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Pattern February Discussion Part II

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pcbjr said:
EPO --> The negative phase corresponds to widespread cooling over central and eastern North America and the positive phase to warming. Don't have any daily history - so now you've sent me on a recon mission! My point being - it is definitely a a driver in the Pac this year and I can't recall a Pac driven season when the EPO wasn't a major player. But on to research now ....
Click to expand...

Let me know! About all I can say based on recalling correlation maps is that the +PNA's highest correlation to cold is centered in the SE US whereas the -EPO's highest correlation to cold is more general in the C/E US but not so highly concentrated in the SE like is the PNA. Also, the PNA based average storm track may very well be more wintry for the SE than a -EPO on avg. A PNA/-EPO would likely be best combo.
 
Let's see if we have the right bait for the GFS
 
GaWx said:
Let me know! About all I can say based on recalling correlation maps is that the +PNA's highest correlation to cold is centered in the SE US whereas the -EPO's highest correlation to cold is more general in the C/E US but not so highly concentrated in the SE like is the PNA. Also, the PNA based average storm track may very well be more wintry for the SE than a -EPO on avg. A PNA/-EPO would likely be best combo.
Click to expand...

The Eastern Pacific Oscillation (EPO) is the upper wind flow over the Eastern Pacific influenced by the ocean. When in a positive phase, the EPO generally is reflected by dominant stronger zonal flow and/or troughing along the West Coast of the U.S. This combination, in turn, tends to funnel milder Pacific air well inland into the country and thus, limits arctic outbreaks by holding them at bay up in Canada. When the EPO is dominated by a negative phase (as with the NAO), more ridging develops along the West Coast as higher pressure extends from the Gulf of Alaska south along the West Coast of Canada (opposite of the positive phase). This, in turn, encourages a northwesterly flow from Canada into the middle and eastern sections of the US and thus, the delivery of polar or arctic air. .

EPO can control how the Pac impacts us ... not the big dog like a great -NAO, but it can & does have major impacts, upstream - and it seems to have/is this year. If not - it's something in the Pac.
Anyway, here's some prelim - and need time to digest (including daily back to 1949) -

Background -
https://www.esrl.noaa.gov/psd/data/timeseries/daily/EPO/
Daily:
ftp://ftp.cdc.noaa.gov/Public/gbates/teleconn/epo.reanalysis.t10trunc.1948-present.txt

Now to translate LOL
 
Parker said:
Well I've got my eye on several cabins near gatlinburg that are between 2400-2800 feet in elevation. I would love to see this trend okay for my current area because I don't need to spend the money, but would def do it if things trended well for the mountains.
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I'd recommend you stay on top of Mt Mitchell, in NC! At 6000+ ft in elevation , you may be cold enough to get snow, if there was to be a storm, and if the moisture could make it back that far! Lots of ifs
 
Larry, you know we love the analogs! Any good ones for this set up?
 
So far, this run is slightly colder and the low is further south.

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Seems to me that ridging is flatter at 102, energy is much stronger but it's taking longer to dig...could be a big storm but may go off coast given how it's not digging already like the 18z was by this time


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If a storm idea appears sometime soon in the 14-16 area, I'll give Larry all the credit in the world for using the teleconnections to call it. A high +PNA is good but nothing has appeared so far.

On topic of 10-11, I haven't seen later slides but it looks like the same thing is about to occur....maybe.
 
pcbjr said:
The Eastern Pacific Oscillation (EPO) is the upper wind flow over the Eastern Pacific influenced by the ocean. When in a positive phase, the EPO generally is reflected by dominant stronger zonal flow and/or troughing along the West Coast of the U.S. This combination, in turn, tends to funnel milder Pacific air well inland into the country and thus, limits arctic outbreaks by holding them at bay up in Canada. When the EPO is dominated by a negative phase (as with the NAO), more ridging develops along the West Coast as higher pressure extends from the Gulf of Alaska south along the West Coast of Canada (opposite of the positive phase). This, in turn, encourages a northwesterly flow from Canada into the middle and eastern sections of the US and thus, the delivery of polar or arctic air. .

EPO can control how the Pac impacts us ... not the big dog like a great -NAO, but it can & does have major impacts, upstream - and it seems to have/is this year. If not - it's something in the Pac.
Anyway, here's some prelim - and need time to digest (including daily back to 1949) -

Background -
https://www.esrl.noaa.gov/psd/data/timeseries/daily/EPO/
Daily:
ftp://ftp.cdc.noaa.gov/Public/gbates/teleconn/epo.reanalysis.t10trunc.1948-present.txt

Now to translate LOL
Click to expand...

Thanks!
1.A quick look at the EPO maps:

https://www.esrl.noaa.gov/psd/forecasts/reforecast2/teleconn/images/epo.composite.gif

OK, this shows that the highest correlation of the -EPO to cold is actually in the NC and NE US & E Canada (+0.6+) and that the correlation in the SE US is actually a good bit lower (under 50% for all; under 40% most of GA/SC/S AL; under 30% S GA; only ~20% for G'ville, FL). This just reiterates what I had suspected: +PNA is more strongly correlated to cold in the SE, especially the further SE you go, where it is much more strongly correlated to a +PNA.

For the NE US, the corr. to -EPO is at least as high as, if not stronger, than that to the +PNA.

2. I think there's a lot of overlap between the -EPO and +PNA as they both favor a ridge on or near the west coast. They both favor NW flow of Canadian air into the E US.

3. The best bet for extreme SE cold is probably +PNA/-EPO but with the +PNA more vital. I need to research the dailies further when ever I get time.
 
The low is hanging up there longer than 18z...the good news the cold isn't in place yet.

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Looks like its kicked out so far but did a few ticks to the north, then again I had the 12z misjudged and realized it after 1-2 slides.

Edit: yep, misjudged it again, but I think its coming, just a little slower.
 
GaWx said:
Thanks!
1.A quick look at the maps:

https://www.esrl.noaa.gov/psd/forecasts/reforecast2/teleconn/images/epo.composite.gif

OK, this shows that the highest correlation to cold is actually in the NC and NE US & E Canada (+0.6+) and that the correlation in the SE US is actually a good bit lower (under 50% for all; under 40% most of GA/SC/S AL; under 30% S GA; only ~20% for G'ville, FL). This just reiterates what I had suspected: +PNA is more strongly correlated to cold in the SE, especially the further SE you go, where it is much more strongly correlated to a +PNA.

For the NE US, the -EPO is at least as high as, if not stronger, than the +PNA.

2. I think there's a lot of overlap between the -EPO and +PNA as they both favor a ridge on or near the west coast. They both favor NW flow of Canadian air into the E US.

3. The best bet for extreme SE cold is probably +PNA/-EPO. I need to research the dailies further when ever I get time.
Click to expand...

EPO is not the SE "be-it-all" - no doubt! But it is a driver in the Pac, and ultimately, in a year like this the Pac seems to be the engine and not the caboose. We've seen just the opposite in the past - but this year, the Pac is not helping -- at all ....
 
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