting composites and comparing the forecasted looks, etc).  This is a great learning thread for us. 

In my mind I'm thinking to myself, just speed up those westerlies to shift the whole map counterclockwise maybe a degree or so and I can see an almost perfect fit. :whistle:

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There's similarities but the placement of the blocking and the lack of a 50/50 low stood out the most to me.

Really great thread Ian, BTR, etc. I need to start doing this more (plotting composites and comparing the forecasted looks, etc). This is a great learning thread for us.

Indeed--And also could be a thread that's opposite the panic room if we see similarities with the +snow strong el ninos...Kinda helps to keep you away from the cliff, haha
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Not sure where or if daily numbers of AO/NAO are... but phase change even if brief of -AO is a sign, no? May also act to shift -NAO block into 'proper' region?

 

Great thread! It looks like the NP low almost seems to split the Greenland block and force a piece of it south into just the perfect position. 

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Here is an interesting chart highlighting how once the AO tanks betwen -1.0 to -2.0 and beyond for that month as a whole, our big recent snowstorms tend to occur. CPC chart edited by wxsouth blogger

AOlist2000_2015.jpg

http://wxsouth.com/wxblog/wp-content/uploads/2016/01/AOlist2000_2015.jpg

Was that -3.0 in March 2013 the snowquester event? lol

 

eta: That seems to me like the only anomaly from that.

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So this thread plus the 1996 anniversary got me to rush out production for an idea I have been working on. I have all the images but it's a bit time consuming to organize them.  Up to the top 5 storms to start. Plan is to do this for all storms 10"+ at DC. If any major critiques feel free to share though I may already be past the point of no return on the 'design' of this one.. heh.

 

Here's the post and below is the Blizzard of 1996 card: http://www.ianlivingston.com/d-c-s-double-digit-snowstorms-a-guide-to-their-development-and-the-patterns-that-produced-them/

 

o7UDJvI.png

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So this thread plus the 1996 anniversary got me to rush out production for an idea I have been working on. I have all the images but it's a bit time consuming to organize them.  Up to the top 5 storms to start. Plan is to do this for all storms 10"+ at DC. If any major critiques feel free to share though I may already be past the point of no return on the 'design' of this one.. heh.

 

Here's the post and below is the Blizzard of 1996 card: http://www.ianlivingston.com/d-c-s-double-digit-snowstorms-a-guide-to-their-development-and-the-patterns-that-produced-them/

 

o7UDJvI.png

I knew you were up to no good. Kidding! Looks great! I would add years to the dates of the event snapshots. Unfortunately if you ask people on the streets if they know about snowmageddon, the success rate may not be as high as we'd expect. lol

 

eta: Think Twitter infographic

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