5/18/04 FCST: Southern/High Plains


Looks to be two possible interesting chase areas developing on Tuesday. One in unstable air, but with mediocre deep-level wind profiles, over southern Central KS, and one with better shear profiles, but lower instability (lower moisture) over the High Plains of Colorado. Definitely worth keeping an eye on.
agreed !!

I agree, looks good for Tuesday and also tomorrow !!!
I'm eyeing SW Kansas tomorrow !!! :shock:

I'm not so good are reading charts and all, but on Weathertap, it shows tomorrow evening that a surface low develops in SW Kansas, with frontal boundary extending ENE through Kansas, dryline sharpens and extends through panhandles.

Could be a good show tomorrow. Who knows ??
Will likely end up sleeping overnight someplace in Kansas after Monday, so will basically be in the area when I wake up Tuesday. No real target area defined yet, but will likely be out for the second day of this week. Will go further into those details tomorrow pending how things go.
Heading BACK out to Kansas tomorrow from WV in time for Tuesday's event, staying for what will hopefully be a great 7 to 10 day chase trip in the central-southern Plains. Hoping these potential setups come to pass!
The new 12z ETA is out and things are looking up. ETA forecasts strong CAPE (3500-4000 J/kg) to build in southern KS from near DDC to ICT (if not slightly south of that line). 850mb flow is slightly backed to the SE, which isn't the best of news, but it does help contribute to 200-300 m2/s2 helicity, which sure isn't bad with ~4000 CAPE. Mid-level flow is rather weak, but doable given instability and low-level shear. I'm really liking the area between (sounds familiar...) Medicine Lodge and Wichita.
I'll be playing the DCVZ in Colorado. Setup looks to be very similar to May 10th when a slow moving supercell dropped 7 tornadoes within an hour's drive of Denver.

From the NWS outlook:
there will be a threat of severe weather with very healthy shear reminiscent of last monday.
0-3 km helicity progged anywhere from 150-250 m2/s2 by tuesday
afternoon. capes 1000-2000 j/kg.
I don't really understand the next Day2, since the ETA is showing a breakable cap by afternoon, assuming convergence along the front/dl/outflow boundaries... In addition, 0-6km deep layer shear is progged to be quite strong (compared to what we've seen this year) at 50-60kts over central and eastern KS... This, along with 3000-4000 CAPE and 250+ helicity still supports tornadic supercells. The only real fly-in-the-ointment now would either be insufficient forcing for the given capping, or the orientation of the front/OFBs by afternoon. Since 0-6km shear vector is easterly, we'd want a SW/NE or S/N boundary to support discrete supercells. If the front comes along and lays out E/W, there may be some issues with regards to discrete activity...
From my analysis... (let me add rookie analysis) it does look like things are setting up to stay fairly active from May 18th - 28th for the S. Central Plains area.

Would others agree / disagree?
Well after looking at the 0z eta I am going to skip out of class early and head up to KS, it looks to be very similar to 12 May. The directional shear looks to be fantastic, along with CAPE values >2500, LI of -6 and dp's around 60-65. Also theta-e values look to be very good again, much like 12 May. I am not sure yet but will probably target the dryline punch in S. KS.
Have to play tomorrow by ear (would have to take some time off of work), but it's worth noting the 00Z eta initialized about 3F too high with dewpoints tonight (~66 analyzed vs. ~63 observed) over Oklahoma and North Texas. Looking back at today's surface charts over Oklahoma and Texas, the dewpoints fell into the lower 60s upon afternoon mixing. The 00Z soundings show boundary layer mixing ratios of ~12 g/kg.

There will be some "pooling" of moisture along the remnant boundary. But in all, I think dewpoints in southern Kansas will struggle to get to ~64, as opposed to the upper 60s with 14-16 g/kg mixing ratios during last week's event. Throw in more clouds and a stronger capping inversion than last week, and there is a much higher clear-sky bust potential tomorrow.

Will evaluate the strength of the cap and moisture pooling late tomorrow morning to decide whether the risk is worth the drive from Norman.
Originally posted by Kevin Scharfenberg
Have to play tomorrow by ear (would have to take some time off of work), but it's worth noting the 00Z eta initialized about 3F too high with dewpoints tonight (~66 analyzed vs. ~63 observed) over Oklahoma and North Texas. Looking back at today's surface charts over Oklahoma and Texas, the dewpoints fell into the lower 60s upon afternoon mixing. The 00Z soundings show boundary layer mixing ratios of ~12 g/kg.

Was wondering what happened ... I chased a totally pooped-out boundary today. The crazy thing was that I could see that the storms were worthless from forty miles away and I still chased them in the hopes that they would somehow miraculously generate into something interesting. They didn't. A few power CGs today though -
I have some concerns about tomorrow as well. Seems like the models have been underestimating the strength of the CAP the past few days. For example, as I was returning home yesterday from my chasecation I hung out in Clovis for about 4 hours hoping for some initiation along the dryline in the afternoon. SPC had the vicinty in a slt risk and boundary layer conditions looked good with 30mph S-SE winds in Clovis and a dew in the upper 50s and a definite moist profile from the surface up. Very good for 4500 feet elevation. Also VERY sharp dryline as dews west of Clovis were in the teens. Needless to say, SLT risk with 2% TOR lasted thru the 20Z outlook.

Anyway, only saw a couple of cumulus towers try and go around 4-5pm. After viewing the 00z AMA sounding after I returned home, it appeared that the models completely missed a pronounced warm nose around 700mb which led to a stronger CAP and a clear air bust.

700mb temp TONIGHT in ABQ as recorded in the 00Z sounding is 13C; indicative of a strong CAP. With SW flow at this level (albeit medicore), this type of atmosphere could be advected NE into tomorrow's target area which could cause a more pronounced CAP tomorrow than models indicate. 700temps as high as 16C were extrapolated across central NM as of the 00z RUC. See:


Tomorrow morning, however, these extremely warm 700 temps are forecasted to decrease, BUT notice how the bubble of warm air is advected NE over the OK/TX panhandles:


If the bubble of warm air stays as warm (or nearly as warm) as it is currently, it could cause some major problems tomorrow.

Then again, I am definitely NOT a professional forecaster so this is literally just my "2 cents" :D
Tuesday evening's prospects certainly look interesting as an area of 3000 J/kg CAPE is progged over south central Kansas at 0Z. A bullseye of 200+ 1 km helicity is forecast over southeastern Kansas, with 400-450 m^2/s^2 3km helicity. Eta forecasts strong southerly flow at 850, drawing up some GoM moisture to bring the sfc Tds to 70F or greater in southeastern KS. Combined with low RH at 500mb, this will lead to LIs approaching -8 in the target area. The shear looks pretty good, but the weak winds at H7 are of some concern. The primary concern, however, is the strong cap forecast to be over the target area. Eta does not forecast a break on Tuesday, so convective development is highly questionable. That having been said, if the cap does break, or even weaken, sufficient energy exists to create explosive development with the potential for some great severe storms.

Kevin and others have some very valid points.. however, just check this out: http://www.wxcaster.com/modelskewts.php3?f...STATIONID=_KICT ... {Click ETA} ... Ok, but 4700 j/kg CAPE and 370 helicity doesn't come around too often! We're talking almost 180 degrees directional shear through the column, and CINH on that sounding is only ~20 (well, technically -20)... Whatever the case, IF we can break the cap, I think the chase is on! I'm still very pumped about it, as RUC advects upper 60 tds northward in KS by late morning...
I'm a bit less concerned about moisture availablity after viewing some METARS this morning. It turns out the 00z ETA from yesterday actually underestimated the moisture in OK/KS this morning. Forecast for OKC DP was 65 but the ob at 8am was 69.

ALSO the ICT 8am DP of 67 surpasses the 00z ETA forecast of 63. This is a good thing of course.

Perhaps MOST interesting is how the ETA completely missed the frontal boundary location this morning. Current ob out of DDC is 58/58 with fog and NE winds. ETA had a forecast of 62/62 with a SE wind. Hmm....

I would opine on the CAP but I can't access the 12z soundings yet.
I am kinda concerned with the winds now. Yesterday it looked GREAT, now not so great. The directional shear is not nearly what it was looking to be yesterday and the area of greatest instability shifted from W. KS to E.KS. I'm not sure if I am going to go today, gonna have to wait for a while.
I know I am playing hot cold right now but wow, those CAPE values on the 12z RUC look to be 4000 j/kg in SE KS. The winds though, not as impressive as yesterday look to be backing to the SE a bit at the SFC.

EDIT: CAPE values of 4500 j/kg in SE KS
Trying to decide how I want to play today. If I chase Colorado, I'll lose out on tomorrow's action in Iowa. If I hang around here and chill, I can drive into Lincoln, NE and get ready for tomorrow's action.

I woke up in WaKenney in a cool drizzle which quickly shot my nearby hopes to crap. I just arrived in Hays and am sitting at the library gathering info on today and tomorrow to decide on how to play things out.

Henceforth, I'll be back with my decision in a bit! 8)
I have to go to class at 1030 but I'm thinking of leaving early, around 1200 and heading to SE KS, not sure what town but in that area. If the CAPE values hold true through the next couple RUC runs I dont think I can pass it up.
RUC is forecasting a pretty Dynamo day near ICT... Still don't know what to do with the fact that 6z ETA and current RUC are 150-200 miles off in regards to instability axis location... still like the ~5000 CAPE and 200-300 helicity near ICT, AND <25 CINH... So, it looks good from here... still many uncertainties, but really seems like a can't miss type of situation given the RUC forecasts... Heading up to ICT soon and will decide from there..
Unfortunately the Unidata circuit missed most of the soundings this morning. I'm a little less worried about moisture this morning looking at the 12Z Norman sounding, with 14 g/kg in the boundary layer. This probably snuck up in a ribbon east of FWD and west of SHV. There should be good pooling of mid-upper 60s dewpoints near the boundary intersection in the Medicine Lodge area this afternoon.

The RUC is showing its usual bias of over-mixing ahead of the dryline. I'll put down money that the Enid/Watonga area will NOT be 100/60 this afternoon. The eta is likely to be handling the thermodynamics much better, so I think the instability hot spot will be near the triple point around Medicine Lodge.

It will still be really tough to get through the capping inversion today, with subsidence behind the departing shortwave trough and rising heights at mid-levels. Will make a final decision in about 3 hours.
Really leaning towards the DCVZ today.. last time the DCVZ was in play, I blew 7 tornadoes on a hailstorm south of Cheyenne.. in theory, I could make it to Iowa in time for tomorrow on a marathon chase trip getting out. Right now, my preliminary target should I choose to head west would be around the Deer Trail area, just off I-70 between Limon and Denver. I believe that things too far east from Denver will not be good for storms, so I imagine storms will form right up against the front range, move out into the Eastern Plains; go tornatic, then move into unfavorable air to their east and fizzle. Still debating, but am definately leaning that direction.
Trigger pulled; going to shoot west and play the DCVZ! With clouds starting to clear, the sun will quickly heat things up in the area. I am going to target a place between Limon, Denver, and Colorado Springs along either I-70, US-24, or CO-86. My gut instinct tells me this is the right choice for the day. :D Weird thing, this weather stuff.. here I am in Kansas targeting the Denver-area! :lol: