Saturday, July 14, 2012
Saturday, June 9, 2012
Some soundings from 06/09/12 sfc-based convective failure in bulk of Dakotas
Above image: 23Z initialized RAP sndg at ABR overlaid on 00Z ABR RAOB. Click to see full image.
Above image: 12Z NAM-WRF sndg overlaid on 09Z NAM-KF sndg; both at ABR, valid times of both = 23Z. Click to see full image.
Wednesday, March 10, 2010
03/10/10 quick forecast
12Z RAOBs show skin-layer moisture at SHV/LIT...with >1km deep moisture now SE of a ~IAH-GLH-BNA line. Not sure BL trajectories will strongly favor pulling deeper moisture up to ne OK/se KS by sundown... so the 12z NAM output showing sfc "dewpoint holes" and high-ish LCLs may be reasonable. Also still dislike this type of pattern (intense UVVs/backing deep shear with time ahead of a compact vort)... as well as the terrain, though it's obviously even worse toward the Ozarks. Not sure hugging the quasi-stationary front in the better terrain in KS is viable given moderate NNE storm motions are expected (and low LCL/LFC may be no more favored there than just SE). It's possible parts of AR would be more favorable for tors (after dark) given stronger moisture/higher likelihood of discrete storms.
Thursday, January 28, 2010
January 21, 2010 review: minisupercell with EF-2 tornado in Huntsville AL
January 21 brought an interesting severe weather scenario to the Tennessee Valley region, with a number of low-topped severe storms--including at least two tornadic mini-supercells. The tail-end charlie storm in particular (see 22Z visible satellite/radar overlay below) produced an EF-2 tornado in the city of Huntsville around 2325Z. Several videos on youtube show a remarkable structure to the storm, with relatively high-contrast features and pretty coloring with sundown.
A stacked low pressure system (see 00Z 500mb RAOB plot and 22Z subjective surface analysis below) moved ENE through the region and, in conjunction with diurnal heating beneath a large scale dry slot, was responsible for the severe storms. The regime had similarities to a "warm sector variety" Davies cold core set-up, although the tornadic storms occurred south of the path of the mid-level low--not necessarily tied directly to PVA ahead of the closed low. As with typical cold core setups, the cold temperatures accompanying the mid-level system contributed to ideal low-level thermodynamics for tornadoes.
Fortuitously, the 00Z RAOBs at BNA and BMX were launched just ahead of the occluded/cold front. With Hunstville sitting exactly between each, a representative sounding was easily created by compositing these two soundings (i.e. an average of the two) and then appropriately modifying the near-surface layer (63/53°F inflow environment). This composite sounding appears below (substituted on the BNA sounding). With -2°C 700mb temperatures overspreading ML dewpoints in the mid-50s°F, 0-3km MLCAPE is very large (175 J/kg); and total MLCAPE is respectable (1051 J/kg). MLLCL heights are also quite low (708 m agl). Again, as per Davies research, strong low-level stretching likely played a substantial role in allowing for the Huntsville tornado. Actually, given that the BMX RAOB used to make the composite actually showed a warm-ish mid-level subsidence inversion "hanging on" beneath or immediately south of the mid-level jet axis (which was no doubt not present to any extent at Huntsville's latitude), it's possible the low-level and total CAPE were even slightly more favorable than I've shown in this sounding.
The shear profiles observed on the BNA and BMX RAOBs were largely straight-line, with only ~60 m2/s2 of 0-1 km SRH using the observed motion of the Huntsville cell. It's possible these observations were a bit too close to the occluded front, which would explain the veering immediately above the surface. The local 88D at Hytop AL (HTX), however, sampled a somewhat more favorable low-level shear environment immediately downstream of the tornadic storm in the warm sector. The VWP data was quite consistent during the course of the event, and looked reasonable when eyeballing the size/orientation of the BNA/BMX hodographs against the FFC hodograph (N of the "wedge front"). The mean HTX VWP hodograph from 2303-2322Z is shown below. This hodograph was characterized by 0-1 km SRH of 155 m2/s2... which is more than sufficient for tornadic development when coupled with the ideal low-level thermodynamics. Deep layer shear and mid- through high-level storm-relative flow were also favorably strong... although with the low ELs/storm tops in this case, it is tough to know what sort of storm depths/heights are appropriate for gauging a parameter such as deep-layer shear.
A stacked low pressure system (see 00Z 500mb RAOB plot and 22Z subjective surface analysis below) moved ENE through the region and, in conjunction with diurnal heating beneath a large scale dry slot, was responsible for the severe storms. The regime had similarities to a "warm sector variety" Davies cold core set-up, although the tornadic storms occurred south of the path of the mid-level low--not necessarily tied directly to PVA ahead of the closed low. As with typical cold core setups, the cold temperatures accompanying the mid-level system contributed to ideal low-level thermodynamics for tornadoes.
Fortuitously, the 00Z RAOBs at BNA and BMX were launched just ahead of the occluded/cold front. With Hunstville sitting exactly between each, a representative sounding was easily created by compositing these two soundings (i.e. an average of the two) and then appropriately modifying the near-surface layer (63/53°F inflow environment). This composite sounding appears below (substituted on the BNA sounding). With -2°C 700mb temperatures overspreading ML dewpoints in the mid-50s°F, 0-3km MLCAPE is very large (175 J/kg); and total MLCAPE is respectable (1051 J/kg). MLLCL heights are also quite low (708 m agl). Again, as per Davies research, strong low-level stretching likely played a substantial role in allowing for the Huntsville tornado. Actually, given that the BMX RAOB used to make the composite actually showed a warm-ish mid-level subsidence inversion "hanging on" beneath or immediately south of the mid-level jet axis (which was no doubt not present to any extent at Huntsville's latitude), it's possible the low-level and total CAPE were even slightly more favorable than I've shown in this sounding.
The shear profiles observed on the BNA and BMX RAOBs were largely straight-line, with only ~60 m2/s2 of 0-1 km SRH using the observed motion of the Huntsville cell. It's possible these observations were a bit too close to the occluded front, which would explain the veering immediately above the surface. The local 88D at Hytop AL (HTX), however, sampled a somewhat more favorable low-level shear environment immediately downstream of the tornadic storm in the warm sector. The VWP data was quite consistent during the course of the event, and looked reasonable when eyeballing the size/orientation of the BNA/BMX hodographs against the FFC hodograph (N of the "wedge front"). The mean HTX VWP hodograph from 2303-2322Z is shown below. This hodograph was characterized by 0-1 km SRH of 155 m2/s2... which is more than sufficient for tornadic development when coupled with the ideal low-level thermodynamics. Deep layer shear and mid- through high-level storm-relative flow were also favorably strong... although with the low ELs/storm tops in this case, it is tough to know what sort of storm depths/heights are appropriate for gauging a parameter such as deep-layer shear.
Saturday, October 31, 2009
May 8, 2009 review: devastating derecho from S Plains to OH/TN valleys
A few weeks ago I put together a simplistic meteorological summary page on the 05/08/09 derecho event, with quite a bit of observational data. This page can be viewed HERE.
Here's two teaser images from the page: a 12Z subjective surface analysis, and the 00Z-12Z RAOB evolution at Springfield, MO.
Here's two teaser images from the page: a 12Z subjective surface analysis, and the 00Z-12Z RAOB evolution at Springfield, MO.
Wednesday, May 20, 2009
May 13 review: Killer tornadoes strike northern MO
A powerful supercell produced a few damaging tornadoes across portions of far northcentral/northeastern MO on May 13. The first of these, rated EF-1, killed a woman in a mobile home near the town of Milan MO. The second, also rated EF-1, passed near the town of Novinger MO but caused no injuries/fatalities. The third tornado produced EF-1 damage in northern sections of Kirksville MO, also killing two more people to the northwest of town. This tornado strengthened to an EF-2 as it moved toward the town of Clay MO. The storm went on to produce two more weak tornadoes north of Edina MO.
A pair of elevated TS clusters were ongoing over portions of the Midwest on Wednesday morning, to the north of the surface warm front. The lead cluster over much of IL was driven by sharp moisture advection/convergence in the exit region of a 60-70 kt westsouthwesterly LLJ, while the trailing, more intense cluster was crossing the northern third of MO in advance of a potent low-amplitude 7H shortwave trough. An MCV, remnants of severe convective storms across the southern High Plains the prior evening, was also crossing the Ozark mountains at this time… and began to ignite surface-based storms after 15Z across far southern MO.
Short-term guidance and conceptual models suggested SRH would be marginal for a significant tornado threat over the majority of the area east of the cold front, given 1) veering of near-surface winds to SSW amidst deep vertical mixing, and 2) the primary LLJ axis shifting away from the area. The obvious exception to this would be in the raincooled, gradually recovering BL airmass across northcentral and northeastern MO… where guidance suggested 0-1 km SRH AOA 250 m2/s2 would be possible given not only weaker BL mixing (more backed near-surface component) but also the maintenance of a somewhat stronger LLJ (~40 kt) nearer the primary low-level cyclone riding the U.S.-Canada border. By mid-afternoon (see crude 21Z sfc analysis below), surface observations showed the warm front rapidly redeveloping northward toward the I-80 corridor in IA/northern IL; while to its south, modifying outflow air was evident via a dense VFR stratocu deck and south-southeast sfc winds amidst low 70s°F over upper 60s°F. Given sfc winds just to the north (e.g. far southeastern IA) were slighly more veered, it is possible that an outflow boundary remained anchored along and just south of the Kirksville-Quincy-Winchester corridor. Regardless, observational trends clearly supported better-than-progged SRH/LCLs for a sig tor threat over this modifying airmass. The primary question was the strength of the low-level destabilization, given that BL heating would remain modest and a formidable 7H thermal ridge was still cresting not far west of the area via the 18Z TOP RAOB.
Finally, below are representative profiler hodographs for the tornadic supercells affecting the Burlington KS and Lamont OK areas, respectively. The latter tornado was a surprisingly long-lived and nearly stationary cone. The thermodynamic environment in these areas was characterized by higher LCL/LFC, but very strong instability (MLCAPE 3500-4000 J/kg) and steep low-level lapse rates/no CINH. This may have facilitated strong near-ground stretching to help in the production of tornadoes. Also, low-level hodographs remained a bit more kinked than forecast... and given the strongly deviant storm motions (almost too strongly deviant in the Lamont case, given the increasingly parallel nature of the storm motion with the near-sfc shear vector)... 0-1 km SRH was actually pretty favorable, in the 140-170 m2/s2 range. Note that deep layer shear is solidly on the low end for supercell storms though (~30 kts of 0-6 km bulk shear)... with the large instability likely playing a role in allowing for sustained supercells.
A pair of elevated TS clusters were ongoing over portions of the Midwest on Wednesday morning, to the north of the surface warm front. The lead cluster over much of IL was driven by sharp moisture advection/convergence in the exit region of a 60-70 kt westsouthwesterly LLJ, while the trailing, more intense cluster was crossing the northern third of MO in advance of a potent low-amplitude 7H shortwave trough. An MCV, remnants of severe convective storms across the southern High Plains the prior evening, was also crossing the Ozark mountains at this time… and began to ignite surface-based storms after 15Z across far southern MO.
In the wake of these convective systems, a pronounced EML was overspreading the central Plains amidst weak shortwave ridging…well downstream and equatorward of the primary, strong shortwave rotating into the northern Plains. In fact, the central Plains capping thermal ridge underwent amplification during the late morning and early afternoon, as evidenced by 7H temps increasing from 11°C to 13°C at TOP between 12Z and 18Z (see RAOB overlay below, with extreme mid-level lapse rates by 18Z). Also note, despite the presence of the stout cap aloft, diurnal mixing still took a pronounced toll on prefrontal boundary layer moisture...with the richest moist layer becoming decidedly shallow by 18Z. Observed 100 mb ML dewpoints on the 18Z TOP and OUN RAOBs only ranged from 60-64°F… not a particularly positive sign. Still, it appears that persistent south-southwesterly low-level flow ahead of the cold front, coupled with evapotraspirative effects, helped boundary layer moisture quality to recover again through the afternoon (ML dewpoints increasing back to the 64-68°F range) per 00Z RAOB data.
Short-term guidance and conceptual models suggested SRH would be marginal for a significant tornado threat over the majority of the area east of the cold front, given 1) veering of near-surface winds to SSW amidst deep vertical mixing, and 2) the primary LLJ axis shifting away from the area. The obvious exception to this would be in the raincooled, gradually recovering BL airmass across northcentral and northeastern MO… where guidance suggested 0-1 km SRH AOA 250 m2/s2 would be possible given not only weaker BL mixing (more backed near-surface component) but also the maintenance of a somewhat stronger LLJ (~40 kt) nearer the primary low-level cyclone riding the U.S.-Canada border. By mid-afternoon (see crude 21Z sfc analysis below), surface observations showed the warm front rapidly redeveloping northward toward the I-80 corridor in IA/northern IL; while to its south, modifying outflow air was evident via a dense VFR stratocu deck and south-southeast sfc winds amidst low 70s°F over upper 60s°F. Given sfc winds just to the north (e.g. far southeastern IA) were slighly more veered, it is possible that an outflow boundary remained anchored along and just south of the Kirksville-Quincy-Winchester corridor. Regardless, observational trends clearly supported better-than-progged SRH/LCLs for a sig tor threat over this modifying airmass. The primary question was the strength of the low-level destabilization, given that BL heating would remain modest and a formidable 7H thermal ridge was still cresting not far west of the area via the 18Z TOP RAOB.
Shortly after 21Z, a combination of frontal lift/convergence, weak height falls aloft, and rapid cooling of the capping layer from the west all resulted in explosive convective initiation along the cold front from the KS Flint Hills up toward Des Moines IA (see visible satellite pic below). More importantly, a prefrontal confluence band—coincident with a narrow low-level thermal ridge with sfc temperatures warming into the low 80s°F—initiated a broken line of storms just east of the I-35 corridor, from Kansas City to Princeton MO. The fact that this latter band of storms was able to initiate ahead of the primary surface boundary was probable confirmation of what afternoon RUC model soundings had suggested: that the very warm capping thermal ridge had held primarily west and south of the MO river; while a very deep/moist boundary layer, with essentially no capping inversion aloft, had evolved amidst the recovering airmass over far northcentral and northeastern MO.
Given westnorthwest-oriented deep layer shear vectors atop the cold front and prefrontal trough, discrete cellular mode actually dominated for the first few hours after initiation. Additionally, stronger flow fields aided the northern storms in moving eastward off the boundaries, while markedly rightward-deviant motions amidst very strong CAPE helped southern storms move off the cold front across portions of KS and eventually northern OK. With a consolidating/strengthening supercell emerging across far northcentral MO and crossing the effective outflow boundary near Milan MO… the stage was set for a cyclic tornadic supercell.
A representative thermodynamic environment for this tornadic supercell was attained by modifying the 00Z DVN RAOB alongside the 00Z TOP RAOB (Kirksville sits about halfway between each). The surface warm front lifted through DVN (~120 miles NE of Kirksville) just prior to the 00Z RAOB launch, which means its sounding--characterized by 2100 J/kg MLCAPE and no MLCINH, despite a saturated boundary layer--was strongly representative of the modifying outflow pool. Meanwhile, just behind the low-level cold front, not only was TOP’s capping inversion aloft (having cooled very markedly the past few hours) similar in magnitude to DVN’s… but the entire thermal profile above the frontal inversion was nearly identical to DVN’s as well. It’s possible that mid-level thermal ridging near Kirksville wasn’t quite as suppressed as at TOP (and yet hadn’t advanced as far NE as DVN)… but this is assumed to be negligible. Below is the modified DVN sounding to represent the Kirksville event. Note moderate-bordering-on-strong instability (MLCAPE = 2455 J/kg); a very deep/moist boundary layer, with remnant EML above 650mb; and strong boundary layer RH (MLLCL < 800 m). Although MLCINH is weak to nil... note that low-level instability is not particularly strong (0-3 km MLCAPE = 41 J/kg), given the nearly saturated, weak-lapse-rate environment below 3 km.
Creating a single, strongly representative sr-hodograph for this event is more difficult given the gradual veering of low-level winds observed in the modified outflow air between 21-00Z. Regardless, the DVN RAOB and Winchester IL profiler were ideally situated to sample the vertical shear within this airmass, and both indicated a very strongly sheared low-level environment for the duration of this event--with very large 0-1 km SRH. Hodographs #1 and #2 below are those observed on the Winchester profiler (N of the effective outflow boundary and ~100 miles ESE of Kirksville) at 21Z and 00Z. Note that veering 0-1 km flow by 00Z is offset by acceleration of the synoptic LLJ to near 50 kt... actually resulting in an increase in SRH, given low-level winds were still strongly backed in a storm-relative sense. The third hodograph, from the raw 00Z DVN RAOB (120 miles NE of Kirksville)--likely launched around 23Z--is a good "medium" between the two... and also produced the largest low-level shear of the three, with 0-1 km SRH at a whopping 460 m2/s2. [Short-term model guidance vastly underestimated the size and pronounced "sickle shape" of these hodographs within the modifying outflow air... with NAM and NAM-KF models forecasting more veered near-sfc winds and a weaker LLJ.] Deep layer shear also appeared favorably strong via these hodographs, with around 50 kt of 0-6 km bulk shear. One final thing to note is that mid- and upper-level storm-relative winds on the three hodographs are pretty modest (20-35 kts)... and when coupled with anomalously rich PWATs (> 1.5"), this probably contributed to HP supercell processes that acted to temper the strength of these tornadoes. [Given that a very rare combination of ~2500 MLCAPE and ~400 0-1 km SRH existed amidst ideal low-level thermodynamics (albeit modest 0-3 km CAPE)... it would seem that the tornadoes from this storm could have been far more violent than they were.]
Finally, below are representative profiler hodographs for the tornadic supercells affecting the Burlington KS and Lamont OK areas, respectively. The latter tornado was a surprisingly long-lived and nearly stationary cone. The thermodynamic environment in these areas was characterized by higher LCL/LFC, but very strong instability (MLCAPE 3500-4000 J/kg) and steep low-level lapse rates/no CINH. This may have facilitated strong near-ground stretching to help in the production of tornadoes. Also, low-level hodographs remained a bit more kinked than forecast... and given the strongly deviant storm motions (almost too strongly deviant in the Lamont case, given the increasingly parallel nature of the storm motion with the near-sfc shear vector)... 0-1 km SRH was actually pretty favorable, in the 140-170 m2/s2 range. Note that deep layer shear is solidly on the low end for supercell storms though (~30 kts of 0-6 km bulk shear)... with the large instability likely playing a role in allowing for sustained supercells.
Thursday, April 30, 2009
April 29 review: mesoscale magic in the TX South Plains
A potent supercell tracked between the Plainview and Matador TX areas yesterday, producing a couple substantial/photogenic tornadoes northeast of the town of Floydada. Surprisingly, not terribly many local chasers were on it... perhaps due to its relatively short tornadic period before going OFD... or due to other sucker storms existing farther E. SPC handled the forecast well IMO. Model signals were pretty subtle for a significant event... though knowing that OFBs might come into play later, coupled with the amount of BL moisture lurking to the southeast, was a sign that some mesoscale magic could definitely occur.
During the morning hours, an elongated shortwave trough tracked eastward thru KS-OK, supporting scattered thunderstorm activity. The airmass feeding into these storms was characterized by anomalously strong precipitable water values and effective parcels already rooted near the surface. A strong MCS was thus gradually born over the Red River valley, on the southern flank of the convective activity. The far western segment of the MCS outflow appeared to settle southwestward, and by early afternoon curved E-NE-N along a Crowell-Turkey-Wayside-Amarillo TX line (see 1945Z visible satellite image below). A second surface boundary was also evident on satellite, extending E-W from Crowell-Matador-Plainview and intersecting the dryline near Springlake. The latter E-W boundary was not apparent via the TX mesonet, but gradually appeared as a fineline of reflectivity on Lubbock's radar... its signature probably becoming blended with an increasingly well-defined RFD gustfront off the supercell-to-be. Also of note, a convergence line/surface trough was present in the moist sector a few counties east of the dryline, generally straddling the I-27 corridor.
A trailing shortwave trough, low-amplitude but well-defined in nature, approached west TX by mid-afternoon. Persistent isallobaric forcing, likely a result of both an upswing in QG ascent and increased heating of the outflow air, produced a well-defined low-level mass response along and east of the dryline between 21Z and 23Z. (See sfc obs below... no frontal analysis done as my usual analysis software doesn't have the TX mesonet data.) Enhanced downward mixing of westerly momentum forced the dryline eastward, where it merged with the convergence line near I-27; meanwhile, surface winds in the moist sector increased and backed substantially to the ESE. The supercell in question developed near the intersection of the E-W boundary and the effective dryline by 21Z, and tracked E to ESE along or just north of that boundary.
The Jayton profiler, located about 50 miles SE of where the storm became tornadic near Floydada, captured the mass response quite dramatically. Note in the 22Z and 00Z Jayton profiler hodographs below, the 500-1000 m flow backing and increasing to near 30 kt. Accordingly, given such a strong sr-inflow component and a perfectly kinked and curving hodo below 1 km... strong to very strong 0-1 km SRH resulted. Using the Plainview storm motion, 0-1 km SRH on the 00Z Jayton profiler was > 330 m2/s2 (with continued strong curvature through 3 km contributing to > 550 m2/s2 of 0-3 km SRH). Also note, 0-6 km bulk shear was moderate to strong, in excess of 50 kt. In comparison, the 00Z Amarillo RAOB hodograph (third hodograph below) showed 0-1 km SRH of ~200 m2/s2... though it's possible the strongest low-level mass response hadn't yet occurred by the time of balloon launch (~23Z) and/or occurred farther south only. With neither OFB evident in surface data and likely becoming increasingly diffuse given increased mixing/heating and mass response... it is tough to know whether or not the boundary enhanced horizontal vorticity available to the storm. Regardless, I would think the shear sampled by the 00Z Jayton profiler is a reasonable estimate for the Floydada area tornadoes, with any changes in the shear due to increased elevation on the caprock escarpment probably marginal.
The thermodynamic environment available to this storm was likewise very impressive, due to the influx of upper 60s surface dewpoints up onto the caprock combined with fairly modest capping aloft. In order to achieve the correct elevation/pressure surface for Floydada (which is a good 500 feet lower than AMA), I used a base NAM-WRF model sounding with a 900mb pressure surface (ideal given relative pressure surfaces in the region that evening) and applied the AMA RAOB data to it, blending the BL using TX mesonet data. The resulting dewpoint lapse rate is dry adiabatic (similar to that observed at AMA)... but this is known to happen when anomalously rich near-surface moisture exists. Bottom line, note the strong instability (MLCAPE > 3100 J/kg), very strong 0-3 km MLCAPE (~150 J/kg), and sufficiently low MLLCLs (1200 m). The second sounding below is the raw 00Z AMA RAOB, which likely got "munched" by anvil-level convection just above 200 mb.
In reviewing this data, it is probably a good thing for TX residents that the storm quickly became outflow dominant (with the gust front apparently undercutting the updraft and encouraging evolution to a small bow)... because the mesoscale environment was truly primed for strong to violent tornadoes. If I had been free to chase on this day, I hope that I woulda taken the chance on it.
During the morning hours, an elongated shortwave trough tracked eastward thru KS-OK, supporting scattered thunderstorm activity. The airmass feeding into these storms was characterized by anomalously strong precipitable water values and effective parcels already rooted near the surface. A strong MCS was thus gradually born over the Red River valley, on the southern flank of the convective activity. The far western segment of the MCS outflow appeared to settle southwestward, and by early afternoon curved E-NE-N along a Crowell-Turkey-Wayside-Amarillo TX line (see 1945Z visible satellite image below). A second surface boundary was also evident on satellite, extending E-W from Crowell-Matador-Plainview and intersecting the dryline near Springlake. The latter E-W boundary was not apparent via the TX mesonet, but gradually appeared as a fineline of reflectivity on Lubbock's radar... its signature probably becoming blended with an increasingly well-defined RFD gustfront off the supercell-to-be. Also of note, a convergence line/surface trough was present in the moist sector a few counties east of the dryline, generally straddling the I-27 corridor.
A trailing shortwave trough, low-amplitude but well-defined in nature, approached west TX by mid-afternoon. Persistent isallobaric forcing, likely a result of both an upswing in QG ascent and increased heating of the outflow air, produced a well-defined low-level mass response along and east of the dryline between 21Z and 23Z. (See sfc obs below... no frontal analysis done as my usual analysis software doesn't have the TX mesonet data.) Enhanced downward mixing of westerly momentum forced the dryline eastward, where it merged with the convergence line near I-27; meanwhile, surface winds in the moist sector increased and backed substantially to the ESE. The supercell in question developed near the intersection of the E-W boundary and the effective dryline by 21Z, and tracked E to ESE along or just north of that boundary.
The Jayton profiler, located about 50 miles SE of where the storm became tornadic near Floydada, captured the mass response quite dramatically. Note in the 22Z and 00Z Jayton profiler hodographs below, the 500-1000 m flow backing and increasing to near 30 kt. Accordingly, given such a strong sr-inflow component and a perfectly kinked and curving hodo below 1 km... strong to very strong 0-1 km SRH resulted. Using the Plainview storm motion, 0-1 km SRH on the 00Z Jayton profiler was > 330 m2/s2 (with continued strong curvature through 3 km contributing to > 550 m2/s2 of 0-3 km SRH). Also note, 0-6 km bulk shear was moderate to strong, in excess of 50 kt. In comparison, the 00Z Amarillo RAOB hodograph (third hodograph below) showed 0-1 km SRH of ~200 m2/s2... though it's possible the strongest low-level mass response hadn't yet occurred by the time of balloon launch (~23Z) and/or occurred farther south only. With neither OFB evident in surface data and likely becoming increasingly diffuse given increased mixing/heating and mass response... it is tough to know whether or not the boundary enhanced horizontal vorticity available to the storm. Regardless, I would think the shear sampled by the 00Z Jayton profiler is a reasonable estimate for the Floydada area tornadoes, with any changes in the shear due to increased elevation on the caprock escarpment probably marginal.
The thermodynamic environment available to this storm was likewise very impressive, due to the influx of upper 60s surface dewpoints up onto the caprock combined with fairly modest capping aloft. In order to achieve the correct elevation/pressure surface for Floydada (which is a good 500 feet lower than AMA), I used a base NAM-WRF model sounding with a 900mb pressure surface (ideal given relative pressure surfaces in the region that evening) and applied the AMA RAOB data to it, blending the BL using TX mesonet data. The resulting dewpoint lapse rate is dry adiabatic (similar to that observed at AMA)... but this is known to happen when anomalously rich near-surface moisture exists. Bottom line, note the strong instability (MLCAPE > 3100 J/kg), very strong 0-3 km MLCAPE (~150 J/kg), and sufficiently low MLLCLs (1200 m). The second sounding below is the raw 00Z AMA RAOB, which likely got "munched" by anvil-level convection just above 200 mb.
In reviewing this data, it is probably a good thing for TX residents that the storm quickly became outflow dominant (with the gust front apparently undercutting the updraft and encouraging evolution to a small bow)... because the mesoscale environment was truly primed for strong to violent tornadoes. If I had been free to chase on this day, I hope that I woulda taken the chance on it.
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