4/4/09 FCST: TX/OK/KS

[Dustin Wilcox]

Once again I really like the looks of the Meso-ETA, in fact it bulls-eyes my new home. Everything I look for in a low-topped sup event looks to co-exist across SE NE. Mid 50 dews (53-55) seem reasonable, with 1000 j/kg SBCAPE across the region by 21Z, better yet a really nice 0-3km CAPE bullseye. LI's reach -8, great low level turning with 0-1km helicity values >300 m/s^2, what I like is the wave/vort max doesn't eject across the region until mid evening (per 13km) allowing things to hold off and giving the moisture time to advect. Another thing that I personally like is unlike many setups similar to this, we don't have the insane midlevel flow, just a solid 50-60kts plenty to get things turning, but not to much that it'll rip things apart. If this run verified I'll chase down here Saturday evening and then head North for the Blizzard, throw in my annual alumni tournament and all that goes with that this could be a fun weekend, Tornadoes, Basketball, Beer and a blizzard, then again its just an off hour run so I might have to make do without all of them...

 

[Jared Farrer]

I think this setup has better shear and even a better shear to instability ratio as compared to March 23rd. I am likeing the last model run, moisture looks a tad bit better. It looks like it will be later in the evening, with possibly a smaller window for success before dark and before a line breaks out.

 

[Derrick Herndon]

Well I had given up on this setup (and I was planning to be more aggressive this season) mainly because I thought moisture would be an issue. But I have to say that the latest NAM run (12Z and 18Z) is compelling. Like others I would settle for dews in the low 50's for this event. That seemed like a stretch but there has been a good amount of precip over KS recently so with some evaporation and sufficient moisture depth this could be a chaseable event. The system is coming ashore now so 00Z run will be interesting.

 

[Jared Farrer]

Well at this point I wouldnt mind being in Beatric, NE tomorrow. It seems there somewhere near the low in the better forecasted instability. With shear being nuts in that area but not over done storm motions should be manageable! I am not an expert on these cold core setups but somewhere along that boundry would probably be nice. Even with the questionable moisture I am not terribly convinced their wont be enough to get the job done. At least one or two decent photo ops should present themselves there! I just wish I lived closer. Given I live 9 hrs from a target in that area it makes driving the 500 miles a little bit tough. But the Lincoln symposium is there so I could come and leave early, if things get to looking a bit better?

Dews for the last system ended up getting up to 68/53 at KS City and 60/53 at around Mitchell!

 

[Chris Allington]

While I do agree that the shear profiles and hodos look pretty amazing for tomorrow I still doubt I will be chasing even though its close. Check out a surface map... the closest you can even find 40s dews is along the Red River Valley and Central AR.

Low 50s dew are just now struggling onto the lower TX coast... .

 

[beaudodson]

Never say never on dew points - we went from lower 30 dew points on Wednesday to upper 50s in a matter of a few hours. Not saying that will happen, however, some of the model data does show a quick return.

 

[Andrew Revering]

I'm actually pretty optimistic compared to everyone else it seems. The cold core scenario looks pretty decent, and perhaps one of the better cold core setups I've seen in some time.

There is a lot of nice mid level dry intrusion which hopefully will keep some good surface heating and relatively clear air before things develop. There's nothing worse than trying to find a cold core tornado amongst a stratus deck of rain. I don't think that should be the case -- so much.

The setup looks great, as with everyone else the concern for me is moisture, however if you look at gridded data you can see that there's a "sand bar" of higher dew points nosing into the low on NAM and GFS. They are in very good alignment. This 'sand bar' gets into the upper 40s which given the low level shear and convergence should be fine for a 'cold core' setup. Whether it's a plus or a minus, on either side of this 'sand bar' you have a drastic drop in dews by about 10 degrees F. This gradient may be helpful.

Most sites are not contouring this moisture well because its such a narrow axis. Contoured data on some sites indicates no better than 30s dew points in this area.

Also, the 00z models have initiated very well with the moisture out there as of 00z. So I'm pretty confident we should be able to get to at least mid 40s dews in a narrow axis. Is that enough??? We'll see. Everything else is in place.

My target is Franklin County, NE (2 counties south of Kearney)... still working out the details but I might make the 8 hour trek from Minneapolis on the outside chance of 1-2 tornadoes out of the whole system.

 

[Jared Farrer]

While I do agree that the shear profiles and hodos look pretty amazing for tomorrow I still doubt I will be chasing even though its close. Check out a surface map... the closest you can even find 40s dews is along the Red River Valley and Central AR.

Low 50s dew are just now struggling onto the lower TX coast... .

Dont count out dews, I have seen dews recover in a 24hr hour period as far north as northern Iowa. And that was checking bouys the night before! With a low as deep as is forecasted I am confident in their being at least a moderate amount by 0z sunday. Its just possible all Im saying.

 

[Chris Hovanic]

50F Tds have reached a Fort Polk, LA to Austin, TX to just south of Uvalde, TX line as of 06z...this is slightly farther north than even the 0z NAM depicted.

Computer model guidance indicates a similar moisture recovery scenario for tonight/tomorrow as compared to this past Monday...dewpoints for that day ended very close to model predictions with a rapid moisture surge verifying.

I'm planning on leaving Kansas City around 10am for either Marysville, KS or Belleville, KS.

50F dewpoints should hopefully support a tornado or two as long as a semi-discrete convective mode persists for a few hours. This is questionable however given the magnitude of large-scale lift in association with the closed 500mb low and potent left exit region of the upper jet streak.

See you out there!

 

[Michael O'Keeffe]

I agree. all the RUC, NAM, and GFS have underdone the moisture so far showing the 50F dews in C Texas by 7am, but looking at the surface obs now the axis of 50F dews is now on the Red River with 48F+ dews into Oklahoma.

With that I think this looks like a TEXTBOOK cold core setup with the plume of steep lapse rates, and position of the low. If the 50F dews can make it which I think will happen then I wouldn't be surprised to see a small tornado event over S NE/far N KS.

 

[Chris Hovanic]

As Michael noted...moisture continues ahead of schedule with mid 40s dewpoints surging toward central Oklahoma.

Potential for a tornado or two later this afternoon/evening seems to be increasing. Hopefully deep-layer shear vectors normal to the dryline will help to maintain a somewhat discrete convective mode despite the magnitude of large-scale lift at play.

 

[Bill Schintler]

Chase Target for today, April 4

Chase target:
Fairbury, NE.

Timing and storm mode:
Storms will develop from west to east across the area after 2 PM CDT, with low-topped supercells likely. A short-lived tornado or two cannot re ruled out, especially between 4 and 5 PM.

Discussion:
H5 analysis indicates a closed low centered over CO with a number of disturbances pin wheeling around the periphery. A 70kt speed max is indicated over central KS while an upstream 90kt streak is racing northeast into the TX and OK panhandle area. At the surface, low pressure is centered west of Garden City, KS; with strongest two-hour pressure falls of -1.5ub located near Fairbury, NE. Dewpoints remain in the 30-35F range, however an area of rapid dewpoint recovery, with a +3 degree F/hr rate, is indicated over eastern KS and is surging NW towards the area. Visible satellite imagery indicates clearing over south and southeastern Nebraska.

Surface low pressure will track E and NE to near Red Cloud, NE by 21Z. A narrow axis of 50-52F SFC dewpoints will surge NW into the area by mid-afternoon along and immediately N of an occluding SFC boundary extending E from the low. ML CAPEs will locally increase to 1000J/kg as the H5 cold-core low tracks E, spreading -20 to -23C mid-level temperatures over the region and steepening lapse rates. SFC-3km hodographs show large clockwise curvatures with SRH of 300-400 m2/s2 just N of the aforementioned boundary. The target is at the triple point of the E/W-oriented WF and a developing DL.

- Bill

10:29 AM CDT, 04/04/09