Medium Range-Long Range thread

[tombo82685]

Today's Euro 10 day looks like its heading to a big MA or SE snowstorm. With massive 50/50 and closed low in southern stream 

 

yup, pretty much

 

[am19psu]

Yeah but KW do not regress either. I agree that KW interact, amplify and suppress the MJO wave signal which can cause "weirdness" on the charts. As the Walker intensifies / CHI fields tighten, the SST gradient/trades may be enough to cause the forcing to stall for a bit, possibly showing this "loop" as the propagation dies. Yes I understand that the models weaken the MJO in the C-E PAC for the reasons already known/stated, but this loop may not be because of that solely.

BTW, CPC AO page has the 50-10mb temperature anomalies:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtml

Oh. Hi.

[Harbourton]

GFS is quickly backing off the cold air outbreak from 0z to 12z. Maybe feeling the MJO hitting a brick wall? 

 

12Z

 

 

0Z

 

[am19psu]

The MJO might hit a wall, but I surely wouldn't use the GFS (or Euro) to diagnose it 10-14 days out.

[Harbourton]

The MJO might hit a wall, but I surely wouldn't use the GFS (or Euro) to diagnose it 10-14 days out.

 

May be just coincidental but the trend is not good.

[Rainshadow]

The MJO might hit a wall, but I surely wouldn't use the GFS (or Euro) to diagnose it 10-14 days out.

 

 

I think it was Matt from MDA who once posted that if an active MJO was able to cross p5, it would have enough of a convectve effect to trigger a downstream pattern change.  But what I forget was this in winter only or does it have to remain active into p8 et al.  One was necessary for the fall (I think the latter statement), but not necessarily so (I think winter).  Do I have this straight?

[tombo82685]

GFS is quickly backing off the cold air outbreak from 0z to 12z. Maybe feeling the MJO hitting a brick wall? 

 

12Z

 

 

0Z

 

 

your time stamps are off. You can't use the same hours on the 0z for the 12z because it will verify for a different time. For instance. Comparing 0z at hr 48 would be 0z friday. If you did the same with the 12z run and did 48hrs again that would be 12z friday.

 

Also, you don't want overwhelming cold, that would be a dry pattern. Having it just cold enough with somewhat of a ridge off the east coast would be good.

[Mike.Ventrice]

I, of course, agree with your explanations on why the MJO typically weakens into these phases but I should also point out that there is a climatology here. When the forecasts are for a loop into phase 6-7, this isn't quite the same thing as what you are saying and I'm worried you are putting too much emphasis on this idea that they are likely "too weak." There is a real Walker Cell conflict with a semi-La Nina-like state over the C PAC. It is a real possibility the convection hits a brick wall, stops the propagation and weakens/loops the MJO. Having said that, I don't think this necessarily means we fail at making it to 8-1-2 either. I think we do make it eventually.

Also, one thought about the SSW and the MJO. I have read the papers about the MJO influencing the stratosphere and I agree that it does. But keep in mind, we have been sparking warmings from Asia long before the sudden "MJO wake up." There is a relationship between AO/AAO warmings and their subsequent equatorial coolings which can promote MJO growth. As the Pac Jet retracted, the EA jet took a break, allowed the +AAM to grow in the "Walker Favored" areas of the equatorial regions which also played a role.

 

Agreed, though while convection might turn off over the "convectively dead regions" such as the East Pacific and Atlantic ITCZ, the upper-level circulation associated with the MJO contineus progressing eastward with time.  Incorporating U200 into RMM is why RMM is capable of detecting MJO-related signals over the Western Hemisphere. The semi-loop that many of the models are suggesting very well may happen in RMM phase 7. However, this doesnt necessarily mean the MJO is weakening... it is just most likely associated with noise projecting onto the RMM PCs. According the space-time filtered VP850, the core of the MJO signature appears to be centered about 150E. In a week, it should be located east of the dateline, two weeks over the East Pacific, and three weeks back over the Indian.

 

There is potential for the development of an oceanic Kelvin wave that could couple convection.  If this were the case, there could be two cores of equatorial convection when the MJO signal gets back over the Indian Ocean. One core associated with the MJO, the second associated with the oceanic Kelvin wave. The development of this oceanic Kelvin wave could throw off some of the extra-tropical circulation signals we commonly acustom with an MJO phase 1-3. Something to keep an eye on.

 

Thanks for the discussion of the MJO-strat relationship. Still learning with respect to polar vortex dynamics and relationships with tropical convection

 

 

[tombo82685]

Really nice euro ens looking image at hr 240. Nice -nao, solidly east based, with a -epo. Would like to see the heights a little higher over alaska and  west coast. You can see how wit the -epo and -nao its pinching off the pv further south over hudson bay..

 

[Harbourton]

your time stamps are off. You can't use the same hours on the 0z for the 12z because it will verify for a different time. For instance. Comparing 0z at hr 48 would be 0z friday. If you did the same with the 12z run and did 48hrs again that would be 12z friday.

 

Also, you don't want overwhelming cold, that would be a dry pattern. Having it just cold enough with somewhat of a ridge off the east coast would be good.

 

The 1996 blizzard started off at 10 degrees F in central Jersey  which was what I would consider overwhelming cold. tt can happen. Along with the Presidents Days storms I and II

[Rainshadow]

Really nice euro ens looking image at hr 240. Nice -nao, solidly east based, with a -epo. Would like to see the heights a little higher over alaska and  west coast. You can see how wit the -epo and -nao its pinching off the pv further south over hudson bay..

 

 

 

Hudson Bay Low >>>>> Baffin Island Low.  Let's see if it makes a home there.

[tombo82685]

The 1996 blizzard started off at 10 degrees F in central Jersey  which was what I would consider overwhelming cold. tt can happen. Along with the Presidents Days storms I and II

 

What i mean by that, is you don't want a huge carved out trof over the east or the pv to far south. The bliz of 96 actually had somewhat of a se ridge. The reason why it got so cold was because their was a 1036 high in a great spot to funnel down cold

 

 

and the high was locked in by a 50/50 low and an east based -nao

 

[Rainshadow]

The 1996 blizzard started off at 10 degrees F in central Jersey  which was what I would consider overwhelming cold. tt can happen. Along with the Presidents Days storms I and II

 

These three were pattern changing storms which made the sharper turn up the coast possible.  With two of those storms, we still managed to get sleet here (Hi Rib). I think what Tom was stating if you remain entrenched in a cold pattern, the storm track likely would stay suppressed.

[NaoPos]

18z GFS woofing at that 196-240 hr.kinda the same as the euro.

[famartin]

The 1996 blizzard started off at 10 degrees F in central Jersey  which was what I would consider overwhelming cold. tt can happen. Along with the Presidents Days storms I and II

 

A lot of classic big snows had "overwhelming cold"... the 2009-2011 double season was unusual in its lack thereof despite all the big storms.

[tombo82685]

A lot of classic big snows had "overwhelming cold"... the 2009-2011 double season was unusual in its lack thereof despite all the big storms.

 

I agree you need the cold. What i trying to show is that you don't want a huge carved out trof over the eastern US. The bliz of 96 had a se ridge. The presidents day storm was an overunning event where again there was some sort of ridging off the se coast.

 

Here is the h5 look for both the bliz of 96 and presidents day. The cold from those storms were from strong high pressures with cad, it wasn't like a huge carved out trof.

 

[Quakertown needs snow]

Glenn was funny on tv "you've been warned" with colder air returning late next week

[am19psu]

I think it was Matt from MDA who once posted that if an active MJO was able to cross p5, it would have enough of a convectve effect to trigger a downstream pattern change. But what I forget was this in winter only or does it have to remain active into p8 et al. One was necessary for the fall (I think the latter statement), but not necessarily so (I think winter). Do I have this straight?

I'm not familiar with what you're describing but all significant MJO waves affect the downstream H5 pattern. Latent heat release affect the position of the jet stream and subtropical highs. The more robust the wave, the stronger the resultant rossby wave train.

[tombo82685]

Tom or adam or anyone with euro ens post day 10. What do they do in the pacific? Do they rotate the pac ridge west, which dumps the trof into west and fires up the se rdige like the gefs are starting to do?

[am19psu]

Pretty flattish Pacific, huge -nao/-ao though

[tombo82685]

Pretty flattish Pacific, huge -nao/-ao though

 

that combo is good, the flat pacific is worrisome. So i take it its breaking down the -epo

[phlwx]

That West Coast ridge breaks down after 1/20 but even then the mean slightly favors a ridge on the coast or across the Western US.

 

The NAO is still clear as day on the mean at 1/23 (day 15)...and Europe & Western Russia will be in the freezer big time as well per the EC ENS.

[tombo82685]

That West Coast ridge breaks down after 1/20 but even then the mean slightly favors a ridge on the coast or across the Western US.

 

The NAO is still clear as day on the mean at 1/23 (day 15)...and Europe & Western Russia will be in the freezer big time as well per the EC ENS.

 

thats good then, because the 18z gefs retrograde that pac ridge west, stick the trof in the west and we go back under the same pattern as december. Though, both models agree on the -nao which is good, the gefs to a lesser degree.

 

[Quakertown needs snow]

0z euro looks wet next week but cold air lagging behind

can we get the cold here in time at all with precip around?

pending clipper around 18th?

[Rainshadow]

I'm not familiar with what you're describing but all significant MJO waves affect the downstream H5 pattern. Latent heat release affect the position of the jet stream and subtropical highs. The more robust the wave, the stronger the resultant rossby wave train.

 

Adam,

 

I think the question was can it get colder east with an active MJO going into the COD after passing phase 5 vs remaining active through the colder phases, is the latter needed for a colder shot to get east?  Because of wavelength differences I thought Matt said one or the other was needed in the fall, but not necessarily in the winter.

[Rainshadow]

I'm not familiar with what you're describing but all significant MJO waves affect the downstream H5 pattern. Latent heat release affect the position of the jet stream and subtropical highs. The more robust the wave, the stronger the resultant rossby wave train.

 

Adam,

 

I think the question was can it get colder east with an active MJO going into the COD after passing phase 5 vs remaining active through the colder phases, is the latter needed for a colder shot to get east?  Because of wavelength differences I thought Matt said one or the other was needed in the fall, but not necessarily in the winter.

[Rainshadow]

0z euro looks wet next week but cold air lagging behind

can we get the cold here in time at all with precip around?

pending clipper around 18th?

 

Looks like a discontinuity between the night and day runs.  I just got off the phone with the Inquirer about the pattern change, MJO phases 6 and 7 are not necessarily cold in the east, although the correlation gets shakier for warm in phase 7.

[am19psu]

Adam,

 

I think the question was can it get colder east with an active MJO going into the COD after passing phase 5 vs remaining active through the colder phases, is the latter needed for a colder shot to get east?  Because of wavelength differences I thought Matt said one or the other was needed in the fall, but not necessarily in the winter.

 

Oh. I've not seen any journal articles on the lag effects of MJO responses if latent heat release is removed. Obviously, there is a non-zero time scale for the RWT to dissipate, but I don't know the order of magnitude of that time scale. The net result, imo, would be a relaxation to the seasonal base state, which this year seems to be -AO/-EPO/-PNA, which as we've seen is bad for us.

[NJwinter23]

Tom or adam or anyone with euro ens post day 10. What do they do in the pacific? Do they rotate the pac ridge west, which dumps the trof into west and fires up the se rdige like the gefs are starting to do?

 

They do this, they were the first to suggest this earlier in the week actually (the extent of which waffling from run to run)..seems like the gefs are catching onto this idea

 

Oh. I've not seen any journal articles on the lag effects of MJO responses if latent heat release is removed. Obviously, there is a non-zero time scale for the RWT to dissipate, but I don't know the order of magnitude of that time scale. The net result, imo, would be a relaxation to the seasonal base state, which this year seems to be -AO/-EPO/-PNA, which as we've seen is bad for us.

 

I would argue its been pretty neutral on the EPO part since Dec 1, if not a bit positive. 

[am19psu]

They do this, they were the first to suggest this earlier in the week actually (the extent of which waffling from run to run)..seems like the gefs are catching onto this idea

 

 

I would argue its been pretty neutral on the EPO part since Dec 1, if not a bit positive. 

 

Yeah, I guess you're right. It's more like -WPO. Either way, the base state has been blerg for snow lovers.