cdcollura
EF5
Holding in Mooreland, OK and watching if any activity forms east of me...
Chase Case #5 (2010 Version)
- Thread starter Jesse Risley
- Start date
Dann Cianca
Was about 10 miles south of Leoti on KS 25 when the tornado touched down southwest of town. Beautiful tornado... but moving fast. Stopped and backtracked south, stopping occasionally to watch. Saw the unfortunate damage in Lydia, which was about two miles to my north at the time. Once the tornado passed and lifted, I headed back into the small outpost of Lydia, if you will. Luckily, there were no injuries. May be a bit behind, but I'm going to continue racing south ahead of the line if possible. Luckily, these storms are not spitting out a lot of hail.
SCORE!
Zack Cooper
EF2
No use in going anywhere... probably busted this one... oh well!
Jesse Risley
Staff member
There were no more tornadoes reported on this day, though a rather substantial damaging wind event ensued. The event date was May 27, 2001.
If you wish to see how you would have fared between 23z and 01z, here are the last few radar scans, which you can correlate with your 23z chase locations on this map:
23z Central Plains
2330z Central Plains
00z Central Plains
0030z Central Plains
01z Central Plains
There were not many reports from Texas this day, at least not until the western edge of the MCS reached the panhandle. Since the event was from 2001, hourly mesoanalysis archives are not available, though this afternoon I was able to actually find some upper air data from 21z (everything else was either 12z or 00z data that far back), which may shed some additional light on the convective environment.
300 mb
500 mb (note the stronger mid-level flow entering the Central Plains)
700 mb
850 mb (one can discern that a stout LLJ might later interact with the mid-level flow / hence forthcoming MCS)
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With all of this having been said, it's time for a review of what we learned through this simulation.
A couple of things that are notable, from what I was able to look at. If you look at the 18z surface map, there is a discernible surface mesolow in NE CO, near AKO, at 18z. Also, though there is a lack of AWOS data in that region, the Garden City (GCR) observation station consistently showed SSE flow between 18z and 21z.
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For reference purposes, the next few hours of remaining LSRs are as follows:
Damaging Winds
If you wish to see how you would have fared between 23z and 01z, here are the last few radar scans, which you can correlate with your 23z chase locations on this map:
23z Central Plains
2330z Central Plains
00z Central Plains
0030z Central Plains
01z Central Plains
There were not many reports from Texas this day, at least not until the western edge of the MCS reached the panhandle. Since the event was from 2001, hourly mesoanalysis archives are not available, though this afternoon I was able to actually find some upper air data from 21z (everything else was either 12z or 00z data that far back), which may shed some additional light on the convective environment.
300 mb
500 mb (note the stronger mid-level flow entering the Central Plains)
700 mb
850 mb (one can discern that a stout LLJ might later interact with the mid-level flow / hence forthcoming MCS)
-------------------------------------------------
With all of this having been said, it's time for a review of what we learned through this simulation.
- What do you take away from this chase case?
- What, if anything, can you learn to possibly help you in your future chasing endeavors?
- Many of those playing would not have seen any tornadoes this day, though most would not have left entirely empty handed, either. If you wanted to score a tornado, what could you have paid closer attention to? Why do you think most of the tornadoes were clustered on the far NW periphery of the initial threat area?
A couple of things that are notable, from what I was able to look at. If you look at the 18z surface map, there is a discernible surface mesolow in NE CO, near AKO, at 18z. Also, though there is a lack of AWOS data in that region, the Garden City (GCR) observation station consistently showed SSE flow between 18z and 21z.
-------------------------------------------------
For reference purposes, the next few hours of remaining LSRs are as follows:
Damaging Winds
cstrunk
EF3
Pretty much figured I wasn't going to see anything after the last update. Although I did catch the west end of the beefy line coming through the OK panhandle.
I learned that I need to pay closer attention to surface features visible on data maps during the day...
I learned that I need to pay closer attention to surface features visible on data maps during the day...
James Gustina
Supporter
That was a tough one for sure. I learned that underscoring one area too much and ignoring the surroundings early in the day is gonna lead to a bust some of the time. I failed to pick up on the mesolow in the least.
I think I could have paid closer attention to the earlier surface charts (which I ignored for the most part going into the 18Z update). I also learned that hand analysis in these situations is extremely valuable (especially considering that the mesolow wasn't show on the composites).
I think I could have paid closer attention to the earlier surface charts (which I ignored for the most part going into the 18Z update). I also learned that hand analysis in these situations is extremely valuable (especially considering that the mesolow wasn't show on the composites).
Skip Talbot
EF5
Wow, northwest Kansas eh? I didn't like the moisture up there with most stations reporting in the mid 50's dewpoint wise. That's more than enough to get tornadoes at that elevation, but the moisture looked so much richer up there. With the low sitting right there, there was probably some nice convergence and steep lapse rates. Looks like quite a bit of veering from the surface up tot he LLJ to (even the 850's are hideously veered). The shortwaves ejected right over the northern targets too. Tricky chase case.
Greg McLaughlin
EF5
I recognized this day right away. This event became the infamous "People Chaser Derecho". Here is an excellent paper on the event:
http://www.spc.noaa.gov/misc/AbtDerechos/casepages/may27-282001page.htm#dopplermay272001
Also, if you are my friend on Facebook, check out the video on my profile from this day. Our group was overrun by the MCS near Meade, KS. We experienced near 100 mph winds and lost a window from flying debris. It was an insane event.
The next day, SPC had forecast a moderate risk for the Oklahoma and Texas panhandles indicating the risk for another severe MCS event. This forecast would bust however, as the MCS from the 27th had made it all the way to the Gulf coast dragging the surface front with it. This front and the moisture to its south failed to lift north into the moderate risk area as the forecast models had indicated.
The next day (May 29th) would feature three incredible supercells in the Texas panhandle including a large tornado near Conway, TX.
http://www.spc.noaa.gov/misc/AbtDerechos/casepages/may27-282001page.htm#dopplermay272001
Also, if you are my friend on Facebook, check out the video on my profile from this day. Our group was overrun by the MCS near Meade, KS. We experienced near 100 mph winds and lost a window from flying debris. It was an insane event.
The next day, SPC had forecast a moderate risk for the Oklahoma and Texas panhandles indicating the risk for another severe MCS event. This forecast would bust however, as the MCS from the 27th had made it all the way to the Gulf coast dragging the surface front with it. This front and the moisture to its south failed to lift north into the moderate risk area as the forecast models had indicated.
The next day (May 29th) would feature three incredible supercells in the Texas panhandle including a large tornado near Conway, TX.
Robert Dewey
EF5
I probably wouldn't have considered this a bust if I had been in the right location to catch this beast, some of those photos of the gust front are insane. http://www.spc.noaa.gov/misc/AbtDerechos/loopimages/may27-282001/oklagust.wmv
Unfortunately, I would have been in OKC, and the derecho didn't come through until around 10PM. Not a complete bust, but I would have rather intercepted it in daylight.
Unfortunately, I would have been in OKC, and the derecho didn't come through until around 10PM. Not a complete bust, but I would have rather intercepted it in daylight.
Wow, what a fuster! Wonder if my car survived with all its glass intact. I probably would have bugged out and found a hotel in ICT or Stillwater. Good case!
Joshua Nall
EF4
I learned I need to learn what all the symbols/numbers mean on the maps, lol.. OK, I understand most of it but the skew-t charts on the first page had me lost. I spent probably an hour just learning how you read CAPE on them and which ones had more. Always been just a storm observer and I know you have to really get into this stuff and stay with it to learn it, which is one reason I never have... way to many hobbies in the off season I guess. Enjoyed it though and I appreciate the time and effort it must take to put one of these together now. Thanks, Jesse.
After my mention of a dryline as well as others...I'm not sure there was a real dryline in this case. I always thought a true dryline occurred when you had a trough out west, and the thing shifted E during the afternoon. If there was one, Didn't seem to come into play. This case has sparked a ton of questions, and some of them concern pretty basic stuff I can certainly learn from reading past threads. Was under the impression that SW surface winds with NW upper winds were sufficient for tornadoes, so the SSE wind did not seem important to me. As for as the mesolow and how to pick it out and several other things mentioned... I'd need some basic understanding of them before I could apply it to this case.
After my mention of a dryline as well as others...I'm not sure there was a real dryline in this case. I always thought a true dryline occurred when you had a trough out west, and the thing shifted E during the afternoon. If there was one, Didn't seem to come into play. This case has sparked a ton of questions, and some of them concern pretty basic stuff I can certainly learn from reading past threads. Was under the impression that SW surface winds with NW upper winds were sufficient for tornadoes, so the SSE wind did not seem important to me. As for as the mesolow and how to pick it out and several other things mentioned... I'd need some basic understanding of them before I could apply it to this case.
Matt Sellers
EF1
I should have recognized this day right away, but didn't; only after seeing the 21-23z suite of data - namely the 100mph DoW wind report and the radar images - did I fully recognize the day and event. (Therefore, my "score" on this case comes with an asterisk; while I had forgotten the conditions in place the morning of 5.27.1, that day was in mind as a template for how to proceed through this chase case as it - for obvious reasons - reminded me very much of that particular day! I should have trusted my hunch about this event and dropped out much sooner.) Thank you, Jesse, for putting this together; as one who chased that day, it was neat to be able to see the big picture of how that significant event unfolded as the only real-time data I had that day came via NWR and occasional nowcaster reports.
For this case, I chose west-central KS initially because, to me, the overall h5 flow across the Plains combined with the weak, disorganized surface wind fields screamed of raging MCS given available instability; on those days, I try to get to where I think initiation will occur because that's about my only shot of seeing tornadoes before the whole thing goes linear. Plus, given the ~30kt westerly h5 flow over the Rockies, I figured that a lee trough would set up across southeast/east-central CO ahead of the cold front, enhancing the low-level southerly flow in far eastern CO/western KS and providing a semi-localized boost to low-level shear in an atmosphere that needed every bit of shear it could in order to support supercells and tornadoes. Combined with the shortwave (I pegged it as being in Wyoming at 12z) moving southeast in the mid-level flow toward northwest KS, that led to my choice of Scott City as my initial target.
I wish I was thinking that way on the morning of May 27, 2001, because my chase that day, while eventful, did not result in a tornadic "score".... caught the storm in Gray Co., KS (already too late) and was overtaken by intense outflow/blowing dust just outside of Montezuma. Zero visibility in blowing dust caused me to drive off a county road into a field for about 20 seconds, though I was able to get back on the road with no damage to my truck.
For this case, I chose west-central KS initially because, to me, the overall h5 flow across the Plains combined with the weak, disorganized surface wind fields screamed of raging MCS given available instability; on those days, I try to get to where I think initiation will occur because that's about my only shot of seeing tornadoes before the whole thing goes linear. Plus, given the ~30kt westerly h5 flow over the Rockies, I figured that a lee trough would set up across southeast/east-central CO ahead of the cold front, enhancing the low-level southerly flow in far eastern CO/western KS and providing a semi-localized boost to low-level shear in an atmosphere that needed every bit of shear it could in order to support supercells and tornadoes. Combined with the shortwave (I pegged it as being in Wyoming at 12z) moving southeast in the mid-level flow toward northwest KS, that led to my choice of Scott City as my initial target.
I wish I was thinking that way on the morning of May 27, 2001, because my chase that day, while eventful, did not result in a tornadic "score".... caught the storm in Gray Co., KS (already too late) and was overtaken by intense outflow/blowing dust just outside of Montezuma. Zero visibility in blowing dust caused me to drive off a county road into a field for about 20 seconds, though I was able to get back on the road with no damage to my truck.
Bob Hartig
EF5
Great case, Jesse. Thank you for putting it together!
This one definitely taxed my forecasting skills. It being a northwest flow event, I had to remind myself that backing surface winds are a relative phenomenon defined by mid- and upper-level flow, not compass direction. Assuming there's adequate moisture, a southwesterly wind isn't necessarily a deal breaker. But that kind of setup can mess with my head a bit.
Like a lot of others, I got snookered by the moisture component. I really wanted at least 60 degree dewpoints. That's a big reason why I stayed in Woodward instead of heading for DDC, as I had contemplated. Had I made that move, I might have had a crack at the tornadic storms.
This one definitely taxed my forecasting skills. It being a northwest flow event, I had to remind myself that backing surface winds are a relative phenomenon defined by mid- and upper-level flow, not compass direction. Assuming there's adequate moisture, a southwesterly wind isn't necessarily a deal breaker. But that kind of setup can mess with my head a bit.
Like a lot of others, I got snookered by the moisture component. I really wanted at least 60 degree dewpoints. That's a big reason why I stayed in Woodward instead of heading for DDC, as I had contemplated. Had I made that move, I might have had a crack at the tornadic storms.
I would've been one of those getting chased. Amazing photos and video from the day. That was some amazing structure on that shelf. I've learned that in chase case games like these, when there's no obvious wave aloft to provide lift and shear, something almost always happens in regions of sloping terrain (i.e., W NE/W KS/far NW OK/TX PH/E NM/E CO). It's my belief that there are just enough heterogeneities in the terrain out there that even in the absence of strong low level shear (and even in the absence of decent deep layer shear), enough instability will still get a storm to pop out a tornado. The environment never looked really good to me anyway. In real life, I wouldn't have chased this day.
Jesse Risley
Staff member
If you look at several hours of surface data, the winds were mostly southerly, with the exception of that one observation around 21z, where they were more SE. At 12z it might not have been evident, just off of that one surface map, where the mid-level impulse (35-45 kts) was going to pass. As Skip noted, it went a bit further north than potentially anticipated by just glancing at 12z data.
With that being said, you do want some S/SW turning to enhance shear. Strongly backed SE winds synchronous with strong NW flow aloft can actually be more of an impedance to tornadogenesis in NW flow events, mainly because the rain-cooled air from the precipitation core (remember that the storm is traveling in a SE direction in the first place) tends to defile the mesocyclone by choking off unstable boundary layer inflow all too easily with those types of low-level inflow vectors. In fact, in NW flow events, especially during the summer, one could ascertain that, in many situations, the directional component to vertical shear becomes more dominant than the speed component, which is often a much more prominent factor earlier in the severe weather season, especially in SW flow events.
The presence of subtle surface boundaries and low-level warm advection (provides upward vertical motion) can serve as indicators of where the better risk might lie, in conjunction with the placement of the H5 core. However, surface parameters in that part of the plains during NW flow events tend to differ from what they might look like here in Illinois in mid-July, because lower dewpoints are partially the result of higher elevations, and the presence of SE surface winds tends to be goaded by the development of troughs on the leeward side of the Rockies.
