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Why was 1997-98 such an awful winter in the mid-Atlantic?


Fozz

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Since there's been some strong Nino talk lately (probably unwarranted but hype sells), I thought I'd bring this up.

 

I was too young to understand weather back then, but over time I learned that it was DCA's least snowy winter on record (tied) and very warm and rainy. It was also the strongest El Nino of the 20th century.

 

But what caused it to be such a horrible year? Are strong El Ninos inherently warm and bad for snow, or did teleconnections keep us locked in an awful pattern?

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The NAO wasn't particular bad but we were flooded with PAC air....that was a super nino...nothing could mitigate it....there was no mechanism to drag in cold air..just a preposterous firehose...a HUGE low anomaly in the North PAC...it was unstoppable..we were flooded with airmasses that came in underneath it

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Thanks all!

so would it be correct to say that in a strong El Nino, a nice -EPO like we had this year is pretty much impossible?

It would defy a typical nino circulation in the pac. Low pressure in the goa is a trademark during Nino's. Blocking is required for us to get good snow during a nino. Without it we end up on the warm/wet side of things. Someone else with more knowledge can go into the details as to why but mod nino's typically combine with -nao's.

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We did have some strong nor'easter type storms, I guess miller A's that ripped up the coast in Jan and Feb but they were mostly if not all rain.   What little snow did fall even out here was wet, mainly grassy type snowfalls that quickly melted.  I still managed to get 16.5" but the biggest one was 4.0" on 12/30/97.

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Super Ninos have all been east based classic El Nino type events...so the low anomaly in the N PAC is further east (and stronger) which is bad combo for getting cold to the east.

 

Theoretically, if we had a super Nino but kept the Nino more modoki (west based)...then it would probably be extremely cold/snowy in the east.

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Super Ninos have all been east based classic El Nino type events...so the low anomaly in the N PAC is further east (and stronger) which is bad combo for getting cold to the east.

 

Theoretically, if we had a super Nino but kept the Nino more modoki (west based)...then it would probably be extremely cold/snowy in the east.

57/58 and 09/10 came as close to that as we're probably ever going to get with a +1.8C in ENSO 3.4 in 12/57 and 1/58 and a +1.6C in 12/09 and 1/10

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57/58 and 09/10 came as close to that as we're probably ever going to get with a +1.8C in ENSO 3.4 in 12/57 and 1/58 and a +1.6C in 12/09 and 1/10

 

 

'57-'58 was actually kind of crappy in the placement of the N PAC anomaly in the mean...but it was overwhelmed by an extreme west based -NAO...and the low anomaly did shift a bit SW with time that winter...so it was an awesome back-loaded winter .Years like '97-'98 never saw that.

 

 

'09-'10 was a nice modoki Nino...and we saw the low anomaly west enough to pump up AK heights. Throw in the NAO blocking and you get historic for M.A.

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So to try understanding what you're all talking about, I obtained composites of the 500 mb height anomalies for those winters so I could clearly see those features you're mentioning. Hope I'm doing it right!

 

The robust blocking in 1958 and 2010 can clearly be seen, but it seems like those low heights south of Alaska are something that must be tempered if we want to have a chance.... it looks hideous in 1998.

 

1958:

post-1069-0-69690200-1395693558_thumb.pn

 

1998:

post-1069-0-73927400-1395693602_thumb.pn

 

2010:

post-1069-0-47948300-1395695971_thumb.pn

 

http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl?var=Geopotential%20Height;level=500mb;mon1=11;mon2=1;iy=2003;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;iy=;ipos%5B1%5D=;ipos%5B2%5D=;ineg%5B1%5D=;ineg%5B2%5D=;timefile0=;tstype=0;timefile1=;value=;typeval=1;compval=1;lag=0;labelc=Color;labels=Shaded;type=2;scale=100;labelcon=1;switch=0;cint=;lowr=;highr=;proj=Northern%20Hemisphere;xlat1=0;xlat2=90;xlon1=0;xlon2=360;custproj=Cylindrical%20Equidistant;level1=1000mb;level2=10mb;Submit=Create%20Plot

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'57-'58 was actually kind of crappy in the placement of the N PAC anomaly in the mean...but it was overwhelmed by an extreme west based -NAO...and the low anomaly did shift a bit SW with time that winter...so it was an awesome back-loaded winter .Years like '97-'98 never saw that.

 

 

'09-'10 was a nice modoki Nino...and we saw the low anomaly west enough to pump up AK heights. Throw in the NAO blocking and you get historic for M.A.

 

I split the composites of 57-58 between Dec/Jan and Feb/March.... the latter one looks a lot like 09-10

 

post-1069-0-32091500-1395696160_thumb.pn

 

post-1069-0-75340000-1395696168_thumb.pn

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  • 1 year later...

I was researching this at the beginning of the winter season. The NAO was strongly negative that winter. But that actually ended up hurting us in the end. South of us had a decent year. The Pac was awful. It just goes to show how much more important the pac is for winter weather in North America. 

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