Central/Western Medium-Long Range Discussion

[raindancewx]

I haven't looked at the impacts in other areas, but the July-June year looks like it is going to average ~29 sunspots per month for 2016-17. We're likely in the first of six low solar years. Here in Albuquerque, we're four times more likely (34% v. 9%) to get a winter with mean highs 2F or more below average when July-June sunspots are below 55 annually. The last era for similar activity was 2005-06 to 2010-11. Right on schedule..with 2016-17 as the first "low sunspot" year. The last min was 2008-09 (centered right around Jan 1 2009), so presumably the next min in 2019-20.

Expecting two of the next five winters to be 2F or more below the long term mean high which is 49.5F. When our mean high is <=47.5F here (-2F), we have about a 60% higher than usual shot at seeing more snow than average from Oct-May.

[bjc0303]

Looks like for the most part the next 10-14 days are going to be pretty darn quiet over the southern and central plains, given large scale ridging over west/central states. 

 

A return to a more favorable pattern for severe weather seems more likely after that, with some signal of a pattern change. AAM will remain low, but will build up magnitude into the 1 and 2 phase spaces, associated with enhanced potential for tornado days. Ensembles do not show a strong signal yeto, although operational models do show breakdown of the ridging, even though it means nearly nothing at its current range. GEFS forecast of AAM: 

[WhiteoutWX]

1 hour ago, bjc0303 said:

Looks like for the most part the next 10-14 days are going to be pretty darn quiet over the southern and central plains, given large scale ridging over west/central states. 

 

A return to a more favorable pattern for severe weather seems more likely after that, with some signal of a pattern change. AAM will remain low, but will build up magnitude into the 1 and 2 phase spaces, associated with enhanced potential for tornado days. Ensembles do not show a strong signal yeto, although operational models do show breakdown of the ridging, even though it means nearly nothing at its current range. GEFS forecast of AAM: 

Do you have an explanation or a link to one that describes how the AAM affects tornado potential? I am unfamiliar with this forecasting technique. 

[bjc0303]

44 minutes ago, WhiteoutWX said:

Do you have an explanation or a link to one that describes how the AAM affects tornado potential? I am unfamiliar with this forecasting technique. 

https://ams.confex.com/ams/28SLS/webprogram/meeting.html#Friday1

 

Look for "tornado frequency in the US related to the Global Wind Oscillation" and watch Gensini's recorded presentation for more information.

[WhiteoutWX]

39 minutes ago, bjc0303 said:

https://ams.confex.com/ams/28SLS/webprogram/meeting.html#Friday1

 

Look for "tornado frequency in the US related to the Global Wind Oscillation" and watch Gensini's recorded presentation for more information.

Fascinating stuff. That might be one of the most promising long range predictors of tornado potential I've seen before, at least looking at historical correlations. However the tricky part is getting accurate forecasts of the AAM. Phases 8,1,2 look the best for central U.S. potential, with 1 being the top of those.

[bjc0303]

1 minute ago, WhiteoutWX said:

Fascinating stuff. That might be one of the most promising long range predictors of tornado potential I've seen before. 

Indeed; I would agree. Accounts for MJO and other influences as he mentioned. I recall seeing forecasts of GWO entering the phase 1/2 space about 14 days or more before the big outbreak Feb 28, of course there are gonna be pitfalls since severe weather events depend heavily on mesoscale factors that this method cannot account for (large MCS wiping out a warm sector, for example)... But it at least gives clues into the large scale pattern/base state for severe weather.

 

Even now, if you look at the deterministic GFS, there are hints that an extension of the NP jet will make its way to the west coast, and the ridge breaking down in response. Also, Gensini and others produce 2 and 3 week outlooks/forecasts for enhanced tornado activity (link: http://weather.cod.edu/~vgensini/ertaf/)

Not sure what they look at in total when making their forecasts, but they agree: "Dynamic models show large amounts of noise for the week 3 period. The current thinking is that a more coherent signal may emerge by week 3 that features a NPJ extension that will need to be monitored. When/if this process occurs, it should lead to a favorable pattern for severe convective storms. This could happen as early as the end of week 3, but likely beyond. Many seasonal climate signals continue to point toward an active base state for severe convective storms. "

 

Next week looks pretty dormant severe weather wise with a western ridge in place, but that looks like it will break down around the 21st or so. Obviously the operational models are inherently super inaccurate this far out but the GFS continues to advertise the breakdown of the ridge and even shows the extension of the mentioned jet into the west coast. We will see. Ensembles have yet to totally show any significant changes/signals for western US troughing.

[WhiteoutWX]

6 hours ago, bjc0303 said:

Indeed; I would agree. Accounts for MJO and other influences as he mentioned. I recall seeing forecasts of GWO entering the phase 1/2 space about 14 days or more before the big outbreak Feb 28, of course there are gonna be pitfalls since severe weather events depend heavily on mesoscale factors that this method cannot account for (large MCS wiping out a warm sector, for example)... But it at least gives clues into the large scale pattern/base state for severe weather.

 

Even now, if you look at the deterministic GFS, there are hints that an extension of the NP jet will make its way to the west coast, and the ridge breaking down in response. Also, Gensini and others produce 2 and 3 week outlooks/forecasts for enhanced tornado activity (link: http://weather.cod.edu/~vgensini/ertaf/)

Not sure what they look at in total when making their forecasts, but they agree: "Dynamic models show large amounts of noise for the week 3 period. The current thinking is that a more coherent signal may emerge by week 3 that features a NPJ extension that will need to be monitored. When/if this process occurs, it should lead to a favorable pattern for severe convective storms. This could happen as early as the end of week 3, but likely beyond. Many seasonal climate signals continue to point toward an active base state for severe convective storms. "

 

Next week looks pretty dormant severe weather wise with a western ridge in place, but that looks like it will break down around the 21st or so. Obviously the operational models are inherently super inaccurate this far out but the GFS continues to advertise the breakdown of the ridge and even shows the extension of the mentioned jet into the west coast. We will see. Ensembles have yet to totally show any significant changes/signals for western US troughing.

Awesome stuff thanks for the info!

[bjc0303]

Wish I could post latest ECMWF ensemble run.

Shows mean west troughing evolving around 22nd or so. We will see.

[jojo762]

GFS seems to like the idea of an interesting system sometime around the 21st through the 23rd time frame across KS and the southern plains. Days of a relatively open GOM before hand would lead me to believe that moisture should not be too much of an issue. Biggest problem will probably be timing, as well as the potential for showers and crapvection in the warm sector. 

[bjc0303]

31 minutes ago, jojo762 said:

GFS seems to like the idea of an interesting system sometime around the 21st through the 23rd time frame across KS and the southern plains. Days of a relatively open GOM before hand would lead me to believe that moisture should not be too much of an issue. Biggest problem will probably be timing, as well as the potential for showers and crapvection in the warm sector. 

Timing looks okay, but timing and any early shower/elevated convection concerns aren't even worth addressing right now. 

[bjc0303]

Feeling pretty confident we are going to see a few severe events evolve over the next several weeks, starting somewhere around mid/late next week. 

Certainly next week could get interesting. 

[Stebo]

17 hours ago, jojo762 said:

GFS seems to like the idea of an interesting system sometime around the 21st through the 23rd time frame across KS and the southern plains. Days of a relatively open GOM before hand would lead me to believe that moisture should not be too much of an issue. Biggest problem will probably be timing, as well as the potential for showers and crapvection in the warm sector. 

I wouldn't worry about that detail, we are still several days out. 

[jojo762]

7 hours ago, bjc0303 said:

Feeling pretty confident we are going to see a few severe events evolve over the next several weeks, starting somewhere around mid/late next week. 

Certainly next week could get interesting. 

The fact that the GOM will be open (at least the western half), and that we will we have southerly surface flow for days in advance is exciting... Still way too far out to determine very many details of any potential trough(s) though. Not a big fan of that H85 high that the GFS and Euro are showing over the western and north-central GOM though. 

[bjc0303]

2017031300 euro weeklies are.... let me say... very exciting  

[SluggerWx]

Last couple days the GFS is picking up on substantial instability Sunday afternoon/evening in S. KS / N. OK. It actually hinted at this area about a week ago for right around this time frame before vanishing for about 5 days. Back again.

[bjc0303]

1 hour ago, SluggerWx said:

Last couple days the GFS is picking up on substantial instability Sunday afternoon/evening in S. KS / N. OK. It actually hinted at this area about a week ago for right around this time frame before vanishing for about 5 days. Back again.

Strong capping 

[jojo762]

Excerpt from D4-8 outlook: 

By Thu/D8, the trough and surface cyclone are forecast to deepen
   further, and at this point, appear to hold the greatest risk for
   severe weather. Moisture and instability will be a bit better than
   on the previous day, and the ECMWF shows a classic deep cyclone
   favoring all modes of severe weather, including tornadoes. However,
   predictability is low at D8, especially considering the current
   level of run-to-run model consistency. Thus, will defer to later
   outlooks for potential areas, which may eventually include the
   central and southern Plains, as well as the Missouri and mid
   Mississippi valleys.

[bjc0303]

I've honestly already lost interest in this upcoming week's days of potential. Wednesday would be ideal for me but moisture doesn't look like it will happen. Thursday is too far east and my schedule doesn't allow for a Thursday chase anyway.

There may be bigger things in store the week after, however.

[jojo762]

00Z GFS is highly volatile along and east of the I-35 corridor next Thursday in S KS into OK. Both deep-layer and low-level shear are very impressive, instability is more than adequate, and moisture is probably doable, not to mention that it develops numerous what I assume would be discrete supercells along much of the dryline. Not too sold on what the GFS is showing moisture wise though with DPs barely reaching 60 along a lot of the dry line. Guess a lot of that will depend on overnight/previous day moisture transport and how far the boundary earlier in the week dives south. 

 

00Z euro is slower than the GFS and much further west with the DL, but also very impressive from what I can tell... should be a fun ride building up to this... impressive seven days out for a march system. 

[nwburbschaser]

The upcoming period should be rather active, and I wouldn't be surprised to see a decent event come from it at some point. With that being said, I wouldn't get into too many details with the system next week. It has potential, but it also has moisture concerns written all over it.

If we get into a period of somewhat prolonged western troughing then I wouldnt mind having that first system prime the moisture pump for something bigger to follow it. 

[bjc0303]

Likely to see a pretty active pattern indeed. we will see how it pans out. The pattern overall will be active but strong frontal intrusions in the wake of these high amplitude systems is going to be an issue. I like what the euro is showing however.. esp Friday and into the weekend

[nwburbschaser]

3 hours ago, bjc0303 said:

Likely to see a pretty active pattern indeed. we will see how it pans out. The pattern overall will be active but strong frontal intrusions in the wake of these high amplitude systems is going to be an issue. I like what the euro is showing however.. esp Friday and into the weekend

This might be key going forward. I'm hoping one of these systems can be a sacrificial lamb and get the moisture flowing without sweeping it back out in its wake. 

[bjc0303]

6 minutes ago, nwburbschaser said:

This might be key going forward. I'm hoping one of these systems can be a sacrificial lamb and get the moisture flowing without sweeping it back out in its wake. 

EPS shows some promise of perhaps something with better moisture return from a  large scale perspective laaaaatee in the forecast cycle... but even tho it's an ensemble mean, being so far out there (300+) it could vanish on any run.

[brettjrob]

Bleh. Everything out through D+10 looks like the wavelengths are too short for anything big. Nothing unusual this early, but it sure has been awhile since we saw a half decent March setup in the southern Plains (3/18/12, perhaps?). At least there are some indications of a continued favorable base state heading into the beginning of April.

[bjc0303]

1 hour ago, brettjrob said:

Bleh. Everything out through D+10 looks like the wavelengths are too short for anything big. Nothing unusual this early, but it sure has been awhile since we saw a half decent March setup in the southern Plains (3/18/12, perhaps?). At least there are some indications of a continued favorable base state heading into the beginning of April.

Well it's not like climo favors anything nice terrain wise. we'll get there. 

Besides deterministic models, as you know, change pretty quickly. I'm not really holding out for anything big until farther down the line...maybe very end of March or early April. I think many expect an average-slightly AA season. 

[bjc0303]

Great example... last 4-6 runs of the GFS (maybe more) wiped out e gulf in the wake of the thurs/Fri system. now the frontal push stalls out around gulf Coast. 

[Jim Martin]

So, the Storm Prediction Center now has Eastern Oklahoma and Northeast Texas for a severe weather risk for Friday (3/24).

[David Reimer]

It'll Ben interesting to see what impact, if any, the very warm GOM SSTs have on moisture return. 

[Quincy]

It's still a long way out, but have to wonder if Thursday may feature an early season west-of-I-35 threat from the Texas panhandle into the central Plains. Wind fields strengthen ahead of a trough ejecting east from the Desert Southwest. Even the Euro shows an area of mid to upper 50s dews with convective precip ahead of a dryline. The quality of moisture return appears to be the biggest question at this stage. Friday seems like the best threat day at this point, especially if models slow down a bit more as they already have over the past few days. 

[bjc0303]

13 hours ago, Quincy said:

It's still a long way out, but have to wonder if Thursday may feature an early season west-of-I-35 threat from the Texas panhandle into the central Plains. Wind fields strengthen ahead of a trough ejecting east from the Desert Southwest. Even the Euro shows an area of mid to upper 50s dews with convective precip ahead of a dryline. The quality of moisture return appears to be the biggest question at this stage. Friday seems like the best threat day at this point, especially if models slow down a bit more as they already have over the past few days. 

climatology, namely moisture return, doesn't seem to support this. Storm potential remains uncertain for this reason (forecast instability is extremely narrow and limited).

 

Focus shifts to the potential down the road, at least for this subforum. What happens in the wake of the upcoming system will largely determine the impact/potential of the next one. Late in the month (or early April) is where the signs seem to be pointing however.. And remarkably GWO/AAM GEFS forecasts seem to remain in favorable phase space for severe through the entire forecast period.

 

Edit: the first part of my post referenced Thursday. Friday could pan out, but the wind fields, upper jet structure, etc all suggest a line of storms type of event to me. Nothing impressive...yet