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Late February will be rocking. February Long range Discussion thread


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I can’t put much rationale into it, but I just have a feeling we’re going to see one moderate coastal event that gets everyone from you guys to SNE. And that’ll probably be it for winter. Lots of hanging onto the OP depictions of the favorable window on the other forums instead of just taking the idea for now. I think there’s a chance, however small. 

Hope for the best, for sure. 

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1 minute ago, Volcanic Winter said:

I can’t put much rationale into it, but I just have a feeling we’re going to see one moderate coastal event that gets everyone from you guys to SNE. And that’ll probably be it for winter. Lots of hanging onto the OP depictions of the favorable window on the other forums instead of just taking the idea for now. I think there’s a chance, however small. 

Hope for the best, for sure. 

C9CB8FAE-B7A7-4BDD-9881-E7337F4A32B9.gif.11a8393cdae7ab3eed6e859e63d484b6.gif

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21 minutes ago, Heisy said:

Todays CMC also has NAO form day 8-10. Not sure if it’s legit yet because not really seeing the same signal on the ensembles yet.


.

 

12 minutes ago, CAPE said:

The 0z ens runs were hinting especially the EPS. Lets see if that continues for a few cycles.

The signal is hidden within the ensembles.  The near neutral heights up top on the ensembles are because there are competing camps.  There is some support for the -NAO the op runs are hinting at.  The problem is, within that camp, there is a split between what the mid latitude impacts are, with most members showing continued ridging in the east regardless of the NAO state.  We've seen that show now in a couple op runs also, the 6z aside.  

This is something we should be watching, and there should be more discussion and analysis on imo, is why havent, and what needs to happen for the NAO to have the canonical mid latitude response.  IMO this is the most important factor because I do think we have entered a long term -PDO cycle.  If we look back at the last -PDO cycle the way we got snow was not typically to get a positive PDO/PNA.  The pacific was stuck in a hostile state about 80% of the time from 1945 to 1980.  The way we got snow during that period was mostly during periods of high latitude blocking that forced the trough in the western US to cut east under the blocking instead of lifting, resulting in a basically a west to east full continent trough.  We didn't ever really get a favorable pacific, we just overcame it.  

Look at the h5 for all our above normal snowfall -PDO years since 1960.  

F8OaekYnB6.png.91a0e3838561f78ae46dbbc5c566955f.png

The blue there is exaggerated because most of those years are from a colder base state and its using todays norms but you can clearly see the longwave pattern.  The pacific is flat out god awful.  Aleutian ridge, western N American trough.  The reason most of the years are from so long ago was that was the last -PDO cycle.  We have had a +PDO 75% of the time from 1980 on so there weren't that many years that had a -PDO for there to be opportunities. 

 

But within that there is a troubling trend where the percentage of -PDO winter months with above normal snowfall is dropping significantly.  That is a big problem if we are going to spend 80% of the next 30 years in a -PDO!   But if we dig even deeper the problem is related to the NAO.  During the last -PDO 35 year cycle positive NAO periods were really really bad by that time periods norms.  But -NAO periods were very very good.  The reason -NAO's worked though was not because they somehow timed up with a favorable pac.  This is why I get annoyed when people blame a NAO fail on the pacific.  In our last hostile pac cycle the NAO was how we overcame the hostile pac.  The hostile pac isn't going away, and I got bad news...thats likely true even in most nino's, many of our ninos during the last -PDO the pac was still a hot mess just like 2019 was, but the -NAO was able to compensate.  But our fail rate in -NAO-PDO months is increasing dramatically. 

SO far though the data set is too small to say anything with statistical significance.  But we really really really need NAO's to start forcing the western trough to broaden into a full west to east coast to coast mid latitude trough and NOT see the SER simply go ape during the -NAO and even link up...because that is the only way we ever got a really snowy winter during the previous hostile PDO period on record.  Yea those years posted above may not seem like that many... but if you remove them from out last PDO cycle it would have made that period god awful.  What I am most interested in frankly is waiting to see that the NAO still has the same impact it did during the last -PDO, which is to say it can OVERCOME the hostile pacific, because if we truly are in the next -PDO that hostile pacific is going to last most of the rest of our lives.  That wasn't a death sentence for snow during previous PDO cycles only because blocking could overcome it.  

 

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The signal is hidden within the ensembles.  The near neutral heights up top on the ensembles are because there are competing camps.  There is some support for the -NAO the op runs are hinting at.  The problem is, within that camp, there is a split between what the mid latitude impacts are, with most members showing continued ridging in the east regardless of the NAO state.  We've seen that show now in a couple op runs also, the 6z aside.  
This is something we should be watching, and there should be more discussion and analysis on imo, is why havent, and what needs to happen for the NAO to have the canonical mid latitude response.  IMO this is the most important factor because I do think we have entered a long term -PDO cycle.  If we look back at the last -PDO cycle the way we got snow was not typically to get a positive PDO/PNA.  The pacific was stuck in a hostile state about 80% of the time from 1945 to 1980.  The way we got snow during that period was mostly during periods of high latitude blocking that forced the trough in the western US to cut east under the blocking instead of lifting, resulting in a basically a west to east full continent trough.  We didn't ever really get a favorable pacific, we just overcame it.  
Look at the h5 for all our above normal snowfall -PDO years since 1960.  
F8OaekYnB6.png.91a0e3838561f78ae46dbbc5c566955f.png
The blue there is exaggerated because most of those years are from a colder base state and its using todays norms but you can clearly see the longwave pattern.  The pacific is flat out god awful.  Aleutian ridge, western N American trough.  The reason most of the years are from so long ago was that was the last -PDO cycle.  We have had a +PDO 75% of the time from 1980 on so there weren't that many years that had a -PDO for there to be opportunities. 
 
But within that there is a troubling trend where the percentage of -PDO winter months with above normal snowfall is dropping significantly.  That is a big problem if we are going to spend 80% of the next 30 years in a -PDO!   But if we dig even deeper the problem is related to the NAO.  During the last -PDO 35 year cycle positive NAO periods were really really bad by that time periods norms.  But -NAO periods were very very good.  The reason -NAO's worked though was not because they somehow timed up with a favorable pac.  This is why I get annoyed when people blame a NAO fail on the pacific.  In our last hostile pac cycle the NAO was how we overcame the hostile pac.  The hostile pac isn't going away, and I got bad news...thats likely true even in most nino's, many of our ninos during the last -PDO the pac was still a hot mess just like 2019 was, but the -NAO was able to compensate.  But our fail rate in -NAO-PDO months is increasing dramatically. 
SO far though the data set is too small to say anything with statistical significance.  But we really really really need NAO's to start forcing the western trough to broaden into a full west to east coast to coast mid latitude trough and NOT see the SER simply go ape during the -NAO and even link up...because that is the only way we ever got a really snowy winter during the previous hostile PDO period on record.  Yea those years posted above may not seem like that many... but if you remove them from out last PDO cycle it would have made that period god awful.  What I am most interested in frankly is waiting to see that the NAO still has the same impact it did during the last -PDO, which is to say it can OVERCOME the hostile pacific, because if we truly are in the next -PDO that hostile pacific is going to last most of the rest of our lives.  That wasn't a death sentence for snow during previous PDO cycles only because blocking could overcome it.  
 

Euro looks like it’s trying to form NAO as well, not like cmc yet, but you can see the beginning stages


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Curious what the red tags think on this. My preliminary theory is “perhaps” the mjo impacts of the expanded indo-pac warm pool along with the expanding pac Hadley cell AND the logical impact of the almost permanently above normal gulf and western Atlantic are all combining to enhance the SER even more so than the pdo alone did during the last -pdo, and that is why we’ve seen patterns that historically were able to mute the SER fail to overcome the SER recently. 
 

2 part question. There is not nearly enough data yet but do you think this COULD have any validity. And if so what other factors could help overcome that?  

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27 minutes ago, psuhoffman said:

Curious what the red tags think on this. My preliminary theory is “perhaps” the mjo impacts of the expanded indo-pac warm pool along with the expanding pac Hadley cell AND the logical impact of the almost permanently above normal gulf and western Atlantic are all combining to enhance the SER even more so than the pdo alone did during the last -pdo, and that is why we’ve seen patterns that historically were able fail to overcome the SER recently. 
 

2 part question. There is not nearly enough data yet but do you think this COULD have any validity. And if so what other factors could help overcome that?  

idk. there were March 2018 and February 2021 which both forced the canonical -NAO trough response and some pretty prolific snow for much of the E US

compday.wTv6eVZMoz.gif.8b580e4332416f67b56ed7f4e079b427.gif.569a7de846bb457566b4d6887a84b29d.gifcompday.462pJ8VOf2.gif.ae245056c8e125d5fbd469cc0950b913.gif.2f6257e0a69afbda72381ffd5e124636.gif

I wouldn't say that the -NAO linked up with the SE ridge for this past December. the TPV just dumped out west, which is really just a matter of chaos more than the -NAO being suboptimal, and we had the system move too far W. a follow up wave arrived, but it was a day too late and deamplified as the pattern broke down. but I would not say that there is a SE ridge here... the TPV could have easily been displaced farther E, but that was the way the cookie crumbled there

give us that pattern 10 times and we would cash in 7 or 8 times... you do run the 20% chance of getting screwed tho

compday.7iUhxuSHYh.gif.335b7724b1e2aedbca8704ed899712c1.gif.4fa138a7bf581490ba37ab78606bd8a0.gif

I do share some of the same concerns as you, tho. -PDO periods are never very fun, but hopefully the change back to a Nino base state at some point will help cool the W Atl and also lead to more WC ridging

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Statements that “this is how it goes in a Nina” are mostly incorrect.  Precipitation has been more like a Nino , strong lows into the lakes with copious moisture is more like a Nino .  The temperature profile has matched Nina

Weather forecasting is like medical practitioners-practice to try and get it done better. The Enso used to be very reliable and many other theories have been circulated but SSW and MJO and the Ever Increasing alphabet indexes are like medicine-in a state of development and practice.  They are too often presented as assured when really it’s unproven yet May in time become proven.

As painfully as many react to this-models do Not predict a weather outcome; they give examples of possibilities.  It’s a good thing my doctor does not say “try this one or try that one” which is what models project with each 6 hour run. 
 

I dont know but some of you very adept do know what mechanism forces cold air down thru  Canada and over western PA and NY.  That’s the source for snow in DC area. Plunging cold air into central USA and then rolling eastward just does not work, phase jobs don’t work, Miller As are our money .

 

 

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3 hours ago, Heisy said:


Euro looks like it’s trying to form NAO as well, not like cmc yet, but you can see the beginning stages


.

Seasons that begin with significant HL +height anomalies tend to sandwich -height anomalies in the middle. Both PSU and even Chuck have noted this several times. It's one of the main reasons I went with the backloaded idea this year. Most years with the early epic HL blocking recently have failed to produce 'early' more times than not. For whatever reason (sst lag?) this revisited HL +height anomalies have produced in the 2nd half of Feb and March. 

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2 hours ago, brooklynwx99 said:

still a pretty nice signal for something on the 11-13th on the EPS... lots of coastal lows on there. probably a decent amount of rainers too, but not concerned with p-type as of now

would be thread-the-needle. but whatever

ecmwf-ensemble-avg-conus-mslp_with_low_locs-1675339200-1676073600-1676246400-40.thumb.gif.50e9233c67bd0f32f04c6a3be624b969.gif

EPS has another chunk of polar air coming down centered around the 12th with 850s near to BN and a mean h5 disturbance sliding under the region. Not a huge signal but not a horrible one either. 

Try and put the thread in the eye of the needle enough times and it will eventually happen.

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