2014-04-27 FCST: KS OK TX NE MO AR

[Warren Faidley]

Have not spent a lot of time on the forecast for Sunday mainly because Saturday is still to be determined and a lot of what happens on Saturday will effect Sunday. I guess the main issue ATM is where the DL is positioned. Some of the North-Central, KS hodographs are crazy.

W.

 

[Michael Riedl]

12z UTC Sunday has come into range for tonights 0z UTC NAM and already some things that give me pause about this day. The NAM wants to close off the low at 500mb and eject it over a weakly capped warm sector in SC KS at 12z Sunday morning. Because of this the vertical wind profile is veer-back-veer with possible convective initiation in the early morning on Sunday. Now the turning in the low levels is very nice as evident by progged 0-1km HEL of >200m^2/s^2. Also because of this the dryline is likely to continue to progress eastward throughout the day and push fairly quick moving storms into unfavorable geography and poorer road network. Would obviously prefer the upper level low to stay as an open wave as it ejects over the warm sector. This weekend holds a lot of promise but some of the finer details will be limiting factors on the extent and strength of the severe weather.

Will be interesting to see what tonights 0z GFS and future model runs prognosticate.

 

[Matt Hunt]

Looks like the GFS is in agreement with closing off the low and breaking the cap wide open by 18z. Looks like it could be a junk fest, but there might be a chance up north on the advancing warm front where there will be backed winds. Still, at that point there may just be too much junk to allow any decent instability to reach that far north. Saturday appears to be the better chance, but looks like timing issues may prevent this from being as big of an event as was originally thought.

 

[Matt Hunt]

Actually, now that I've looked into this day a little more, I do see some potential here early in the period, around 15-18z. The setup bears a striking resemblance to June 20, 2011, at least in terms of a cut-off low and arcing dryline in almost the exact same spot. There will already be 2000+ J/kg CAPE in place with the cap completely eroded at 15z. LCLs will not be an issue at this time, as temperatures will have yet to climb. We're looking at more like 70/60. This may reinforce my decision to choose the SE Nebraska target on Saturday, putting me in position for Sunday morning. SPC is pretty bullish with their wording about strong tornadoes possible, but I'm not sure what specific region they are looking at. Further south along the dryline winds are more unidirectional.

 

[Zack Cooper]

After looking at the 12z GFS and NAM, I am planning to chase Sunday Somewhere in the Arklatex area. Great moisture return, and the wind profiles in this area are extremely impressive. Near 00Z, from both the NAM and the GFS, I pulled soundings with near 400 m^2/s^2 esrh. One concern is that the capping will break pretty quickly, but the environment looks potentially primed for supercells and tornadoes ahead of the boundary pushing east out of OK and TX.

 

[Andrew Stoller]

Todays 12Z ECMWF has the system slowed down so much, I'm thinking Sunday will end up being what Saturday looked like a few days ago. By 00z Mon, the surface low sub 990 mb will be located around Hastings, NE with the dryline through central KS. If the NAM/GFS verify this solution, Sunday will be a much more potent day than Saturday, especially at the bottom of the speed max in southeastern KS.

 

[Brandon Jenkins]

Someone's gotta do the dirty work.

As for Sunday, I am hoping the slow down trend on the ecmwf continues and can at least bring the dryline back to the 35 corridor (NWS FWD seems to favor this solution atm). As it is (not driving to Nebraska for the CC play) I would be hard pressed to get out with such unidirectional profiles along the dryline in such poor terrain. As Zack pointed out, however, there are some pretty impressive parameters progged to be in place over East TX and the Arklatex region that are hard to ignore regardless. If there are any storms that can manage to stay discrete for any extended period of time in this area I would expect a few tor reports. Will continue to wait for some consensus among models, luckily it's not that far and I can probably wait until late sat night or early Sunday to pull the trigger.

 

[Kyle Soldani]

Let's get back on topic, with decent language.. shall we? Google is available for all boys and girls.

I'm pretty heavily leaning towards ERN/SERN KS. I do agree it appears to be an early day with CIN eroding at the 15z mark in the 12z NAM - 12z GFS @ 15z has a good slot down by the Wichita area. 12z NAM EHI @ 15z tends to lean towards the Wichita area, in concurrence with GFS. Supercell Composites are both in decent agreeance for ERN KS, good overlap by the Wichita area. SigTOR lights up at 15z in NAM for SE KS which is nice to see. Li's have a nice -7 @ 15z in GFS, again in the Wichita area with dews hovering in the upper 60's-70's. I'm confident'ish in calling Emporia my initial spot to get to early Sunday and play it out from there, in the event my noobile estimates throw me off.

 

[Zack Cooper]

With the 06Z run, it was the war of the GFS and NAM. GFS is quite unimpressive, whereas the NAM shows a potentially major outbreak over portions of the Arklatex. The GFS shows veered surface winds and sloppy wind profiles, with a sloppy and diffuse dryline.

The NAM, however, has multiple rounds of convection over the Arklatex, with the first between 18z-21z, and the second developing along the dryline in east Texas by 00Z. Dewpoints look to rise into the middle to upper 60's, with backed surface winds, and large looping hodographs with a 50-60 kt LLJ developing over LA and AR. Looks like the atmosphere could be able to recharge after the morning and early afternoon convection, and allow for some tornado producing supercells in the evening over slightly more chaseable terrain than AR, east TX.

As of now I plan on chasing SOMEWHERE, just not sure where yet, home town of Shreveport doesn't look like a terrible place to start.

 

[Zack Cooper]

00Z NAM this evening came in showing a really bad scenario for LA, AR, and potentially into southern MO. Incredibly potent negatively tilted trough, 50 jk srly LLJ, and sharp dryline with middle 60's dewpoints and backed surface winds in the warm sector. Hodographs become extremely large, curved, and looped by 00Z over SW AR, and the NAM is breaking out precip along the dryline. ESRH of 450 m^2/s^2 or so with CAPE values nearing 2500 j/kg in this same area. Could be a very dangerous day. Still planning on being out somewhere in the Arklatex.

 

[Russ Conlon]

00Z NAM this evening came in showing a really bad scenario for LA, AR, and potentially into southern MO. Incredibly potent negatively tilted trough, 50 jk srly LLJ, and sharp dryline with middle 60's dewpoints and backed surface winds in the warm sector. Hodographs become extremely large, curved, and looped by 00Z over SW AR, and the NAM is breaking out precip along the dryline. ESRH of 450 m^2/s^2 or so with CAPE values nearing 2500 j/kg in this same area. Could be a very dangerous day. Still planning on being out somewhere in the Arklatex.

Agreed. The NAM is extremely impressive in SW AR. Texarkana looks like a great target.

 

[Matt Hunt]

The Arklatex area looks like a dangerous place to be living on Sunday evening. Unfortunately this is not the greatest area to chase. The biggest hodographs are right on the Ouachita National Forest. There are some openings in SW Missouri, but the 00z NAM is showing much less instability up there, and the 500mb and higher winds begin to back, so there is a veer-back-veer pattern and S-shaped hodos. If this area begins to looks better, I may shoot down there on Sunday for the chance to see something in the clearing.

 

[Russ Conlon]

Staying near or along the I30 corridor from Texarkana toward Little Rock seems to present the best road options and viewing. Though the terrain and viewing isn't ideal, it's far better in SW AR so long as you stay south of the forest.

 

[Bob Schafer]

This morning's 06Z NAM suggests that convection will blow through the MDT area early in the afternoon with no cap in place. As you all know, that would be a bunch of garbage.

 

[Zack Cooper]

This morning's 06Z NAM suggests that convection will blow through the MDT area early in the afternoon with no cap in place. As you all know, that would be a bunch of garbage.

The NAM also redevelops convection along the dryline by 00Z in the MDT risk area. Yeah, no capping throughout the day, but despite morning storms the atmosphere still appears to destabilize nicely with a large area of 2000 j/kg + CAPE in AR. Not to mention, the shear is insane in this area.

The morning convection will be a limiting factor, but that's probably something to be thankful for, because it could still be pretty big even with that as a limiting factor. Remember, 4/27/11 had a lot of morning convection issues with little capping.