Chase Case #12

I'm still in Little Rock, looking for a Waffle House. I'm gonna get a double waffle, a double cheeseburger, and a side of bacon. After I eat, I'm gonna hang around and wait. I'm willing to take a chance on surface-based convection, rather than race north into the WW for elevated stuff.
 
As I suspected, the surface front is screaming ese at 25 or 30kts. The satellite shows the surface front through OKC and the developing squall line out ahead trailing down to somewhere east of Shawnee.

It could be an early show along I-40 in eastern OK/western AR but you're either lucky or in the trees, and I probably can't get there in time. I'm going to shoot for the triple-point where the squall-line impulse hits the lollygagging warm front. I'm going to ride US60 east, stopping frequently for data, so the "target" is a little vague; however I'll pick Poplar Bluff, MO at about 2330Z.
 
Well its 1830Z and unfortunately there's not too much additional data available (I can't really find any profilers or special soundings or anything) so here's the updated data that you found at your recent stop.

:arrow: A new radar image with updated watch boxes. A new watch was issued for NE Illinois and E Wisconsin but since nobody is in that area I won't post the text.

:arrow: A new IR satellite image.

:arrow: A new surface map but no analyzed fronts this time.

:arrow: Convergence/Wind barb surface plots for the Upper Midwest and the Southern Plains.

:arrow: Temperature advection/Streamline surface plots for the Upper Midwest and the Southern Plains.

:arrow: A couple of new SWOMCDs discussing potential supercells. Here they are (excerpts) in order of issuance...

CONVECTIVE TRENDS ARE BEING MONITORED. WW WILL LIKELY BE NEEDED
LATER THIS AFTERNOON.

SHARP THERMAL GRADIENT WAS EVIDENT IN 17Z SURFACE ANALYSIS...ALONG
BOUNDARY ENHANCED BY MORNING CONVECTIVE ACTIVITY. THIS EXTENDS
FROM SOUTHEAST MISSOURI...WEST OF CAPE GIRARDEAU...INTO PARTS OF
SOUTHERN MIDDLE TENNESSEE...SOUTH OF NASHVILLE. BOUNDARY WILL
BEGIN TO SHIFT EASTWARD INTO THE LOWER OHIO VALLEY AS 30 TO 40 KT
WEST SOUTHWESTERLY LOW-LEVEL JET DEVELOPS ACROSS THIS REGION

18Z SURFACE DATA INDICATE STRONGEST 2 HOUR PRESSURE FALLS ARE NEAR/
JUST NORTH OF THE ST. LOUIS MO AREA...WHERE RAPID NEW CONVECTIVE
DEVELOPMENT APPEARS POSSIBLE WITHIN THE NEXT COUPLE OF HOURS. MID-
LEVEL CAP WILL LIKELY BREAK BENEATH INCREASINGLY DIFLUENT UPPER
FLOW ON TAIL END OF UPPER MISSISSIPPI VALLEY SHORT WAVE TROUGH.
VERTICAL SHEAR PROFILES ARE SUFFICIENT FOR SUPERCELLS...AND
DAMAGING WIND GUSTS WILL BECOME LARGER THREAT...IN ADDITION TO
POSSIBILITY OF VERY LARGE HAIL...WITH INCREASINGLY SURFACE-BASED
ACTIVITY.

:arrow: Your friend at a local NWS office in the middle of all this tells you there hasn't been a conference call on a new watch yet, but does tell you that the outlook forecaster at SPC is becoming increasingly concerned about the unfolding situation and is weighing upgrading portions of his Slight Risk area to a Moderate Risk at 20Z.

Good luck! Next plethora of info will be either when substantial severe reports come in or at 00Z if nothing happens by then 8) So now would be the time to make your final moves!

...Alex Lamers...
 
Well. 70/59 is not ideal for surface-based instability but there is no need to break the cap by insolation as the front is going to be more than enough to trigger convection. I look for the front to fill in pretty quickly with intense convection so i am going to sit tight here in Carbondale, Illinois
 
I don't know the geography of the area very well as far as whether or not it is conducive for chasing, but I am very attracted to the outflow boundary from west of Cape Girardeau eastward to near Nashville. I would be headed for the area just west of Paducah, expecting that the boundary will advect northeastward with time. Any storms that fire along this boundary will likely be able to utilize the increase shear near the outflow boundary. Also there appears to be a little more juice available for storms in this area verses those farther north due to morning contamination.
 
Well, at 1830Z I'm probably still en route to Texas County, MO because I set up way too far west early in the day, but hopefully I still have a couple hours. Once I get there I'll probably stick around unless the winds veer SW (they are already showing signs of doing so in SC MO) and can head in whatever direction necessary from there. I do like the low LCLs (69/63) along the MS River and the warm front is pretty obviously in there somewhere (81/70 near the MO/AR border).

If I'd stayed home today I would have definitely seen a storm...albiet a crappy, linear one.
 
Mmmmm...I keep on moving southward along I 55 till Sikeston where I've got a road option to go westward and I wait for convection that breaks the cap. I hope that cells will be somewhat isolated.
Nice chase to all guys :wink:
 
I'm heading northeast to Piggott, AR, where I'm hoping to see an isolated sup earlier in the day. I still think central AR is good but might not go before dark.
 
At 1630Z I realize that I am at a terrible spot and start racing to stay ahead of this system. I make my way over to I 44 and begin to drive northeast towards St. Louis. After the 18Z data, I continue to drive on I 44. Right now I am targeting somewhere south or southeast of St. Louis. I'll go to Arnold, Missouri (small town just south of St. Louis) and hope something happens nearby.
 
Wow, lucky me. I over slept, and the best western didn’t charge me a late checkout fee! The best thing though, is that I believe surfaced based tornadic storms are about the get going right here in Dexter, MO!
 
I'm past Bartlett, MO, right on the glideslope toward Poplar Bluff by about 2030Z -- no change to the plan. Then we snack and wait to see if/where it busts loose. I like the 25kt south wind, 70 dew, and 11F depression southwest of me, plus the leftover convergence line just to the east.

Hmmm. Reading Stormtrack now. With the rightward storm motion probably about 280, wouldn't be surprised if I, Shane, Andrea, and Kurt (after he checks out) don't crash into one another around Malden. :)
 
After eating lunch in Springfield, seeing the latest changes inspires me to head about 30 miles southeast, to Taylorville IL.
 
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