2014-05-08 FCST: TX, OK, KS, MO, IA, MN

[Marcus Diaz]

Well, let me be the first to jinx this day since its the only decent day in this whole system coming up. I'm going to focus my discussion on the OK/KS target. According to the 12z NAM, everything is in place for some supercells Thursday evening. NAM has been consistently showing morning precip south of I-40 that *should* clear east of I-35 by 18z. Assuming that is true, that should be efficient enough to vigorously recover the atmosphere. A very well defined N-S dryline looks to be situated over the US 81 corridor. Low to mid 60 dewpoints in the moist sector and those weak but dry west winds on the backside of the dryline should provide good moisture convergence for initiation. Looks like a decent dryslot through most of the day up until late afternoon, which along with 1500 SBCAPE and decent 0-3km lapse rates, should provide a good firing mechanism for storms. The 110kt upper level jet and 50-60 kt bulk shear should rotate any storms that form. The unfortunate thing about this setup is the displaced LLJ off to the east. Nevertheless, the hodographs sure have a nice clockwise curve that get larger towards 3z. The NAM has come around the past few runs and really recovered this setup from being completely blown. I'm sure there's more to discuss, so have at it.

 

[Taylor Wright]

I usually wouldn't chase a setup this bleak in mid-May, but seeing as how the atmosphere is changing there may not even be tornadoes next year, so I'm taking everything I can get. I initially was targeting around Coffeyville, KS, where low-level shear looked decent, and I figured if there was a tornado within my reach it would be around there. Now I'm thinking moving that target west a bit closer to the dryline where instability might have an extra hour or two to recover. I also plan on waiting for this to come within the range of the RAP before solidifying a target, as it seems to handle localized areas of instability better than the NAM. The NAM has increased forecast 1 km helicity over the past few runs as well as 850 mb winds which keeps me from totally throwing this system out. I might target somewhere just southeast of Wichita to catch the second round of convection and follow it east into the area of better rotation (may still end up in Coffeyville). Instability is weak there, but if there's a small area where sunlight was able to poke through for a couple extra hours I could maybe get lucky and catch a tornado. It's only about a two hour drive, so I can even get a couple things done before I leave to chase. Good luck.

 

[chrisbray]

SPC given a moderate risk with 10percent, hatched for tornados in central Iowa through southern Minnesota. Man, My friend and I totally blew off this chase about Monday, thinking it would be too long a drive in one day for too small a chance. Doesn't look like too bad of a setup though, Cape approaching 3000 in Iowa this afternoon and while the helicity values aren't great, the forecast soundings show some nice low level curvature overall

 

[E Hale]

I'm gonna go out on a limb and say there will be 15+ tornado reports today. adequate shear and an erosion of the cap should allow for development of supercells in KS and OK today. Clearing is already beginning in Western Oklahoma well ahead of earlier forecasts. cape should reach 2000 in many areas, with pockets approaching 3000 JKG. I believe one or two cells will produce several low end tornadoes with a possible short-lived strong tornado.

The Northern target near iowa will also produce with several cells (3-5) producing some short lived weak tornadoes as well.

 

[Logan Karsten]

As I look at current observations, short-range models, and reflect on my bust in southern MN yesterday, all I can say is yuck yuck yuck for today's setup across the moderate SPC outlook region. Why SPC is throwing the "strong tornado" wording out there is beyond me. For starters, the models are too aggressive in bringing the warm front into MN. As the warm air is still way down in IA, I question if it will even get north of the IA/MN border today. Second, there is a large shield of mid-upper cloud covering a large chunk of the warm sector, and moving northward - not good for destabilization. Next, the short-range HRRR is showing an ugly line of crap firing near the IA/NE border near 18Z and riding across the risk area, which will further limit destabilzation for discrete supercells later on. Also, as I noticed yesterday, the models are too high in surface dew points, most likely due to the use of climatological greenness in the LSMs that doesn't reflect reality. Models had 65+ degree dew points getting up to the IA/MN border yesterday, which was nearly 5 degrees too high as I only saw 58-62 in the warm sector, so the models are slightly over-estimating surface instability. Are supercells possible in the warm sector today? Sure. Do I expect strong tornadoes? No. Do I even expect any tornadoes? Perhaps, but I don't even know if it's worth chasing at this point. I definitely question any surface-based development in Minnesota.

 

[Will Campbell]

I think the southern area of the higher categorical risk will pay off a bit better. There are already mid-60 Td laying across the I-80 border from Omaha to central IA, and latest VIS suggests "some" thinning of the clouds in the warm sector. With the front pushing through I hope to see a line of semi-discrete cells firing somewhere east of the river, even though short-range models have them really hauling to the NE. With adequate moisture, 40-50kt H5 flow, and a nice 100+kt H3 stream, shear, and good low level curvature I hope for a close to home success story. The only problem is this flow is dang close to parallel to the boundary, so could end up with a linear mode with embedded rotations. Then again after the way this year has been going I got giddy taking lightning shots from elevated qlcs that pushed through Omaha last night.

In any case, good enough for me to head out of work a couple hours early and hope to have a fun evening.

 

[Taylor Wright]

The models are all over the place with timing of convection on this system, but that actually gives me a little hope. I think instability will be slightly higher than what is forecast by the NAM and RAP. Dewpoints are already in the mid 60s in KS, and convection going on right now is very light, so the sun shouldn't have any problem poking through in a couple of hours. Still targeting somewhere in eastern Kansas. RAP and NAM show isolated cells firing off the dryline at some point later today and if they can move east into the better low level shear and hit a pocket of increased instability, I like my chances. I'm wishcasting this one like crazy, but finals are next week and I'll be moving to Wichita on the 17th to start my internship, so I might not be able to chase for at least a couple weeks.