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Central/Western Summer Medium/Long Range Discussions

Srain

By Srain,
in Central/Western States

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Ian

Ian

Posted
Posted

Every day between May 21-May 24 (Sat-Tue) had at least one great storm, and all but the 23rd had awesome tornadoes. The last great multi-day stretch in the Plains we've seen.

That was painful after being out the first two weeks of May.
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Chinook

Chinook

Posted
Posted

Eastern Iowa, South of I-80 could be a sleeper play tomorrow along the warm front, High bust potential here, but that's what it's all about in this business. Strong cap in place, but if they can warm up nicely there is a slight chance the cap could go with some surface based storms...Instability is probably a tad overdone.

Tomorrow they may call for a slight risk. NAM and GFS runs seem to be showing big CAPE, with a localized area of 40-50 knot winds at 500mb in Iowa.

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AgeeWx

AgeeWx

Posted
Posted

Tomorrow they may call for a slight risk. NAM and GFS runs seem to be showing big CAPE, with a localized area of 40-50 knot winds at 500mb in Iowa.

 

Tomorrow is a Slight Risk already on the D2 and I'd be surprised if it doesn't stay that way for the D1. Big bust and hail potential tomorrow.

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ZackH

ZackH

Posted
Posted

That was painful after being out the first two weeks of May.

 

Yup... that was the day after our 2 week trip... watched all the footage live cursing after something like 3 moderate busts... had to get back for a buddy who had a summer class starting on the 24th... when he got back he got an email saying the class had been canceled... 

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ZackH

ZackH

Posted
Posted

Tomorrow they may call for a slight risk. NAM and GFS runs seem to be showing big CAPE, with a localized area of 40-50 knot winds at 500mb in Iowa.

 

 

Its too bad there's not more upper level support (above 500 mb)... but hey, for 2013, I'd give it a shot if I were closer.

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MidwestChaser

MidwestChaser

Posted
Posted

Yup... that was the day after our 2 week trip... watched all the footage live cursing after something like 3 moderate busts... had to get back for a buddy who had a summer class starting on the 24th... when he got back he got an email saying the class had been canceled... 

 

:axe:  That must have hurt.

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HM

HM

Posted
Posted

 

FWIW, the 00z Euro in the latter stages of the run doesn't look so bad at all.

 

If you notice, the GFS/GEFS do develop a coherent MJO wave, like the ECMWF, but propagate roughly through phase 1-3 before diminishing. The ECMWF/EPS is more robust in bringing it back to life and having it propagate beyond phase 3. This has implications on how long the western trough sticks around and manifests.

The situation is complicated with a kelvin wave currently pushing through the IO. It is possible this is tampering with the modeling and possibly muddying the signal. Time will tell of course. Either way, this should at least bring a window for the potential of widespread severe towards that 5/9-5/10 (roughly) period (which was signaled on the analog data if you remember).

The 12z GFS does develop a blocking ridge in the NW USA, which forcing over the IO favors; but, the positioning makes more sense on the ECMWF, per MJO climatology. Ultimately, the GFS does retrograde the blocking post-truncation. Clearly, the tropical forcing is playing a major role here in the timing.

My guess is that a middle ground scenario is the best approach. The KW will likely produce a favorable pattern (SW trough) ahead of something more substantial 5/15-20 as forcing consolidates over the eastern IO/Indonesia sector mid to late May.

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HM

HM

Posted
Posted

 

FWIW, Jim Bishop (operational met and veteran chaser) sees hope for late May into early June. http://stormgasm.com/blog/?p=1505

 

The effects of the "MJO" could even get started sooner than that but I generally agree that the "MJO" is going to save the season from being a total dud. There are a lot of sources suggesting an El Niño is on the way but I'm not sold yet. Even the latest JMA guidance suggests the IOD/ENSO system will trend more "La Niña-like" this warm season.

The MJO / KW area currently is trumping any help from the western Pacific, generally residing from the C-E PAC into the Atlantic/African Sector. The KW is already moving into the IO. So we are just about at the worst positioning you can imagine for severe weather fans. So in a way, his logic is correct that these waves can only migrate into better positioning with time.

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andyhb

andyhb

Posted
Posted

If you notice, the GFS/GEFS do develop a coherent MJO wave, like the ECMWF, but propagate roughly through phase 1-3 before diminishing. The ECMWF/EPS is more robust in bringing it back to life and having it propagate beyond phase 3. This has implications on how long the western trough sticks around and manifests.

The situation is complicated with a kelvin wave currently pushing through the IO. It is possible this is tampering with the modeling and possibly muddying the signal. Time will tell of course. Either way, this should at least bring a window for the potential of widespread severe towards that 5/9-5/10 (roughly) period (which was signaled on the analog data if you remember).

The 12z GFS does develop a blocking ridge in the NW USA, which forcing over the IO favors; but, the positioning makes more sense on the ECMWF, per MJO climatology. Ultimately, the GFS does retrograde the blocking post-truncation. Clearly, the tropical forcing is playing a major role here in the timing.

My guess is that a middle ground scenario is the best approach. The KW will likely produce a favorable pattern (SW trough) ahead of something more substantial 5/15-20 as forcing consolidates over the eastern IO/Indonesia sector mid to late May.

 

Yes I noticed that all the Euro suites on the MJO forecasts were very nicely progressive with the MJO and at a fairly decent amplitude, which is a good sign as we move past this cut off low this week into early next week.

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HM

HM

Posted
Posted

 

The LRC guys seem to be on board with the second half of May because of some trough in October. #imgame

 

This type of logic (although if you link me to their thoughts I can know for sure) sounds similar to "the temperature departure of some month, let's call it "w", means a certain temperature departure for seasonal period xyz." In other words, merely a loose correlation which may or may not have a broader explanation which may or may not trend to 50/50 with a larger data set. And yet in another word: bogus.

As you know, I told you back on twitter a long time ago that wave timings may work out for mid-late May for us. This definitely had nothing to do with some October trough, lol. ;)

Yes I noticed that all the Euro suites on the MJO forecasts were very nicely progressive with the MJO and at a fairly decent amplitude, which is a good sign as we move past this cut off low this week into early next week.

We'll see if the kelvin wave ahead of the actual MJO pulse is screwing up the ECMWF forecasts. It could simply be rushing the process a bit because of it. The weeklies should be coming out today with an updated MJO forecast. That will shed some light.

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Ian

Ian

Posted
Posted

 

 

This type of logic (although if you link me to their thoughts I can know for sure) sounds similar to "the temperature departure of some month, let's call it "w", means a certain temperature departure for seasonal period xyz." In other words, merely a loose correlation which may or may not have a broader explanation which may or may not trend to 50/50 with a larger data set. And yet in another word: bogus.

As you know, I told you back on twitter a long time ago that wave timings may work out for mid-late May for us. This definitely had nothing to do with some October trough, lol. ;)

 

yes.. i was getting nervous with you seemingly not as gung ho lately. bring it back. ;)

 

http://www.wisn.com/weather/weather-blog-may-long-range-forecast/-/9374846/19934152/-/item/2/-/vuhqvmz/-/index.html

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ZackH

ZackH

Posted
Posted

I believe there was a recent study that showed statistical evidence in a phase 2 MJO being associated with violent tornado outbreaks more than any other phase... man... can't remember where I read that, it was a very recent study, though.  I will search through some AMS papers.

 

EDIT:  Here we go!  Interesting read for sure.  I need to read it closer as I just skimmed it a couple weeks ago.

 

http://journals.ametsoc.org/doi/pdf/10.1175/MWR-D-12-00173.1

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HM

HM

Posted
Posted

 

yes.. i was getting nervous with you seemingly not as gung ho lately. bring it back. ;)

 

http://www.wisn.com/weather/weather-blog-may-long-range-forecast/-/9374846/19934152/-/item/2/-/vuhqvmz/-/index.html

 

I'm trying these days to keep time scales and thoughts/predictions expressed at those time scales isolated from each other. So, in other words, if I said something would happen in late May back in the winter, I don't want to let my thoughts closer in, like April, get affected by those older thoughts. If they happen to come out to the same conclusion, then I'll jump for joy! lol This is a typical bias of many long range forecasters and I'm sure I've made the same mistake too (sticking with older thoughts and twisting newer thoughts to be consistent with older thoughts). I find it is better to revisit the older forecasts after verification, too, to help improve the longer term accuracy. Predicting the way the Tropics are going to behave is tough but doable. Hopefully late May ends up a good example!

I think I've heard of these "LRC" methods. There could be something legitimate behind the scenes and it could even be intraseasonal oscillations. But, from what I've gathered of what little I know about it, it seems like a major disaster statistically. They are seeing what they want to see out of a limited number of outcomes at one time. So, in a given week, I may have a ridge or a trough, let's say. There is usually going to be a ridge or trough in any future week and so you can easily paint a picture, believing there is a signal.

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baroclinic_instability

baroclinic_instability

Posted
Posted

 

 

I'm trying these days to keep time scales and thoughts/predictions expressed at those time scales isolated from each other. So, in other words, if I said something would happen in late May back in the winter, I don't want to let my thoughts closer in, like April, get affected by those older thoughts. If they happen to come out to the same conclusion, then I'll jump for joy! lol This is a typical bias of many long range forecasters and I'm sure I've made the same mistake too (sticking with older thoughts and twisting newer thoughts to be consistent with older thoughts). I find it is better to revisit the older forecasts after verification, too, to help improve the longer term accuracy. Predicting the way the Tropics are going to behave is tough but doable. Hopefully late May ends up a good example!

I think I've heard of these "LRC" methods. There could be something legitimate behind the scenes and it could even be intraseasonal oscillations. But, from what I've gathered of what little I know about it, it seems like a major disaster statistically. They are seeing what they want to see out of a limited number of outcomes at one time. So, in a given week, I may have a ridge or a trough, let's say. There is usually going to be a ridge or trough in any future week and so you can easily paint a picture, believing there is a signal.

Bogus seems like a good description, at least from the little I have seen from it. A classic case of confirmation bias based on some of the maps used to claim correlation from one event to the next. Complete busts are also tossed and ignored. There is probably a legit reason why there is no peer reviewed literature on it even though the hypothesis has existed for many years.

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Thundersnow12

Thundersnow12

Posted
Posted

 

 

If you notice, the GFS/GEFS do develop a coherent MJO wave, like the ECMWF, but propagate roughly through phase 1-3 before diminishing. The ECMWF/EPS is more robust in bringing it back to life and having it propagate beyond phase 3. This has implications on how long the western trough sticks around and manifests.

The situation is complicated with a kelvin wave currently pushing through the IO. It is possible this is tampering with the modeling and possibly muddying the signal. Time will tell of course. Either way, this should at least bring a window for the potential of widespread severe towards that 5/9-5/10 (roughly) period (which was signaled on the analog data if you remember).

The 12z GFS does develop a blocking ridge in the NW USA, which forcing over the IO favors; but, the positioning makes more sense on the ECMWF, per MJO climatology. Ultimately, the GFS does retrograde the blocking post-truncation. Clearly, the tropical forcing is playing a major role here in the timing.

My guess is that a middle ground scenario is the best approach. The KW will likely produce a favorable pattern (SW trough) ahead of something more substantial 5/15-20 as forcing consolidates over the eastern IO/Indonesia sector mid to late May.

 

Always love your mid-long range thoughts. Staying optimistic for our trip. 

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andyhb

andyhb

Posted
Posted

The 12z GFS does develop a blocking ridge in the NW USA, which forcing over the IO favors; but, the positioning makes more sense on the ECMWF, per MJO climatology. Ultimately, the GFS does retrograde the blocking post-truncation. Clearly, the tropical forcing is playing a major role here in the timing.

 

00z GFS builds that ridge and basically keeps it in place for the entire run (which doesn't go out to the period you are suggesting could get interesting, but needless to say there'd be a lot of things riding on that period should this take place).

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