2021-05-08 EVENT: KS/OK

Feb 19, 2021
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Wichita
Given all of the commiserating about the "state of the season" in that thread, I'm surprised no one has started a thread pertaining to Saturday's potential in Kansas east of 100°W (DDC-HLC) and in Oklahoma north of a BVO-SWO-CSM line. All models show rapidly dropping central pressure in the KS surface low (to quite low values for May) which expected to be about 30 SSE of DDC at 00Z = nearly perfect.The 18Z 3km NAM's SIGTOR reaches a value of 9 between ICT and PTT at 01Z.

In terms of "chase-ability" (speed of storms, "classic" supercells, road network) this looks like one of the better Great Plains opportunities of the last two years.

As I live in ICT, I have the luxury of waiting until Saturday late morning to make a decision. If I were coming from a distance, I would probably start out in PTT.

The Oklahoma threat is conditional: if the cap is breakable, there may be 2-3 tornadic supercells. If for some reason you could only chase in Oklahoma, I would start in WWD.

Stay safe, happy hunting, and let's hope the tornadoes stay in yet-to-be-planted corn fields.
 
Mar 6, 2010
15
15
1
Manhattan, KS
Given all of the commiserating about the "state of the season" in that thread, I'm surprised no one has started a thread pertaining to Saturday's potential in Kansas east of 100°W (DDC-HLC) and in Oklahoma north of a BVO-SWO-CSM line. All models show rapidly dropping central pressure in the KS surface low (to quite low values for May) which expected to be about 30 SSE of DDC at 00Z = nearly perfect.The 18Z 3km NAM's SIGTOR reaches a value of 9 between ICT and PTT at 01Z.

In terms of "chase-ability" (speed of storms, "classic" supercells, road network) this looks like one of the better Great Plains opportunities of the last two years.

As I live in ICT, I have the luxury of waiting until Saturday late morning to make a decision. If I were coming from a distance, I would probably start out in PTT.

The Oklahoma threat is conditional: if the cap is breakable, there may be 2-3 tornadic supercells. If for some reason you could only chase in Oklahoma, I would start in WWD.

Stay safe, happy hunting, and let's hope the tornadoes stay in yet-to-be-planted corn fields.
Does indeed look like possibly the first real shot for the plains as far North as I am (I70 kansas ) for a little while now . The past Few years have been quiet in KS so to speak...with minimal to work with. Anywho, the sounding from SC KS and Central KS look pretty decent for a few tornadoes and Supercells per the NAM. Cap erodes in the evening allowing what looks to be a few or 2-3 cells to be chased before going MCS mode well after Dark...per NAM soundings CAPE values bursting to near 3000j/kg and bulk 0-6km shear of wide spread 40+plus knots intrigues me to hit the Dryline/ Warm front intersect just a tad South of 70 in Central KS. Although Shear values could be stronger hodographs point to classic super cellular mode early on . Target now maybe St johns Area pushing to the NE as storms progress...cap can make or break any set up but as with such, I do like the NAM keeping them discrete for awhile only going with a couple cells before 04-06z..overall looks like a good chase OP to catch at least a couple quality cells and a few tornadoes before night fall and even after. Can't wait to break out the Nikon again..
 

James Gustina

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Mar 9, 2010
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Both the 12Z HRRR and NAM3K have painted a broad area of reasonably good instability (AOA 2000 j/kg MLCAPE) with rapidly increasing low level shear around 00-01Z but I've got some reservations about this one:
  • Late moisture return coupled with moderately high surface temps in the mid mid to upper 80s seems to be the failure mode for this one outside of the triple point target (which seems to be the only real target for tornadic supercells at the moment). CIN is relatively high and filled in immediately south of the low down the dryline and coupled with LCLs in the 1500 meter range around 00Z.
  • The possibility for weaker mid-level flow depicted on both the HRRR and NAM3K, with the Euro providing a more classic wind profile for reasonably well-ventilated storms. 30-35 knots isn't a death sentence for any setup in May but with the possibility of anvil-level winds hovering around the 50-55 knot threshold it makes me worried that it'll end up as a more HP storm mode that congeals into a complete mess before sunset at the TP.
Not a bad setup to take a flyer on it as this appears to be the only show in town for the next 6-7 days, but I'm still a bit hesitant to pull the trigger on it until we see what moisture return looks like tonight/tomorrow morning.
 

Jesse Risley

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Apr 12, 2006
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12z/07 data continues to look interesting for tomorrow afternoon/evening. The moisture question seems to be factoring into marginal LCLs on the models. Other parameters, however, look to offer the potential for a narrow window for tornadogenesis, particularly if storm mode remains discrete for the first few hours. It looks like storms initiate near the triple point in WC KS. 0-3 km MLCAPE and SBCAPE values seem to be juxtaposed, along the WF, with rapidly improving low-level shear towards 0z where CINH looks to improve to favorable levels as well. There looks to possibly be a few hour window where supercells could have tornado potential, INVO the warm front, as cells track parallel to the boundary. If discrete or quasi-discrete modes prevail, as LCLs and low-level shear improves, NC KS and perhaps a few counties in extreme S NE near the surface WF have a chance to yield a few rewards. This signal appears consistent on the 12z HREF suite as well. The obvious fail factors for a more substantive tornadic threat would include too meager of moisture to substantiate a more robust threat, stronger CIN and/or too quick of an evolution to a more linear mode that limits tornado potential.
 
Mar 6, 2010
15
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1
Manhattan, KS
12z/07 data continues to look interesting for tomorrow afternoon/evening. The moisture question seems to be factoring into marginal LCLs on the models. Other parameters, however, look to offer the potential for a narrow window for tornadogenesis, particularly if storm mode remains discrete for the first few hours. It looks like storms initiate near the triple point in WC KS. 0-3 km MLCAPE and SBCAPE values seem to be juxtaposed, along the WF, with rapidly improving low-level shear towards 0z where CINH looks to improve to favorable levels as well. There looks to possibly be a few hour window where supercells could have tornado potential, INVO the warm front, as cells track parallel to the boundary. If discrete or quasi-discrete modes prevail, as LCLs and low-level shear improves, NC KS and perhaps a few counties in extreme S NE near the surface WF have a chance to yield a few rewards. This signal appears consistent on the 12z HREF suite as well. The obvious fail factors for a more substantive tornadic threat would include too meager of moisture to substantiate a more robust threat, stronger CIN and/or too quick of an evolution to a more linear mode that limits tornado potential.
Per Latest NAM and HRRR (18z) as stated the best area is trending to be Id say NC, NE and East central KS...as far as betterbacked low level winds along the WF and higher quality moisture. I still prefer the NAMS solution opposed to the HRRR having the lower end of the dew points and overall placement moved further east for tornado chances as far as the winds etc go. 00Z should yield a better look into things, but I really like the NAMS Wf play at this time, lower LCLs as well as having some nicer hodos out there in NC/E Central KS.. It indeed looks like best Tornado chances will lie right around sunset and or best action looks to be 00Z and on, with things looking to at least be semi discrete til 03z ... which I guess isn't ideal for those not welcome to close to dark/ night chasing. As a spotter I've chased pea sized hail and so many after dark 60mph mcs type deals, so not much to complain about here...lol. Goal is too get on something that rides that boundary off into the better enviorment, but placement isn't obviously for sure yet. Overall I wouldn't fly here form the UK but I live and Kansas here in the risk area and I love this stuff so Lets chase whatever goes up is the mode. Still not looking terribly bad yet for least a few quality cells and possibly a few tornadoes for sure. I suppose the new fixed target would be head to Salina/Central KS early as a way to head any direction out of there as needed...will move and correct that based on tonights/AMs data of course if called for.
 
Last edited:
Apr 10, 2008
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Looking at 00z observed soundings from Corpus Christi and Brownsville, TX where the edge of the warm sector lies and you can see while 70's dewpoints have made it ashore, the moisture is rather shallow, ~800mb. This is concerning in regards to quality moisture advection overnight and Saturday and mixing that will occur during the diurnal cycle on Saturday.


The warm front appears to be the best bet for something surface based, however convection forming at the triple point will likely be in a well-mixed boundary layer and should become outflow dominant before reaching the warm front which will lie northeast of the initation zone. Not sure a rogue storm can fire in close proximityof the warm front. To me, that would be the best opportunity for a tornadic supercell.

I am on the fence about chasing tomorrow, but may still give it a shot with the expectations of making the most of whatever storms we end up with and try to get some decent photos of possible structure, sunset and lightning. Screenshot_20210507-194410_Samsung Internet.jpg Screenshot_20210507-194356_Samsung Internet.jpg
 
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Mar 30, 2008
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Like Greg, I am not impressed with the abysmal moisture at the gulf coast. This is middle May.

The other concern for me is the capping. The LFC will likely be high, so the storms will struggle. The 00Z NAM pretty much caps everything except for right along the warm front. The soundings I pulled up showed an inverted-V lower level. Not worth a trip up to I-70 for that.

The positive is that the LLJ cranks up starting around 00Z and really looks to strengthen around 2-3Z. The NAM, HRRR and RAP are all in agreement on this. There are some definite "loaded gun" soundings in south central Kansas tomorrow evening, but moisture seems to be the big negative.

Good luck to those going out. If I do end up going, I will likely target somewhere between Wichita and Salina
 
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Jul 5, 2009
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If I were out there on my chase vacation I would certainly consider it a “chase day,” but I am not too bullish on it. What may have been depicted as a warm front in earlier forecasts is now a cold front, making the triple point a less attractive target. No backed winds, risk of storms getting undercut, etc. The greatest moisture (setting aside its shallowness as noted above) is well east of the dryline, and there does not appear to be much convergence along the dryline in KS at 21Z. This seems to improve by 00Z but the cold front is crashing down by then. Dryline sharpness appears better in OK, and 500mb flow is also stronger there, but still hard to find backed winds in the warm sector and, more importantly, capping looks too strong there. Still, might be a day to take a flyer that a storm can form along the dryline in OK. If it can, it seems likely to remain discrete and could get interesting as the LLJ strengthens. But I have the feeling it becomes one of those days where surface winds veer out ahead of the dryline and the potential falls away quickly.
 
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Jeff House

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Jun 1, 2008
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I still interpret the boundary as a stationary front. It sinks south as the surface low sinks; but, it's not going all cold front crash on us. Otherwise it'll behave as a warm front.

Ben's concerns about LFC are even worse in Oklahoma. So my virtual target remains just off the TP. I do want a cell or two east into better moisture. Also perhaps the south end of the TP cluster, NOT the south end of any broken line. Target is likely north-central Kansas.

This is far from an ideal chase day. I did not travel for it. However if I live in Kansas or Nebraska I go today. Trescott had JIT moisture and LLJ.
 

Lucas McIntyre

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Apr 12, 2018
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Manhattan, Kansas
Being mere hours from the target area (in the middle of the 30% hatched hail risk) it's definitely a day to go out for the accidental chance at a danger noodle. But goodness does it look like a day that if something does produce, it'll be the only game in town, or maybe that's just me.