Mike Smith
I'm still liking IAB to Perry.
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2/27/11 FCST: KS, OK, TX, MO, IL, AR, LA, MS
- Thread starter Mark Sefried
- Start date
Kevin Crawmer
EF2
My thoughts from a chasing standpoint:
Positive
Strong warm front with a sharp gradient to the north due to snow cover, snow melt, and fog/stratus.
Eastward progressing dryline
Vast warm sector that appears to have a good lid on it through the day
Strong upper level support
50-70 knot Surface to 500 bulk shear
*Opportunity to be a valuable spotter after dark
Negatives
Poor directional shear for the most part. E OK/W AR/SW MO looks interesting late in the afternoon and early evening. This lack of directional turning can be made up for with 0-1 km helicity values over 200.
850s are out of the southwest the KS/OK target until you get to the far eastern parts of those states where there is a bit of a southerly turn to help usher in moisture out of the south-southwest.
Poor chase terrain for the most part
Fast moving and after dark
I’ve been burned too many times by weak CAPE/strong shear setups as far as chasing photogenic storms
Of course the strong cap that has been discussed
I have to work Monday and I don’t feel like making a marathon trip giving the chance of a bust in terms of daytime chasing. One thing that intrigues me is if that warm front progresses north of I-70 and if the existing snow would create some kind of cold pool south of the front for a firing mechanism in the warm sector. I don’t have any prior knowledge of this…just a thought. If I were able to chase tomorrow I would probably try to hang out between Tulsa and Joplin and watch things unfold.
Good luck everyone.
Positive
Strong warm front with a sharp gradient to the north due to snow cover, snow melt, and fog/stratus.
Eastward progressing dryline
Vast warm sector that appears to have a good lid on it through the day
Strong upper level support
50-70 knot Surface to 500 bulk shear
*Opportunity to be a valuable spotter after dark
Negatives
Poor directional shear for the most part. E OK/W AR/SW MO looks interesting late in the afternoon and early evening. This lack of directional turning can be made up for with 0-1 km helicity values over 200.
850s are out of the southwest the KS/OK target until you get to the far eastern parts of those states where there is a bit of a southerly turn to help usher in moisture out of the south-southwest.
Poor chase terrain for the most part
Fast moving and after dark
I’ve been burned too many times by weak CAPE/strong shear setups as far as chasing photogenic storms
Of course the strong cap that has been discussed
I have to work Monday and I don’t feel like making a marathon trip giving the chance of a bust in terms of daytime chasing. One thing that intrigues me is if that warm front progresses north of I-70 and if the existing snow would create some kind of cold pool south of the front for a firing mechanism in the warm sector. I don’t have any prior knowledge of this…just a thought. If I were able to chase tomorrow I would probably try to hang out between Tulsa and Joplin and watch things unfold.
Good luck everyone.
cedwards
EF5
I agree with Mike Smith. (Going off of the NAM) The CAP erodes away by 21-00Z CAPE is maximized. Nice backing of the low level winds. The downside will be storm motion 30-35kt. Manageable, but difficult in the road network there.
Jeff Snyder
EF5
I have previously-scheduled and immovable commitments tomorrow afternoon in Tulsa, so I'm really going to be limited to >1 UTC activity in the area between TUL and OKC. At any rate, the 12z NAM indicates that much of the surface convergence in OK tomorrow will be provided by the Pacific cold front, with the NAM showing the dryline - Pacific front intersection somewhere in southwestern Oklahoma tomorrow. See THIS chart (36 hr sfc convergence and theta-e forecast), which shows the convergence associated with the dryline and Pac front quite well. Of course, there's nothing wrong with convergence from slow-moving Pacific fronts (which won't be slow-moving after 3z), but I'm not sure it'll be a true dryline day for northern Oklahoma. In addition, the forecast right-moving Bunkers motion for a supercell tomorrow is 40-45 kts, which isn't surprising considering the 60-75 kt 500 mb flow across the OK part of the target area tomorrow. This, obviously, is a significant "con" for chasers.
That said, if deep-moist convection can develop near OKC, there's a pretty prime-oriented surface boundary that the 12z NAM shows lying WSW-ENE across far northern OK (+/- a few counties), which may provide tornadic bliss should a supercell spend much time moving along that boundary.
Edit: The above is based largely on the 12z NAM. As such, as the 00z run comes out, the above may or may not become invalid.
That said, if deep-moist convection can develop near OKC, there's a pretty prime-oriented surface boundary that the 12z NAM shows lying WSW-ENE across far northern OK (+/- a few counties), which may provide tornadic bliss should a supercell spend much time moving along that boundary.
Edit: The above is based largely on the 12z NAM. As such, as the 00z run comes out, the above may or may not become invalid.
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cedwards
EF5
I am not liking the 00Z NAM it strengthens the cap in my target area and the CAPE is much less than the 18Z run. Chase may not be on unless things improve.
Mike Smith
Took a look at the 00Z soundings and compared them to the 12 hour forecasts from today's 12Z NAM. The moisture, and instability, are farther north than the NAM forecast.
FWD has 0.94" inches of Pw compared to a forecast of 0.6". It was forecast to have a max. CAPE of 300 at 00Z. The new sounding has a max CAPE of 1,194j.
CRP has Pw of 1.16" with max CAPE of 879j. The forecast values were 1.0" and 500j, respectively.
The 01Z RUC (which should have these initial values in its initialization) has a small area of 1,500 j over END with a very weak cap. There is a band of 1,000+ from LTS to PNC. While the RUC tends to overpredict CAPE, given that the forecast is for 19Z, those seem reasonable values for late afternoon given the FWD sounding. The RUC also has helicity values of 250+ over much of OK.
The warm front at 19Z is forecast by the RUC to extend from GAG to AAO to COU. Dryline extends from GAG to LTS to ABI. And, the RUC breaks out a couple of cells on the dryline. There is a tremendous temperature gradient from around 45° at EWK to 70° at South Haven.
The area from Perry to IAB is in the left front quadrant of a 130+kt 250mb jet stream.
Given the weak cap, I think things might go before the PVA arrives given the strong jet. The PVA arrives around 23-00Z or very shortly thereafter.
The new NAM has an even more favorable jet divergence pattern than the RUC. The 00Z warm front forecast is a little south of the RUC's 19Z forecast (WWD to CNU to COU) with light precip. in Kansas north of the wrm front and thunderstorms in SW KS on the simulated radar reflectivity (i.e., along the PVA).
From a chasing standpoint, I would probably put out a chaser's tornado watch from Chickasha to ICT on the west and Eureka, KS to 20 N of Shawnee on the east. If I had to place myself somewhere tomorrow it would probably be Blackwell.
Like many, I believe the unconditional probabilities of SVR are better in eastern OK and southeast KS later in the evening but it will likely be after dark before that occurs.
Good luck and stay safe.
FWD has 0.94" inches of Pw compared to a forecast of 0.6". It was forecast to have a max. CAPE of 300 at 00Z. The new sounding has a max CAPE of 1,194j.
CRP has Pw of 1.16" with max CAPE of 879j. The forecast values were 1.0" and 500j, respectively.
The 01Z RUC (which should have these initial values in its initialization) has a small area of 1,500 j over END with a very weak cap. There is a band of 1,000+ from LTS to PNC. While the RUC tends to overpredict CAPE, given that the forecast is for 19Z, those seem reasonable values for late afternoon given the FWD sounding. The RUC also has helicity values of 250+ over much of OK.
The warm front at 19Z is forecast by the RUC to extend from GAG to AAO to COU. Dryline extends from GAG to LTS to ABI. And, the RUC breaks out a couple of cells on the dryline. There is a tremendous temperature gradient from around 45° at EWK to 70° at South Haven.
The area from Perry to IAB is in the left front quadrant of a 130+kt 250mb jet stream.
Given the weak cap, I think things might go before the PVA arrives given the strong jet. The PVA arrives around 23-00Z or very shortly thereafter.
The new NAM has an even more favorable jet divergence pattern than the RUC. The 00Z warm front forecast is a little south of the RUC's 19Z forecast (WWD to CNU to COU) with light precip. in Kansas north of the wrm front and thunderstorms in SW KS on the simulated radar reflectivity (i.e., along the PVA).
From a chasing standpoint, I would probably put out a chaser's tornado watch from Chickasha to ICT on the west and Eureka, KS to 20 N of Shawnee on the east. If I had to place myself somewhere tomorrow it would probably be Blackwell.
Like many, I believe the unconditional probabilities of SVR are better in eastern OK and southeast KS later in the evening but it will likely be after dark before that occurs.
Good luck and stay safe.
cedwards
EF5
Thanks for that information, Mike. I will take a closer look. I was planning on heading north on I-35 to around Tonkawa based on the 18Z NAM, I was thinking initiation as early as 5pm. Of course I will look over everything in more detail in the morning. The RUC forecast is indeed encouraging.
Trey Thee
EF2
I agree, that area continues to look ripe. I hope people are paying attention to the weather tomorrow. It appears at the very least a pretty good line of SVR could move through the Tulsa metro late evening...perhaps some discrete supercells early evening. It also seems that the moisture return will be in place and if we get just two or three degrees warmer than forecast tomorrow, that could make a significant difference in the instability.
Brandon Sullivan
EF5
Just a quick note.... The 01z 18 hour RUC progs near or just above 2k CAPE by 19z across Central and Northern OK tomorrow.. This is much more generous than the NAM, but the HRRR looks to be trending similar with the surface features.. Tomorrow definitely looking good in my books... These short term models seemed to have a good handle on the event on Thursday, so I am going to pay close attention to them tonight.
There is probably just going to be a pretty narrow corridor for favored convective development before dark.. Likely where the speed max crosses the dryline, across central or northern OK.. I see a period hopefully from around 22-00z to get the show started, probably across northern OK..
Need to be really careful, and do constant analysis, because if a storm goes up to your east, its probably too late.
See everyone tomorrow
There is probably just going to be a pretty narrow corridor for favored convective development before dark.. Likely where the speed max crosses the dryline, across central or northern OK.. I see a period hopefully from around 22-00z to get the show started, probably across northern OK..
Need to be really careful, and do constant analysis, because if a storm goes up to your east, its probably too late.
See everyone tomorrow
Lanny Dean
EF5
Mike, I would like to personally thank you for your input and a wonderful post on your thoughts!
Looking at 00z NAM 21-23z seems to me to weaken CAP just enough...1100-1500j., with 250-300m2/s2 I really like the area from Wakita to Caldwell to Braman and back to Wakita which is just north and west of where Mike is interested. Here is where I think that we may see a decent punch right on the face of the dryline from the speed max. Again, great post, Mike, I appreciate it if for nothing else than to verify my thoughts.
Edit, sorry Brandon, I didn't see your post but I agree with the speed max and placement. If this is the case then we could certainly see a very nice show and possibly a decent tube or two. I think someone used the word "tornadic bliss"....good choice of words IMHO if in fact we get the placement of the speed max.
Looking at 00z NAM 21-23z seems to me to weaken CAP just enough...1100-1500j., with 250-300m2/s2 I really like the area from Wakita to Caldwell to Braman and back to Wakita which is just north and west of where Mike is interested. Here is where I think that we may see a decent punch right on the face of the dryline from the speed max. Again, great post, Mike, I appreciate it if for nothing else than to verify my thoughts.
Edit, sorry Brandon, I didn't see your post but I agree with the speed max and placement. If this is the case then we could certainly see a very nice show and possibly a decent tube or two. I think someone used the word "tornadic bliss"....good choice of words IMHO if in fact we get the placement of the speed max.
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Colt R Forney
EF0
Tomorrow definitely has potential to be an interesting event and a tough one to forecast for and as Brandon mentioned you are going to have to continuously monitor the situation closely to stay in the game. My plan is to leave from 35.16°N 97.47°W around 10am and head North on I-35 to 36.69°N 97.34°W. Then decide if I want to head east to 36.75°N 96°W or west toward the dryline around 36.41°N 97.89°W. Going to closely watch the HRRR and RUC this evening.
I think its funny that people use random small airport codes that 90% of people on stormtrack dont know where the are so the reader has to research the location to decipher where they are talking about. I saw 3 different airport codes from Wichita, KS in this thread...why not say Wichita????? or KICT a common one where everyone knows the location of. I couldnt help myself with poking a little fun at this.
I think its funny that people use random small airport codes that 90% of people on stormtrack dont know where the are so the reader has to research the location to decipher where they are talking about. I saw 3 different airport codes from Wichita, KS in this thread...why not say Wichita????? or KICT a common one where everyone knows the location of. I couldnt help myself with poking a little fun at this.
Mike Smith
Sorry, Colt. I thought people were familiar enough with KS that they knew Jabara Airport was AAO. I used it because that is where the warm front was forecast to be by the RUC, not over ICT. You'll note I did not use the codes for Eureka (13K) and Shawnee (SNL) because I thought those were too obscure.
OK, last posting of the night: The 02Z RUC only has profiler and aircraft data to update the one hour RUC "first guess" as its initial analysis so don't put high confidence in this. Nevertheless, there may be some valuable information here. The first graphic is the 20Z CAPE:
Note the tiny dot of 1,500j of CAPE right over Tonkawa and the uncapped 1000+j from PNC to SPS.
Here is the forecast helicity:
That is a value of 400+ in the Flint Hills in extreme southern KS. Most of the threat area is above 250.
Finally, and this is the most interesting:
The implied thunderstorm over END develops at 19Z on the RUC and the two other smaller cells make their debut on this forecast.
Given the jet stream at 250 mb and the rapidly increasing difluence along the KS-OK border (250mb winds from 200° at DDC and 250° at TXK), I think the RUC's convection, while perhaps an hour or two early, has a significant chance of being correct.
If so, my earlier "tornado watch" is looking pretty good.
OK, last posting of the night: The 02Z RUC only has profiler and aircraft data to update the one hour RUC "first guess" as its initial analysis so don't put high confidence in this. Nevertheless, there may be some valuable information here. The first graphic is the 20Z CAPE:
Note the tiny dot of 1,500j of CAPE right over Tonkawa and the uncapped 1000+j from PNC to SPS.
Here is the forecast helicity:
That is a value of 400+ in the Flint Hills in extreme southern KS. Most of the threat area is above 250.
Finally, and this is the most interesting:
The implied thunderstorm over END develops at 19Z on the RUC and the two other smaller cells make their debut on this forecast.
Given the jet stream at 250 mb and the rapidly increasing difluence along the KS-OK border (250mb winds from 200° at DDC and 250° at TXK), I think the RUC's convection, while perhaps an hour or two early, has a significant chance of being correct.
If so, my earlier "tornado watch" is looking pretty good.
Chris C Sanner
EF5
@Colt -- That's standard Meteorology my brotha, gotta learn those 
Ok my thoughts on tomorrow are summed up in my blog post here: http://www.tornadotitans.com/blog.php
But I hate when peeps just post links with no additional info so a cliff notes of sorts:
-Thinking the boundaries will be a bit west of the NAM's location.
-NAM isn't showing much lift from surface, which is probably why it doesn't initiate. With winds on the backside of the dryline gusting to 50 and on the front at 30, anywhere you get some favorable SElys with SWlys will see some extreme convergence for sure.
-Cap will definitely be a problem, NAM showing a ConvT of 81 in NE Oklahoma tomorrow. Forecast highs in the warm sector are 70 - 75, so that's obviously a problem. But the cap can be overcome.
-Storm motions will be 40 - 55, depending on the motion a storm takes. Thinking we want to set up ahead of the dryline a bit depending on visibility. Would like to be about 40 miles east, but blowing dust and whatnot might make visibility as such that you have to be in closer to get a good view of the towers as they go up.
-Favored area is north of I-40 in Oklahoma and extreme S. Kansas ahead of the dryline (obviously). As far as where/when, that'll take some constant monitoring of Vis Satellite and some check-ins of mesoanalysis.
Nonetheless, we'll chill out until Sunset and then that's it for us. Not going to chase storms moving 50 through C/E Oklahoma at night -- hard enough to do that in the day.
Ok my thoughts on tomorrow are summed up in my blog post here: http://www.tornadotitans.com/blog.php
But I hate when peeps just post links with no additional info so a cliff notes of sorts:
-Thinking the boundaries will be a bit west of the NAM's location.
-NAM isn't showing much lift from surface, which is probably why it doesn't initiate. With winds on the backside of the dryline gusting to 50 and on the front at 30, anywhere you get some favorable SElys with SWlys will see some extreme convergence for sure.
-Cap will definitely be a problem, NAM showing a ConvT of 81 in NE Oklahoma tomorrow. Forecast highs in the warm sector are 70 - 75, so that's obviously a problem. But the cap can be overcome.
-Storm motions will be 40 - 55, depending on the motion a storm takes. Thinking we want to set up ahead of the dryline a bit depending on visibility. Would like to be about 40 miles east, but blowing dust and whatnot might make visibility as such that you have to be in closer to get a good view of the towers as they go up.
-Favored area is north of I-40 in Oklahoma and extreme S. Kansas ahead of the dryline (obviously). As far as where/when, that'll take some constant monitoring of Vis Satellite and some check-ins of mesoanalysis.
Nonetheless, we'll chill out until Sunset and then that's it for us. Not going to chase storms moving 50 through C/E Oklahoma at night -- hard enough to do that in the day.
Zack Cooper
EF2
I am beginning to become a little more optimistic about tomorrow. I've known for a while this could be a significant outbreak, but from a chasing standpoint, have been unimpressed. However, based on the latest GFS and SREF... I think there may be a decent potential for late afternoon supercells for SE KS. I think CAPE values will easily rise to 500 j/kg... with forcing arriving and allowing the cap to break by 0z. With bulk shear 60 kts or so and better directional shear than with the last event, there could definitely be a pretty good chase potential tomorrow afternoon towards sunset.
Kevin Rolfs
I am starting to be a little more optimistic about tomorrow's chase as well. Like everyone else the model progged strength of cap had me worried about the chances initiation before sundown. But as it appears, the NAM might be an outlier compared to the GFS/RUC in holding the cap too strong. The 0Z GFS weakens the cap considerably along the dry line from central Oklahoma into south central Kansas at 21Z. The RUC is also showing a similar weakness in the cap albeit further west. So, daytime tornado potential is looking slightly better than anticipated.
As for the airport codes, I feel like using the commons ones I.E. KOUN, KICT, KDDC, KTUL.. is ok. But I often find my self looking up some pretty obscure airport codes whose location are not obvious by looking at the last three letters of the code. It definitely breaks my concentration/flow of reading to have to look it up. I would definitely use a little more discretion when using airport codes. And for the record, I've been through Wichita many many times in my life and have never heard of Jabara Airport let alone KAAO
As for the airport codes, I feel like using the commons ones I.E. KOUN, KICT, KDDC, KTUL.. is ok. But I often find my self looking up some pretty obscure airport codes whose location are not obvious by looking at the last three letters of the code. It definitely breaks my concentration/flow of reading to have to look it up. I would definitely use a little more discretion when using airport codes. And for the record, I've been through Wichita many many times in my life and have never heard of Jabara Airport let alone KAAO
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