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MJO/LR Forecasting Thread


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You can thank the dominant -QBO/low relative HC intensity for the elongated Walker Cell variance. Problem is these regimes are tough to maintain..so any break in the mass transfer/export fields will remove most longitudinal inhibition.

 

I'll give the current MJO wave a 40% chance to break the barrier set by the QBO.

Man, this wave is trying hard to break through..EPF is going weakly poleward (strong eddy flux) w/ mt-progression now beginning..this was one of my worries..that the combination of a strong wave and changing export field may allow a fundamental shift in the tropical circulations..

 

Biggest +AAM response since summer/autumn of 2014..

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If tropical forcing continues on the path we've seen so far, this current wave should push over the Pacific and weaken/die around phase 6/7 during mid month. As the wave progresses east, we should see the PNA ridge shift over us (+PNA), the jet stream strengthen and extend, and the mean trough will shift over the east, resulting in a El Nino type pattern. Once a new wave fires up over the IO sometime around the second half of Jan (looks like the 15th-20th at this point), I'm expecting to see a gradual shift to La Nina conditions once again. 

 

 

 

As the MJO pushes further into the Pacific, the jet stream roars over the Pacific resulting in an Aleutian low, returning us to the stormy and atmospheric river setup we saw earlier this month. The current wave should die off around the dateline (phase 6/7), then return to the western Indian Ocean sometime around the 20th +/- a few days. This allows the Pacific jet to relax and a pattern reset to take place. Once we see the new wave push over the Maritime Continent, that's when our next chance will be. To give a time frame would probably be foolish of me due to extrapolating something that shouldn't be extrapolated in the first place, but I'd say keep an eye on early Feb for a return to cold and hopefully snow this time around.

 

 

 

Not a bad call in my opinion. 

 

http://i.imgur.com/OlT2bOf.png

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Very good call.

 

What's your take on the poleward-biased WPAC Hadley Cell screwing with mass transport E of the dateline? Literally a brick wall there..

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Very good call.

 

What's your take on the poleward-biased WPAC Hadley Cell screwing with mass transport E of the dateline? Literally a brick wall there..

 

I know that the WC is definitely displaced this season and the upper lvl convergence hasn't allowed passage as of yet, don't really know if it will at all this winter. -NAO has been lacking, which in my opinion, directly correlates to the WC displacement, not allowing MJO to hang over the Pacific long enough to get the -NAO rolling. We see continued hits on the PV, but not much in the way of progress towards a significant SSWE, which also seems to correlate to the displaced WC. Honestly though, not very knowledgeable on the subject and I'm pretty much talking out of my a** :)

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Looks like the recent MJO forcing coupled with the WPAC Hadley Cell contraction/poleward AAM transport may prevent a significant tropical forcing excursion into the IO. Can throw seasonal wave forcing transition(s) under a -QBO into the mix. Going to be an interesting 10 days, I suspect.

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  • 2 weeks later...

Well, on the bright side, the MJO looks to become favorable for the west around the midway point of next month. Roundy plots show the MJO stalling out over the IO for a while before finally propagating across the MC. We'll see

 

 

Taking a look back at this call, it may end up coming to fruition if the typhoon rule continues to verify. Taking a look at Asia, we see a quick hitting low pressure system digging to the SE before being replaced by a ridge a few days later. What would this mean for us? Given the location of the system, if the correlation held true, we'd see a trough dig into the west around the 14th-16th. My only fear is the trough may be centered too far to the east for us to really benefit, leaving us in more of a NW flow rather than a N flow.

 

http://i.imgur.com/Rt3avMg.png

 

 

On that note... MJO is really stalling out this go around. We'll see if it ends up working out for us.

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As it's been all winter, I think it's a battle between inertia/top-down forcing and tropical/bottom-up forcing. This winter, the former has been winning out, much like it did in 2013-14, which I did not really anticipate. The Greenland/Hudson Bay Vortex has become so entrenched in the flow field(s) that it is now the perturbative epicenter of the mid latitude mass transfer system. We've seen strong bouts of tropical forcing lead to large swings in the NPAC circulations, but the inertia contained within that vortex has allowed it to resist external forcing, with the aid of a very elastic stratospheric PV.

 

The key to breaking up the tropospheric vortex was the early January SSW..which ultimately failed..now that the PV and tropospheric vortex are constructively feeding back off one another, it's going to be very hard to get the pattern to change until Spring, or maybe even Summer.

 

Regarding the MJO, my fear was that we'd see this transition occur, where the IO is no longer favored for large scale convergence. That appears to be the case..I'd look towards region 6-7 for future initialiazation, if a new wave is to emerge.

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As it's been all winter, I think it's a battle between inertia/top-down forcing and tropical/bottom-up forcing. This winter, the former has been winning out, much like it did in 2013-14, which I did not really anticipate. The Greenland/Hudson Bay Vortex has become so entrenched in the flow field(s) that it is now the perturbative epicenter of the mid latitude mass transfer system. We've seen strong bouts of tropical forcing lead to large swings in the NPAC circulations, but the inertia contained within that vortex has allowed it to resist external forcing, with the aid of a very elastic stratospheric PV.

 

The key to breaking up the tropospheric vortex was the early January SSW..which ultimately failed..now that the PV and tropospheric vortex are constructively feeding back off one another, it's going to be very hard to get the pattern to change until Spring, or maybe even Summer.

 

Regarding the MJO, my fear was that we'd see this transition occur, where the IO is no longer favored for large scale convergence. That appears to be the case..I'd look towards region 6-7 for future initialiazation, if a new wave is to emerge.

Are we experiencing something unusual either with the solar activity or the atmosphere in recent years that is favoring this behavior of the Greenland / Hudson Bay vortex? I have never seen such persistence of this type of pattern before and it is leading to a potentially catastrophic drought situation in California. I am very eager for this pattern to change and I don't want to see any more repeats of either 2013-14 or 2014-15 for a very long time, if ever!

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Can be blamed on the +Hadley/+Solar regime w/ low-freq IO forcing from September-present..that inertia is now hard to break as the strat-PV & Hudson Bay Vortex are now constructively feeding back off one another and overwhelming the tropical forcings.

 

If Sun hadn't dampened the efficiency of the +EPF/wave driving regimen, the tropical forcing/-QBO stress would have combined to force a SSW and enlarge the wave field, replacing the Hudson Bay Vortex with a deep -NAO..

 

Scary thing is, 2015-16 is setting up to be nearly a carbon copy of 2013-14, forcing wise. Could we go another year w/ this circulation? :lol:

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Can be blamed on the +Hadley/+Solar regime w/ low-freq IO forcing from September-present..that inertia is now hard to break as the strat-PV & Hudson Bay Vortex are now constructively feeding back off one another and overwhelming the tropical forcings.

 

If Sun hadn't dampened the efficiency of the +EPF/wave driving regimen, the tropical forcing/-QBO stress would have combined to force a SSW and enlarge the wave field, replacing the Hudson Bay Vortex with a deep -NAO..

 

Scary thing is, 2015-16 is setting up to be nearly a carbon copy of 2013-14, forcing wise. Could we go another year w/ this circulation? :lol:

I certainly hope not, as California will be in HUGE trouble! What will it take to break this circulation pattern, another SSW event at some point in the future or will we have to wait until the solar max starts to go toward minimum? California just hasn't experienced this degree of dryness in other solar maxes of the past, even though the late 80's and early 90's drought was near the max and quite dry at its peak, but not quite as severe as this drought has been.

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  • 7 months later...

Hey everyone. This winter isn't looking good for snow lovers unfortunately, but I plan on starting this thread back up regardless. Hopefully I'll continue to learn and anyone else who'd like to learn can join in. I have a feeling the following will be a common occurrence this winter....

 

http://i.imgur.com/tV0W510.gif

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2015-16 is setting up to be nearly a carbon copy of 2013-14, forcing wise. Could we go another year w/ this circulation?

This will probably be a bust.

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Hey everyone. This winter isn't looking good for snow lovers unfortunately, but I plan on starting this thread back up regardless. Hopefully I'll continue to learn and anyone else who'd like to learn can join in. I have a feeling the following will be a common occurrence this winter....

 

http://i.imgur.com/tV0W510.gif

Ah, the dreaded Alaskan low. The kiss of death to winter for everyone west of the Mississippi.

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Yes, not something we like to see. So close yet so far away. You in agreement with this at all?

I'm definitely in agreement overall. I'm just trying to figure out where the low will set up. Key is the progression of the low frequency tropical forcing through the next 10-15 weeks. If the Alaskan low sets up far enough west (south of the Aleutians), it's possible you guys in the PNW can encounter Arctic air behind a wave breaker (November 2014 being an example of this).

 

Also, forcing from the MJO/higher frequency forcing & the stratosphere can overwhelm the Niño forcing anytime, so that's also something to watch, imo.

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Not for the American southwest.

I think it depends on where the vortex is located. If it's up in Alaska, then everyone west the Mississippi (at least) roasts. If it's in the Southern Gulf of Alaska, that's another story.

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