Severe Weather Outbreak (Jan 29-30, 2013)

[Eric]

An update on my thinking based on reviewing some 12z data...

I'm more confident now that 70+ will be attained in Memphis at least Tuesday, and possibly Monday as well. If there is sufficient sun on Tuesday I would not rule out as high as 75 and that would well exceed the record (Tue record is a mere 72).

As far as severe weather, the main model spread I see revolves around the timing of certain features...which may impact areas that end up under the threat of strong to severe storms. Either situation brings a threat, however, to some people. Not saying this is shaping up to be an outbreak by any means and all the normal caveats that are present several days out are there.

That said...just because there isn't a powerhouse, consolidated SLP or massive dynamical forcing doesn't mean it's time to back off. Most like to look for that in their severe weather threats...and we've seen where that's ended us up over the last year. I like to look for the subtle signals and for this potential event...I see a few that makes me intrigued. We shall see how models trend over the weekend...

ETA: I should note right now TN is not necessarily in that "target" area for severe weather. If so...it would most likely be W TN. As noted earlier...my main area of interest is a bit further west of the state.

Isn't it true that one only needs a "ripple" in the H5 flow to enhance/initiate organized convection?

[andyhb]

Isn't it true that one only needs a "ripple" in the H5 flow to enhance/initiate organized convection?

Pretty much, it can be subtle little shortwaves like that within the mean flow that can lead to intensification of storms over a localized area...there is a rather long list of events that have featured these types of anomalies.

[andyhb]

Impressive looking analog severe report map from the CIPS Cold Season guidance via the 12z GFS at 120 hrs.

Highslide Image Viewer

[Archiver Bot]

Impressive looking analog severe report map from the CIPS Cold Season guidance via the 12z GFS at 120 hrs.

Highslide Image Viewer

I believe that's the second time now (that you've posted about at least!) its triggered 2/5/08? Didn't work out so well the first...  

[andyhb]

I believe that's the second time now (that you've posted about at least!) its triggered 2/5/08? Didn't work out so well the first...  

It also triggered the Enterprise/Americus outbreak for 2/28-3/1, 2007.

The first time I posted the 2/5/08 thing, btw, was not very serious..

[Archiver Bot]

It also triggered the Enterprise/Americus outbreak for 2/28-3/1, 2007.

Which is equally excessive. I'm on the side of some severe weather for this system but I can't pay attention to an analog model that gave the very same output (a very bold one at that) mere weeks ago and massively failed...

The first time I posted the 2/5/08 thing, btw, was not very serious..

Of course...but it doesn't make the actual model more reliable right now...

[andyhb]

Which is equally excessive. I'm on the side of some severe weather for this system but I can't pay attention to an analog model that gave the very same output (a very bold one at that) mere weeks ago and massively failed...

Of course...but it doesn't make the actual model more reliable right now...

Knowing when to take it with a grain of salt and when to take it with ocean-sized deposits of minerals is where I'm leaning with this, not trying to get into an argument.  ::shrug::

[Archiver Bot]

Knowing when to take it with the grain of salt and when to take it with ocean-sized deposits of minerals is where I'm leaning with this, not trying to get into an argument.  ::shrug::

LOL. Not getting into an argument...you should have just said that from the start then instead of without context.

[Bruce]

i do like the timing of this event as of now, course things will change... but looks like late afternoon west of here, into early evening for most of west tennessee, kind of like the 2 05 08 system on super tuesday... not comparing events. just time wise

[Archiver Bot]

Early look at the 0z GFS remains consistent with its 12z run...in suggesting a legitimate severe threat centered about the state of AR Tuesday afternoon/evening...potentially sweeping east overnight (possibly parts of TN) as a QLCS-type system as linear forcing increases.

The same uncertainties continue...however. Those not surprisingly are the degree of instability that will depend on the amount of cloud cover and mid-level dry air present, etc. The GFS is a bit prohibitive on that front but the overall synoptic look of the system remains intriguing enough while not overwhelmingly powerful...which again IMO can be a bit more concerning with a cool-season system.

[Archiver Bot]

The more I look at the 00z GFS...the more I do become concerned about its solution should it verify. All the tell-tale synoptic indicators I'm looking for in higher-end cool season events are there...with the only possible questions in the thermodynamics (which its too soon to make a call either way but this is the type of system that best equipped to overcome such weaknesses).

While there's plenty of room for less serious solutions to verify...including some ongoing model data already out there...folks should be paying attention to this one as shifts could put the state more directly in a threat. I would advise putting any of the winter weather hopes and discussions aside for now...

[Thundersnow]

We'll be paying attention here.

[Archiver Bot]

The 00z ECMWF remains a weaker solution overall...while still supportive of some severe threat...but also took a big step in moving toward the GFS in eliminating its cut-off low scenario and moving toward a larger, broader based H5 trough. Lower-level and surface features will keep some model spread alive, however, for now.

Again...both models are supportive of severe weather but the 0z GFS's trend was toward better support of something more notable and concerning...and also noting the 0z ECMWF was a trend toward it. Also worth noting the GFS has support of the GGEM as well.

I fully expect SPC to put its risk area back on its morning Day 4-8...about where it was previously. If they don't...I've really lost faith in them.

[andyhb]

The more I look at the 00z GFS...the more I do become concerned about its solution should it verify. All the tell-tale synoptic indicators I'm looking for in higher-end cool season events are there...with the only possible questions in the thermodynamics (which its too soon to make a call either way but this is the type of system that best equipped to overcome such weaknesses).

While there's plenty of room for less serious solutions to verify...including some ongoing model data already out there...folks should be paying attention to this one as shifts could put the state more directly in a threat. I would advise putting any of the winter weather hopes and discussions aside for now...

Sorry for getting a bit frisky earlier.

But yes, I would agree with all of this, to a t.

[Archiver Bot]

Sorry for getting a bit frisky earlier.

But yes, I would agree with all of this, to a t.

Not a problem. I was more pointing out the model/analog than you...so I should have clarified I wasn't directing my comments toward you at all really.

Of course...I'd be lying if I didn't say a verification of the 0z GFS would make the CIPS much more realistic this go-around than last...keeping in mind to all that it's impossible and thus futile to make such comparisons to specific past events at this juncture.

All of you know me...I'm not going to get you concerned if there's no need to be. There's beginning to be some need this time. Plenty of time to back off if needed later.