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Medium-long range thread


tombo82685

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12zGGEMEnsembles500mbHeightAnomalyNH384.gif

not sure how reliable the ggem ens have been. Tony or adam would probably have a better understanding of this.

Meh EMC stops verification of the Canadian at day 6. Statistically the Canadian and GFS are about the same (500mb) the past month off the 00z run; 12z run of the Canadian has been statistically weaker. Idk the naefs didn't have it (less of a positive PNA). To be honest, I don't like where the Canadian ensembles are progging the MJO to be for this to occur this quickly. Can the GWO be the instrument of change instead? I really don't know. The mountain torque is low right now.

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Rainshadow, just ran a GWO Monthly analog for November values with La Nina's, fast forwarded, it looks like What the Canadian Ensembles are saying could possibly happen, but I dunno if it will occur that quick (I generalized between Christmas and Jan 10th, because of lag of stratospheric conditions, and MJO timing). It make sense though, that blocking finally develops, QBO has finally dropped & going Easterly, 50mb EQ value has dropped some as well. Looking at Stratospheric plots of temps over the pole, we are finally spiking up the last 3-4 days. From the point of view that these temps have been near or below all time lows and are coming up, the sudden rate of change in T could cause a some sort of PV displacement scenario negating the +AO even if numbers only hang around the Climatological Mean Line...

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Meh EMC stops verification of the Canadian at day 6. Statistically the Canadian and GFS are about the same (500mb) the past month off the 00z run; 12z run of the Canadian has been statistically weaker. Idk the naefs didn't have it (less of a positive PNA). To be honest, I don't like where the Canadian ensembles are progging the MJO to be for this to occur this quickly. Can the GWO be the instrument of change instead? I really don't know. The mountain torque is low right now.

yea i dont see much to be happy about right now with the patter. The storm around the 20th may offer something, but again your relying on timing with the storm ejecting out of the south as the same time the pv rotates through se canada. What will most likely happen, the storm will wait for that to pass then cut to the west of us as the pattern shows it should.

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http://www.atmos.alb...S_7.5N/2011.png

See that quick shot of -OLR anomalies near the dateline around Dec 17-20? That COULD be something to watch in that timeframe. We'll see if the Nina dominance continues or not.

im not fully grasping the map so i circled the areas, which one are you referring to. The pink circle, black or blue? I would imagine its the pink since thats -olr

untitled-3.jpg

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Sometimes it doesn't look too good at day 7 either.

post-623-0-15148100-1323387178.gif

Actually in terms of corroboration for scientific purposes, I thought the overnight Euro run was better than the 12z run.

Lat night's run looked more reasonable than the 12Z euro. That said, the models are showing a little different in that they're getting rid of the massive vortex over canada so instead of having way below normal heights there, they look to be trending towards normal. Still not a game changer but maybe a step towards something down the road.

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Lat night's run looked more reasonable than the 12Z euro. That said, the models are showing a little different in that they're getting rid of the massive vortex over canada so instead of having way below normal heights there, they look to be trending towards normal. Still not a game changer but maybe a step towards something down the road.

both ens means look very gradient. trof in the sw will enhance the se ridge, but the vortex in canada is lowering hgts esp in the northeast..could see winter like threats in new england, down here though looks like we are on the wrong side.

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im not fully grasping the map so i circled the areas, which one are you referring to. The pink circle, black or blue? I would imagine its the pink since thats -olr

LOL, neither.

Here's how to read the image: longitude is on the x-axis (the prime meridian is at the edges and the dateline is in the middle) and time is on the y-axis (increasing as you go up). Blues indicate -OLR anomalies (more convection) and oranges indicate +OLR anomalies (less convection). The thick red lines are the statistically derived progression of the MJO (through EOF, which you don't need to worry about, but I can explain if you need me to).

Now, focus on the thick red line between Dec 17-23. Notice how a fast moving piece jumps out to near 160W-180? That has a chance to screw things up for my torchcast around Dec 20 or so. It's certainly not a definite shift, but it is something to keep an eye on.

Feel free to ask more questions about the image if you have them.

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LOL, neither.

Here's how to read the image: longitude is on the x-axis (the prime meridian is at the edges and the dateline is in the middle) and time is on the y-axis (increasing as you go up). Blues indicate -OLR anomalies (more convection) and oranges indicate +OLR anomalies (less convection). The thick red lines are the statistically derived progression of the MJO (through EOF, which you don't need to worry about, but I can explain if you need me to).

Now, focus on the thick red line between Dec 17-23. Notice how a fast moving piece jumps out to near 160W-180? That has a chance to screw things up for my torchcast around Dec 20 or so. It's certainly not a definite shift, but it is something to keep an eye on.

Feel free to ask more questions about the image if you have them.

is it that area with the black circle lol

untitled-4.jpg

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what phase is that on the dateline? Is this mjo method better than the other ncep site stuff?

P8 is convection on the dateline, but there isn't enough subsidence over the Western IO for it to show as a P8 signature on the Phase Space diagrams.

I like using this method better because it gives me a better idea of everything going on in the tropics and allows me to forecast based on what's actually occurring, rather than some idealized phase, but it took me 12 months of looking at it everyday and following along with others' discussion to get a good grasp of how to use it.

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P8 is convection on the dateline, but there isn't enough subsidence over the Western IO for it to show as a P8 signature on the Phase Space diagrams.

I like using this method better because it gives me a better idea of everything going on in the tropics and allows me to forecast based on what's actually occurring, rather than some idealized phase, but it took me 12 months of looking at it everyday and following along with others' discussion to get a good grasp of how to use it.

axesmiley.png i just would need it for the mjo for winter...how often does it update, daily?

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00zallwestnao.gif

The threat in the longer range on the 20th by the euro could be tied with its forecast of a west based -nao. Considering the euro and gfs have been pulling the trigger on a -nao in the longer range a couple of times for it to not materialize should make people feel wary. That whole setup by the euro looks like it would need to be timed right. The pv traversing southern canada is not a permanent feature, if that wave doesnt eject out of the south while that pv is still influencing our weather that storm is just going to cut west. It may bring some wintry mix briefly with some remnant cold over the region but it would warm up quickly.

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Some thoughts from JB on the upcoming pattern....

"This is not a "winters over" pattern by any means. In fact the atmospheric avenger goes over a similar evolution in late 70 and 71. The fact is I drew a map for you as to how this la nina should work, remember..with troughs down the west coast and then trying to come out. The phasing ones cut to the lakes and go wild, and a couple of them are going to do that this year, that is where we will see ( plains to western lakes) the threat of blockbusters. For the east, its front running storms with secondary development, the occasional storm where the southern branch is suppressed to allow a low to stay south coming over the ridge if its retreated far enough, or what we just saw.. pressing new cold air with a final wave on it. In fact that could happen again next week."

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tombo, this is pretty good, too... this is the MJO EOF signature isolated on the Phase Space diagram. Now, it's probably wrong, because the phase speed should be a little faster in the forecast, but hopefully, you get the point I was trying to make earlier.

RMMpredmjo523.png

i see, right in that 19-27 period signals a shot at a storm a long the east coast, with the mean trof over the lakes

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how accurate is this, because none of the other ensemble forecast show the mjo going to phase 7-8, they have cod, then into phase 2-4

Keep in mind, that it is the MJO ONLY. There are other types of convection (e.g. Kelvin waves, mixed Rossby-gravity waves, etc) that project onto the "MJO" phase space. Now again,I'm not totally on board with the Roundy forecast, but here is the total tropical convection around the phase space... it's also not accurate because it doesn't do a good job of forecasting other types of convection until about 5-7 day window (like anything else), but note that it is very accurate in hindsight...

So, what to take away from all of this? The Roundy algorithm does a good job of breaking tropical convection into its component pieces and that its MJO forecast is ok, but a little slow (in this case).

RMMpred523.png

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Keep in mind, that it is the MJO ONLY. There are other types of convection (e.g. Kelvin waves, mixed Rossby-gravity waves, etc) that project onto the "MJO" phase space. Now again,I'm not totally on board with the Roundy forecast, but here is the total tropical convection around the phase space... it's also not accurate because it doesn't do a good job of forecasting other types of convection until about 5-7 day window (like anything else), but note that it is very accurate in hindsight...

So, what to take away from all of this? The Roundy algorithm does a good job of breaking tropical convection into its component pieces and that its MJO forecast is ok, but a little slow (in this case).

ahh now i see with that plot firmly backs up the roundy one we were posting early that shows the little bump into phase 6-7ish.

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