04/21/05 FCST: Central/Southern Plains

[John Farley]

I am planning on targeting an area farther east in Missouri, tentatively around Hermann or Union. This is partly a matter of how far I can drive in the time I have, as well as a desire to avoid the poor chase terrain in SW MO (though the Union area ain't so great in that regard either), but also based on the decent helicity (especially in the lower levels) along the warm front across central MO. This shows up on both the RUC and NAM models, though NAM has it a little farther north (which would be better in terms of chase terrain, but I suspect that, using more current data, the RUC may be more accurate on the frontal position). I do think that if a storm can ride along the warm front toward the SE or ESE, it may be able to get enough storm-relative helicity to make things interesting. Depending on where the storms develop, crossing the MO river could be an issue in keeping up with the storms, as bridges are limited across central and east-cental MO west of the STL area.

 

[Shane Adams]

RUC keeps surface winds at least southerly if not backed in Missouri, east of the KS border through 0Z. Expect intiation in EC/SE KS-NE OK around 21-22Z. Environment east of initiation should remain favorbale for sups and isolated tornadoes, with the better backed surface winds. Plan is to head to Chanute, wait for intiation, find our storm, and let it chase us east into the better air. This plan of attack is similar to our May 29 chase last year when we targeted west of the juice in anticipation of development, and then flanked the storm east.

Sorry for the "talk" portion towards the end, but forecasts lead to chases in conversation.

 

[Glen Romine]

Well, my first region looks right on track according to SPC:

http://kamala.cod.edu/offs/KWNS/0504211613.acus11.html

Note how the boundary across central - eastern KS is really starting to firm up from EWK-EMP. Pressure fall bullseye near SLN, holding together so far. Would expect another box further south soon.

Glen

 

[Bill Schintler]

RE: Chase target for April 21

Busy today, no time for discussion. A quick look at things - I'm voting for Washington, KS today as a primary chase target - bill

 

[John Sickels]

1700

1700 mesoscale analysis shows cap eroding over eastern Kansas south and east of current tornado watch #175. The sun is out here in Lawrence and wind now steady from the south.

I'd expect a new watch out soon covering topeka, lawrence, down towards Emporia.

 

[Mikey Gribble]

It looks like the best combination of ingredients for tornadic supercells are setting up across SE E central Kansas. I am still liking my starting point of Yates Center. I am expecting storms to initiate along the dryline around 3:30 and am leaving Wichita shortly. Good luck everyone.

 

[Ryan McGinnis]

Looks like initiation might be occuring in both south central Nebraska and just northwest of TWX. You can also see some sort of boundary (outflow?) lifting northeast just to the southwest of TWX on the TWX base reflectivity loop.

You can also see the strong line of CU on the full-res ARM sat shot here (warning Dialup, very very large image):

http://www.cira.colostate.edu/Special/Curr...Wx/g12arm10.asp

 

[Glen Romine]

Promising new convection developing near Westmoreland KS. Looks yummy, great environment - hope some of the KC/Manhattan crowd can get on it.


[edit]Ack! Put this is in the wrong thread. Guess I should add more detail. Environment around this developing new convection characterized by MLCAPE approcing 2500 J/Kg, effective shear near 40 knots and . With 0-3km CAPE values at 75 and rapidly rising, along with surface boundary vorticity associated with remnant outflow boundary yeilding effective helicity > 100, so convection developing in the Above noted region should have a favorable environment for storm rotation. Early radar estimated cell motions is NNE, but should turn more ENE with time.[/edit]

Glen

 

[George Flickinger]

If I were chasing, I would target Emporia as a starting point...GF

 

[Ryan McGinnis]

Definately initiation northwest of TWX. Tops now to *edit* 40,000. It's the only storm around in its area and it has backing winds to the east. (LLJ is pretty pathetic today, given what it was progged by the NAM). If I were in Lawrence, which is my virtual chase target today, I'd be driving west a bit right now to get closer to the initiation area.

That said, I'm armchair chasing from Lincoln, NE today. Looking at the sat shot and the line of CU marching this way, I'm thinking it's going to be a lot more interesting day here than I thought it would be when I checked the RUC this morning.

 

[Anthony Silver]

For all who have target areas in east central KS and W Central MO, Heads up, the SPC is about to issue a new tornado watch which will cover those areas. Just read the most recent MD issued by the SPC, shear profiles are becoming increasingly favorable for tornadic supercell development along the warm front.

 

[Glen Romine]

From the KEAX radar, clearly indicated boundary running along to just north of I-70 through MO, arcing north across the KC metro and up the MO river valley. Air mass north/east of this boundar characterized by much cooler conditions as well as backed surface flow. Cells crossing nearly perpindicular with boundary may briefly benefit before becoming elevated. Further south, newer convection may be able to remain along boundary for greater period of time - however current southern extent of convection may clip right along this boundary - giving an enhanced tornado potential next few hours from Atchinson, Platte to Clay counties in MO.

[edit]Further south, flow remains backed across a modest portion of ne OK to se KS - where additional convective development is again trying to get its act together per vis sat. Minimal tornado threat could develop with convection as LLJ intensifies this evening.[/edit]

Glen

 

[Shane Adams]

I've had some questions about how I came up with my target of Chanute, KS on this day. Seems many veterans have analyzed the situation from that day's data and cannot find the "mesolow/DL buldge/surface low "thingy" I based my target on. I went digging and found perhaps the most credible post that mentiones this "thingy" I was seeing. I don't pretend to know meteorology or terms therin. However Glen does know his stuff. So here's a snippet from one of his posts regarding the anomoli I based my target on. Maybe his explanation/analysis will make sense of this to all of you who've had questions. At the very least, it will show I'm not the only one who was seeing it that day.

Originally posted by Glen Romine
So, where to target? Earliest surface based convection appears will be across southern NE /n KS where convergence cumulus field is already starting to firm up. As the surface low strengthens later today, expect the wind fields to improve some across southern NE. So, there is a definite target potential in there from say HJH-STJ. Next, is the feature/low across southcentral KS right now - that is also very poorly handled in the models. Extrapolation has this drifting to between HHT and SLN, with very moist conditions to the southeast, and locally backed winds to the east, so if there is adequate convergence to get a storm this might be the big mutha of the day. Just follow the bullseye of moisture convergence.