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Meteorological Autumn Pattern Discussion


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00z/23rd Ensemble Comparison 8/23-9/7. Normal 850mb temp around +13C. 

 Oh models, don't you can kick.  Don't you can kick. Don't you can kick.  Sigh.

@irishbri74, might have to give this one to the GEFS. Last time I did this, near the edge of modeling skill, they were showing a decent CFP early next week and a nice end to met summer. Well it is still there (sort of), but the Bermuda high is now outlooked to be more stubborn. Last night's Euro did a 180.  Well at least we can say confidence is not strong is flips like that are occurring near the edge of skill beginning time.  Regardless once Henri departs, the 90s return this work week.  There is a backdoor system that should cool us off some this weekend (normals are now lower, so mid-upper 80s are now above normal) before we rebound and a more muted CFP early next week.  Beyond that the ensembles have done a nearly perfect can kick when it comes to cooler weather arriving (well EPS says never).  This is beyond skill time and if we avoid an active (as in convection in phase 3), we may have to wait longer.  BTW if the MJO stays in phase 2 would seed more Verde systems and a -NAO (Henri) would clog the exit. 

 

GEFS Start Of Teleconnection Fcst Skill:  NAO Day 7;  PNA Day 10; AO Day 7.5

Recent Verification Tendency:  All more negative

GEFS: (4 days longer) Above normal 850mb temp anomalies thru Sep 1st, near normal anomalies Sep 2nd, above normal anomalies Sep 3rd & Sep 4th, near normal anomalies Sep 5th & Sep 6th, below normal anomalies Sep 7th (end of run).

GEPS: (4 days longer) Above normal 850mb temp anomalies thru Sep 3rd, near normal anomalies Sep 4th & Sep 5th, below normal anomalies Sep 6th & Sep 7th (end of run). 

EPS:  Above normal 850mb temp anomalies thru Sep 6th, thanks (end of run).   

NAEFS Week 2: Period of Aug 31st-Sep 7th. Moderate confidence of above normal temperatures. Trended warmer from "I don't know".  

 

Teleconnections: 

EPS:      +EPO thru 8/26; neg 8/27-9/6

              -PNA thru 9/1;  (a week later) pos 9/2-9/6

               -NAO 

GEPS:    +EPO thru 8/26; neg 8/27-9/7

               -PNA thru 9/2; (a week later) pos 9/3-9/7 

                -NAO 

GEFS:    +EPO thru 8/18; neg 8/19-8/23; new pos 8/24-8/26; neg 8/27-9/2

               -PNA thru 9/2; pos 9/3-9/6; neg 9/7

               -NAO  

  WPO:   Negative throughout

 

MJO:    (WH Sectors) Strongest Convection & Vel potential Phases 1 & 3  

GEFS Phase 2 to COD middle; EPS Phase 2 to COD Phase 3 (runs ends 9/6). 

MVentrice Strong Phase 2, Moderate Phase 5 at end.    

MJO: Going to include map at end going forward.  Phases 1 & 3 (where convection currently is) are warm.  Phase 2 if active would be cooler.

                    

Strat: NASA Wave 1 & Wave 2 generally below normal.  

NAM/SPV:  SPV this winter.  NAM n/a. 

 

mjo.JPG

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5 minutes ago, JimCaruso said:

My favorite season! Used to be summer... Funny how we change as we get older LOL

 

Lets hope it’s a fall-like Fall !

After this WET, humid summer I'm just about there. I also enjoyed summers more living on the coast vs. here inland.

Give me Aug 15-Nov 15 as my favorite 90 day stretch. Only thing that sucks about the end of the stretch is the shortening days and time change. 

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34 minutes ago, Parsley said:

After this WET, humid summer I'm just about there. I also enjoyed summers more living on the coast vs. here inland.

Give me Aug 15-Nov 15 as my favorite 90 day stretch. Only thing that sucks about the end of the stretch is the shortening days and time change. 

It is getting truncated as the summer lingers longer.  I was just thinking looking at the GFS's non stop 90s for the next 7 days beyond the GFS just being the GFS.  Nonsense like this did not routinely occur 20 to 30 years ago.

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2 hours ago, Rainshadow101 said:

It is getting truncated as the summer lingers longer.  I was just thinking looking at the GFS's non stop 90s for the next 7 days beyond the GFS just being the GFS.  Nonsense like this did not routinely occur 20 to 30 years ago.

As much as I hate this weather, I think only need like 10 more 90's after this week...🙂  

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00z/26th Ensemble Comparison 8/26-9/10. Normal 850mb temp around +13C. 

 A Little Cautious Optimism As We Head Into September. 

Unless I caught a cool run, this looks better than it was three days ago. But it is still in week 2 at this point.  Next week me might get cooler, but because of cloudiness and rain associated with Ida or Julian (don't know who is going to be named first).  It depends upon how much of a push from the +PNA ridging clears (or does not clear) a cold front through the area.  After that the ensemble means are showing a zonal flow, but all suppress any heat ridging well south.  Our 500 mb heights are near to below normal over the CONUS with above normal heights over Canada.  So we have three different solutions as to how "cool" it could get (probably the reason NAEFS has gone "I don't know". )  Regardless this is something to follow vs a non-stop heat look.

 

GEFS Start Of Teleconnection Fcst Skill:  NAO Day 7.5;  PNA Day 10; AO Day 7

Recent Verification Tendency:  more positive NAO, more negative PNA, neutral AO

GEFS: (same) Above normal 850mb temp anomalies into Sep 1st, (cooler) below normal anomalies Sep 2nd into Sep 6th, near normal anomalies Sep 7th thru Sep 10th (end of run).

GEPS: (same) Above normal 850mb temp anomalies into Sep 3rd, near normal anomalies Sep 4th, (warmer) above normal anomalies Sep 5th, (warmer) near normal anomalies Sep 7th thru Sep 9th, above normal anomalies Sep 10th. (end of run). 

EPS:  (new breaks in the non stop warmth) Above normal 850mb temp anomalies into Sep 1st, (new) near normal anomalies Sep 2nd, above normal anomalies Sep 3rd thru Sep 5th, (new) below to near normal anomalies Sep 6th thru Sep 9th (back/forth). (end of run).   

NAEFS Week 2: Period of Sep 3rd-Sep 10th. Gosh if I know. This typically has verified cooler than normal. 

 

Teleconnections: 

EPS:      +EPO thru 8/28 (2 days longer); neg 8/29-9/4; new pos 9/5; neg 9/6-9/9.

              -PNA thru 9/2;  (a day later) pos 9/3-9/8; neg 9/9

               -NAO 

GEPS:    +EPO thru 8/28 (2 days longer); neg 8/29-9/10

               -PNA thru 9/2; pos 9/3-9/6; neg 9/7-9/10 

                -NAO 

GEFS:    +EPO thru 8/28; neg 8/29-9/3; pos 9/4-9/5; neg 9/6-9/10

               -PNA thru 9/2; pos 9/3-9/6; neg 9/7-9/10

               -NAO  

  WPO:   Weakly Negative throughout

 

MJO:    (WH Sectors) Strongest Convection & Vel potential Phase 3  

GEFS Phase 2 to it is alive Phase 4; EPS Phase 2 to COD Phase 3 (runs ends 9/9). 

MVentrice Strong Phase 2, Weak Phase 5 at end.    

MJO: Going to include map at end going forward.  Active Phase 4 looks like a Bermuda Ridge

                    

Strat: NASA Wave 1 & Wave 2 generally below normal.  

NAM/SPV:  SPV this winter.  NAM n/a. 

mjo.JPG.c0d6cd5081db2613f1b12af143ef6c21

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On 9/2/2021 at 9:50 AM, snowlurker said:

As Bill Lundbergh said: If you can post a pattern yielding three 90+ days in September allowing me to win the contest, that'd be great.

I can make a halfway there post.  It is a little bit too warm a look for September.  Non 80s would have been better.

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00z/7th Ensemble Comparison 9/7-9/22. Normal 850mb temp around +12C. 

  At least September warmth is cough, "cooler".  90s contest threats next week.

Going to have to side with the EPS & GEPS with this one. The outlooked 500mb flow looks too zonal to be near normal.  Granted there will be a couple of days like that beyond September 12th, but not overall like the GEFS, I think.  Active MJO progressing slowly into Phase 4 favors a Bermuda ridge look.  Granted our winter wavelengths are not there yet, but a +WPO/+EPO/-PNA (the look more important) does not favor below normal temperatures.  On the plus side with the MJO on the other side of the globe, the tropics should be less active than normal.  This is a test for me as after all since it is September. 

 

GEFS Start Of Teleconnection Fcst Skill:  NAO Day 7.5;  PNA Day 10; AO Day 8

Recent Verification Tendency:  more positive NAO & AO, more negative PNA

GEFS: Below normal 850mb temp anomalies Sep 7th, above normal anomalies Sep 8th into Sep 9th, below normal anomalies Sep 9th thru Sep 11th, above normal anomalies Sep 12th thru Sep 15th, below normal anomalies Sep 16th, near normal anomalies Sep 17th thru Sep 21st, above normal anomalies Sep 22nd (end of run).

GEPS: Below normal 850mb temp anomalies Sep 7th, above normal anomalies Sep 8th into Sep 9th, below normal anomalies Sep 9th thru Sep 11th, above normal anomalies Sep 12th thru Sep 22nd. (end of run). 

EPS: Below normal 850mb temp anomalies Sep 7th, above normal anomalies Sep 8th into Sep 9th, below normal anomalies Sep 9th thru Sep 11th, above normal anomalies Sep 12th thru Sep 21st. (end of run).  

NAEFS Week 2: Period of Sep 15th-Sep 22nd. High confidence of above normal temperatures. 

 

Teleconnections: 

EPS:      +EPO (except neg today & 9/11)

              +PNA thru 9/10;  neg 9/11-21

               -NAO thru 9/11, pos 9/12 & 9/13; neg 9/14-9/20; pos 9/21 

GEPS:     +EPO after today

               +PNA thru 9/10;  neg 9/11-22

               +NAO thru 9/8; neg 9/9-9/11; neut 9/12-9/22 

GEFS:     +EPO (except neg today & 9/11)

              +PNA thru 9/10;  neg 9/11-22

               -NAO thru 9/19, pos 9/20-9/22 

 

  WPO:   Predominately positive GEFS, all positive EPS & GEPS

 

MJO:    (WH Sectors) Strongest Convection & Vel potential Phase 3  

GEFS Phase 3 to strong Phase 4; EPS Phase 3 to alive Phase 4 (runs ends 9/21). 

MVentrice Strong Phase 3, moderate Phase 5 at end.    

MJO: Going to include map at end going forward.  Active Phase 4 looks like a Bermuda Ridge

                    

Strat: NASA Wave 1 bouncing around 90th percentile & Wave 2 generally around normal.  

NAM/SPV:  SPV this winter.  NAM, cool shots 9/10 & 9/17. 

mjo.JPG.c0d6cd5081db2613f1b12af143ef6c21

 
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Just from a heating / air conditioning perspective it would be nice to see highs in the 70-75 range instead of 80-85. My worry is that when the pattern flips (which doesn't appear to be anytime soon), we will be far enough into the calendar that highs will mainly be in the 60s and lows in the 40s. Would be nice to have at least a 1-2 week stretch where I could leave the windows open.

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7 hours ago, ACwx said:

Just from a heating / air conditioning perspective it would be nice to see highs in the 70-75 range instead of 80-85. My worry is that when the pattern flips (which doesn't appear to be anytime soon), we will be far enough into the calendar that highs will mainly be in the 60s and lows in the 40s. Would be nice to have at least a 1-2 week stretch where I could leave the windows open.

Yeah this September has the look of the more recent Septembers.

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1 hour ago, irishbri74 said:

Well… ever since @Mitchnick started the winter thread, guidance started to get real torchy… 90’s this week coming up, and still chances for 90’s down the road…. And the humidity is still going to be around making pushes into the regions: 

 

 

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