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Meteorological Spring Pattern Discussion


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00z/22nd Ensemble Comparison 2/22-3/9. Normal 850mb temp around -3C. 

Changing thermal patterns every 4-6 days.

"So that (+)EPO switch is at the edge of skill time and we are talking March at this point. This brings us to another predicted stout Wave 2 hit at the the end of the month.  Does this supersede the warm MJO Phase 5 and make me eat my words about sustained cold not there yet?  We will find out in the days ahead."

Well for today, I don't get to eat my words.  It is not that the EPO outlook was inaccurate, but (I am inferring) colder ensemble members overwhelmed the thermal picture. First that is a cold blast coming.  Don't get much better angles of the cold than this.  On the flip side it may plow drive any chance of weekend snow away, otoh too deep into the cold air. Now we have the flip today with the EPO. It's change to negative is at the edge at my estimate of where its skill starts.  The ensembles extended the +EPO period and the GEPS is on its way to missing it. We will see if  the date of switching to negative holds.  Regardless there is a 3-5 day lag with a EPO switch to make it east, so we are toward the end of this outlook period.  Of course if we accept the teleconnection outlook as is we get back to angle of the cold debates. The brief -PNA switch was way much shorter than other pattern changes with it.  More volatility heading into spring?  The other change heading into March is the shortening wavelengths and how the MJO phases/temperature correlations are changing.  Phase 5 which was stout warm in Feb, not so much in March.  Its Phases 2 & 3 that are coldest. The SPV will be taking to Phase 2 hits, but keeps on ticking.

So in summary, a really cold shot is coming.  A warmer early March recovery is gaining confidence. A colder transition could be waiting in the wings (no lack of cold in Canada regardless).

 

   

Teleconnection Fcst Skill Starts At:  NAO Day 10.5;  PNA Day 12; AO Day 9

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

GEFS: (same) Above normal 850mb temp anomalies into Feb 25th, (colder) below normal anomalies later Feb 25th (Barney 2/28) into Mar 3rd, (new, warmer) above normal anomalies Mar 4th thru Mar 7th, below normal anomalies Mar 8th & Mar 9th (end of run). 

GEPS: (same) Above normal 850mb temp anomalies into Feb 25th, (three days shorter) below normal anomalies later Feb 25th thru Mar 2nd, (new, warmer) above normal anomalies Mar 3rd into Mar 6th, below normal anomalies later Mar 6th thru Mar 9th (end of run).

EPS: (same) Above normal 850mb temp anomalies into Feb 25th, (two days shorter) below normal anomalies later Feb 25th into Mar 2nd, (new, warmer) above normal anomalies later Mar 2nd into Mar 8th (end of run).    

NAEFS Week 2: Period of Mar 2nd-Mar 9th. Low confidence of above normal temperatures. Trending warmer. 

 

Teleconnections: 

GEFS:       -EPO thru 2/24 (same); pos 2/25-3/2 (2 days longer); neg 3/3-3/9

                 -PNA thru 2/24 (same); pos 2/25-3/2 (day longer); neg 3/3-3/9

                 +NAO  (same)

GEPS:       -EPO  thru 2/25; (new, missed it?) pos 2/26-3/1; neg 3/2-3/9   

                 -PNA thru 2/24 (same); pos 2/25-3/3 (day longer); neg 3/4-3/9

                 +NAO (same)

EPS:         -EPO thru 2/25 (same);  pos 2/26-3/2 (3 days longer); neg 3/3-3/8

                 -PNA thru 2/24 (day shorter); pos 2/25-3/1 (day shorter); neg 3/2-3/8

                +NAO  (same)

WPO:        Positive thru 3/3 or 3/4 (2 days longer), then negative  

 

MJO:    (WH Sectors) Strong Convection/Vel Potential Phase 4.

GEFS  Phase 3 to Phase 6;  EPS Phase 3 to Phase 5/6 border  (runs ends 3/8). 

MVentrice Strong Phase 3/4 border, Strong Phase 6/7 border at end. 

             

Strat: NASA Wave 1 peak around 65th percentile now (800 gpm) falling to 20th percentile before start of rebound; Double Wave 2 hits 90th percentile (800 gpm) & A Third On Way.  EC similar, NASA went its Wave 2 strength way.   

SPV/NAM:  (GFS) Fluctuating ending around 1 SD above (40kts). SPV ensembles end about 1 SD above 40-45 kts.  EC ends around 40kts. Strat warm wx coupling now, trop cooling hit early March. 

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/Composites/Temperature/FMA/combined_image.png

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You can upgrade it until the cows come home, but somehow, it still finds its way back to its inherent biases.

Yeah Monday looks legitgfs_T850a_us_23.png.2d9f9f65c3890f65ec1a6921d1e7145d.pnggem_T850a_us_23.png.e6bf9b05039d3ba607f10b9d7f083311.pngecmwf_T850a_us_45.png.01ae9b5a35534f30dd5f51ecc5ddc90d.png

But now Thursday??????  (Not only this, but shortest warm-up and longest cold down)

 

 

ecmwf_T850a_us_59.png

gem_T850a_us_35.png

gfs_T850a_us_34.png

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A very silly question: I need to defrost and clean our big chest freezer (yes, yes, we've now had thoughtful and productive discussions about, for instance, the best ways to keep frozen cherries from dripping like a horror movie) and that's a lot easier to do when it's still cold outside and I can just out stuff in boxes and chuck it in the back yard for an hour or two.  But... It also gets easier the longer I put it off because were eating the freezer down. I'm guessing next Monday may be my last best bet, but I'd be delighted if it looks like there's something farther along the timeline. Any luck for me? Everything I'm interpreting thus far looks like y'all are saying the next waves are getting warmer. 

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1 hour ago, philastorian said:

A very silly question: I need to defrost and clean our big chest freezer (yes, yes, we've now had thoughtful and productive discussions about, for instance, the best ways to keep frozen cherries from dripping like a horror movie) and that's a lot easier to do when it's still cold outside and I can just out stuff in boxes and chuck it in the back yard for an hour or two.  But... It also gets easier the longer I put it off because were eating the freezer down. I'm guessing next Monday may be my last best bet, but I'd be delighted if it looks like there's something farther along the timeline. Any luck for me? Everything I'm interpreting thus far looks like y'all are saying the next waves are getting warmer. 

Are you in Philadelphia and do you need below freezing temperatures the whole night?

Normal temperatures are rising.  So (for example) a -15F departure next week would still be not as cold as a -15F departure in late January.

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5 minutes ago, Allsnow said:

Mjo croaking in IO? 

ACAFFC24-2D8D-4C22-9C23-E4C4D6588827.gif

Its demise may be prematurely advertised.  This looks pretty healthy to me today.  Yes its vel potential vs convection, but it looks pretty good right now.

 

mjo.JPG

mjo2.JPG

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1 minute ago, DebShadow23.0 said:

Its demise may be prematurely advertised.  This looks pretty healthy to me today.  Yes its vel potential vs convection, but it looks pretty good right now.

 

mjo.JPG

mjo2.JPG

That might mean smarch after the 15th….

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4 hours ago, DebShadow23.0 said:

Are you in Philadelphia and do you need below freezing temperatures the whole night?

Normal temperatures are rising.  So (for example) a -15F departure next week would still be not as cold as a -15F departure in late January.

No, just a few hours below freezing, preferably during the day so I don't have to do silly things to my sleep schedule!  But I *think* what I'm seeing in the discussions is that new Monday (2/28) might fit the bill but after that it might be slim pickings?  Just want to confirm that if possible! 

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2 hours ago, Allsnow said:

 

28156994-FFA2-40C3-811C-C19E3705E634.png

Imho, I think we are done with any significant snow/ice events until next winter. Even when a predicted favorable pattern evolves, the temperature winds up above normal and we revert back to the same general boring pattern since Ida. 

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10 hours ago, philastorian said:

No, just a few hours below freezing, preferably during the day so I don't have to do silly things to my sleep schedule!  But I *think* what I'm seeing in the discussions is that new Monday (2/28) might fit the bill but after that it might be slim pickings?  Just want to confirm that if possible! 

Monday looks okay, but may have to be during the early evening. 

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9 minutes ago, DebShadow23.0 said:

I said this yesterday Philadelphia did get its climatological normal number of 6 inch or more events for any given cold season. 

True. Somehow it’s hard to remember the moderate event for those of us away from the coast. Probably because there was almost no need to shovel a thing all winter. I guess that colder late January event. 

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59 minutes ago, Parsley said:

True. Somehow it’s hard to remember the moderate event for those of us away from the coast. Probably because there was almost no need to shovel a thing all winter. I guess that colder late January event. 

13'' isn't really a winter to complain about for PHL, but it definitely is at your location. My main complaint is that our 6+ event here was very fine snow that blew everywhere, leaving chunks of bald grass in the parks. Maybe March can bring me 2-4'' of heavy wet snow. Otherwise...wait till next year

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