4/6/2006 DISC: NE/KS/OK/TX/IA/MO/AR

Since this could be a big one, I decided it might be a good idea to give everyone a rough idea of where you will be chasing on Thursday. This would allow for some networking between chasers before the main action comes. Then some discussion after the event.

I'll be chasing somewhere in NE KS, probably close to the Manhattan-Topeka-Lawrence-KC region on north to the Nebraska/Missouri border. Limiting factor is a grad. seminar at 3:30 (just announced Tuesday, after everything fell into place to get out before noon), otherwise I'd be in my target position well before then.
 
I am going to try and stay in the local viewing area for KFSM (Western Arkansas, Far Eastern Oklahoma, and maybe start out a little west toward Tulsa, or Stroud.

Also if anyone needs a ride on Thursday and is in my area, I can swing by and pick you up. I have room for 1 passenger, but be ready for a long night, because depending on the damage, I may head to one of the areas that may be hit hard to help out, and possible even open a shelter for the Red Cross.
 
If someone near Kansas City is chasing tomorrow and wouldn't mind taking along a newbie, send me a line. I would chase on my own, but I don't have any experience or equipment. It's been several years since my training seminar (not that that teaches everything) and I could definitely learn more. All I know is I love weather and I would love to see what a real chase is like. If no one wants an inexperienced tag-along, that's cool too. Good luck to everyone tomorrow. I look forward to reading your chase reports.

MODS: Delete this if you think it inappropriate.

Jennifer
 
Simply a gut feeling, but it seems like SPS keeps moving the convective outlook back to the W on every update. so I wouldn't be surprised to see more of KS under the gun before it's over.

I'm stuck in Topeka most of the early afternoon for a Dr. appointment, then physical therapy on an injured ankle in the early afternoon. With luck I'll be in the field by 1500.

I'm probably going to remain in the Topeka area and limit my chasing to the outlying counties surrounding Shawnee county.

As I was writing this, SPC put all of NE KS into High risk category. Topeka appears to be dead center.


JH
 
I pointed this out on my blog this morning, but after the rough weather last week in Nebraska (F0 tornado), the local news in Omaha has done a superb job of alerting the public all week to the lead up for today. It looks like it might have paid off as we're looking for what could be quite a show around this area, even though the more violent stuff looks to stay somewhat south of the Omaha metro.
 
Much like Scott Olson, I have a work meeting at 3:30 that I have to attend and as soon as that's done with, I am screaming down I-29. Look for the blue blur of a Ford Escort B)

For SwiftWX 2.5(new version out) users, you will see my Baloo beacon.
 
I think I will be out monster hunting along the Red River in extreme SE Ok. There is a small area of decent terrain from Idabel, Ok to Texarkana where everything is really coming together nicely. I hate being in such a limited space and having to worry about a potential cap bust but I am also pretty certain that there will be at least one massive tornado down in this area. If anyone would like to come for the ride let me know, I have everything needed but could really use an extra hand. I do not want to get too far north because everything is setting up to be quite a show tomorrow in the Ms Delta and the terrain there is too good to miss.
 
Chasers chasing near Omaha, please take note

PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
825 AM CST THU APR 6 2006

THE KOAX RADAR WILL BE DOWN UNTIL 1530Z FOR EMERGENCY REPAIRS. ADJACENT RADARS INCLUDE KLNX...KUEX...KTWX...KEAX...KDMX AND KFSD.

Edit, if this is out of place, please delete
 
Looks like I picked the right location on accident.

More details: I'll be at the scenic overlook on 177 S. of Manhattan from 1 PM to 2:30PM or when initiation starts occurring. If I can get out of half of my lecture, I'm booking it to the NE.

Edited for time I'll be at the overlook.
 
I'm sitting 28 miles east of Kansas City in good ol' Missouri ... will hopefully have internet available out in the field to post on the trends

Figuring to either pass through Kansas City or head into SE Nebraska

Hoping as well to meet up with Sean McMullen

203 260 2596
 
Benjamin, I too will be with Sean as soon as katie gets off work at 3:30 which should be early enough to get to the best storm, she is a great driver ;) look forward to meeting you!!


I'm sitting 28 miles east of Kansas City in good ol' Missouri ... will hopefully have internet available out in the field to post on the trends

Figuring to either pass through Kansas City or head into SE Nebraska

Hoping as well to meet up with Sean McMullen

203 260 2596
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I'll be concentrating on the Lawrence/Topeka/Atchison tirangle unless I get out of town late. Then I'll play eastern Kansas on the dry line stuff.
 
I'll be working today and nowhere near the storms. Hopefully I can get off in time to do some virtual chasing and maybe help some of you who are actually out in the field. Keep your wits about you today. I think things could get really ugly, especially closer to sunset. Take care and good luck everyone! I look forward to reading 4 full pages(at least) of storm reports tomorrow.
 
Now sitting in Marysville, KS(?) ... along 36 ... notice storms developing down by ICT but hesitant ... CAP is still strong .... dewpoints way lower than expected though have to see how elevated mixed layer will tie into everything ... concerned over backed flow ... unsure as if to proceed northward or stay put ...
 
I called off my chase today since I was having problems with the Wxworx, got a late start and due to the limited chase terrain in my target I decided to cut my losses early and focus on tomorrow closer to home in better terrain with all my equipment working. I still think extreme SE Oklahoma is going to be explosive late this afternoon into the evening hours. I regret not being able to go but as long as tomorrow looks as good as it does I can deal with it. Good luck to anyone in the field and stay alert.
 
I must say that today was very disappointing for me. Here in KCK we never even got any rain, let alone a thunderstorm. That is the second time in recent days that we were in the 'highest risk' for tornadoes and didn't get anything. Oh well, maybe next time.
 
I would like to start some post event analysis when we get a chance and if anyone has any energy left. Some things I noticed yesterday -

*poor handling of boundary/dryline motions by the models

*not the vigorous warmth or moisture return we expected - everytime I checked, the general spread in the target area was around 71/54 or something ... and didn't seem like there was anything over 55 in the way of dewpoints that I could tell.

*I also wonder what the winds were actually doing aloft. As we came back through new storms that went up through Nemaha Co., Nebraska and near Falls City/Hiawatha - we noticed how far the anvils were pushing back to the west and southwest of the storms. And while the updrafts were strong, I wonder if UL winds were generally on the weak side.

Anyway - any thoughts on the situation would be really appreciated. The day was interesting if you were on one of the two or three storms that actually managed to produce, but hardly the outbreak scenario expected.
 
I posted this part in my 4/6 report, but figured it was most post-analysis than report, so I've moved it over here...

Overall, another rather disappointing chase. The structure wasn't particularly noteworthy, and cloud-base rotation was weak. I noticed that, on radar, many of the cells exhibit some anticyclonic rotational tendencies intermittently. Looking at the RUC/SPC mesoanalysis valid for 0z, it's no wonder why storms struggled, with only ~500 j/kg CAPE near the storms in northeastern OK and southeastern KS. The 0z NAM initialized 750-1250 mlCAPE in the same area.

Similar to what happened on 3/30, I think one of the main failure modes was lack of strong instability in the face of strong shear (the supercell that moved from Paul's Valley to McAlester on 3/30 was also located in marginal CAPE -- 250-500 j/kg CAPE per SPC mesoanalysis by late afternoon and early evening). 0z NAM initialization indicates 0-6km shear of 70kts, with 80-85kt 500mb winds across that area at 0z. Broken strato-cu developed east of Osage county through the afternoon, which kept temps largely in the low-mid 70s. Farther west near and just east of I35, temps rocketed into the 80s. I don't think it's any coincidence that storm updrafts looked quite solid as they first approached Bartlesville, before turning more "mushy" in appearance as they marched northeastward. With relatively cool sfc temps, CINH was relatively significant. I do think that some storms were able to sustain themselves long enough to establish decent vertical perturbation PGF fields, which helped maintain the storms as they moved into the weaker/weak instability in se KS and ne OK. I do think we would have seen an event more like what was forecast if temps had warmed a bit and Tds would have risen a few more degrees. 0-1km SRH wasn't a problem, with RUC mesonanalysis at 0z indicating >400 0-1km SRH in se KS / ne OK. I think the cooler surface temps likely prevented storms from ingesting surface-based parcels (or at least not stretching them much owing to relatively weak CAPE), which is turn made the very strong low-level shear rather irrelevant.
 
Just one other thing I wanted to mention here ... yesterday in the fcst thread, I mentioned the unidirectional shift in RUC forecast soundings over TOP after the 15z run. It appears this may have been an accurate forecast sounding, judging from storm behavior. Anyone have any details on actual obs during the period of say 18-21z from TOP? ... I'd be pretty curious to see whether these were pretty much unidirectional at this point. Thanks -
 
Here is the 18z ob sounding from TOP (click) and it shows the quite small/straight hodograph (and small 0-1km SRH) and also exhibits the very shallow boundary layer moisture present. The strong insolation through the afternoon helped to support the strong instability (e.g. 1500-2000j/kg MLCAPE across the open warm sector) but also helped to mix out much of the already shallow moist layer. In fact, compare the 12z and 18z ob soundings from TOP, which pretty much shows the moist layer mixing out even further (from the strong convective mixing) -- with the 18z TOP showing a hydrolapse right above the surface! I'm not totally saying the shallow moisture was the problem... But the small 0-1km SRH (e.g. 50-100m2/s2) definitely didn't help any potential significant tornadic activity.

The shallow boundary layer moisture also helped contribute to high LCLs over a lot of the warm sector (per SPC mesoanalysis, around 1400-1600m~ AGL invof most of the KS activity) which also didn't help tornado potential. Take the one supercell near Junction City, KS yesterday afternoon, which showed quite a bit of promise (per ICT and TOP radars) with strong rotational velocity in the lowest SRV tilts for at least a half hour (which prompted the TOR issued by TOP) but the rotation quickly was lost as it moved north-northeast (at a decent clip of about 55-65mph). In addition, thermodynamically speaking, yesterday reminded me of last Saturday in the eastern TX panhandle/western OK (with our supercell near Sayer/Elk City looking awesome with a striated appearance and rotating wall cloud with strong inflow) with our storm quickly losing low-level rotation and turning to outflow dominant crap, owed to

1. Weak low-level shear (e.g. 50-100m2/s2 0-1km SRH)
2. High LCLs owed to a dry boundary layer (very low boundary layer RH / large Td depressions) in turn allowing for stronger evaporational cooling within the supercell's downdraft, which will tend to lead to greater outflow dominance (and destroying the potential for low-level mesocyclones/tornado development) within storms

The storm of the day appears to have been well documented by numerous chasers (e.g. Darin, Dick, Mike H, JB Dixon and at least a handful of others) and this storm was the closest to the surface low than any others (and perhaps ingested roughly ~100m2/s2 0-1km SRH and ~1500j/kg MLCAPE -- perhaps less once the storm approached Hanover and produced those tornadoes) but quickly weakened as it moved into cooler and drier air in southeast NE (with even higher LCLs) and quickly destroyed itself as it moved through Beatrice (and likely began to feed off inflow parcels above the surface layer). Most of yesterday's 19 tornado reports were from that supercell (about a dozen of them)! At any rate, if we would have gotten stronger low-level shear (and lower LCLs) during peak heating then we would have probably seen more tornadoes across KS (and into NE) as the surface pressure falls led to an isallobaric response in low-level wind fields -- by backing them within a matter of a couple hours during the mid-afternoon as the sfc low shifted northeast -- and increased the low-level shear quite a bit (0-1km SRH increased from 50-100m2/s2 to 250-300m2/s2 in portions of eastern KS between 20z and 23z) but MLCAPE had already decreased by the evening and the high LCLs certainly didn't help tornado potential.
 
I was getting discouraged that the dewpoint in Manhattan was at 60 and then fell all of a sudden to the 55 area, along with much of NE KS. This had to be the reason the Junction City-Manhattan storm did not produce. It also didn't help that another cell to the south of Manhattan decided to break to speed limit to merge with the decent looking cell. Looking on the southern end as it passed through, it definitely looked like LCLs were way too high for anything. Disappointing for a very strong system, which is doing it's damage in the south today (April 7th).

If it wasn't for the southern cell, I wouldn't have gotten a few shots of quarter to ping-pong ball sized hail in the SE part of Manhattan.
 
The SPC website has confirmed that there was a tornado to the south of Adams, NE. Local news stations were reporting damage, now we know what caused it.
 
It's been annoying me all day that I actually went to the effort of CHECKING the LCL numbers before leaving work yesterday, knowing full well that they were way high at the time. I even posted about it in the FCST thread for heaven sakes ... little did I know how much this one statement would have made a difference had I just acted on what we were seeing:

Originally posted by myself
We could stand more in the way of Theta-e and quality deep moisture as well ... this will take a little time this afternoon to really develop. MNK is reporting 79/58 ... Junction City 75/61. Not hard to see where moisture is already starting to stack. LCLs and LFCs in the forecast target also have a ways to fall before we are ready for surface-based convection.

... but I flew out of here on total faith that things would modify and those numbers would drop. Just shows how valuable obs can really be on the day of. Even though we managed to catch up with a good storm, it ended up being a ton of work (and not nearly as much to show for it as the folks who were one county west) ... definitely not the situation I had been expecting of being able to just run out and bag one and come home. lol
 
One other post-event observation...recall that the SPC outlook noted the presence of surface low over NE but mentioned the expectation of another surface low to develop over western KS. As it turned out out, although the NE low troughed down into N Central KS, the isobars never closed around any secondary KS low, and by peak diurnal heating time, the strongest low-level helicity (over W IA) was well N of the crest of the instability axis. As noted by others, not only did LCL's run into a brick wall close to KC metro, LFC's were also very high -- the case study of dissipation was a cell over Miami Co, KS that began with a very nice kidney bean shape, consistent with all of the other cells along that nice negatively-tilted line, but then just evaporated.

As it turned out, the key factors were limited in space and time, but I do not second guess the SPC at all for the High Risk outlook. An overlap in parameters of perhaps one more hour in time or 70 miles in space would have resulted in an outbreak of exponential proportions to actual.

Seems to me if anyone figures out a way to truly forecast the N/S orientation of lee cyclogenesis, that would come pretty close to the holy grail of chase targeting on the plains.

One other bigger picture comment: it seems the traditional dry line has move about 1/2 of a state east so far this season. Taking a long view of history, from time to time the "desert" has done this little dance to the east, and sometimes it has lasted through two or three seasons. No prediction from here, but a good rule of thumb on pattern changes like this is to expect more of the same until mother nature has firmly demonstrated a reversal of course. I can't help but believe that at least some feedback loop on evapotranspiration has set in. For now, go east, young man.
 
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