10/13/07 FCST: KS/OK/TX/CO

[Dick McGowan]

Nice setup for the weekend, assuming everything verifies. Great directional shear, a nice deep surface low, nice dryline, but marginal dewpoints. GFS seems to be quicker with the timing of the h5 jet, while the WRF is a little slower. Regardless, if upper 50 to low 60 dewpoints can make it, there will be at least a few tornadoes. If I didn't have an afternoon class, I'd probably venture out to Western KS, playing the warm front, and where the low-level jet starts to pull more to the SE. Upper-level support could be tricky also, but all models showing great divergence there by 0z. If moisture can make a comeback, this could be an active day. Still a few days out...

 

[Mark Blue]

The moisture return does seem to be the issue at this point for Saturday (mid 50 dewpoints), but there are still a few days left for the ingredients to get their act together. I'm considering the cold core play, just east to northeast of the surface low, which for now is progged to form in east central Colorado. Only time will tell though!!

 

[Brandon Lawson]

Latest NAM run shows some pooling of the dewpoints in central KS on Saturday. Perhaps this well help a little with the moisture. I was looking at some forecast soundings and this one out of Dodge City isn't half bad.
http://beta.wxcaster.com/cgi-bin/parse_skewt_trace.cgi?model=NAM&fcsthr=048&STATIONID=KDDC

(I tried uploading the image to photobucket, but it shrinks the image and quality of the picture)

 

[Eddie Natenberg]

A few days I would have never thought that stuff would break the cap on Saturday but the way the NAM is handling this next trough, I must say I am very impressed. Backed 850 winds near the low in SW KS just shows how strong the AGEO flow is due to the PGF, jeez the 00z NAM is really coming in line the GFS finally, fun stuff! But errrr, even if the cap doesn't break, I might start chasing pressure falls (thats the SDS talking or maybe I just love synoptic!)

Anyway, If Saturday starts off with cloudy fog that burns off and a banging return flow, count me in. MY2cents: You can never loose with this much DPVA!

Current Target: Coldwater, KS.

 

[Brandon Lawson]

As of right now, I'd say Saturday is starting to look better than Sunday. The NAM is showing more cape in the area of 2500-3000 J/Kg and better winds with the surface low still in CO. Granted it's only in a small isolated area and this according to the NAM, which ultimately failed last weekend. I wouldn't be surprised to see everything flip flop again tomorrow, but I'm keeping an eye out for SW Kansas on Saturday. I'll wait till the 00z GFS run comes out before I let myself get too excited.

 

[Gabe Garfield]

I don't know if Saturday looks better than Sunday, but it very well may turn out to be (if strong forcing on Sunday leads to a convective mess). Saturday shows real promise, especially in NW KS where a warm front will be lifting through the day. Deep-layer shear should be more than sufficient for supercells in the central High Plains, where easterly surface winds veer to ~40 kts at 500 mb. Low-level shear should also be very impressive in this area, according to the NAM. In my opinion, the best op for tornadoes will be in NW KS, due to cooler mid-level temps, better low-level shear than further south, lower LCLs near the boundary, and the baroclinic generation of vorticity along the boundary. Nevertheless, supercells are possible along the entire length of the dryline, and there may be a Caprock surprise to be had.

Gabe

 

[Brandon Lawson]

Even with the cap, I think I'm willing to take a chance on busting tomorrow in NW Kansas. The best shear and lapse rates are farther north, west of Hill City, but the less frightening cap is around Dodge City. I guess I may play the warm front, or follow my nose along the dryline north of Dodge City. If I fail, I can always hope for Sunday to salvage my pride. Maybe I should bring a flashlight, too.

 

[Brandon Ivey]

Yeah I think I will have to venture out as well. It may be a bust for diurinal activity but nocturnal activity is almost certain. Just depends on if you like chasing elevated activity in the dark. I don't mind...a storm is a storm. My target for trying to bag that isolated supercell that develops and produces before the sun goes down is just to the south of the Goodland/Colby area. If moisture quality was not such an issue then I would be a little more excited, but you have to play the cards you get dealt. Everything else looks good other than moisture. Nice hodographs, forecast sounding are looking good for the most part. It's a roll of the dice.

 

[Brett Roberts]

The 12z RUC is making things interesting again for today. Continuing the southward shift in the low/WF placement, it also breaks out convection over the central and north-central TX Panhandle late this afternoon in an environment with 2500+ SBCAPE and a weakened cap, along with impressive shear. Of course, the new 12z NAM shows no such precip in the warm sector, but still weakens the cap enough to hope for a miracle around LBL-GUY.

I'm not sure what to make of this, especially since SPC has not even outlooked anywhere south of the OK/KS border with any probabilities. If nothing else, at least things look a bit closer for those of us based on the Southern Plains if the RUC solution were to come to fruition.

 

[Jeff Snyder]

I've been back and forth (go or no-go) for the past few hours, and I'm still undecided. The RUC forecast soundings show fantastic hodographs / wind profiles across much of southwestern KS this afternoon and evening, with very impressive shear in southwestern KS near LBL as winds back to the east on the east-northeast side of the SFC low. The 12z NAM is also showing nice shear profiles in this area as well. My primary hesitation at this time involves initiation. I continue to think the dewpoints will be in the 57-59F range by afternoon across southwestern KS,which won't help LCL height much. In addition, morning DDC and AMA soundings show relatively shallow moisture, which indicates that Tds may drop this afternoon as the boundary layer deepens. Both the 12z RUC and 12z NAM depleted CINH in a narrow corridor from near DDC to LBL, then southward to near Perryton. The conditional probability of supercells is quite high, but the absolute probability of warm-sector, surface-based initiation seems quite low given capping concerns.

Since tomorrow certainly doesn't look like a guarantee (instability issues, timing issues, etc -- will we see robust convective development before 6pm in order to have hope of mature supercells before sunsetn?), I hate the idea of blowing off today. However, I have enough stuff to do that the most prudent course of action is to chase one day. Given my concerns over Tds (and the effect on CINH, initiation, LCL height), I leaning towards letting today pass. If I do end up heading out, it'll probably be towards LBL, and I like the LBL-DDC-Ulysses wedge.

 

[Andrea Griffa]

I've been back and forth (go or no-go) for the past few hours, and I'm still undecided. The RUC forecast soundings show fantastic hodographs / wind profiles across much of southwestern KS this afternoon and evening, with very impressive shear in southwestern KS near LBL as winds back to the east on the east-northeast side of the SFC low. The 12z NAM is also showing nice shear profiles in this area as well. My primary hesitation at this time involves initiation. I continue to think the dewpoints will be in the 57-59F range by afternoon across southwestern KS,which won't help LCL height much. In addition, morning DDC and AMA soundings show relatively shallow moisture, which indicates that Tds may drop this afternoon as the boundary layer deepens. Both the 12z RUC and 12z NAM depleted CINH in a narrow corridor from near DDC to LBL, then southward to near Perryton. The conditional probability of supercells is quite high, but the absolute probability of warm-sector, surface-based initiation seems quite low given capping concerns.

Since tomorrow certainly doesn't look like a guarantee (instability issues, timing issues, etc -- will we see robust convective development before 6pm in order to have hope of mature supercells before sunsetn?), I hate the idea of blowing off today. However, I have enough stuff to do that the most prudent course of action is to chase one day. Given my concerns over Tds (and the effect on CINH, initiation, LCL height), I leaning towards letting today pass. If I do end up heading out, it'll probably be towards LBL, and I like the LBL-DDC-Ulysses wedge.

The cap remains really a concern as both WRF and Ruc seem to put very warm T at 850mb; anyway it seems there's a hope along the southern part of the dryline in Perryton's neck of the woods, where models give some convective precipitation and impressive shear even if 850T is very high.
Anyway, at this point, watching those models, it seems more probable to have convection on the northeast side of the SFC low in North -Central Ks where there are lower 850 Ts.

 

[Brandon Ivey]

I agree with Brett and Jeff. Latest Ruc model supports this with convection in the OK/TX panhandle this evening. 4km wrf also shows a cell developing around the dodge city area. I think low clouds will keep the warm front further south as opposed to it making it to the KS/NE border like previous runs had depicted. Sould be a nice supercell or two out there by sunset. Looks like the warm front/dryline intersection will end up somewhere in SW Kansas this evening. I am going to play the OK panhandle SW Kansas area this evening.

 

[Brandon Lawson]

Well, it doesn't exactly look wonderful, but I've been thinking about chasing today since early last week. I too would be disappointed if anything happened today and Sunday fell apart.

The 4KM WRF does have a lone cell exploding right around 00z north of Dodge City and the Ruc has been consistent in showing some precipitation breaking out in the texas/oklahoma panhandle for its last two runs.

Long story short... I've been talking with Brett Roberts on the phone and we are going to head out just for the heck of it. Perhaps some unforeseen factor will aid in breaking the cap today and we'll get lucky. I'll have my cell phone on me if anyone else goes out, gets bored and wants to chat. 417-499-8789

I think we'll head up to Woodward, OK and decide on where to go from there, after we get the chance to look at some more data.

Oh I almost forgot. I better go ahead and bring my human-sized lucky rabbits foot. We may need it.

 

[Tony Laubach]

I think I've lost all faith in today for my NW Kansas target... the main issue screaming at me right now is the cloud cover, not to mention it looks as if the SFC low is already sitting over central Kansas as evident in SFC wind flow out of the north in eastern Colorado. SW Kansas looks like the best play ATTM, but I'm sitting on the edge of too late from here in Denver. It looks as if a secondary low is tying to form along the CO/NM border where SFC pressure is a bit lower and there are a couple obs showing a weak cyclone in the region. Whether that will amount to anything to swing around the winds in Kansas, I don't know. None-the-less, I think I am going to make a last second back out.

 

[Andrew Stoller]

Something magical may happen in the Oklahoma/Texas Panhandles to southwest Kansas me thinks. RUC is showing upwards of 2500 j/kg CAPE, insane helicity, and it's breaking out nice precipitation at around 2300Z. Should provide at least an hour or two of good daylight to see what happens. Dewpoints and spreads may put a dead halt on any tornado threat, but there's the opportunity for a nice photogenic, structured supercell or two.

I agree Tony; it's majorly socked in northward with temps only in the low to mid 50s.