History Question: What became of Lid Analysis?

[gdlewen]

This is more of a history question, but after 2007 or so there seem to be no references in the literature to lid analysis of sounding data, as described in Carlson, T., and Farrell R. J. , 1983: The lid strength index as an aid in predicting severe local storms. Natl. Wea. Dig., 8 (2) 27–39. (As well as others by Carlson and his students/colleagues in the mid-late 80's and early 90's.)

Was the technique found to be too difficult to implement operationally? unreliable? or perhaps superseded by the continued development of numerical weather prediction models?

I'm not sure if Stormtrack is the best forum for posting a question like this. Before their demise, WX-TALK or WX-CHASE would have been the best targets. (Hopefully, maybe someone here on Stormtrack can recommend a forum for this question if this is not a good venue.)

Many Thanks.

 

[rdale]

Here's some history...

Lid Strength Index

Skip, thanks for your analysis. Would you mind sharing a link for the lid strength index you use? And could you explain how it is different from, and advantageous to, simply looking at 700mb temps? Thanks! Sent from my iPad using Tapatalk HD

stormtrack.org

Basically many of these indices (K, LI, etc.) were developed when you had limited soundings and VERY limited model soundings. They were "shortcuts" that are now no longer relevant given the current analysis abilities.

 

[gdlewen]

Here's some history...

Lid Strength Index

Skip, thanks for your analysis. Would you mind sharing a link for the lid strength index you use? And could you explain how it is different from, and advantageous to, simply looking at 700mb temps? Thanks! Sent from my iPad using Tapatalk HD

stormtrack.org

Basically many of these indices (K, LI, etc.) were developed when you had limited soundings and VERY limited model soundings. They were "shortcuts" that are now no longer relevant given the current analysis abilities.

rdale, many thanks for your response. I would expect that, when a technique like this doesn't catch on, there's a reason. From your reasoning I can certainly understand why it would not be in use today. Personally, I find the full technique of lid analysis (i.e. classifying a sounding as Lid, Capped-EML, etc.) very interesting. For example: as used below in Figure 5 from Farrell, R. J., & Carlson, T. N. (1989). Evidence for the Role of the Lid and Underunning in an Outbreak of Tornadic Thunderstorms, Monthly Weather Review, 117(4), 857-871.)

Given the quality of current model performance, my question about an analysis scheme from the 80's must seem frivolous, so I appreciate your taking the time to respond.
.

 

[rdale]

No problem! And it's not there there is NO value in it - I still see AFDs with "K Index" in them. It's just that when you get ready for a mesoscale analysis, they really don't offer muchj.

 

[Bill Barlow]

Models still have difficulty with areas of strong CINH, especially the HRRR. They tend to erode it much too fast resulting in widespread convection when the visible satellite shows mushy cumulus being suppressed under the strong cap. This was very evident when I worked at the AWC forecasting convection. Models have gotten better at not eroding the cap when strong CINH (say -200 J/kg or higher) is observed on soundings but you still have to take them with a grain of salt if there is not a decent triggering mechanism to break the cap.

Indicies like the K are still used, especially in the western US where the 700Mb temp/dew point spread is important given the higher elevations, higher LCL/LFC's and more frequent inverted-V type storm environments. Don't retire them yet.

 

[gdlewen]

This is related to my question about "Lid Analysis", so rather than create a new discussion topic, it seems reasonable to post it here. Sort of a survey question.

In the figure below: EML Sounding? or not an EML Sounding?



I'm interested in the reasoning for your conclusion. (Note: the brown dashed-line is just an estimate of the PBL based on the sounding, and the orange curve is the parcel profile through the Convective Condensation Level.) As always, I appreciate folks in this group taking the time to reply and help me learn.