Historic -NAO intensity coming Mar 31 through early April

[GaWx]

 - The 3/29 0Z GEFS run’s mean NAO prediction (see image below) of ~-1.75 for 3/31 is ~tied for the daily record low NAO for all of March (records go back to 1950)! The current March record is -1.75 (3/22/1980). It will also easily beat the current record low for March 31 of -1.3 (1975).

- This run is predicting the lowest NAO to be ~-1.95 to -2.00 (on 4/1). Should that verify closely, it would be a record low NAO (back to 1950) for the entire period covering Feb 15th through April 7th! It will also obliterate the current record low for April 1 of -1.2 (1975).

- This run implies there will be daily record low NAOs March 31-April 2nd and possible daily record lows April 3rd-5th.

- Related to this, the model consensus has a very strong nor’easter for ~April 4th.

 

 Daily NAO back to 1950:

https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.nao.cdas.z500.19500101_current.csv

[KChuck]

What impact will this have on the upcoming April 8th eclipse weather across the country?

[GaWx]

6 minutes ago, KChuck said:

What impact will this have on the upcoming April 8th eclipse weather across the country?

Not much directly as it will fortunately be over before then. 

[GaWx]

This very strong -NAO has included record daily strong -NAOs Mar 31 through today with another record for the date expected tomorrow. Tomorrow’s is being forecasted by GEFS to be the strongest -NAO daily of this stretch. Daily records go back to 1950.

[GaWx]

 Today’s NAO is -2.00, which is the most negative of any day Feb 15th through April 7th for the years 1950-present. The old record for that period was -1.84. Also, there have been record daily -NAOs the last five days:
 

https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.nao.gefs.z500.120days.csv

[Stormchaserchuck1]

That is interesting. We had a 4-contour Greenland block, but nothing rivaling the strength of even what we have seen the past few Winters.  There seems be a major disconnect between CPC's NAO numbers and what is occurring in the NAO area, measured by sea-level pressure between Iceland and the Azore islands. This Winter came up with something like a +0.7 NAO for DJFM, but if you look at sea-level pressure and 500mb, it should have been measured negative. 

Either way, hopefully this is some sign that we will see more persistent -NAO's in coming cold seasons, as we had seen 41/46 +NAO Winter months, going back to 2013. and 16/16 of the NAO's >1.11 in the monthly's during that time were all positive. 16-0 since 2013. I think the larger reasoning is issues with CPC's measurements, but maybe the overall signal is turning around..

[weatherwiz]

5 hours ago, Stormchaserchuck1 said:

That is interesting. We had a 4-contour Greenland block, but nothing rivaling the strength of even what we have seen the past few Winters.  There seems be a major disconnect between CPC's NAO numbers and what is occurring in the NAO area, measured by sea-level pressure between Iceland and the Azore islands. This Winter came up with something like a +0.7 NAO for DJFM, but if you look at sea-level pressure and 500mb, it should have been measured negative. 

Either way, hopefully this is some sign that we will see more persistent -NAO's in coming cold seasons, as we had seen 41/46 +NAO Winter months, going back to 2013. and 16/16 of the NAO's >1.11 in the monthly's during that time were all positive. 16-0 since 2013. I think the larger reasoning is issues with CPC's measurements, but maybe the overall signal is turning around..

Isn't the Hurrell NAO method a bit better overall than the CPC's method? 

[Stormchaserchuck1]

16 hours ago, weatherwiz said:

Isn't the Hurrell NAO method a bit better overall than the CPC's method? 

I don't know that they are the ones that developed the NAO originally, but it wasn't the CPC. NAO was defined in the 1950s/60s, I think, as sea-level pressure differences between ~the Azores islands and Iceland regions. 

[Stormchaserchuck1]

According to todays 12z GFS ensembles, this may be one of the more -NAO June's on record. Permanent, big ridge over Greenland and the Davis Strait is what I have in mind for -NAO, not some small closed off blocking area (like we had late March/early April).