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Mitchg

Meteorological Winter Pattern Discussion Act II, The Return Of Winter

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2 hours ago, Mitchg said:

Eps pattern change almost complete by day 15. 

Yup, it's getting there. Probably wouldn't start to get below normal temps till about day 18 or so. You can see the mjo doing the dirty work with a -epo/+pna-ao/ Nice Aleutian low/siberian high for some wave 1 hits to strat. Be nice to get Gigi back into the 0s club 

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I realize people are anxious to restart the auspicious pattern, but I would just caution that there are some potential timing issues with respect to the propagation of the MJO wave and the concomitant rossby wave induced alterations downstream. The ECMWF ensembles are a bit slower with the ewd propagation, with a progression through p7 in the first 10 days of the month. Keep in mind, there is a possibility that the EPS is rushing the eastward expansion of the lower geopotantial heights. It may not be, but there are still some uncertainties as far as timing. The state of the SPV will continue to support a +NAO in early February, so that particular signal looks accurate to me.

 

2qvxcgl.gif

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7 minutes ago, Isotherm said:

I realize people are anxious to restart the auspicious pattern, but I would just caution that there are some potential timing issues with respect to the propagation of the MJO wave and the concomitant rossby wave induced alterations downstream. The ECMWF ensembles are a bit slower with the ewd propagation, with a progression through p7 in the first 10 days of the month. Keep in mind, there is a possibility that the EPS is rushing the eastward expansion of the lower geopotantial heights. It may not be, but there are still some uncertainties as far as timing. The state of the SPV will continue to support a +NAO in early February, so that particular signal looks accurate to me.

 

2qvxcgl.gif

I have given up on any help from the NAO. I don't even look at it anymore and if the modeling shows it in the long range I just assume it is wrong. 

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1 minute ago, Feb said:

I have given up on any help from the NAO. I don't even look at it anymore and if the modeling shows it in the long range I just assume it is wrong. 

Problem has been the stratospehre orientation is not conducive for a -nao to develop

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6 minutes ago, tombo82685 said:

Problem has been the stratospehre orientation is not conducive for a -nao to develop

 

That among other factors which pre-season strongly suggested a +NAO. A couple of indicators I've developed have shown excellent success retrospectively; the one accurately prognosticates the +NAO sign 86% of the time since 1950, and when coupled with the other indicator, works in almost every case. I have been using it for the past few winters. Both indicators strongly suggested a +NAO for this winter.

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Just now, Isotherm said:

 

That among other factors which pre-season strongly suggested a +NAO. A couple of indicators I've developed have shown excellent success retrospectively; the one accurately prognosticates the +NAO sign 86% of the time since 1950, and when coupled with the other indicator, works in almost every case. I have been using it for the past few winters and it has done well. Both indicators strongly suggested a +NAO for this winter.

What are the other factors? AMO?

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16 minutes ago, tombo82685 said:

Problem has been the stratospehre orientation is not conducive for a -nao to develop

What ever the problem has been, it has been a problem for a good bit of winters lately. 

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2 minutes ago, Feb said:

What ever the problem has been, it has been a problem for a good bit of winters lately. 

 

The good news is I think we're finished with this cycle - in the means - this winter.

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12 hours ago, Isotherm said:

 

That among other factors which pre-season strongly suggested a +NAO. A couple of indicators I've developed have shown excellent success retrospectively; the one accurately prognosticates the +NAO sign 86% of the time since 1950, and when coupled with the other indicator, works in almost every case. I have been using it for the past few winters. Both indicators strongly suggested a +NAO for this winter.

I was trying to use a paper Jack gave to me to outlook the nao and it gave me a negative for this winter.  Although most of the failures were false -naos.  The NF ssta going back to the mid 90s had about a 70% success ratio.  If it isn't proprietary, do you mind sharing?

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13 hours ago, Feb said:

I have given up on any help from the NAO. I don't even look at it anymore and if the modeling shows it in the long range I just assume it is wrong. 

Modeling falls apart on nao skill around day 8.  Plus all the models (Euro in particular) outlook a fairly large number of false -naos beyond day 8 anyway.  So I am with you on this.

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13 hours ago, tombo82685 said:

Yup, it's getting there. Probably wouldn't start to get below normal temps till about day 18 or so. You can see the mjo doing the dirty work with a -epo/+pna-ao/ Nice Aleutian low/siberian high for some wave 1 hits to strat. Be nice to get Gigi back into the 0s club 

It almost sounds like the first full week of February.

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12z EPS look like a little step back from the 0z run bringing the cold east at the end of the run 

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10 minutes ago, Feb said:

12z EPS look like a little step back from the 0z run bringing the cold east at the end of the run 

 

Yeah, the EPS does what I alluded to yesterday, and is a bit slower with the eastward progression of the trough. The timing of tropical forcing suggests the East Coast higher height signal will try to hold for the first week or so of Feb before we begin to see the axis adjust ewd in response to the mechanisms discussed ad nauseam by many here.

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The cold is coming, ens will probably rush it a bit as usual. See no reason to back off earlier call of it coming just inside of mid month

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1 minute ago, tombo82685 said:

The cold is coming, ens will probably rush it a bit as usual. See no reason to back off earlier call of it coming just inside of mid month

Another case where some lingering se ridge could be helpful to get some snow chances. Really no changes long term. 

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14 hours ago, tombo82685 said:

The cold is coming, ens will probably rush it a bit as usual. See no reason to back off earlier call of it coming just during the first full week of Feb.

Fixed for you. :smiley-dance017:

Well there may come a time in Feb  when the GFS forecasting full boar cold will work, but for now the 00z run once again gets the prize for the coldest run of the 21 members.  The signs (whether rushed, science fiction or not) of a change to colder are starting to show up.

f360.gif.de6ee84e56c77a33198bfb26ac09470d.gif

 

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EPS continue the progression. Might be a little quick still but it's coming no and or buts about it.

 

eps_z500a_exnamer_61.png

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9 minutes ago, Rainshadow said:

Fixed for you. :smiley-dance017:

Well there may come a time in Feb  when the GFS forecasting full boar cold will work, but for now the 00z run once again gets the prize for the coldest run of the 21 members.  The signs (whether rushed, science fiction or not) of a change to colder are starting to show up.

 

 

Oooo so now your're the first full week of Feb? You're running into my dates now. 

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39 minutes ago, tombo82685 said:

Oooo so now your're the first full week of Feb? You're running into my dates now. 

I always was the first full week of Feb. Consistency is my name, even if its Mr. Consistency Wrong.

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