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The March Long Range Discussion Thread, Winter's Last Stand


stormtracker
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The most extreme March NAO's and the months that followed.

 

-1.83  -0.30  -1.25  -0.05  -0.51   0.37   0.63  -0.98  
1.85   0.28   1.38  -0.27   0.97   0.01   2.05 
-2.47   0.99  -0.10   0.16  -2.47   0.14  -0.37   
-1.96   0.37  -0.24  -1.38  -1.73  -1.56  -0.07

pp.gif

Edit: 2 February's in a row with <-1.00 PNA. 4/5 times the following February is +PNA. 

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4 hours ago, AfewUniversesBelowNormal said:

When every month DJFM has similar NAO, the following Winter is same-NAO 16/19 times for the whole, 53/76 months. 

I think it has to do with Atlantic tripole

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https://www.americanwx.com/bb/topic/50292-negative-nao-winter/?do=findComment&amp;comment=5059074

Chuck what do you think next winter in regards to the  -NAO ? 

 

 

 

 

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On 3/9/2019 at 10:55 PM, psuhoffman said:

Warning signs are always easier to see in hindsight.  There are always going to be some factors that could throw a wrench in things.  There are so many variables and they are never going to be 100 percent perfect.  There were some legit "warning signs" which I will get into below but It's hard to say how easy it would have been back in the fall to see that they would indeed interfere so heavily with the nino signal. 

IMO the nino didn't so much as fail as it was offset and muted by other influences.  We did have a weak nino.  The ONI peaked at +.9 in OND and the DJF number was +.8.  It actually wasn't far off from the top analogs I picked out back in the fall.  2002/3 had a winter ONI of .9.  1978 was .7, 2015 was only .6 and 1964 was 1.1.   2009/10 was always low on my analog list because it was a much stronger Enso peaking around 1.6. 

And there were "hints" of a nino pattern from time to time, even when the MJO went into god awful phases again in January we still had a major arctic outbreak and some snow events.  So in the end the real pattern ended up a blend of the nino forcing and the mjo forcing. 

Regarding the MJO, it does seem there is some truth to what JB was saying about the warm pool east of Australia.  Others have also said that could be what caused the persistently +SOI and convection near the Maritime Continent.  Problem is that wasn't really easy to see from back in the fall.  That warm pool didnt ramp up until winter and wasn't on any of the guidance. 

Some of the experimental work to assess the impact of MJO on tangible North American weather is yielding interesting results.  For example, typically, Phase 8 of the MJO is typically cold in the east DJF but, when the experimental Multivariate PNA (MVP) is negative, it actually trends warm.  MVP is assessing OLR as a decent proxy for tropical convection in the MJO domains as well as streamwaves at 850 and 200 hPA in near real time .  If you look at the MVP plot for the last 90 days, you can see it has indeed been negative during the time period we expected the best outcomes according to the ENSO and MJO forecasts.  

849375815_90DayMVP.thumb.jpg.83e7083c75fd65c104d80c5e2714e5f5.jpg

 

If y'all want to dig into MVP a bit, here's some decent reading.  

Peer-reviewed, evidenced-based paper:

mwr-d-13-00118.1.pdf

White paper inject for NWS staff:

https://www.nws.noaa.gov/ost/climate/STIP/37CDPW/37cdpw-cschreck.pdf

Easy-to-digest slide deck from the researchers:

https://slideplayer.com/slide/13103907/

Link to real-time Multivariate PNA outputs:

https://ncics.org/portfolio/monitor/mjo/extratropics/

BTW, click around that site if you are interested in tropical forcing outputs.  There's an absolute treasure trove of MJO & tropical forcing data there.

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