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Meteorological Autumn Pattern Discussion, It Is Here.


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00z/24th Ensemble Comparison 8/24-9/8.  Normal 850mb temp around +14C.  

I Will Believe When I See It.  A Fitting End To Our Coolest Summer Since 2009 I Believe.  

 

I am going to have to be briefer this morning.  The ensembles have trended either stronger or better timed with a very robust +PNA ridge during the start of next week.  Even in summer, the downstream implications are for a chilly end to our meteorological summer.  This is going to be our coolest summer since 2009 (I think) or 2014 at the worst.  Since the +PNA has trended stronger, the alleged warmer relaxation in the pattern has nearly been can kicked from three days ago.  Now a brief +EPO period (welcome EPS) does infer some sort of warmer recovery.  Granted it is getting out there, but the EPO is suppose to go negative again and the PNA conversely not negative until well into la la land. Some day, some way there will be a paradigm switch in which la la land pattern switches actually occur.  For now this is too much of a can kick and only the GEFS unto MJO Phase 4 for me to buy into it.

Tropics:  Hard to pat one's back saying the tropics will get more active in late August (just like saying it will get cold in January), but the MJO being on our side of the globe has not hurt one bit.  It looks like a pretty active (at least) two week pattern until the MJO gets on the other side of the globe whenever that is.  For now the weaker Bermuda Ridge and the emergence of a +NAO is providing an exit strategy in this period (hello Franklin), but that is far from being etched in stone throughout the two week period.  

 

 

GEFS: (0.5 day longer) Below normal 850mb temp anomalies thru Aug 24th, (0.5 day less) above normal anomalies  Aug 25th into Aug 26th, (3 days less) below normal anomalies Aug 27th into Aug 28th, (new, warmer) above normal anomalies Aug 29th into Aug 30th, (new, cooler) below normal anomalies Aug 31st and Sep 1st, (same) above normal anomalies later Sep 2nd thru Sep 8th (end of run). 99F or higher for at least one ensemble member on last 4 of 16 days (okay). 

Sep Torchfest For Mississippi Valley.   

 

GEPS:  (0.5 day longer) Below normal 850mb temp anomalies thru Aug 24th(0.5 day shorter) above normal anomalies Aug 25th into Aug 26th, (now split) below normal anomalies later Aug 27th & Aug 28th, (new) above normal anomalies Aug 29th into Aug 30th, below normal anomalies later Aug 30th thru Sep 1st, (new) primarily newar normal anomalies Sep 2nd & Sep 3rd, (near can kick) above normal anomalies Sep 4th thru Sep 8th, above normal anomalies Sep 5th (end of run). 99F or higher for at least one ensemble member on 0 of 16 days.

Local near Barney experience 8/31.  

 

EPS: (0.5 day longer) Below normal 850mb temp anomalies thru Aug 24th, (0.5 day longer) above normal anomalies Aug 25th into Aug 27th, (warmer, way less) near normal anomalies night of Aug 27th, above normal anomalies Aug 28th into Aug 30th, (a 180) below normal anomalies later Aug 30th thru Sep 1st, (can kick) above normal anomalies Sep 2nd thru Sep 6th (end of run).  99F or higher for at least 1 ensemble member on 3 of 15 days

Local near Barney experience 8/31.   

 

NAEFS Week 2: Period of Sep 1st thru Sep 8th. I don't know yet again. Take that GEFS.   

 

 

Teleconnections: 

GEFS Teleconnection Fcst Skill Starts At:  NAO Day 10.5;  PNA Day 8;  AO Day 13

            Recent Verification Tendency:  Spot On NAO; More Negative PNA; More Positive AO      

 

GEFS:     -EPO thru 8/29 (day less;) neut 8/30-8/31; neg 9/1-9/8 (same)

               +PNA thru 9/6 (3 days more, +5SD 8/28); neg 9/7-9/8  

              -NAO thru 8/25 (same) pos 8/26-8/30; neg 8/31 (2 days less); pos 9/2-9/8 (dropped neg -> 9/3)        

 

GEPS:     -EPO thru 8/30 (day less) pos 8/31-9/2 (2 days more); neg 9/3-9/8 

               +PNA thru 9/6 (same, +5.75SD 8/29)      

               -NAO thru 8/25 (day less); pos 8/26-8/30 (2 days more); neg 8/31-9/1; pos, not neut 9/2-9/8 

 

EPS:      -EPO thru 8/29 (same :rolleyes: deserved, new) pos 8/30-9/1; neg 9/2-9/7

              +PNA thru 9/3 (3 days more, +5.75SD 8/28); neg 9/4-9/7   

              -NAO thru 8/25; (day less) pos 8/26-8/29; neg, not neut 8/30-8/31; pos 9/1-9/7 

 

WPO:  Positive after 8/25; neg aft 9/4 on GEFS & EPS

 

 

MJO:       (Vel Potential & Convection) moderate Phase 8 & Phase 1.  

GEFS:     Phase 8 thru COD to Phase 4. 

EPS:       Phase 8 into COD to Phase 5 COD.  

GEPS:    Phase 1 into COD to Phase 4 COD. (All runs end 9/7)

MVentrice (Vel Potential Only):  GFS Forecast Phase 8 to Phase 1  

 

 

Strat: NASA   Wave 1: 40th -> 80th -> 50th -> 70th -> 50th Percentile  

                       Wave 2: 0.1st -> 70th -> 50th -> 90th Percentile  

                       FU Berlin, back for this winter?                    

SPV:    Euro (thru day 10): See Ya This Winter. 

            GFS (thru day 15):  See Ya This Winter.    

SPV NASA 10 days:  See Ya This Winter.  

Ensembles 15 days:  See Ya This Winter.   

 

NAM: Blocked beyond current. 

 

**************  September Centered  *******************

image.png.948a4d83e4a50d98cf17fc8acbf4d6ce.png

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21 hours ago, Qtown Snow said:

"Like" this thread, Love Autumn 

 

19 hours ago, DelcoWx said:

My most, all-time, hands-down favorite time of the year. 

Until it snows. Then my loyalty to fall changes. 😊

We have many memberships available in the October Weather Fan Club.

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On 8/24/2023 at 9:06 AM, Rainshadow said:

00z/24th Ensemble Comparison 8/24-9/8.  Normal 850mb temp around +14C.  

I Will Believe When I See It.  A Fitting End To Our Coolest Summer Since 2009 I Believe.  

 

I am going to have to be briefer this morning.  The ensembles have trended either stronger or better timed with a very robust +PNA ridge during the start of next week.  Even in summer, the downstream implications are for a chilly end to our meteorological summer.  This is going to be our coolest summer since 2009 (I think) or 2014 at the worst.  Since the +PNA has trended stronger, the alleged warmer relaxation in the pattern has nearly been can kicked from three days ago.  Now a brief +EPO period (welcome EPS) does infer some sort of warmer recovery.  Granted it is getting out there, but the EPO is suppose to go negative again and the PNA conversely not negative until well into la la land. Some day, some way there will be a paradigm switch in which la la land pattern switches actually occur.  For now this is too much of a can kick and only the GEFS unto MJO Phase 4 for me to buy into it.

Tropics:  Hard to pat one's back saying the tropics will get more active in late August (just like saying it will get cold in January), but the MJO being on our side of the globe has not hurt one bit.  It looks like a pretty active (at least) two week pattern until the MJO gets on the other side of the globe whenever that is.  For now the weaker Bermuda Ridge and the emergence of a +NAO is providing an exit strategy in this period (hello Franklin), but that is far from being etched in stone throughout the two week period.  

 

 

GEFS: (0.5 day longer) Below normal 850mb temp anomalies thru Aug 24th, (0.5 day less) above normal anomalies  Aug 25th into Aug 26th, (3 days less) below normal anomalies Aug 27th into Aug 28th, (new, warmer) above normal anomalies Aug 29th into Aug 30th, (new, cooler) below normal anomalies Aug 31st and Sep 1st, (same) above normal anomalies later Sep 2nd thru Sep 8th (end of run). 99F or higher for at least one ensemble member on last 4 of 16 days (okay). 

Sep Torchfest For Mississippi Valley.   

 

GEPS:  (0.5 day longer) Below normal 850mb temp anomalies thru Aug 24th(0.5 day shorter) above normal anomalies Aug 25th into Aug 26th, (now split) below normal anomalies later Aug 27th & Aug 28th, (new) above normal anomalies Aug 29th into Aug 30th, below normal anomalies later Aug 30th thru Sep 1st, (new) primarily newar normal anomalies Sep 2nd & Sep 3rd, (near can kick) above normal anomalies Sep 4th thru Sep 8th, above normal anomalies Sep 5th (end of run). 99F or higher for at least one ensemble member on 0 of 16 days.

Local near Barney experience 8/31.  

 

EPS: (0.5 day longer) Below normal 850mb temp anomalies thru Aug 24th, (0.5 day longer) above normal anomalies Aug 25th into Aug 27th, (warmer, way less) near normal anomalies night of Aug 27th, above normal anomalies Aug 28th into Aug 30th, (a 180) below normal anomalies later Aug 30th thru Sep 1st, (can kick) above normal anomalies Sep 2nd thru Sep 6th (end of run).  99F or higher for at least 1 ensemble member on 3 of 15 days

Local near Barney experience 8/31.   

 

NAEFS Week 2: Period of Sep 1st thru Sep 8th. I don't know yet again. Take that GEFS.   

 

 

Teleconnections: 

GEFS Teleconnection Fcst Skill Starts At:  NAO Day 10.5;  PNA Day 8;  AO Day 13

            Recent Verification Tendency:  Spot On NAO; More Negative PNA; More Positive AO      

 

GEFS:     -EPO thru 8/29 (day less;) neut 8/30-8/31; neg 9/1-9/8 (same)

               +PNA thru 9/6 (3 days more, +5SD 8/28); neg 9/7-9/8  

              -NAO thru 8/25 (same) pos 8/26-8/30; neg 8/31 (2 days less); pos 9/2-9/8 (dropped neg -> 9/3)        

 

GEPS:     -EPO thru 8/30 (day less) pos 8/31-9/2 (2 days more); neg 9/3-9/8 

               +PNA thru 9/6 (same, +5.75SD 8/29)      

               -NAO thru 8/25 (day less); pos 8/26-8/30 (2 days more); neg 8/31-9/1; pos, not neut 9/2-9/8 

 

EPS:      -EPO thru 8/29 (same :rolleyes: deserved, new) pos 8/30-9/1; neg 9/2-9/7

              +PNA thru 9/3 (3 days more, +5.75SD 8/28); neg 9/4-9/7   

              -NAO thru 8/25; (day less) pos 8/26-8/29; neg, not neut 8/30-8/31; pos 9/1-9/7 

 

WPO:  Positive after 8/25; neg aft 9/4 on GEFS & EPS

 

 

MJO:       (Vel Potential & Convection) moderate Phase 8 & Phase 1.  

GEFS:     Phase 8 thru COD to Phase 4. 

EPS:       Phase 8 into COD to Phase 5 COD.  

GEPS:    Phase 1 into COD to Phase 4 COD. (All runs end 9/7)

MVentrice (Vel Potential Only):  GFS Forecast Phase 8 to Phase 1  

 

 

Strat: NASA   Wave 1: 40th -> 80th -> 50th -> 70th -> 50th Percentile  

                       Wave 2: 0.1st -> 70th -> 50th -> 90th Percentile  

                       FU Berlin, back for this winter?                    

SPV:    Euro (thru day 10): See Ya This Winter. 

            GFS (thru day 15):  See Ya This Winter.    

SPV NASA 10 days:  See Ya This Winter.  

Ensembles 15 days:  See Ya This Winter.   

 

NAM: Blocked beyond current. 

 

**************  September Centered  *******************

image.png.948a4d83e4a50d98cf17fc8acbf4d6ce.png

"Coolest summer since 2009 or 2014" both of those following winters turned out pretty good :smileys-snowman-924988:

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1 hour ago, Rainshadow said:

That in spite of different enso(s) strength.

14-15 was a “technically” a nino by just the 3.4 index, although it was not organized really or had much of an influence.

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2 hours ago, ErieWX said:

Ensembles turning up the heat in September? 

We’ve had a good run this summer generally, but when’s the last cool September we’ve had in recent years? Somehow they seem to end up warm anecdotally. 

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21 minutes ago, fireguy286 said:

We’ve had a good run this summer generally, but when’s the last cool September we’ve had in recent years? Somehow they seem to end up warm anecdotally. 

2013 was the last cool Sept

mtdpt_northeast_sep13.png.43589930d2a7c241d9ed99c87dd45d94.png

Last year might have been the 2nd coolest September since 2013, close to average for most locations.

mtdpt_northeast_sep22.png.4b2cbc202a96deddc64eef6e94ad92fd.png

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1 hour ago, ErieWX said:

The GFS treats soil moisture like it’s the dust bowl. You’d think this would be been an easy fix the last upgrade. 

I read not until version 17 comes along whenever that is.  Until then, for your dining pleasure:

IMG_2745.png

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33 minutes ago, Rainshadow said:

I read not until version 17 comes along whenever that is.  Until then, for your dining pleasure:

IMG_2745.png

It is almost exclusively a boundary layer issue. It hasn’t performed too terribly from time to time with column heat (500 mb) over the Midwest, especially under areas of maximum subsidence. With the GFS, the upper level track is at least something to watch, but take the details with a grain of salt. 

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Looks like a +AO stretch ahead past Labor Day.  Zonal.  As things come into focus it may reveal an Omega look with troughs west and east to keep our heat somewhat in check and central relentless ridging.  I'll leave the tea leave reading to Tony.

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9 hours ago, ErieWX said:

It is almost exclusively a boundary layer issue. It hasn’t performed too terribly from time to time with column heat (500 mb) over the Midwest, especially under areas of maximum subsidence. With the GFS, the upper level track is at least something to watch, but take the details with a grain of salt. 

The bias beyond others has been for it to extend the heat too far north and northeast. It cooking places too much under the dome doesn't help, having too intense tropical systems don't help. But the idea of upper percentile heat ridges has worked.

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2 hours ago, susqushawn said:

Looks like a +AO stretch ahead past Labor Day.  Zonal.  As things come into focus it may reveal an Omega look with troughs west and east to keep our heat somewhat in check and central relentless ridging.  I'll leave the tea leave reading to Tony.

It would stink to get that paradigm shift now. Hopefully what you said comes to fruition.

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I am not going to drink any tea until tomorrow morning, but yeah the la la land look with troffing in Alaska, Northwest Territories, British Columbia is problematic. There has been some +PNA ridging that has saved the day from time to time. Granted the PNA skill scores have been very poor, we shall see.

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5 hours ago, Rainshadow said:

I am not going to drink any tea until tomorrow morning, but yeah the la la land look with troffing in Alaska, Northwest Territories, British Columbia is problematic. There has been some +PNA ridging that has saved the day from time to time. Granted the PNA skill scores have been very poor, we shall see.

I am not going to drink whatever it is drinking.  

Amazing how this marks the 4th time the GFS has had a run that has tied or broken the all-time Philadelphia record, the 3rd month out of four in which it has forecast a new monthly all-time record high and the 7th time it has had a forecast that has tied or exceeded PHL's consecutive number of days with maximum temperatures of 100F or higher.   Reason #238,546 that EMC should have stopped the operational at day 10 like the Euro & GGEM.

OTOH, there is decent la la land consensus on it being warmer than normal in GEFSland.

image.png.c3cd5bc45dbc2801726a1a1333a5ff2e.png

 

fhfhfhfhfhfh.JPG

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