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Mid-Atlantic winter storm patterns and analogs


Ian

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Really nice job Ian, just finished reading your blog post.  That blocking, specifically for Knickerbocker and Snowmaggedon  :wub:

Let's see here. 2 weeks prior=warm + 1 week prior cold air starting to pour in to midatlantic ~= 2016 January early warmth + current week transitional cold == Simple Math! :P

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Looks great. Am I seeing right that a west based -NAO a week prior was trending toward positive territory at the time of the storm?

Think it was probably pretty standard for the week prior and more west based two weeks out. Overall it's a squashing/diminishing block into storm time it would seem. The big northern stream dominated events seem to have more of an elongated "hudson bay block" that sort of peters out a bit as the storm gets cranking around us.

 

Really nice job Ian, just finished reading your blog post.  That blocking, specifically for Knickerbocker and Snowmaggedon  :wub:

Thanks, something I've been planning on doing a while. Finally got the motivation. Hopefully can add 5 storm chunks fairly rapidly.

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Does anyone remember the board mood around this time in '10? Pretty despondent, and that was after getting the Dec. '09 gift.  In any event, pretty clearly we had blocking for the Dec. '09 goodness - but my recall is it relaxed and that was when people got worried.

 

I am not looking to make this an analog for Feb. '10 in terms of what we are in in now, but what I cannot recall is what the maps looked like from say 1/5 - 1/25 as it led up to that epic 12-day period from 1/30/10 - 2/10/10. And I am trying to recall because the negative AO and NAO as currently hinted at upcoming put me in mind of 2010 in terms of that.  Per psuhoffman's thoughts in the other threads, was it similar with the northern stream ripping along with vorts well to our north due to Nino influence? I have no recall of what the set-up was between 12/19/09 and when we cashed in again with the surprise event on 1/30/10.  I know we had a warm and rainy system just after Christmas, and then Ji canceled the rest of winter at some point over the next several weeks. Just trying to figure out if there are any clues from that time to when we might see something this winter (if not as epic, at least a measureable set of flakes). Sorry for rambling.

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Does anyone remember the board mood around this time in '10? Pretty despondent, and that was after getting the Dec. '09 gift.  In any event, pretty clearly we had blocking for the Dec. '09 goodness - but my recall is it relaxed and that was when people got worried.

 

I am not looking to make this an analog for Feb. '10 in terms of what we are in in now, but what I cannot recall is what the maps looked like from say 1/5 - 1/25 as it led up to that epic 12-day period from 1/30/10 - 2/10/10. And I am trying to recall because the negative AO and NAO as currently hinted at upcoming put me in mind of 2010 in terms of that.  Per psuhoffman's thoughts in the other threads, was it similar with the northern stream ripping along with vorts well to our north due to Nino influence? I have no recall of what the set-up was between 12/19/09 and when we cashed in again with the surprise event on 1/30/10.  I know we had a warm and rainy system just after Christmas, and then Ji canceled the rest of winter at some point over the next several weeks. Just trying to figure out if there are any clues from that time to when we might see something this winter (if not as epic, at least a measureable set of flakes). Sorry for rambling.

I was literally plotting that exact scenario within the last hour. Let me see what I can grab. Any preference on what period to plot?

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Leading up to snowmageddon prior to Ian's maps. NOTE: Ian plotted averages around these days for these particular weeks. The ones below are for specific days.

eta Feb 2017: Updated maps for long term analoging

5 days prior

500mb January 31_2010_5 days prior.jpg

10 days prior

500mb January 26_2010_10 days prior.gif

15 days prior

500mb January 26_2010_15 days prior.gif

20 days prior

500mb January 16_2010_20 days prior.gif

30 days prior

500mb January 6_2010_30 days prior.gif

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Ian, responding to your tweets with the gifs of the upcoming pattern and past snowy patterns:

 

Not sure how robust/important those low heights right at the pole are.  Seems weird.  What I note is the low heights through southern Canada that rotate east and become a 50/50 for the snowstorm itself.  Then higher heights replace it over the Lakes and Canadian prairies.  That supports high pressure to our north and holds in the cold air.  Seems like we still keep seeing low heights over the Lakes for the next week to 10 days or so. 

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Yeah I'm not sure either. It is only 10 events so could be even one or two weighting it. I need to expand in various ways probably. I'm just less sold the day of snapshot tells the whole story as I go. Then again including multiple 09/10 events in a composite probably weights that year a bit too much too.

That said while perhaps a low height area over the poll isn't really across events I think lowering of heights there might be.

Agree we have problems next 7-10 at least. Beyond that is guesswork. We do chase HECS tho. ;)

Btw Im not even sure I follow you, should pm me your account handle.

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Yeah I'm not sure either. It is only 10 events so could be even one or two weighting it. I need to expand in various ways probably. I'm just less sold the day of snapshot tells the whole story as I go. Then again including multiple 09/10 events in a composite probably weights that year a bit too much too.

That said while perhaps a low height area over the poll isn't really across events I think lowering of heights there might be.

Agree we have problems next 7-10 at least. Beyond that is guesswork. We do chase HECS tho. ;)

Btw Im not even sure I follow you, should pm me your account handle.

I think you do follow me, but I rarely tweet myself.  Mostly a Twitter lurker. 

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Here's some storms from NARR.. I slowed them down during the key timeframes (eyeballed etc).

 

Feb 1979

 

sNfZy5U.gif

 

Feb 2010

 

cpus6O3.gif

 

Jan 1996

 

nZLeh8U.gif

 

Feb 2003

 

PGAXQsG.gif

 

Feb 1983

 

TxFgjmX.gif

 

Dec 2009

 

XeDkbgZ.gif

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Ian nice analogs.  It would be interesting to divide out the northern stream ones from the southern stream.   Years ago I did a similar graphic of 8 inch or greater events at DCA focusing on 24 hours prior tot he storm (10 of them picked from the KU book) and got a similar look to what you found.  I used the graphic in yesterday's Outlook article to show that most of the progs have been lacking the negative anomaly/low heights near Nova Scotia.  Lol, then the 18Z GFS came in with the negative.  

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Ian nice analogs. It would be interesting to divide out the northern stream ones from the southern stream. Years ago I did a similar graphic of 8 inch or greater events at DCA focusing on 24 hours prior tot he storm (10 of them picked from the KU book) and got a similar look to what you found. I used the graphic in yesterday's Outlook article to show that most of the progs have been lacking the negative anomaly/low heights near Nova Scotia. Lol, then the 18Z GFS came in with the negative.

And so the plot thickens! Lol
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They are great-- thanks for taking the time to load them, Ian. Just FYI: I think you loaded PDII again under 12/09. 

Yep, oops. Fixed it. Thanks all! I love patterns. Probably too much. :P

 

I'll add some more with time too, just ran out of patience to keep going last night.

 

And yes Wes splitting streams would be worthwhile. Have a few ideas with that, will try to get them done in the next few weeks.

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Here's some storms from NARR.. I slowed them down during the key timeframes (eyeballed etc).

Feb 1979

sNfZy5U.gif

Feb 2010

cpus6O3.gif

Jan 1996

nZLeh8U.gif

Feb 2003

PGAXQsG.gif

Feb 1983

TxFgjmX.gif

Dec 2009

XeDkbgZ.gif

Sweet, always love looking at the NARR. Ian, you should of added January 25, 2000. Not sure how DC did but near the bay we were in the jackpot area. I got 17" from that surprise storm. I remember looking at the radar around 8pm on the 24th and saw the precip coming straight north. Sure enough at about 9pm The Weather Channel started going nuts with the red screen Winter Storm Warning. I always wondered what forecasters and the models missed with that storm.
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Top 15 snow days since 1948 composite maps by city up and down the coast. Used 1948 so I could pull from the 81-2010 climo period set and it's the most updated dataset. Also put them here: http://imgur.com/a/FLusc

 

Bangor, ME

 

doOWOPe.gif

 

Boston, MA

 

gRCspZZ.gif

 

NYC, NY

 

u4PFleP.gif

 

Philadelphia, PA

 

IrsocT4.gif

 

Washington, DC

 

fXuSJZP.gif

 

Richmond, VA

 

feGUZb3.gif

 

Raleigh, NC

 

ldIKyVX.gif

 

Columbia, SC

 

ldIKyVX.gif

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This is a small list .. would like to get it up to 15 or so but that could take a while the way I'm doing it now. BUT.. these are 12"+ DC storms that featured significant blocking in the Greenland to Hudson Bay region on day of biggest snow. Others have it around prior and out for storm, others have not much etc. Dominated by Ninos.

 

IEVanxW.gif

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I don't even really know what to do with this stuff yet but I was bored and pulled up top height anomalies (since 1948) for certain regions. Def not all snowy, tho a general cold lean. The first is random, the second is the northern box of the NAO region. They only have monthly stuff for now which is not as useful as daily perhaps.

 

zfsUWpM.png

http://imgur.com/zfsUWpM

 

ZgQ8Ali.png

http://imgur.com/ZgQ8Ali

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