Chase case #4

[Jeff Snyder]

OK, so here's a chase case that probably won't too recognizable. If you do figure out the day of this case, please do NOT reveal it (not even a "I think I'll target *** [hint hint hint]").

I'll be back to post some 18z IR, radar, and surface plot images this evening.

Here are the 12z maps:

850mb
700mb
500mb
300mb

Soundings
Amarillo
Dodge City
North Platte
Omaha
Topeka
Springfield
Nashville
Little Rock
Shreveport
Norman / Oklahoma City
Lake Charles
Fort Worth - Dallas
Midland

 

[Mike Peregrine]

Well now that the exercise is reserved for those who don't know the solution, I'm forced call Lake Placid, New York as my target.

 

[Jeff Snyder]

Well now that the exercise is reserved for those who don't know the solution, I'm forced call Lake Placid, New York as my target.

LOL You know the event already?

You'd think that the bad ob in southeastern Canada would have been data-qualitied out...

 

[Gabe Garfield]

Interesting case...I really haven't the foggiest idea what day this was.

I really like the fast flow in the upper-levels within a fairly low-amplitude trough. This is a synoptic pattern that favors tornado outbreaks when combined with sufficient moisture/instability. A jet max can easily be seen entering the base of the trough, which probably led to further deepening/digging of the large-scale trough. This undoubtedly led to the formation of a lee trough, and the subsequent return of moisture across the S. Plains and the S.E.

The only thing I don't like about the setup is the relative lack of directional shear (in the lowest kilometer or so) and the relatively poor (upstream) lapse rates for this early spring severe weather day. I think the directional shear probably improved later in the day as the surface winds backed in ageostrophic response to the deepening lee trough. Also, I really like the quality of the moisture (Tds ~70F along the Gulf Coast). The moisture depth isn't that great, which is typical of early spring.

I'm going to say that the dryline/cold front probably propagated relatively far to the east, and set up somewhere close to/just west of the OK/AR border.

Target: Arkadelphia, AR

Gabe

 

[David Wolfson]

Well it sure isn't July.... It's a question of where there's going to be enough low level moisture and directional shear, a cap that can break for isolated storms rather than lines, and mid-level winds that don't rip storms to shreds. Then, maybe....

Waaal, the surface low about over OKC looks to deepen just a bit as it follows the baroclinic path of least resistance north of Fayetteville and Cairo at maybe 25kts. This early in the year with limited insolation, best not get too tricky, and I don't really see the front as much of a focus.

The best upper-layer and atmospheric ingredients seem to come together in about eight hours around Jonesboro, AK, and it's chaseable there at least. So that's my final morning answer, not exactly dripping with enthusiasm.

 

[Jason McKittrick]

Yes, it definitely looks like a central and southern Arkasas event.

 

[Mike Peregrine]

LOL You know the event already?

You'd think that the bad ob in southeastern Canada would have been data-qualitied out...

lol - I'm just being a smart aleck. I sent a private message with the day I thought it might possibly be. But it's pretty much just a guess, along with every other observation I've made to this point -

 

[Kurt Silvey]

The low over OKC should move off to the nw towards se KS / sw MO. I think this will enhance clearing in the warm sector over n AR and s MO (east & se of the low). Think I’ll start the day in Joplin, MO as it provides good road options to the south (AR) and sw (ne OK).

 

[Andrea Griffa]

I think Fayetteville could be a good target and there're some road options..I start from there then we'll see.

 

[Joel Wright]

I'm liking the area around Monroe Louisianna. I'll take warmer air and deeper moisture, especially for the time of year, assuming it's early spring. The winds are still backed fairly nicely this far south too. Winds upstairs aren't as good as to the north, but still not too shabby. 8)

 

[Fred Gossage]

I think I would play the Little Rock, Arkansas area.....or central Arkansas in general. Close to the backed flow to the north.....but also closer to the warmer air and deeper moisture to the south........ many north-to-south oriented outbreaks occur in the area between the strongest directional shear and the strongest instability.....where you get enough of both ingredients juxtaposed. Also, climatology shows us that in this part of the world, the strongest tornadoes in a possible outbreak setup like this are usually southeast of the surface low in the warm sector......... as to compared further north, where they are often associated with storms along warm fronts.

 

[Shane Adams]

My target is Atlanta, TX.

 

[Jeff Snyder]

Here's some 16-18z data. I'll put out the 0z data tomorrow morning, at which time folks can make one final adjustment (obviously, this isn't chaser reality, but it'll allow folks to make a best-guess nowcast before I release the reports map).

 

[Charles Kuster]

I will start in Fort Smith, Arkansas.

 

[samuel stone]

I think I'll steup in little rockcentral Arkansas area. So I'll be able to drop soth to better instability or head north towards more backed winds. Allthogh I think I'm leaning towards southern/southwest arkansas at this point.