Jump to content

Rainshadow

Meteorological Winter Pattern Discussion

Recommended Posts

1 hour ago, tombo82685 said:

euro seasonal h5 monthly look 

ecmwf_seasonal_201812_z500a_201812.png

ecmwf_seasonal_201812_z500a_201901(1).png

ecmwf_seasonal_201812_z500a_201902.png

ecmwf_seasonal_201812_z500a_201903.png

Lol four straight months of a -nao.  It's the Euro equivalent of the GFS ssw's call. It has nailed 55 out of the last 17 -nao(s).  

Anyway seriously, it is going to take some wave 1 action to get December right as its own MJO outlook contradicts that map. Beyond that heck it could be undergoing the troffing for all I know. (Not much).

Share this post


Link to post
Share on other sites

The gefs look text book nino in long range after possible cutter next friday with abv normal hgts to the north and below in the southeast. Eps seem to bring more of a -pna look to the pattern which would build a se ridge look. Looking at the ensembles I don't see anything right now overly cold but if you get the the right track something could work out post dec 16. Need to get the trough into the Aleutians first before we can really start building the good cold back in. MJO doesn't look to favorable till probably Christmas or after most likely

Share this post


Link to post
Share on other sites

I don't know how they measure what phase the mjo is in. Is it where the start of the convection is or where the strongest anomalies are? Regardless just starting to come into IO now, but looks like bulk of mjo wave is still over part or Africa or in phase 1 getting ready to come into phase 2

image1

Share this post


Link to post
Share on other sites
14 minutes ago, tombo82685 said:

The gefs look text book nino in long range after possible cutter next friday with abv normal hgts to the north and below in the southeast. Eps seem to bring more of a -pna look to the pattern which would build a se ridge look. Looking at the ensembles I don't see anything right now overly cold but if you get the the right track something could work out post dec 16. Need to get the trough into the Aleutians first before we can really start building the good cold back in. MJO doesn't look to favorable till probably Christmas or after most likely

Agreed. Pac jet extension looks pretty wild in the 7-12 days range:

 

40A8CD98-FF3D-43C0-B656-A87A3D91E4DF.png.449a5e465384c3c8b8c15baf9b0728b1.png

That storm signal around the day 8-10 range looks cutter’ish to me. And our source region in Canada looks fairly stale by that point. Would imagine we’d need to see some higher heights in the PNA/EPO domain to reload. 

  • Like 1

Share this post


Link to post
Share on other sites
27 minutes ago, tombo82685 said:

I don't know how they measure what phase the mjo is in. Is it where the start of the convection is or where the strongest anomalies are? Regardless just starting to come into IO now, but looks like bulk of mjo wave is still over part or Africa or in phase 1 getting ready to come into phase 2

image1

CPC MJO model sites have it in phase 2.  Their initialization is a day later than this map.  MJO is almost in the same exact spot it was a month ago, relatively fast cycling.

Share this post


Link to post
Share on other sites

Nice twitter thread on SSW. Looks like odds are higher if there was one the year before.

 

sswshistoric.jpg

Share this post


Link to post
Share on other sites

00z DEC 1st GEFS (Welcome to winter!)

Above normal 500mb heights are replaced by below normal 500mb heights on December 3rd.  Rexish block along the eastern Pacific and a weak -nao keep below normal 500mb heights til December 7th.  At that point Aleutian ridge / Alaska trof / Western NOAM ridge set-up.  Below normal heights associated with potential snow/-nao arrives back on December 9th.  That western NOAM ridge moves southeast & brings above normal heights on December 12th (no can kick).  Above normal heights persist thru the end of its run on the 16th. This is maintained as there is a neg tilt trof from the Bering Sea to south of Alaska & lack of a negative nao.  GEPS has a more amplified pattern with ridging persisting in the Rockies during this time with heights closer to normal.  EPS positive 850mb anomalies still arriving on 12/12. looks closer to GEFs than GEPS.

NAEFS 12/9-12/16 has near normal temperature confidence so whatever happens the last couple of days is still outweighed by what occurs before.  Obviously if it snows on/about the 9th, one would have to chunk at least 5F off of max temps.

 

00z DEC 3rd GEFS

General below normal 500mb heights into early next week aside from Saturday the 8th.  The ridging in the Aleutians looks transitory and there is an East -NAO indexed or not.  The return to above normal heights remained on the 12th. The can kick is it looks later in the day. At that time the GEFS has a rather stout +EPO/West Coast Trof combo outlooked.  Going forward for the rest of the run differences between it and the EPS is to the strength of that trof.  The GEFS weakens it as it moves east leaving above normal heights thru the 18th while the EPS maintains it stronger. The GEPS is in the GEFS camp.  Regardless west coast ridging is outlooked and this consequently leads to below normal/near normal heights (18th onward) at the end of the GEFS run.  Any warm up with the EPS looks more transitory vs the other two.  Either way a snow cover could really mute any affect from it.

NAEFS 12/12-12/19 has high confidence of near normal temperatures, yet to see this turn warm.

 

00z DEC 6th GEFS

General below normal 500mb heights until Sunday the 9th.  The one day kick which meant the Newfoundland closed low is predicted to be slower to leave looks like it had implications (along with a sinking NAO) of the southern low not being able to turn the corner.  Heights go below normal again in wake of the system and above normal heights (a one day can kick) is now on Thursday the 13th.  After that things get interesting.  The above normal heights remain until the neg tilt trof arrives on the 15th.  At that time a deep trof (stout +epo) is outlooked through Alaska.  But rather pronounced western NOAM ridge also is outlooked.  This combination (more so than the GEPS or EPS) keeps below normal heights (not near normal) going until December 20th with above normal heights returning on December 21st.  Given that Canada is getting flooded with Pacific air, one would need a rather stout +PNA to offset the rather stout +EPO.  The NAO is outlooked to be positive, but who knows about that.

NAEFS 12/15-12/22 has a Monmouth County slight confidence of being above normal, but the rest of the east pretty much remains highly confident of near normal temperatures which would probably be the most prudent way to lok at this for now.  There is some wave 1 action outlooked, but the MJO (not in the GEFS and maybe why it does what it does) is also heading toward warmer phases.

 

Share this post


Link to post
Share on other sites
3 minutes ago, Chubbs said:

Nice twitter thread on SSW. Looks like odds are higher if there was one the year before.

 

sswshistoric.jpg

Kind of just blows the QBO state out of the water, can't have 6-9 consecutive winters of favorable or unfavorable states.

  • Like 1

Share this post


Link to post
Share on other sites
1 minute ago, Rainshadow said:

Kind of just blows the QBO state out of the water, can't have 6-9 consecutive winters of favorable or unfavorable states.

Interesting chart. Doesn't line-up in an obvious way with solar or philly snow either.

Share this post


Link to post
Share on other sites

After cycling down in the 2nd half of November, the nino has perked up again and is back at moderate levels in 3.4.

That Alaska warm pool sure would enhance any pattern that is conducive to western NOAM ridging

cdas-sflux_ssta_global_1.png.c6e76db1095b7b5503fae73c9b77efb0.png

Share this post


Link to post
Share on other sites

Our cool period since mid-Oct lines up well with a period of prolonged dateline forcing.

olr.orig.eqtr.png

  • Like 1

Share this post


Link to post
Share on other sites

Here’s the big time attack on the PV:

Day 10: check out the warmer anomalies towards Eurasia 

06FC7510-9264-4D91-BE89-FECF6B853880.png.e75290f3db036a1f67e171edaab684d9.png

Day 12: rapidly strengthening

 

A89F449B-670A-4C6D-A248-6E5B56110931.png.6ec59efa525e3c397028460e2074ef87.png

And by day 16, we get close to a wind reversal @10hPa. 

2C28A69A-8945-4BA7-8027-8B2C3819CD65.png.0c7a727facbd42239cf1f269eed0dfea.pngMeanwhile,

 

30mb & 50mb have a solid punch to the lower strat.

Not quite sure if we’ll see a true SSW, but even if we don’t, should see some decent responses in the Troposphere. This looks like it would be a strat displacement, and not a strat split? But long way to go. Nice seeing the signal manifesting at day 10, instead of day 15-16.

 

D0DB3F7D-5967-42BD-BE34-3055435683C7.png.fb871006275976acd90d76bd5af27230.png

 

expect day 8-16 op and Ens guidance to be a bit more fluent in their pattern depictions. You can see how the op GFS @18 and 0z started showing more blocking .

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, irishbri74 said:

Here’s the big time attack on the PV:

Day 10: check out the warmer anomalies towards Eurasia 

 

Day 12: rapidly strengthening

 

 

And by day 16, we get close to a wind reversal @10hPa. 

Meanwhile,

 

30mb & 50mb have a solid punch to the lower strat.

Not quite sure if we’ll see a true SSW, but even if we don’t, should see some decent responses in the Troposphere. This looks like it would be a strat displacement, and not a strat split? But long way to go. Nice seeing the signal manifesting at day 10, instead of day 15-16.

 

 

 

expect day 8-16 op and Ens guidance to be a bit more fluent in their pattern depictions. You can see how the op GFS @18 and 0z started showing more blocking .

yea, thats a displacement not a split. Looks like a solid wave 1 pattern after day 10 with building Aleutian low and siberian high to put pressure on pv. The 10mb epv flux are still pointed towards equator still. So need to see them to go poleward before we can really start to do some damage. we have another solid wave 1 signal showing up around mid month, so that would translate maybe to another cold shot right around or just before Christmas. Need to see wave 2 activity pick up as strong wave 1 then wave 2 is what does it to the pv This all looks like solid displacement right now 

waves.gif

Share this post


Link to post
Share on other sites

CFS2 lines up well with the euro weeklies presumably as strat/mjo lead to a wintry pattern. Hopefully mother nature has read the playbook.

cfs-avg_z500aMean_nhem_fh168-1008.gif

  • Like 1

Share this post


Link to post
Share on other sites

Looking at the mjo progression I'm thinking we don't get into a favorable winter pattern till after Christmas. I wouldn't be surprised though if we sneak an event in between the 20th and Christmas especially if strat effects start appearing but I think it's after Christmas. EPS have a nice -epo forming in the long range but the cold on them looks to dump into the plains/west first so that means another grinchy Christmas could be in the works as it will pump a se ridge. It def could be stormy leading into depending on where the boundary sets up. 

Share this post


Link to post
Share on other sites

With the exception of the Christmas miracle in 2002 which brought snow in the middle a warm stretch, Nino seasons favor warmth for Christmas to New Years.

1969 and 1976 were also cold exceptions.    Will we have sunny and warm or rainy and warm for Christmas?

Share this post


Link to post
Share on other sites
1 hour ago, iceman56 said:

With the exception of the Christmas miracle in 2002 which brought snow in the middle a warm stretch, Nino seasons favor warmth for Christmas to New Years.

1969 and 1976 were also cold exceptions.    Will we have sunny and warm or rainy and warm for Christmas?

Nino Decembers are usually not that great (except for exceptional winters), it's the Januaries & Februaries that outperform climo.

 

Share this post


Link to post
Share on other sites
On 11/25/2018 at 6:52 PM, Rainshadow said:

Other MJO guidance is faster than the GEFS, not as fast as the Euro, but closer to it than the former.  Regardless even if it is stretching beyond teleconnective skill forecasts,  the period beyond December 3rd based on Wave 1 & MJO should be colder east.  Looks like the NAEFS dumps more cold west, it is actually trending away from cold east for whatever reason.  Beyond this the OP GFS has hitched its wagon to another stout -NAO in la la la la land. This could crash and burn as I suppose so could the Aleutian Ridge (making it right for the wrong teleconnection).

 

2018112512_054@007_E1_north@america_I_NAEFS@TEMPERATURE_anomaly@probability@combined@week2_186.png

I wish I captured the outlook, but here is where we are today:

 

 

ECMF_phase_51m_small.gif

Share this post


Link to post
Share on other sites
3 minutes ago, Rainshadow said:

I wish I captured the outlook, but here is where we are today:

 

 

ECMF_phase_51m_small.gif

Yup, the eps were much closer to reality with their mjo forecast. Thought the gefs had the better speed from what I was seeing on the olr charts but that was wrong 

Share this post


Link to post
Share on other sites
On 12/4/2018 at 9:00 AM, Chubbs said:

GEFS more aggressive on strat weakening than other guidance, with a few GEFS members at or heading toward a full SSW.

ens_nh-stratwinds_010hPa_20181203.png

Three days later, no member wind reversal prior to 12/20 (now one member can kick to 12/24).  To me the GEFS is as SSW happy as it is -AAM happy at longer ranges.  Regardless colder MJO phases would be on their way with/without stratospheric help.

1.JPG.5d07ac0c95d22b54512dd15140bcfec8.JPG

 

Share this post


Link to post
Share on other sites
12 minutes ago, Rainshadow said:

Three days later, no member wind reversal prior to 12/20 (now one member can kick to 12/24).  To me the GEFS is as SSW happy as it is -AAM happy at longer ranges.  Regardless colder MJO phases would be on their way with/without stratospheric help.

1.JPG.5d07ac0c95d22b54512dd15140bcfec8.JPG

 

I’m already sick of hearing about the ssw and it not even mid dec. displacement looks good but the boy who cried wolf keeps showing up on these ssw forecast. 

Share this post


Link to post
Share on other sites

00z DEC 6th GEFS

General below normal 500mb heights until Sunday the 9th.  The one day kick which meant the Newfoundland closed low is predicted to be slower to leave looks like it had implications (along with a sinking NAO) of the southern low not being able to turn the corner.  Heights go below normal again in wake of the system and above normal heights (a one day can kick) is now on Thursday the 13th.  After that things get interesting.  The above normal heights remain until the neg tilt trof arrives on the 15th.  At that time a deep trof (stout +epo) is outlooked through Alaska.  But rather pronounced western NOAM ridge also is outlooked.  This combination (more so than the GEPS or EPS) keeps below normal heights (not near normal) going until December 20th with above normal heights returning on December 21st.  Given that Canada is getting flooded with Pacific air, one would need a rather stout +PNA to offset the rather stout +EPO.  The NAO is outlooked to be positive, but who knows about that.

NAEFS 12/15-12/22 has a Monmouth County slight confidence of being above normal, but the rest of the east pretty much remains highly confident of near normal temperatures which would probably be the most prudent way to lok at this for now.  There is some wave 1 action outlooked, but the MJO (not in the GEFS and maybe why it does what it does) is also heading toward warmer phases.

 

00z DEC 8th GEFS

Near normal 500mb heights arrive later today and pretty much remain except for briefly on the 12th as the southern stream system exits to our southeast. The 12th was the aforementioned often start of the return of above normal 500mb heights now kicked back to the 13th-15th until the next negative tilt (below normal heights) trof arrives.  On the 15th a pretty stout through Alaska trof is outlooked (+EPO) and the NAO looks to be trending more positive.   Going forward differences between the GEFS, GEPS & EPS is on the western NOAM ridging in response to that trof.  The GEFS is longer than the GEPS in keeping below normal heights locally thru the 19th (one day earlier than on 12/6).   Then it becomes a typical nino look with low heights south and higher heights in Canada with us flirting with above normal heights.   At the end of the run Aleutian troffing is back, but the EPO stioll "looks" positive as does the NAO.   Canada is bathed in relative warmth.   EPS not that different overall, I would say with cutter looks looks milder than the GEFS.

NAEFS 12/17-12/24 continues the high confidence of near normal temperatures.  There is some wave 1 (weakening wave 2) action outlooked, but the MJO (even in the GEFS now) is heading toward warmer phases.

Share this post


Link to post
Share on other sites
10 minutes ago, tombo82685 said:

I’m already sick of hearing about the ssw and it not even mid dec. displacement looks good but the boy who cried wolf keeps showing up on these ssw forecast. 

LOL this is "biased corrected" GWO and still probably going to verify too low.  They probably somehow go hand in hand.

gefsbc_gwo_fcst_current.png.8e17901973bd798fba66f1ddd8f78f49.png

 

Yeah if it was a strong nina winter, I could see the concern/interest as it may be the only game in town, but this winter it isn't.

 

Share this post


Link to post
Share on other sites
1 hour ago, Rainshadow said:

Three days later, no member wind reversal prior to 12/20 (now one member can kick to 12/24).  To me the GEFS is as SSW happy as it is -AAM happy at longer ranges.  Regardless colder MJO phases would be on their way with/without stratospheric help.

1.JPG.5d07ac0c95d22b54512dd15140bcfec8.JPG

 

The bigger picture here is we can still benefit from the weaker PV and other favorable tropospheric forcings.  

  • Like 2

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×