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Meteorological Spring Pattern Discussion Does May Starts Like Early April, Will It End Like July?


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00z/21st Ensemble Comparison 2/21-3/8.  Normal 850mb temp around -3C. 

Ensembles In A State Of Flux; March 9th Hasn't Failed Yet.  

Granted this does not look full head on cold, but this is the first time in a while that the continuity from looking at the ensemble runs a couple of days ago really is poor. This has been rare this winter, but we have one instance this upcoming weekend in which the thermals have trended colder.  Unfortunately for anyone looking for snow as of today, it has shredded/suppressed what once looked like a robust day 9 system. Okay, true like that never happened before this winter.  maybe not this way though.

The eastern U.S. remains in the throws of a very persistent -PNA pattern which keeps the SE ridge going. So while there will be outlooked periods of -EPO cold, the angle overall remains poor .  On the one hand the developing -NAO should make an exit strategy harder. But on the other hand, the TPV  over Hudson's Bay is suppose to escape to the North Pole before the Greenland blocking keeps it in place. 

I can hear the moaning that this looks like December all over again with a "marriage" of the Greenland & SE ridging in the la la land period of modeling skill. So we wait. Yes there are all beyond skill time, but a continuing -NAO, a new -EPO and a weakening -PNA any other time would signal a colder period.  That is what showing up on all of the ensembles after about 3/5.  I know this is my 3 week onset chirp period, so for now just going to wait and see if this plausible outcome becomes another junk yard vehicle in this "cold" season. At the least the pattern does not look as non stop warm as it did earlier this month.  

 

 

GEFS: (an overhaul) Above normal 850mb temp anomalies into Feb 24th, (new) below normal anomalies later Feb 24th into Feb 27th, above normal anomalies later Feb 27th thru Feb 28th, near normal anomalies Mar 1st, above normal anomalies Mar 2nd thru Mar 4th, below normal anomalies Mar 5th & Mar 6th, near normal anomalies Mar 7th & Mar 8th.  Did you get all of this?  (end of run).  Torchy peak 2/23). Not much continuity. 

GEPS: (same) Above normal 850mb temp anomalies into Feb 24th, (colder, longer) below normal anomalies later  Feb 24th thru Feb 26th, (near can kick) above normal anomalies Feb 27th & Feb 28th, (shortened) below normal anomalies Mar 1st, above normal anomalies Mar 2nd into Mar 7th, near normal anomalies later Mar 7th & Mar 8th (end of run). Torchy peak 2/23; better continuity than the GEFS.

EPS: (uncan kick, three days shorter) Above normal 850mb temp anomalies into Feb 24th, (new split) below normal anomalies later Feb 24th thru Feb 25th, above normal anomalies Feb 26th into Feb 28th,  (amazingly nearly the same) below normal anomalies later Feb 28th thru Mar 2nd, above normal anomalies Mar 3rd thru Mar 6th, near normal anomalies Mar 7th (end of run).  Torchy Max 2/23; Barney warmed on 3/1.  

NAEFS Week 2: Period of Mar 1st thru Mar 8th. High confidence of above normal temperatures.  Trended higher confidence.  

 

Teleconnections: 

GEFS Teleconnection Fcst Skill Starts At:  NAO Day 11;  PNA Day 9.5;  AO >> Day 14

            Recent Verification Tendency: More Positive for all

 

GEFS:       +EPO thru 2/21 (same); neg 2/22-2/24 (day longer); pos 2/25-3/4 (day less); neg 3/5-3/8 

                  -PNA (same) below -2.5SD thru 3/5 

                  +NAO thru 2/25 (5 days longer); neg 2/26-3/8                   

 

GEPS:       +EPO thru 2/21 (same);  neg 2/22-2/24 (day longer); pos 2/25-3/4 (lost 3/1 neg);

                       neg 3/5-3/8      

                  -PNA (same); below -2.5SD thru 3/5

                  +NAO thru 2/25 (day shorter); neg 2/26-3/8 

 

EPS:          +EPO thru 2/21 (same); neg 2/22-2/24 (day longer); pos 2/25-2/27;  (new split) neg 2/28;

                      pos 3/1-3/5; neg 3/6-3/7 

                  -PNA (same); below -2.5SD thru 3/6 

                 +NAO thru 2/25 (day longer);  neg 2/26-3/7

 

 WPO:        Positive thru 3/3-3/5 

 

 

MJO:       Split between Phases 5 & 8  

GEFS:     Phase 8 then short cutting back to Phase 7. 

EPS:       Phase 8 then short cutting to Phase 8.

GEPS:    Phase 7 and then looping in Phase 7.     (Runs end 3/7)

MVentrice: (Current) Strong Phase 8 to weaker Phase 2. 

             

Strat: NASA   Wave 1: 70th -> 50th -> 55th -> 40th Percentile  

                       Wave 2: 40th -> 50th -> 25th -> 30th Percentile                       

 

SPV:    Euro (thru day 10):  Vortex hangs in Russia; tries to come back to North Pole and next Wave 1 hit

                     sends it nearly to Kazakhstan.   

            GFS (thru day 15):  Vortex in Russia, Tries to come back to North Pole and Next Wave 1 hit sends it

                     into Kazakhstan. Vortex remains more intact than three days ago. Ridge ends over North Pole again.

          

SPV NASA 10 days:  Brief recovery to west winds before next hit brings east winds to 99.9th percentile   

Ensembles 15 days: A pair of weak west recoveries before Wave 2 death(?) blow starts on 2/26.

                                     

NAM: Stratospheric connections trying in March, getting closer.

 

****** March Centered *********

image.png.e5c496cc797ee685218f59fdd37d6d7b.png

 

nam.JPG

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1 hour ago, Rainshadow said:

00z/21st Ensemble Comparison 2/21-3/8.  Normal 850mb temp around -3C. 

Ensembles In A State Of Flux; March 9th Hasn't Failed Yet.  

Granted this does not look full head on cold, but this is the first time in a while that the continuity from looking at the ensemble runs a couple of days ago really is poor. This has been rare this winter, but we have one instance this upcoming weekend in which the thermals have trended colder.  Unfortunately for anyone looking for snow as of today, it has shredded/suppressed what once looked like a robust day 9 system. Okay, true like that never happened before this winter.  maybe not this way though.

The eastern U.S. remains in the throws of a very persistent -PNA pattern which keeps the SE ridge going. So while there will be outlooked periods of -EPO cold, the angle overall remains poor .  On the one hand the developing -NAO should make an exit strategy harder. But on the other hand, the TPV  over Hudson's Bay is suppose to escape to the North Pole before the Greenland blocking keeps it in place. 

I can hear the moaning that this looks like December all over again with a "marriage" of the Greenland & SE ridging in the la la land period of modeling skill. So we wait. Yes there are all beyond skill time, but a continuing -NAO, a new -EPO and a weakening -PNA any other time would signal a colder period.  That is what showing up on all of the ensembles after about 3/5.  I know this is my 3 week onset chirp period, so for now just going to wait and see if this plausible outcome becomes another junk yard vehicle in this "cold" season. At the least the pattern does not look as non stop warm as it did earlier this month.  

 

 

GEFS: (an overhaul) Above normal 850mb temp anomalies into Feb 24th, (new) below normal anomalies later Feb 24th into Feb 27th, above normal anomalies later Feb 27th thru Feb 28th, near normal anomalies Mar 1st, above normal anomalies Mar 2nd thru Mar 4th, below normal anomalies Mar 5th & Mar 6th, near normal anomalies Mar 7th & Mar 8th.  Did you get all of this?  (end of run).  Torchy peak 2/23). Not much continuity. 

GEPS: (same) Above normal 850mb temp anomalies into Feb 24th, (colder, longer) below normal anomalies later  Feb 24th thru Feb 26th, (near can kick) above normal anomalies Feb 27th & Feb 28th, (shortened) below normal anomalies Mar 1st, above normal anomalies Mar 2nd into Mar 7th, near normal anomalies later Mar 7th & Mar 8th (end of run). Torchy peak 2/23; better continuity than the GEFS.

EPS: (uncan kick, three days shorter) Above normal 850mb temp anomalies into Feb 24th, (new split) below normal anomalies later Feb 24th thru Feb 25th, above normal anomalies Feb 26th into Feb 28th,  (amazingly nearly the same) below normal anomalies later Feb 28th thru Mar 2nd, above normal anomalies Mar 3rd thru Mar 6th, near normal anomalies Mar 7th (end of run).  Torchy Max 2/23; Barney warmed on 3/1.  

NAEFS Week 2: Period of Mar 1st thru Mar 8th. High confidence of above normal temperatures.  Trended higher confidence.  

 

Teleconnections: 

GEFS Teleconnection Fcst Skill Starts At:  NAO Day 11;  PNA Day 9.5;  AO >> Day 14

            Recent Verification Tendency: More Positive for all

 

GEFS:       +EPO thru 2/21 (same); neg 2/22-2/24 (day longer); pos 2/25-3/4 (day less); neg 3/5-3/8 

                  -PNA (same) below -2.5SD thru 3/5 

                  +NAO thru 2/25 (5 days longer); neg 2/26-3/8                   

 

GEPS:       +EPO thru 2/21 (same);  neg 2/22-2/24 (day longer); pos 2/25-3/4 (lost 3/1 neg);

                       neg 3/5-3/8      

                  -PNA (same); below -2.5SD thru 3/5

                  +NAO thru 2/25 (day shorter); neg 2/26-3/8 

 

EPS:          +EPO thru 2/21 (same); neg 2/22-2/24 (day longer); pos 2/25-2/27;  (new split) neg 2/28;

                      pos 3/1-3/5; neg 3/6-3/7 

                  -PNA (same); below -2.5SD thru 3/6 

                 +NAO thru 2/25 (day longer);  neg 2/26-3/7

 

 WPO:        Positive thru 3/3-3/5 

 

 

MJO:       Split between Phases 5 & 8  

GEFS:     Phase 8 then short cutting back to Phase 7. 

EPS:       Phase 8 then short cutting to Phase 8.

GEPS:    Phase 7 and then looping in Phase 7.     (Runs end 3/7)

MVentrice: (Current) Strong Phase 8 to weaker Phase 2. 

             

Strat: NASA   Wave 1: 70th -> 50th -> 55th -> 40th Percentile  

                       Wave 2: 40th -> 50th -> 25th -> 30th Percentile                       

 

SPV:    Euro (thru day 10):  Vortex hangs in Russia; tries to come back to North Pole and next Wave 1 hit

                     sends it nearly to Kazakhstan.   

            GFS (thru day 15):  Vortex in Russia, Tries to come back to North Pole and Next Wave 1 hit sends it

                     into Kazakhstan. Vortex remains more intact than three days ago. Ridge ends over North Pole again.

          

SPV NASA 10 days:  Brief recovery to west winds before next hit brings east winds to 99.9th percentile   

Ensembles 15 days: A pair of weak west recoveries before Wave 2 death(?) blow starts on 2/26.

                                     

NAM: Stratospheric connections trying in March, getting closer.

 

****** March Centered *********

image.png.e5c496cc797ee685218f59fdd37d6d7b.png

 

nam.JPG

Great write up as always, even when you're in a time pinch with banana stacking calling.  

So...let's say the strat does bleed down to the surface.  How would that typically reveal itself in long range guidance?

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2 minutes ago, susqushawn said:

Great write up as always, even when you're in a time pinch with banana stacking calling.  

So...let's say the strat does bleed down to the surface.  How would that typically reveal itself in long range guidance?

Greenland blocking is one of the main impacts. 
 

 

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3 minutes ago, susqushawn said:

Interesting since blocking will already be in place, possibly fading.  I guess that means it could be reinforced

Sort of, it starts out as more of a scandi/east based block before retrograding and really growing some serious teeth. Normally wouldn’t think much that far out but that’s a strong signal. Question is do we get some PNA cooperation, which is way less of a guarantee with SSW sfc impacts and might not even be correlated. 

BA45ACA5-1B10-49EE-A5E6-D29826FB975C.gif

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7 minutes ago, Rainshadow said:

Good discussion. I checked the PNA for March 2018, it averaged negative, but did not dive into individual days, which in reality is more important.

Big 3 big events in bold

2018  3  1 -1.234
2018  3  2 -1.094
2018  3  3 -1.018
2018  3  4 -0.880
2018  3  5 -0.853
2018  3  6 -0.783
2018  3  7 -0.743
2018  3  8 -0.511
2018  3  9 -0.311
2018  3 10 -0.162
2018  3 11  0.015
2018  3 12  0.299
2018  3 13  0.346
2018  3 14  0.295
2018  3 15  0.003
2018  3 16 -0.290
2018  3 17 -0.459
2018  3 18 -0.643
2018  3 19 -0.774
2018  3 20 -0.903
2018  3 21 -0.705
2018  3 22 -0.297
2018  3 23 -0.249
2018  3 24 -0.472
2018  3 25 -0.442
2018  3 26 -0.293
2018  3 27 -0.474
2018  3 28 -1.005
2018  3 29 -1.350
2018  3 30 -1.552
2018  3 31 -1.567
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1 hour ago, ErieWX said:

Sort of, it starts out as more of a scandi/east based block before retrograding and really growing some serious teeth. Normally wouldn’t think much that far out but that’s a strong signal. Question is do we get some PNA cooperation, which is way less of a guarantee with SSW sfc impacts and might not even be correlated. 

BA45ACA5-1B10-49EE-A5E6-D29826FB975C.gif

The fruits of the strongly -Pdo and strength of the Aleutian Ridge are likely to keep the SE Ridge on roids. If that is true, it will link up with the Greenland ridge and stifle the typical benefits of the -Nao and SSW. I'm not saying that the 2 ridges linking is a per se death knell. But do believe the SE Ridge will maintain itself and die too late for most of us.

Hope I'm wrong really, really bad.

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Interesting that from an index standpoint this winter hasn't been a wall to wall raging -PNA. For the month JAN ended up with a slightly positive figure. Looking at a 36 day period thru the heart of winter from 12/22 - 1/26 there were only 5 of those dates in which the daily index was actually negative & overall the figure was 0.39.

 

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30 minutes ago, colonel_kurtz said:

Interesting that from an index standpoint this winter hasn't been a wall to wall raging -PNA. For the month JAN ended up with a slightly positive figure. Looking at a 36 day period thru the heart of winter from 12/22 - 1/26 there were only 5 of those dates in which the daily index was actually negative & overall the figure was 0.39.

 

Yeah it had the Aleutian Low which is the primary ingredient for a +PNA but instead of it pumping up a downstream ridge over the west it fed a pac jet extension in a feedback loop which blowtorched most of North America/CONUS

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Another aspect of MAR 2018 was the monthly minimum temp was really quite warm. Monthly low at PHL was only 28 degrees which represents the 5th warmest on record. Warmest MAR minimum is 30 degrees. Overall the solidly negative monthly departure was a reflection of the daily high temps which averaged over 5 degrees below normal.

Top 5 warm min coupled with the snowiest MAR on record, even in MAR it doesn't have to be frigid just cold enough. Heavy rates also played a role during a couple of those events as those 2 storms the 1st week of MAR 2018 were big ticket events.

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3 hours ago, JamieO said:

Be careful measuring, hate to see someone here knocked out by a baseball-sized, uh, flake. 

The hail ended up like the snow depth this winter. Non existent 

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Mehh.. the block is nice, but we’ll probably waste it again. 
 

1. the constant negative heights along the west coast is just brutal. (Thanks to the aluetian ridging). 
 

2. it’s a nice , retrograding block. Interior areas can probably cash in. 
 

3. the lack of cold air (maybe not as bad as December) will be an issue. As you can see below, the bulk of the TPV lobe is again, on the other side of the globe. 

EB66602C-586E-442C-A5F8-BDD3B1C77F15.png

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  • Rainshadow changed the title to Meteorological Spring Pattern Discussion Does May Starts Like Early April, Will It End Like July?
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