3/27/10 FCST: KS/OK/TX

[Ben McMillan]

Tonight’s 00z GFS shows a 998mb surface low on the Kansas-Oklahoma border with moderate-strong flow accompanying it in the mid and upper levels. Model consistency on this southern piece of energy ejecting southeastward has been meager at best, but I think with the continued strengthening of the surface low and the forecast increase in moisture this makes it a day worth watching.

 

[Connor McCrorey]

And, it's a Saturday! I'm keeping an eye on this day as well. CAPE nearing 2000 J/Kg for the first time this year looks possible between northern Texas and southern Kansas, with a southerly 35 kt jet at 850 mb and 500mb flow near 50 kts out of the WSW. Dewpoints in the upper 50s may not make too many people happy, but it's better than anything we've seen so far this year, and this certainly hasn't been a bad March. I like the nice N/S orientation of the dryline as well.

 

[Jason Boggs]

A day to watch amongst a few days in the end of March-1st of April time period.

Not too many negative factors from what I've seen other than cool temps in south central KS may limit the CAPE potential, but other factors look pretty decent. Decent Td will advect northward with the approach of the low. Low to mid 50's Td will probably be achieved in South central KS and Td in the upper 50's may be a good bet somewhere in SW OK or Central OK. Right now, I'm looking more at the possibility of chasing in OK rather than KS, but it's still a few days out and many things will change.

Just for sh*ts and giggles...TARGET: FAIRVIEW, OK

 

[Eric Sipes]

I pretty well agree with Jason on this one. Some of the limiting factors include possible cloud cover and somewhat low surface temps which could limit SBCAPE. Although, if clouds break and the 1500-2000 J/kg SBCAPE can verify early enough, we're in business. This really looks to be the best potential so far this year.

It's still a ways out but, I'm prefering the dl in W OK right now. With better moisture, higher surface temps, and 55kt SW H5 winds, it looks to have the best potential. That being said, the cap could hold off initiation until sunset or later. On the other hand, the low will have better 0-1km SRH and initiation will occur sooner. It's a real coin toss.

If it still looks the same on Sat morning (unlikely), I'll likely chose a middleground target. Like Jason, I think Fairview, OK would be a good bet.

View my complete forecast HERE

-Eric

 

[Jacob Ferden]

I tend to agree in general with most of what Jason and Eric have said. Obviously, it means nothing this far out, but based off the 00z GFS runs I have been looking at, the best target to me appears to be the dryline in southwest Oklahoma / western North Texas, but capping is a concern. CAPE AoA 1500 J/kg is progged in a narrow tongue just ahead of the dryline. Nice SW flow, shear looks great, good speed at H5 and H7, good directional shear, nicely backed at the surface.

Then again, closer to the surface low, you don't have the capping issue, making it easier for storms to form. However, moisture becomes more of a concern the further north you go.

It this were tomorrow, I would go for the southern area. Given it's still several days out, it's merely talk. Suffice it to say, it looks to me to be by far the best setup so far in the southern plains this season, and given it's on a weekend, I'll likely be chasing.

 

[Adam Lucio]

Taking a peak at the sounding shows some pretty steep lapse rates, but the moisture looks to be somewhat shallow. Very cold temps aloft are causing the GFS to spit out the generous CAPE values it seems.

http://www.twisterdata.com/index.ph...iew=large&archive=false&sounding=y&sndclick=y

The hodo looks decent, nice curvature but the surface flow is a bit weak. The upper 50s dews progged along with the mid to upper 60s surface temps will get the job done, however I seem to notice the models tend to underestimate temps this time of the year so I wouldn't be surprised to see a larger spread. Also, this looks to be one of those "just in time" type moisture return scenarios with dews in the morning only progged to be in the low to mid 40s and with the weak surface flow I wonder if it will be able to advect in time.

Definitely bears watching though. Ill be keeping an eye on it for sure as it has my interest.

 

[Niccolò Ubalducci]

Preliminary target: Altus -OK- with a good way N-S on road 283 and W-E on road 62.

I trust in the area where the ground winds bend more to WNW and where the DryLine becomes closer.

 

[Shane Adams]

The northern target looks solid ala 3-8 or 3-10 via the cold pool aloft at h5, but the GFS is also hinting at a true WS dryline bulge in SW Oklahoma. To my eyes the shear seems as good as we've seen all year, with a nice LLJ which is finally not displaced 100 miles east of the main energy. It's only been a few runs now, but the trend with the GFS so far in '10 is for it to stay rather consistent with a system if it can hang around a few days. The meager moisture return (a 2010 staple thus far) doesn't worry me, as it seems to have been slightly under-done on a few earlier systems this year.

My confidence in this system is probably higher than I'm admitting to, because I'm actually posting about it five days out. We'll all find out together I guess.

 

[Skip Talbot]

This setup has only been present on three runs of the GFS, so I'm not sure I buy into it yet. Also, what went from potentially the best setup so far this year on the 0z run, now looks more like a marginal opportunity for local chasers on the 6z run. The ECMWF, however, is also showing a system passing through the southern Plains on the 27th, so hopefully that 6z GFS run was off and its locking in on a solution more like the 0z run.

The three previous runs before the 6z run were showing a potential cold core setup over southern Kansas with a stacked low over the panhandles/SW Kansas. This area has my attention the most as it looks like it could make the best use of the still relatively meager dewpoints (forecasted to be in the low 50's) underneath the steep lapse rates created by the 500 mb cold pool. Areas to the south in western OK and TX also look nice with instability forecasted >1000 J/Kg thanks to 55+ dewpoints, but I'm more skeptical about this area. The 850's are much more veered thanks to the stacked system, and the 0z run might be an outlier showing excessive instability and moisture return. Either way, several runs and more than one model are showing a potential chase op on the 27th so this is definitely one to watch.

 

[Adam Penney]

How quickly things can change. The 12Z GFS basically just trashed this setup, with exception of perhaps NE TX and WC AR.

850mb winds are now out of the NW A0A 35 knts across the western half of Oklahoma with very meager dewpoints. Even in the possible favorable chaer area, SBCAPE has been reduced to 500-750 J/kg. Im hoping for a turn for the better. There is still time.

 

[Bryan Draper]

18z looks like it brought back some form of a low.. dewpoints don't look real great but there might be some hope. It looks like just west of dfw towards wichita falls might be of interest. HOWEVER I'm really new to reading these models so if I'm way off i apologize. But never the less it looks like a low is back in the model

 

[matt patterson]

I may be looking at this all wrong, but a silver lining to Saturday (at least here in OK) would be that we may have a pretty decent shot of a Cold Core setup.. 500 temps are forecast to be in the -20 to -25 range and getting upper 40s/low50s Tds doesnt seem like that much of a stretch with a fairly strong sfc low. Is it the setup we were looking for 2 days ago..... NO, but it is a saturday so it may be worth a shot if we could get this thing to verify and being Tuesday you must take this Cum Granis Salis!

 

[Skip Talbot]

I agree with Matt about the cold core setup. The 12z NAM is now in range and in pretty good agreement with the 12z GFS. Both are showing a stacked low with a cut off 500 mb low over south central KS/north central OK by Saturday evening. With dewpoints in the low 50's forecast to wrap around the surface low and the -20C temps aloft, it has the ingredients of a classic cold core setup. However, the timing looks like it might be a little off. Ideally, I'd like to see those dewpoints established by early afternoon to take advantage of the solar heating and low level lapse rates. At noon though both models are still showing dewpoints in the low 40's. By the time we get better moisture advection, we might lose our low level lapse rates to take advantage of it. There is also quite a bit of precip being plotted on the north end of the surface low on the NAM and GFS, that could hinder the cold core setup quite bit. In the warm sector of eastern OK, there is better moisture and CAPE forecasted over 1000 J/Kg along with cold air advection aloft. This area could see some more substantial storms including supercells given the impressive speed and directional shear that also exists in this area. Storm motions will be higher though and send any cells flying off into the jungles of western AR. Given the problems with the cold core setup to the north and the storm motions over bad terrain in the warm sector play to the south, I'd say both areas look about the same right now for chasing. Its going to be a trade off between picking the right cell from a bunch of unimpressive low topped cells struggling in an area with existing precip, to a frustrating pursuit of more significant yet faster storms through the jungles of eastern OK and western AR.

 

[Chris Wilburn]

I pretty much agree with Skip's assessment above based on the 12z NAM data. I would like to see dew's higher than right at 40 by 18z, but they do reach low 50's by 00z in a small swath of area in eastern OK. CAPE is close to 1,000 J/kg in a small area and there is a larger area of 500 J/kg which should be enough. Nice surface low in southern KS/northern OK by 00z with a closed 500mb nearby. 500mb temps. near or just above -20 C should create some fairly steep lapse rates. It appears everything is there for a possible cold core setup for sure. Storms will quickly move into the unfavorable terrain of eastern OK and western and northwestern AR. I would play extreme NE OK from say Bartlesville down to Tulsa and over towards Pryor and up to Miami where terrain isn't that much of an issue. Setup looks similar to March 10th as things stand now. If we can actually get the position of the lows to verify and maintain the closed nature of the 500mb we should be in business. Also, if dews can actually reach 50 to low 50's with the forecasted 500-1,000 CAPE that will also greatly help. An area with more back surface winds may play a key role as well.

 

[Brian Stertz]

Still looks like a small window for supercells Sat. afternoon ...particularly across SE Kansas...WC/SW Missouri...and possibly down into extreme NE Oklahoma/NW Arkansas. Although good LL moisture is lacking, there is a considerable amt. of vorticity and steep lapse rates that should overcome the apparent LL moisture deficiency. It looks like there is also the good chance for low topped supercell development in the dry slot zone and southeast of the main vort somwhere between Emporia and Coffeyville KS. The small storms should be rocketing northeast so chasing may be quite a challenge. Still lots of time to watch things on this setup. 12z NAM data not as exciting as last night's...but still looks like there will be a few to maybe gawk at as they race by.