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Chase case #4

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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:

12zMWSTsfc.gif

12zSPsfc.gif

12z300mb.gif


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
 
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...
 
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
 
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.
 
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 -
 
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).
 
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)
 
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.
 
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).

1650zRadar.gif

1715zIR.gif

18zMWSTsfc.gif

18zSPsfc.gif
 
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.
 
Quite a range of temperatures across the board with some very cold air to the north and rapid warming across Texas and Louisiana. This is looking like a very early spring or very late fall sort of day - possibly even winter. The saturated airmass is easily visible on satellite, with several lines of Cu now forming in extreme eastern Texas into Arkansas, and another line out ahead that seems to be developing in northern MS into TN. Personally, I feel like it would be good to keep an eye on the area from Junction City up to El Dorado, where we have extensive clearing and a 75/61 spread, but if this is too early or late in the year, it's not going to be that chase-able anyway, since the majority of this particular show will probably be in the dark or late at night, and the storms should be moving quickly.

--------------------

EDIT - I'm going to adjust my target just a bit to Searcy, Arkansas.
 
surface maps show 16 degrees up in nortern minesota. C'mon thats too cold to even be on the same map as a tornado outbreak! :shock:

This event is Likely sometime in February judging by that.
 
Just noticed you guys were doing these case studies so I thought I'd give it a go.

I'm drawn south into Tx where I see better dewpoints and temperatures advecting throughout the day. The Shreveport and Lake Charles soundings show some spicy readings for later in the day. Also note the apparent srfc convergence toward the AUS area with some bit of the dryline pushing from that direction. In the region across central / eastern Tx and Louisianna there are also good winds in the upper areas with possible slight divergence near the Tx/La border at 500mb - though it is early in the day at 12z. There also seems to be better backing of sfc winds down in that area which should increase as the low intensifies throughout the remainder of the day due to heating. Already the Lake Charles / Shreveport soundings are showing promising Cape, Helicity, Li, etc and the southern area will also receive more heating from less clouds.

Given also that near 16:50 radar is showing small (but hard) convection beginning to break out near the Tx/La border probably from convergence and overhead jet lifting I would have to go with that area. I'd probably box the whole Tx/La border with a torn box, but I would also be concerned with later nocturnal convection in La as the evening wears on.

My initial target would be San Augustine, Tx with expectations to work my way east into darkness. Note that this would be a terrible chase into tall pine trees and then the swamps and whatever at night in Louisianna. I've actually done a similar chase to this near and after dark back around 2000 or so. It was pretty spooky.
 
I wish I knew the actual date because I'd post it to piss everyone off. Since I don't I guess I'll just go with somewhere in far wc AR. And hey look at me, I'm posting without reading others thoughts! It is soooo hard to do.

I'd stay away from that ofb sinking south with very cold air behind it in sw mo into nw ok, hooking up to the sfc low. Notice the thick cloud sheild south of it too.

Well damn it I know the date again. I can't help myself. I looked up Jarrell and then Ft. Worth. I thought I looked up the right one before those but must not have because I went back to it and I'll be another Monkey's uncle if I'm wrong.....beings I found the exact same sfc chart, lol. PM me if you want the answer early.
 
I guess I need a town. I'll go to a town in AR with 3 e's and 2 b's in it.
 
I'm happy to see these chase cases have taken a life of their own, although I do wish those who figure out the dates of these would stop dropping hints considering it basically ruins the intent of the excercise. I really wish I could participate in this one . . . but, it's been cool reading everyone's forecasts for this case. :)
 
Originally posted by Mike Hollingshead
I wish I knew the actual date because I'd post it to piss everyone off. Since I don't I guess I'll just go with somewhere in far wc AR. And hey look at me, I'm posting without reading others thoughts! It is soooo hard to do.

Wow
 
I'm happy to see these chase cases have taken a life of their own, although I do wish those who figure out the dates of these would stop dropping hints considering it basically ruins the intent of the excercise. I really wish I could participate in this one . . . but, it's been cool reading everyone's forecasts for this case.

Sigh. It must be terribly hard to read the data and post your thoughts.
 
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