5/19/2010 FCST: TX, OK, KS

[Jonathan Whitehead]

Tomorrow looks to be a good day for storm chasing for SRN OK/N TX. Models push the dryline east to about an SPS to CSM line by mid afternoon. Plenty of moisture and instability will be present. Cap will also not be too much a problem. The only fly in the ointment is 0-1km SRH, which appears to be lacking somewhat west of 35. Would like to see aoa 120 kts but SPC SREF has it around 70-90 with the highest shear east of 35.

Overall I dont see this as an esp high end threat, more of a middle of the road, but one I wouldnt want to miss out on. I wouldnt be surprised to see supercells as far south as I-20 tomorrow, and thats WAY south for this time of year. I plan on heading up 287 tomorrow and potentially crossing into OK on 81 depending on how things look in the morning.

 

[Matt Gingery]

I like this set up for many reasons, most of which is the supercell glue. SFC-500mb bulk shear bullseye from Clinton to Enid with winds backed at the sfc. Hodos look great. Td's in the high 60's, 3000 CAPE, with little if any convective inhibition. I am targeting NW Oklahoma as of now because there is somewhat of a CAP in this location and may hold off convection til later in the day when destabilization is maximized. Clinton Ok. to start because of data and adjust from there.

 

[Greg McLaughlin]

Supercell Glue? Can you pick that up at Home Depot? I too am starting to like northcentral Oklahoma per the 18z NAM and the latest RUC. Both models are shifting the warm sector a little further north.

 

[James Aydelott]

00z nam is still keeping the highest CAPES S of I40. Its all conjecture until the AM convection is finished and lays down where the outflow boundary will be.

 

[Greg McLaughlin]

00z nam is still keeping the highest CAPES S of I40. Its all conjecture until the AM convection is finished and lays down where the outflow boundary will be.

Wherever that OFB is, I will likely be there as well. I find it interesting the 00z RUC (runs out to 18 hours) has the morning convection shifting north into Kansas, thus allowing for more destabilization across most of central and western Oklahoma. The NAM is more bullish with convection across Oklahom and Kansas and has the warm sector further south. The NAM is known for not handling the evolution of nocturnal convection on the morning of an event. This paper gives some insight: http://www.spc.noaa.gov/publications/weiss/wrf-hrw.pdf.

In further review, the NAM and RUC are at odds with each other with regards to surface low placement, strength of upper low, instabililty, and boundary placement. I agree James, it is pure speculation until tomorrow morning.

 

[tedchaat]

I like this set up for many reasons, most of which is the supercell glue. SFC-500mb bulk shear bullseye from Clinton to Enid with winds backed at the sfc. Hodos look great. Td's in the high 60's, 3000 CAPE, with little if any convective inhibition. I am targeting NW Oklahoma as of now because there is somewhat of a CAP in this location and may hold off convection til later in the day when destabilization is maximized. Clinton Ok. to start because of data and adjust from there.

i agree with this one but mid level forcing could result in the cap breaking further south than expected depending on the cloud cover in sw okla from over night t-storms preventing surface heating in the afternoon . i think were looking at an unzipping effect from north to south ,not an mcc unzipping effect but a staggard developing effect with the dryline sharpened, and any storms that do fire up will take more of a easterly (north easterly track) giving the flow of the jet thats gonna be over sw oklahoma , the shear will be too great out west in the panhandle and will get sheared off but the ones that make it into oklahoma into the unstable air will become tanks with overshooting domes and knuckles , and with the cape the way it is , they will go very severe quick. all in all my target area would be 50 miles radius of altus oklahoma, anywhere in that area.

 

[Mike Hollingshead]

If I were chasing tomorrow I'd probably be staying away from the warmfront/ofb. Severe lack of cap and likely morning convectively enhanced cold pool up there....eh....feels messy to me. What was the date of that El Reno tornado, maybe 06. That's what I keep seeing, early gooo north. I'd be planting my butt south near the Red River ahead of the dl rather early(which is probably why I'm not chasing it). Of course last several years more often than not I'm way the heck off, so I'd get on that triple point and warm front.

18z JWG no cap

18z GAG no cap

 

[tedchaat]

If I were chasing tomorrow I'd probably be staying away from the warmfront/ofb. Severe lack of cap and likely morning convectively enhanced cold pool up there....eh....feels messy to me. What was the date of that El Reno tornado, maybe 06. That's what I keep seeing, early gooo north. I'd be planting my butt south near the Red River ahead of the dl rather early(which is probably why I'm not chasing it). Of course last several years more often than not I'm way the heck off, so I'd get on that triple point and warm front.

18z JWG no cap

18z GAG no cap

i dont care what the models say theres a cap in place but it wont last long ,LOL
and i think im 70% percent right some one message me if i am right, kk

 

[Jacob Ferden]

Preliminary Chase Target: Clinton / Weatherford, OK and points east

Chase Plan: Will probably leave Norman around 12 PM CDT. Due to this setup's proximity to home, will be ready to head back in the direction of Norman if things start to look dangerous for that area.

Reasoning: Both the 0z GFS and NAM show a potent setup for central, western, and southwestern Oklahoma for Wednesday. Will eye the triple point, with the idea of staying with storms firing near and to the east along the I-40 corridor, with the idea of basically chasing them back towards the I-35 corridor. Looking at the possibility of one or more cyclic tornadic supercells, with an attendant strong to violent tornado threat, particularly later in the afternoon and evening as storms move closer to OKC and vicinity.

 

[Mikey Gribble]

I posted a brief forecast earlier on my blog so I don't want to spend much time on it now, but I just don't see this being a good strong tornado setup. There is a lot more uncertainty with this setup than most when we're 24 hours out in my mind though. There has been so much spread with the models in regard to low level winds that its virtually impossible to accurately forecast any tornado threat right now IMO. The GFS has been wanting to veer 850mb winds while the NAM wants to back off the speeds and both models want to keep the stronger 850mb winds out over the warm sector quite a ways (which normally might be a problem but with no cap tomorrow storms should fire plenty early to realize the stronger 850mb winds farther out over the warm sector). The fate of 850mb winds tomorrow is directly tied to the tornado potential IMO.

I am seriously concerned about the total lack of a cap tomorrow afternoon. COD is out of operation so I didn't get to do the kind of forecasting I'd like to tonight btw (why can't they shut down in like August lol). Without seeing the higher resolution charts like you get on COD it is tough to tell exactly how much convection models are showing over the warm sector. There is certainly plenty of convective debris being shown along the frontal boundary, but whether or not it will develop over the western portions of the CAPE tounge or south of the front into the warm sector is tough for me to tell right now with the model products I've looked at.
Forecast hodographs are okay farther south along the dryline, but if you shove the issues of convective debris and insolation aside the paramaters look a fair amount better for cyclic tornadic storms near the warm front IMO. Strongly backing surface winds should enlarge hodographs a decent bit in the lowest km. The Clinton hodograph wasn't bad and is certainly supportive of cyclic tornadic storms given strong instability, but it just isn't enough for a persistent strong tornado threat I don't think. I think a good cyclic tornadic storm coming off the triple point seems pretty likely and a strong tornado or two is possible, but this isn't a higher end tornado threat IMO.
You never know what is going to happen in May when you throw a boundary into the mix though (especially when LCL's are low) so I'll certainly be there tomorrow to keep an eye on it lol. Right now I like the Clinton area for an initial target.
I was pretty shocked to see SPC mention a high risk. Honestly I was pretty shocked to see a moderate risk on the day 2 outlook. Personally I think this is a lower end moderate near the triple point with a higher end slight risk along the dryline. I could very easily be wrong though. Low LCL's and strongly backing surface winds along a warm front oriented pretty favorably to storm motions are definitely red flags tomorrow. It could end up surprising me.

 

[cdcollura]

Good day all,

I just arrived and am staying on the west side of OKC, possibly targeting El Reno tomorrow (actually later today) and points north and east from there.

SPC has wording that an upgrade to high-risk might be required if conditions warrent. What I really like is storm motions of 25 Knots, not 50+ as with a week and a half ago (May 10).

 

[Matthew Piechota]

For all wondering, COD will be back up working in the morning. There is construction going on at the school which caused the problems today and tonight.

We (Team COD) is in AMA for the night heading to probably sw OK tomorrow. gotta love the jet max into the area by afternoon/evening with dew points in the upper 60's possibly low 70's in the area near the TP down along the dryline with good instability with better low level lapse rates then today.

Some of the hodos for tomorrow are just insane and probably some of the best I have ever seen. I personally like around the Lawton area. We'll see what happens but good luck to all out there.

 

[Chris Hayes]

MCS moving through northern Oklahoma has left fairly decent cloud shield over the state. However, looking at the infrared animation and most recent visible satelite and some obs, it appears as if the cloud cover thismorning wont be too big of a destabiliztion inhibitor. Latest GFS and NAM runs diverge on placement of the dryline again. GFS has a more bullish push eastward at 00z while the NAM keeps it back in far western Oklahoma. GFS and RUC are more bullish on destabilization with CAPE values to 3000+. RUC is also more bullish on EHI, both 1km and 3km than the NAM is. Dry line is currently still way back in the far western Texas panhandle. Will continue to monitor everything but righ now I'm targetting a triangle from Clinton, to Altus, to Lawton.

 

[Mikey Gribble]

Thats a relief to know COD will be back up and working. Thanks for the update.
Here is a link to both the GFS and NAM hodograph for Lawton at 00Z today.
http://beta.wxcaster.com/cgi-bin/parse_skewt_trace_overlays.cgi?fcsthr=024&STATIONID=KLAW
Both have decent curvature and length, but its really not that impressive IMO. Here are some numbers from it.
0-1km SRH is 107 with NAM and 150 with GFS
0-3km SRH is 179 with GFS and 184 with NAM
0-6km is 45kts
When we were looking at forecast soundings for May 10th a week ago values were literally 4 times higher than that for 1km and 3km SRH. 0-6km shear was like 80kts or something ridiculous. The Greensburg hodograph looks like it could have given birth to todays hodograph lol. I'm not trying to be a wise ass or anything. Obviously I am missing something here because a lot of smart people are on board with this, but I haven't seen anything terribly impressive up to this point. Don't get me wrong I think it looks like a good setup for a cyclic tornadic supercell off the triple point and maybe one or two other tornadic storms farther south, but this doesn't look like a setup with an obvious strong tornado threat IMO.

 

[Greg McLaughlin]

Thats a relief to know COD will be back up and working. Thanks for the update.
Here is a link to both the GFS and NAM hodograph for Lawton at 00Z today.
http://beta.wxcaster.com/cgi-bin/parse_skewt_trace_overlays.cgi?fcsthr=024&STATIONID=KLAW
Both have decent curvature and length, but its really not that impressive IMO. Here are some numbers from it.
0-1km SRH is 107 with NAM and 150 with GFS
0-3km SRH is 179 with GFS and 184 with NAM
0-6km is 45kts
When we were looking at forecast soundings for May 10th a week ago values were literally 4 times higher than that for 1km and 3km SRH. 0-6km shear was like 80kts or something ridiculous. The Greensburg hodograph looks like it could have given birth to todays hodograph lol. I'm not trying to be a wise ass or anything. Obviously I am missing something here because a lot of smart people are on board with this, but I haven't seen anything terribly impressive up to this point. Don't get me wrong I think it looks like a good setup for a cyclic tornadic supercell off the triple point and maybe one or two other tornadic storms farther south, but this doesn't look like a setup with an obvious strong tornado threat IMO.

I see your point. If we recover in wake of this morning's convection and the outflow boundary orients itself in such a way a storm can deviate and latch onto the boundary, we can throw those forecast hodographs out the window.