The Mystical Month of February--Long Range Discussion

[Ji]

there was def less SE ridge today on the 12z EPS than the 0z EPS

[frd]

24 minutes ago, Bob Chill said:

It's already building. I've said this like 100 times. We're not talking about flipping from a +NAO into a fantasy -NAO in 15 days. Heights are building over the next 5 days (that's a lock) and are forecast to continue by all global ensembles.

Not sure whether the NAO going in our favor has to do with the processes HM described such as wave breaking, or if it has something to do with the wholesale changes in the SST profiles near and around Greenland, actually a portion of the Atlantic.    

I remember for years the theory of the tripole SST profile talked about by certain mets. Maybe we get several factors to work in our favor during Feb to produce a long lasting NAO block that eventually retros to the Davis Straights. 

Boy the look is sweet by Valentine's Day, if the PAC improves further near this date and afterward, could be in for multiple threats.     

[aldie 22]

1 minute ago, Ji said:

there was def less SE ridge today on the 12z EPS than the 0z EPS

You seem nervous 

[Ji]

Just now, leesburg 04 said:

You seem nervous 

i have a big winter forecast right? Need 10-20 more inches right?

[Isotherm]

5 minutes ago, frd said:

Not sure whether the NAO going in our favor has to do with the processes HM described such as wave breaking, or if it has something to do with the wholesale changes in the SST profiles near and around Greenland, actually a portion of the Atlantic.    

I remember for year the theory of the tripole SST profile talked about by certain mets. Maybe we get several factors to work in our favor during Feb to produce a long lasting NAO block that eventually retros to the Davis Straights. 

Boy the look is sweet by Valentine's Day, if the PAC improves further near this date and afterward, could be in for multiple threats.     

 

 

Frd, there are a couple [major] reasons why the NAO is becoming increasingly negative. One is the z10 reintegration of the vortex and attendant push downward of the -ve circulation anomalies; aka, the downwelling is finally reaching the critical layers of the troposphere. And, secondly, the tropospheric receptivity to high latitude blocking is increasing by way of vicissitudes in the Pacific tropical forcing regime. Reweighting of centrally based warmth, easterly trades increasing in region 1+2, enhanced LL convergence/UL divergence near the dateline, signalling canonical walker cell emergence.

Posted this on another board. U850 wind proxy is instructive.

 

 

 

It's incontrovertible that the walker-cell orientation and attendant tropical forcing is altering for February, toward a more stable regime which has been largely elusive to date; namely, enhanced low-level convergence and upper level divergence near the more canonical dateline location. The U-wind at z850 is a valuable proxy to ascertain this eastward propagating WLY wind and thus convergence line, serving as a focus for tropical convection. The result of which should be the induction of the canonical Aleutian low / +PNA regime once the contaminating intra-seasonal signal propagates toward late phase 7 / near phase 8 [circa Feb 8th]. 

 

The Western troughing is courtesy of the slowly propagating MJO phase 6-7 signal, which has already been covered numerous time. We saw the same situation in late December w/ amplified 6-7 and resultant trough deepening in the West. I think we all realize that this winter has not "cooperated with the time scales delineated in many winter forecasts" but I believe the apposite thought in everyone's mind at this point is as follows: one no longer cares how it has been timed, but will winter ever show up? And the answer is that there's a good chance for 4-5 weeks of winter [which quite frankly, if one thinks about, a large percentage of our good winters have came in about a month's period]. The debate of course is the precise z500 structure going forward.

 

Let me refrain from equivocating: the GEFS is dead wrong with the circling back to phase 6. The ECMWF is closer, but still a bit too much wandering in phase 7. The VPM has been most instructive, and indicates some slowing in phase 7 in early February before phase 8 entrance at the beginning of the second week of February. So the bottom line is that the pattern, a priori, should become progressively improved.

 

 

[aldie 22]

4 minutes ago, Ji said:

i have a big winter forecast right? Need 10-20 more inches right?

Make it happen man

[psuhoffman]

10 minutes ago, C.A.P.E. said:

If we get a west based block we should be able to mitigate the issues with the Pacific- which are not likely to disappear completely at this point. That's what I am saying.

I was agreeing with you. Normally that pac would be a disaster. With only some AO or NAO help it wouldn’t work. But with a true west based block suddenly it actually works. You get systems ejecting into the east that might try to cut but run unti the confluence and blocked flow and it works in a convoluted way. But a west based block can fix a lot of imperfections for us. Especially in February and March 

[SnowGoose69]

1 hour ago, psuhoffman said:

I am not so sure if we get a west based block that the pacific really is a problem.  I went digging and found the analog I was thinking of.  This is kind of what we are shooting for here imo.  This period produced 3 snowfalls in our region, one minor, one moderate, and one warning to HECS level depending on elevation.  Of course the period was in March so get this displaced a couple weeks earlier and results would be better imo.  But this is kind of the inevitable end progression of that EPS look day 15 imo.   No 2 years are the same but look at the EPO ridge location and PNA.  This is what that pattern turns into if you get a west based NAO block.  

The wavelength change may be a factor too.  It’s entirely possible in this pattern we have now that a big snow might happen in March with a +NAO but is less likely in January 

[CAPE]

13 minutes ago, Isotherm said:

 

 

Frd, there are a couple [major] reasons why the NAO is becoming increasingly negative. One is the z10 reintegration of the vortex and attendant push downward of the -ve circulation anomalies; aka, the downwelling is finally reaching the critical layers of the troposphere. And, secondly, the tropospheric receptivity to high latitude blocking is increasing by way of vicissitudes in the Pacific tropical forcing regime. Reweighting of centrally based warmth, easterly trades increasing in region 1+2, enhanced LL convergence/UL divergence near the dateline, signalling canonical walker cell emergence.

Posted this on another board. U850 wind proxy is instructive.

 

 

 

It's incontrovertible that the walker-cell orientation and attendant tropical forcing is altering for February, toward a more stable regime which has been largely elusive to date; namely, enhanced low-level convergence and upper level divergence near the more canonical dateline location. The U-wind at z850 is a valuable proxy to ascertain this eastward propagating WLY wind and thus convergence line, serving as a focus for tropical convection. The result of which should be the induction of the canonical Aleutian low / +PNA regime once the contaminating intra-seasonal signal propagates toward late phase 7 / near phase 8 [circa Feb 8th]. 

 

The Western troughing is courtesy of the slowly propagating MJO phase 6-7 signal, which has already been covered numerous time. We saw the same situation in late December w/ amplified 6-7 and resultant trough deepening in the West. I think we all realize that this winter has not "cooperated with the time scales delineated in many winter forecasts" but I believe the apposite thought in everyone's mind at this point is as follows: one no longer cares how it has been timed, but will winter ever show up? And the answer is that there's a good chance for 4-5 weeks of winter [which quite frankly, if one thinks about, a large percentage of our good winters have came in about a month's period]. The debate of course is the precise z500 structure going forward.

 

Let me refrain from equivocating: the GEFS is dead wrong with the circling back to phase 6. The ECMWF is closer, but still a bit too much wandering in phase 7. The VPM has been most instructive, and indicates some slowing in phase 7 in early February before phase 8 entrance at the beginning of the second week of February. So the bottom line is that the pattern, a priori, should become progressively improved.

 

 

Now I know how my poor students feel when I am trying to explain simple first order natural(open loop) transfer functions irt closed loop, negative feedback control theory.

[CAPE]

17 minutes ago, psuhoffman said:

I was agreeing with you. Normally that pac would be a disaster. With only some AO or NAO help it wouldn’t work. But with a true west based block suddenly it actually works. You get systems ejecting into the east that might try to cut but run unti the confluence and blocked flow and it works in a convoluted way. But a west based block can fix a lot of imperfections for us. Especially in February and March 

YES. Agreed.

[Bob Chill]

6 minutes ago, C.A.P.E. said:

Now I know how my poor students feel when I am trying to explain simple first order natural(open loop) transfer functions irt closed loop, negative feedback control theory.

I developed an Isotherm decoder ring. Just scanned his enitre post (without a dictionary or thesaurus) and you know what my ring says? It says the gefs sucks with the mjo and get your shovel ready cuz it gon be yuuuuuge

[clskinsfan]

54 minutes ago, Ji said:

i have a big winter forecast right? Need 10-20 more inches right?

Thats doable with one storm though. I think you are fine.

[Ji]

Does anyone know how to read those uwnd charts?

[Ji]

HM on Twitter is taking to me in language I can understand

[Grothar of Herndon]

Just now, Ji said:

HM on Twitter is taking to me in language I can understand

Did he explain the uwnd charts?

[Bob Chill]

8 minutes ago, Ji said:

HM on Twitter is taking to me in language I can understand

It's really easy. There are only 2 reasons HM posts complicated stuff. To tell us we're royally f'd or multiple KUs are on the way. Just scroll down to replies and see if people are happy or sad and you know the answer.

[Maestrobjwa]

5 minutes ago, Bob Chill said:

It's really easy. There are only 2 reasons HM posts complicated stuff. To tell us we're royally f'd or multiple KUs are on the way. Just scroll down to replies and see if people are happy or sad and you know the answer.

His Twitter description literally says "annoyingly esoteric"...lol And he lives up to that to a tee! But if he's high on February, then we must be heading a pretty good spot (or better!)

[CAPE]

6 minutes ago, Bob Chill said:

It's really easy. There are only 2 reasons HM posts complicated stuff. To tell us we're royally f'd or multiple KUs are on the way. Just scroll down to replies and see if people are happy or sad and you know the answer.

Well considering he has said "KU" at least twice over the last 24 hours, I am gonna guess we aren't ****ked.

[AfewUniversesBelowNormal]

When the Low in a few days with warm front moves through, it looks like still a cold pattern. I have feeling there will be a snow event this year. I wonder if this is the one. (That Low in SE Canada is always there!)

 

[MD Snow]

Both the fv3 and gfs have the storm next weekend. It’s south of us because of a disturbance to the north but it’s there. Seems to be showing up a lot on ensembles. 

[BristowWx]

1 minute ago, MD Snow said:

Both the fv3 and gfs have the storm next weekend. It’s south of us because of a disturbance to the north but it’s there. Seems to be showing up a lot on ensembles. 

It’s north of the 12z GFS so there is something.  Lots of time but need steady movement north.  

[poolz1]

GEFS coming in with a PNA ridge building by D12.  Big dif from 12z....

[frd]

Reaction to changes in the Pac/MJO.  Tomorrow's run might be even better. I am starting to get slightly excited again.   I like the GEFS seems to pick up on a trend many times.  Did you see that the off hour runs of the Euro are not doing well ? Heard it from a met(s). They were studying it. I never did hear back as to the reason behind the poor verifications though. 

 

4 minutes ago, poolz1 said:

GEFS coming in with a PNA ridge building by D12.  Big dif from 12z....

 

[Jandurin]

48 minutes ago, Bob Chill said:

It's really easy. There are only 2 reasons HM posts complicated stuff. To tell us we're royally f'd or multiple KUs are on the way. Just scroll down to replies and see if people are happy or sad and you know the answer.

Lmao that's so true

[poolz1]

11 minutes ago, frd said:

Reaction to changes in the Pac/MJO.  Tomorrow's run might be even better. I am starting to get slightly excited again.   I like the GEFS seems to pick up on a trend many times.  Did you see that the off hour runs of the Euro are not doing well ? Heard it from a met(s). They were studying it. I never did hear back as to the reason behind the poor verifications though. 

 

 

I havent seen the ind members yet but the with panels like this...I would imagine its another weenie run.  Active and colder than 12z..

[Scarlet Pimpernel]

1 hour ago, Bob Chill said:

I developed an Isotherm decoder ring. Just scanned his enitre post (without a dictionary or thesaurus) and you know what my ring says? It says the gefs sucks with the mjo and get your shovel ready cuz it gon be yuuuuuge

Well...as long as it doesn't translate to "Be sure to drink your Ovaltine!"

[Scraff]

1 hour ago, Bob Chill said:

I developed an Isotherm decoder ring. Just scanned his enitre post (without a dictionary or thesaurus) and you know what my ring says? It says the gefs sucks with the mjo and get your shovel ready cuz it gon be yuuuuuge

Glad you were able to decode. I went to school at WVU. Dem werds dat Iso dood youzed was yuuuuuuuge!!

[Bob Chill]

Gefs keep painting a sweet 7 day qpf anomaly chart

A lot of sprawling high pressure to our north on the mslp panels too. We're so used to riding edges with amplified flow that we've forgotten what it can be like with some blocking. There are a lot of ways to get snow in these parts with hp sprawled to the north instead of pressing in from the west. Even a west track can produce a very nice event. Mixed precip is likely with that track but mixed with a good front end thump of snow beats the heck out of rain.

Gefs looks similar to the euro for d10-12 with precip streaming up from the tn valley and CAD sig. Feb 10th-12th is slowly becoming a legit window.

[nj2va]

We can work with this

[psuhoffman]

@Bob Chill @frd@C.A.P.E.@Ji

This is the same system the eps was keying on. It’s as strong a signal as I’ve ever seen at this range.  Look at the signal for high pressure in front of it...

Then day 16 there is the stj crashing into the Southwest with cold locked in so let’s just do it again.