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Meteorological Winter Pattern Discussion II


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33 minutes ago, PRINCETON ANGLER said:

GEFS not showing any significant change in the Pacific so perhaps this is the result of the wave 2 hit? Would make sense as the -NAO ridge building west begins to squeeze the SPV.

After the initial change on the 20th Canada will start to get some good air for us to work with rather than the mild pac garbage it’s had almost all winter. At that point anything that sends the tpv south, such as an nao block will give us something

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4 hours ago, Will said:

Another good GEFS run in the long range 

BE991CB7-5CC6-43E2-8BA9-912BBF17F864.gif

Yes, below is an animation of days 7 to end-of-run. The bad news is the steady westward motion of the Pacific ridge. The good news is the TPV sinking as far S as SE Baffin Is/NW Quebec. This lowers heights in SE Canada and could give us confluence/cold High pressure. The flow also becomes much flatter which will alter the storm track and work against cutters. Not perfect with strong W-->E flow and a lingering SE ridge, but much better than present. Not sure how long it will last, will turn into a very unfavorable pattern if the TPV heads back N.

gfs-ens_z500a_namer_fh168-384.gif

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40 minutes ago, Chubbs said:

Yes, below is an animation of days 7 to end-of-run. The bad news is the steady westward motion of the Pacific ridge. The good news is the TPV sinking as far S as SE Baffin Is/NW Quebec. This lowers heights in SE Canada and could give us confluence/cold High pressure. The flow also becomes much flatter which will alter the storm track and work against cutters. Not perfect with strong W-->E flow and a lingering SE ridge, but much better than present. Not sure how long it will last, will turn into a very unfavorable pattern if the TPV heads back N.

gfs-ens_z500a_namer_fh168-384.gif

Agree with everything but the part I don't like is that the Eps and Gefs are building/deepening the west side of the trough over Pacific  NW. Actually, it looks very close to the progression shown on the Cfs weeklies, for better or worse. In short, we get 2-3 weeks max favorable period with 2 legit shots and a 3rd if we're lucky. Then close the blinds until late February into March for a late season response, if we're lucky, to strat interference. 

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31 minutes ago, Mitchnick said:

Agree with everything but the part I don't like is that the Eps and Gefs are building/deepening the west side of the trough over Pacific  NW. Actually, it looks very close to the progression shown on the Cfs weeklies, for better or worse. In short, we get 2-3 weeks max favorable period with 2 legit shots and a 3rd if we're lucky. Then close the blinds until late February into March for a late season response, if we're lucky, to strat interference. 

Yes, nina and mjo teaming up in an unfavorable fashion in February has been well anticipated. Ironically, CFS projects that ruining our February is Ninas last stand. Per CFS chart below, the next mjo wave becomes powerful and is able to overcome nina interference (solid red is active mjo/dashed is inactive).  The nina strong trade regime ends when the MJO wave reaches the west Pacific.  No more blues in your go to chart after early March perhaps.

 

Screenshot 2023-01-16 at 06-48-39 Real Time Hovmollers.png

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35 minutes ago, Chubbs said:

Yes, nina and mjo teaming up in an unfavorable fashion in February has been well anticipated. Ironically, CFS projects that ruining our February is Ninas last stand. Per CFS chart below, the next mjo wave becomes powerful and is able to overcome nina interference (solid red is active mjo/dashed is inactive).  The nina strong trade regime ends when the MJO wave reaches the west Pacific.  No more blues in your go to chart after early March perhaps.

 

Screenshot 2023-01-16 at 06-48-39 Real Time Hovmollers.png

Not being totally facetious, Smarch.

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1 hour ago, Mitchnick said:

Agree with everything but the part I don't like is that the Eps and Gefs are building/deepening the west side of the trough over Pacific  NW. Actually, it looks very close to the progression shown on the Cfs weeklies, for better or worse. In short, we get 2-3 weeks max favorable period with 2 legit shots and a 3rd if we're lucky. Then close the blinds until late February into March for a late season response, if we're lucky, to strat interference. 

Too far out to worry about. Just enjoy what ever we get during the favorable period. 2-3 weeks is basically our winters anymore. 

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4 minutes ago, Chubbs said:

Sign of a different flatter pattern? Day 10+ 06z gefs has 4 snow misses to our south. Haven't seen many of those in the ensembles this year.

gefsnow.png

Those are hideous for mby.

Eps and Geps are much improved.  0z Gefs isn't bad either. Toss 6z.

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38 minutes ago, Mitchnick said:

Those are hideous for mby.

Eps and Geps are much improved.  0z Gefs isn't bad either. Toss 6z.

all the day 10+ snowmaps get tossed

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00z/16th Ensemble Comparison 1/16-1/31.  Normal 850mb temp around -4C. 

For All The Angst, The Arrival Of Colder Weather Remains On/Close To Schedule, Yes There Is Uncertainty After That.  SPV Not The Winter Of 2021-22 Any Longer (Soon)...

It is still about 10 days away and verifying a forecast with a forecast can go like the Chargers' "winning" on Saturday.  But, the 5 day lag time to the EPO switch and the arrival of a more prolonged period of colder weather is holding and has been holding for about a week or so.  Whether the EPO will remain negative thru the end of January is up to conjecture.  Any warming effect from it switching would be in February with the lag time.  Backing up, through confidence time some eastern Pacific ridging should continue and this will effectively make Canada colder.  Now comes the rub(s).  The first is the NAO.  I am seeing a bunch of changes past day 7 every time I do this and that day 8 or so start of skill time is very richly deserved.  Some sort of a -NAO would be welcome for colder air because at least a piece of the TPV is taking residence in Hudson's Bay and the farther south, the better if you want cold air.  Second is the PNA.  Doesn't do one any good if the angle of the cold is Idaho even with a favorable for cold EPO.  As we move away from skill time into la la land we do see (hello La Nina again) ridging outlooked to return to the Aleutians and a SE ridge fight starting to emerge.  More so with the GEPS & EPS which I (2 out of 3 aint bad) favor.  No matter which direction, the GEFS seems always have outlier members that take the pattern to an extreme (here cold in SE Canada).  I am not big on talking about weather events here (so why are you?).  The general pattern looks active and the normal 850mb temperature is around -4C.  One could be above normal this time of year and get snow. Well maybe any other winter that followed the laws of physics.  

This part has not changed: This is a pattern change which will affect the west coast (get a chance to dry out) more significantly, but for now has the look of losing some of its teeth as it progresses eastward.  Is that PNA poorer angle of the cold switch wrong?  I don't know.  But it is something to look for in the days ahead.     

A difference is emerging with the SPV vs last winter.  We are going our separate ways with the SPV outlooked to return to normal strength vs remaining a near record vortex. The Wave 2 hit on the 21st supports the colder shot but after that it looks like we will have to wait til February for the next one.  I am not great with this, but I thought it was odd that a Wave 1 hit by the GFS was causing the vortex split, then again odd and GFS beyond day 8 go together quite often.  Based on the ensembles, we are in Mid February as the earliest average impact lag time were a SSW (10mb wind reversal).      

 

    

GEFS Teleconnection Fcst Skill Starts At:  NAO Day 8.5;  PNA Day 10;  AO Day 13.5

Recent Verification Tendency: More Positive NAO & AO, Neutral PNA

GEFS: (0.5 day longer) Above normal 850mb temp anomalies thru Jan 26th, below normal anomalies Jan 27th & Jan 28th (end of run).  Local Heatmizer peak Jan 19th; coldest day Jan 29th. 

GEPS: (new split) Above normal 850mb temp anomalies into Jan 20th, (new) below normal anomalies later Jan 20th thru Jan 21st, (ending day later) above normal anomalies Jan 22nd thru Jan 25th, below normal anomalies Jan 26th thru Jan 31st, can see SE ridge battle (end of run). Local Heatmizer peaks Jan 19th & Jan 24th; coldest day Jan 30th.

EPS: (earlier, colder split) Above normal 850mb temp anomalies into Jan 20th, (colder, same), below normal anomalies night of Jan 20th, (ends half a day later),  above normal anomalies later Jan 21st into Jan 26th, (colder trend) below normal anomalies later Jan 26th thru Jan 28th, near normal anomalies Jan 29th, below normal anomalies Jan 30th (end of run). Local Heatmizer Peak Jan 19th; coldest day Jan 28th

 

NAEFS Week 2: Period of Jan 24th thru Jan 31st. Weak confidence of above normal temperatures. Confidence of above normal temperatures eroding.  

 

Teleconnections: 

GEFS:          +EPO thru 1/21 (day longer); neg 1/22-1/31   

                    -PNA thru 1/15 (sameish); neutral 1/20 & 1/23

                    -NAO thru 1/20; (new) pos 1/21-1/23; neg 1/24-1/28; pos 1/29-1/31                   

GEPS:         +EPO thru 1/21 (day longer); neg 1/22-1/31 

                   -PNA thru 1/19; pos 1/20-1/21 (2 days less); neg 1/22-1/31

                   -NAO thru 1/19 (day longer);  pos 1/20-1/23 (same); neg 1/24-1/31

EPS:           +EPO thru 1/21 (day longer);  neg 1/22-1/30  

                   -PNA thru 1/19 (same); pos 1/20 (5 days shorter than week ago); neg 1/21; neut (new) 1/22; neg 1/23-1/30

                  -NAO thru 1/18 (same); pos 1/19-1/20; neg 1/21-1/27 (180 switch back); pos 1/28-1/30 

 

 WPO:        Positive ->  neut/neg aft 1/29 or 1/30

 

 

 

 

 

MJO:       Dull Phase 8 & 1.  

GEFS:     COD Phase 8/1 border to Phase 3.

EPS:       COD Phase 8/1, active then COD Phase 3.

GEPS:    COD Phase 8 to Phase 3.     (Runs all end 1/30)

MVentrice: Active Phase 1 to Active Phase 2 to Weakening Phase 3.

             

Strat: NASA Wave 1: 85th ->60th -> 75th -> 74th Percentile  

                     Wave 2: 70th -> 98th (900 gpm) -> 50th Percentile (Strongest Of Winter)

                      

SPV/NAM:  Euro thru day 10:  SPV decent Wave 2 hit peaks 1/21. Wave 1 Displacement Day 10 Toward Scandinavia; Warming Aleutians. 

GFS Series of Wave 1 hits Push Vortex to Scandanavia; Strong Wave 2 hit 1/21. Hint of another in early Feb.  Runs that had vortex split stopped.     

SPV NASA 70th percentile 45 m/s dips to 32m/s (60th percentile). Bifurcation from last winter's continuing strength. Ensembles steady 40-45 m/s thru Wave 2 hit and then drop to around 20 m/s (near normal) with slight uptick at end. Normal around 22m/s Jan 31st.  Four members with vortex split; 10 of 74 with wind reversal.  

NAM: trop hit 1/19, a deeper trop hit 1/24, a blocked Strat potential hit at the end of the month. 

 image.png.bb2bf9f97effabaa974aa18d2b6c496e.png

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16 minutes ago, Rainshadow said:

00z/16th Ensemble Comparison 1/16-1/31.  Normal 850mb temp around -4C. 

For All The Angst, The Arrival Of Colder Weather Remains On/Close To Schedule, Yes There Is Uncertainty After That.  SPV Not The Winter Of 2021-22 Any Longer (Soon)...

It is still about 10 days away and verifying a forecast with a forecast can go like the Chargers' "winning" on Saturday.  But, the 5 day lag time to the EPO switch and the arrival of a more prolonged period of colder weather is holding and has been holding for about a week or so.  Whether the EPO will remain negative thru the end of January is up to conjecture.  Any warming effect from it switching would be in February with the lag time.  Backing up, through confidence time some eastern Pacific ridging should continue and this will effectively make Canada colder.  Now comes the rub(s).  The first is the NAO.  I am seeing a bunch of changes past day 7 every time I do this and that day 8 or so start of skill time is very richly deserved.  Some sort of a -NAO would be welcome for colder air because at least a piece of the TPV is taking residence in Hudson's Bay and the farther south, the better if you want cold air.  Second is the PNA.  Doesn't do one any good if the angle of the cold is Idaho even with a favorable for cold EPO.  As we move away from skill time into la la land we do see (hello La Nina again) ridging outlooked to return to the Aleutians and a SE ridge fight starting to emerge.  More so with the GEPS & EPS which I (2 out of 3 aint bad) favor.  No matter which direction, the GEFS seems always have outlier members that take the pattern to an extreme (here cold in SE Canada).  I am not big on talking about weather events here (so why are you?).  The general pattern looks active and the normal 850mb temperature is around -4C.  One could be above normal this time of year and get snow. Well maybe any other winter that followed the laws of physics.  

This part has not changed: This is a pattern change which will affect the west coast (get a chance to dry out) more significantly, but for now has the look of losing some of its teeth as it progresses eastward.  Is that PNA poorer angle of the cold switch wrong?  I don't know.  But it is something to look for in the days ahead.     

A difference is emerging with the SPV vs last winter.  We are going our separate ways with the SPV outlooked to return to normal strength vs remaining a near record vortex. The Wave 2 hit on the 21st supports the colder shot but after that it looks like we will have to wait til February for the next one.  I am not great with this, but I thought it was odd that a Wave 1 hit by the GFS was causing the vortex split, then again odd and GFS beyond day 8 go together quite often.  Based on the ensembles, we are in Mid February as the earliest average impact lag time were a SSW (10mb wind reversal).      

 

    

GEFS Teleconnection Fcst Skill Starts At:  NAO Day 8.5;  PNA Day 10;  AO Day 13.5

Recent Verification Tendency: More Positive NAO & AO, Neutral PNA

GEFS: (0.5 day longer) Above normal 850mb temp anomalies thru Jan 26th, below normal anomalies Jan 27th & Jan 28th (end of run).  Local Heatmizer peak Jan 19th; coldest day Jan 29th. 

GEPS: (new split) Above normal 850mb temp anomalies into Jan 20th, (new) below normal anomalies later Jan 20th thru Jan 21st, (ending day later) above normal anomalies Jan 22nd thru Jan 25th, below normal anomalies Jan 26th thru Jan 31st, can see SE ridge battle (end of run). Local Heatmizer peaks Jan 19th & Jan 24th; coldest day Jan 30th.

EPS: (earlier, colder split) Above normal 850mb temp anomalies into Jan 20th, (colder, same), below normal anomalies night of Jan 20th, (ends half a day later),  above normal anomalies later Jan 21st into Jan 26th, (colder trend) below normal anomalies later Jan 26th thru Jan 28th, near normal anomalies Jan 29th, below normal anomalies Jan 30th (end of run). Local Heatmizer Peak Jan 19th; coldest day Jan 28th

 

NAEFS Week 2: Period of Jan 24th thru Jan 31st. Weak confidence of above normal temperatures. Confidence of above normal temperatures eroding.  

 

Teleconnections: 

GEFS:          +EPO thru 1/21 (day longer); neg 1/22-1/31   

                    -PNA thru 1/15 (sameish); neutral 1/20 & 1/23

                    -NAO thru 1/20; (new) pos 1/21-1/23; neg 1/24-1/28; pos 1/29-1/31                   

GEPS:         +EPO thru 1/21 (day longer); neg 1/22-1/31 

                   -PNA thru 1/19; pos 1/20-1/21 (2 days less); neg 1/22-1/31

                   -NAO thru 1/19 (day longer);  pos 1/20-1/23 (same); neg 1/24-1/31

EPS:           +EPO thru 1/21 (day longer);  neg 1/22-1/30  

                   -PNA thru 1/19 (same); pos 1/20 (5 days shorter than week ago); neg 1/21; neut (new) 1/22; neg 1/23-1/30

                  -NAO thru 1/18 (same); pos 1/19-1/20; neg 1/21-1/27 (180 switch back); pos 1/28-1/30 

 

 WPO:        Positive ->  neut/neg aft 1/29 or 1/30

 

 

 

 

 

MJO:       Dull Phase 8 & 1.  

GEFS:     COD Phase 8/1 border to Phase 3.

EPS:       COD Phase 8/1, active then COD Phase 3.

GEPS:    COD Phase 8 to Phase 3.     (Runs all end 1/30)

MVentrice: Active Phase 1 to Active Phase 2 to Weakening Phase 3.

             

Strat: NASA Wave 1: 85th ->60th -> 75th -> 74th Percentile  

                     Wave 2: 70th -> 98th (900 gpm) -> 50th Percentile (Strongest Of Winter)

                      

SPV/NAM:  Euro thru day 10:  SPV decent Wave 2 hit peaks 1/21. Wave 1 Displacement Day 10 Toward Scandinavia; Warming Aleutians. 

GFS Series of Wave 1 hits Push Vortex to Scandanavia; Strong Wave 2 hit 1/21. Hint of another in early Feb.  Runs that had vortex split stopped.     

SPV NASA 70th percentile 45 m/s dips to 32m/s (60th percentile). Bifurcation from last winter's continuing strength. Ensembles steady 40-45 m/s thru Wave 2 hit and then drop to around 20 m/s (near normal) with slight uptick at end. Normal around 22m/s Jan 31st.  Four members with vortex split; 10 of 74 with wind reversal.  

NAM: trop hit 1/19, a deeper trop hit 1/24, a blocked Strat potential hit at the end of the month. 

 image.png.bb2bf9f97effabaa974aa18d2b6c496e.png

How does a wave 1 or wave 2 hit cause colder shots at the surface here when there is yet to be coupling of the stratosphere and troposphere?

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I don’t know/expect to see totals like that period, but you get the point. 
 

If this plays out how the eps show, we’ll get a decent window. 
 

Step 1 is getting the cold air/PV back into Canada. 
 

then let’s see if we get some Scandinavian ridging to return and retrograde towards the NAO region. Should help lock in some confluence.

the individual eps members and GEFS members are pretty active , so depending where storms clash with cold air, could be  a nice windkw for some folks to pick up snow. It may not be big time nor’easters; but a couple quick hitters def not a bad thing. 

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5 hours ago, susqushawn said:

How does a wave 1 or wave 2 hit cause colder shots at the surface here when there is yet to be coupling of the stratosphere and troposphere?

Tom can correct me if I am wrong, I think it is just the process of it emanating from the mid lats and progressing northward and upward that causes more meridional flow.  Granted it may not necessarily be North America.  This is just observational, I think wave 2(s) do better than wave 1(s). 

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41 minutes ago, Rainshadow said:

Tom can correct me if I am wrong, I think it is just the process of it emanating from the mid lats and progressing northward and upward that causes more meridional flow.  Granted it may not necessarily be North America.  This is just observational, I think wave 2(s) do better than wave 1(s). 

Here's a presentation by Jason Furtado. tl:dr - Upward waves originating in Siberia can be reflected downward by stratosphere, warming the troposphere in Canada/Alaska and forming high pressure leading to downstream cold air outbreaks. When waves are reflected downward get a more immediate effect vs waves that aren't reflected and warm the stratosphere. He also had a nice twitter thread before the December cold outbreak showing the role of this process in aiding.

https://www.cpc.ncep.noaa.gov/products/outreach/CDPW/46/sessions/presentations/session4_oral2.pdf

 

 

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