Chase Case #10

This day may or may have not had tornadoes or severe weather

18z data will be avaliable at 5p.m. and the chase will occur tonight. Please don't guess the date until everyone has had a chance to adjust their targets with the 18z data.

NOTE: Make sure to adjust your anaylsis as previous charts were an anaylsis from the RUC but not actual plotted sounding data.

Enjoy!







KABR- http://img308.imageshack.us/img308/6549/75pz.gif
KRAP- http://img246.imageshack.us/img246/1522/84rm.gif
KDNR- http://img246.imageshack.us/img246/306/104qd.gif
KLBF- http://img307.imageshack.us/img307/548/112gk.gif
KGRB- http://img307.imageshack.us/img307/584/120ms.gif
KDVN- http://img307.imageshack.us/img307/4253/139xv.gif
KOAX- http://img307.imageshack.us/img307/6081/148da.gif
KTOP- http://img307.imageshack.us/img307/6426/152cm.gif
KDDC- http://img307.imageshack.us/img307/1958/160na.gif
KILX- http://img432.imageshack.us/img432/4816/175mg.gif
KBIS- http://img432.imageshack.us/img432/2511/185sl.gif
 
the two surface obs you gave are not matching. IL has temps in the 80's and the other one says 60's for example, and they are supposed to be 12z time frame right? Am i missing somthing here
 
[I'm assuming the bottom SA is the right one for 12Z because it covers where I'd want to be anyway.]

Holy moley! 66 dew in Lamar, 68 in Goodland!?? The DDC and LBF soundings are outta sight! Hmm. I think I'll target Peoria, IL.... :)

Noooo.... I think I'll go to North Platte, NE, where the upper environment is a little better, and be prepared to go north, east, south, or west.
 
hmmm ... zonal pattern ... looks like two possibilities in my mind are in western Nebraska or in southwest Wisconsin at the time being. For now I think I'll pick Wisconsin for some dairy country chasing.

EDIT - good grief ... does that OAX sounding show L.I. at -18? ... Something looks like it's about to explode ... I definitely need to re-think this ... wish I had more time to devote to it. The Missouri River valley just looks primed for something now to me, so I'm going to call Sioux City, Iowa as my first official target.
 
good grief ... does that OAX sounding show L.I. at -18? ...

Nope, -1.8C :lol:

LOL - thanks for bringing me back to reality. I still like the wind there, so until that target gets officially rejected as a possibility I guess I'll just stay with it .... goodnight Olson, props on picking the tough forecast days.
 
I'm heading to York, Nebraska for this one based on the 12Z data. Realistically, I would probably never drive this far for a chase (especially such a tough forecast with the zonal flow at UL). The LBF sounding shows a pretty stout cap but the best shear environment is located slightly downstream at Omaha and LL warm advection should help to weaken that cap slightly. The thunderstorms currently rolling into western Iowa look like they may have put down an OFB as well.

Good case, Scott!
 
Well, wind profiles really look good on most of the soundings, and good SFC moisture seems to be the standard across most of the area... A SFC low exists across southwestern NE with a decent dryline extending southward from that point. A weak warm front also appears to be situated from the SFC low eastward into MI...

But... I REALLY don't like the weak lapse rates seen on almost all of the soundings, and the massive mid level thermal ridge spreading into the region. That to me would spell trouble for any widespread convection... Also, there doesn't really appear to be any significant upper level support. The main shortwave is way over in the northwestern portion of the US, and we are left to rely only on a weak warm front and decent dryline to overcome a very strong CAP.

Right now, I will call the area around DVN "home" since it's farthest away from the low to mid level thermal axis, and there is a nice little dip in the 500MB temps. Also, I would expect the decent shear found that is located a bit further west to advect into the region later in the day.

Overall though, I'm VERY close to calling this a bust day.
 
Doesn't look like the soundings are for the same day as the charts above. Compare the raw values at the height levels, and they don't seem to match. Please recheck the sounding dates that you collected Scott.

Glen
 
Doesn't look like the soundings are for the same day as the charts above. Compare the raw values at the height levels, and they don't seem to match. Please recheck the sounding dates that you collected Scott.

Glen

Nope, they are the same. All matched up re-checked with date, im doing some comparsion with other charts to to try and identify similarities differences.
 
Doesn't look like the soundings are for the same day as the charts above. Compare the raw values at the height levels, and they don't seem to match. Please recheck the sounding dates that you collected Scott.

Glen

Nope, they are the same.

I think I see what Glen's saying... For example, according to the RAOBs, the hieghts at LBF at 300mb, 500mb, 700mb, and 850mb are 9590m, 5840m, 3093m, and 1420m. On the upper-air charts, however, these heights (respectively) are given as 9590m, 5800m, 3080m, and 1450m. In addition, the 300mb temp at LBF is given on the RAOB to be about -36/-37, while the 300mb chart yields -34.
 
I see a broad area of interest from western KS to north central NE. It appears the moisture has mixed deep and pooled in the north and remains pretty shallow in KS. It would also appear that western KS and most of western NE might be capped. Even with these negatives there may still be enough juice to get things rolling on the high plains. But, I also think things could be primed for a good north central NE s-se mover. So this morning I’ll head out to Valentine and check data there. I’ll still have a chance to shoot sw if things start looking better under the cap. Will have to grab a breakfast burrito to go, as we have many miles to travel!
 
Yeah - actually it looks like the contours on the plots might be ok - but the 'data' overlayed on the plots is totally different from the soundings and from the contours. Maybe there is an error in the plotting program that generated the maps, but either way something is seriously wrong and makes it really tough to use the images provided since you aren't sure what to believe. I hate to suggest it - but you may want to either replace the pressure surface maps with some from a different source, or pick a different case with clean maps.

Glen
 
Okay, it looks like the charts are bad (soundings are good) New charts in twenty minutes. :)

I compared some features with a different set of charts and it looks good. Though if you guys find a lot of problems with the new ones let me know and we will start over.

-Scott.
 
Okay, it looks like the charts are bad (soundings are good) New charts in twenty minutes. :)

great ... if you cause me to miss a tornado I'm going to charge you for gas ...

hehe ... no rush ... I have a feeling the new charts won't make a tremendous impact in the difficulty.
 
These new charts look much better, so now that everything is squared away and we have verified our data let's get some targets.

Mike if you need some gas just send your receipt and a letter requesting reimbursement to:

Attn: Executive Officer Rex Tillerson
Exxon-Mobil
5959 Las Colinas Blvd. Irving, TX




LOL,
Scott.
 
Well Scott, this one appears even tougher than the last one when verifying a Bust/No Bust day.

Current analysis of the situation has already done, so I'll skip that. Wide range of interest from central KS, up through NE, IA, and MO. I'm worried about the lack of forcing, with mentioned primary short wave being well out of targeted zone - as well as the numerous amount of soundings with poor lapse rate near moist adiabatic.

Being unable to ignore the DDC sounding for fear of isolated convection, I'm going to leave myself with good options to push in numerous directions - with a bias towards to the North/Northeast.

Target as of 12Z: St. Joseph, MO - with good options to dart into central KS should initiation commence, as well as options to head up I-29 or I-35 into SE Nebraska or Southern Iowa.
 
Target as of 12Z: St. Joseph, MO - with good options to dart into central KS should initiation commence, as well as options to head up I-29 or I-35 into SE Nebraska or Southern Iowa.

I'm glad you saw this ... I had a question in my mind about STJ after looking at that last map ... forcing is definitely the big question - hard to pinpoint where the kinks in the system will come from when the air is sailing smoothly along in a zonal regime. My biggest concern down in Missouri was the capping, though ... so it's hard to know what to do ... plus I still like the wind further north ... ugh ... this one has me as indecisive as I usually am in an actual chase day scenario.
 
Definitly agree with you Mike on the indecisiveness with this 12Z data. I don't really see anything happening in MO at this time, but wanted to keep some southern positioning just in case some isolated supercells spawn in KS.

Kansas City, MO seemed too far south putting me behind on the northern game. I'm leaning towards a Northern push at the current time, but who knows what the 18Z data will hold :D .
 
Now the upper charts are right, but I lost the surface chart. Darn computer.... Ah, well based on the new 12Z charts, from what I recall of the SA I want to be northeast of where I am. Adjusted target is Oneill, NE.
 
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