Research

Case postage stamps here

Date Comments
19990402 Tornadoes swrn OK. The max DPI event (F1) occurred at 0125z.
19990604 Tornadoes n-cntrl NEB. The max DPI event (F2) occurred at 0222z.
20000224 F1 tornado nern TX pnhdl into nwrn OK at 0213z.
20010421 Significant tornadoes cntrl KS beginning 0020z. The max DPI event (F4 Hoisington, KS) occurred at 0215z.
20020417 Significant tornadoes nwrn OK beginning 0432z. The max DPI event (F2) occurred at 0527z.
20020507 Significant tornadoes swrn KS. The max DPI event (F2) occurred at 0134z.
20020523 F1 tornado nrn TX pnhdl. The max DPI event (F1) occurred at 0425z.
20030507 Significant tornadoes srn OK beginning 0631z. The max DPI event (F2) occurred at 0754z.
20030509 Significant tornadoes cntrl OK beginning 0315z. The max DPI event (F3) occurred at 0328z.
20030623 Significant tornado (F4) nern NEB 0243z.
20040512 Significant tornadoes swrn/s-cntrl KS beginning 0101z. The max DPI event (F4) occurred at 0139z.
20050511 Significant tornadoes swrn KS. The max DPI event (F2) occurred at 0202z.
20060401 Significant tornado swrn KS. The first tornado occurred at 0020z. The most intense tornado (F2) occurred at 0220z.
20070420 Significant tornadoes swrn NEB beginning 0216z. The max DPI event (F2) occurred at 0302z.
20070423 Tornadoes nwrn and swrn KS and nwrn OK. The first tornado (brief) was reported at 2340z in nwrn OK. The more intense tornadoes occurred across the border into
KS around Sitka and Protection. The longest-track tornado occurred in nwrn KS around 0415z. Other tornadoes occurred in TX along the I-20 corridor from Colorado City
to Sweetwater and Trent.
20070504 Significant tornadoes swrn KS. The most intense tornado (EF5 – Greensburg, KS) occurred at 0203z.
20070523 Significant tornadoes nern TX pnhdl. The first tornado report (F0) occurred at 2128z. The longest-track and widest tornado (F2) occurred at 0350z.
20071016 F1 tornado srn TX pnhdl. Tornado touched down 13 s of Canyon at 0516z.
20080330 Tornadoes cntrl OK. The first tornado report (F0) occurred at 0244z. The most tornado (F1 – Edmond, OK) occurred at 0539z.
20080424 Significant tornadoes n-cntrl KS. The first tornado report (F0) occurred at 0342z. The longest-track and widest tornado (F2) occurred at 0523z.
20090425 Four tornadoes n-cntrl OK. North Enid F2. Southeast of Kremlin F2.

Null Case Listing

Date Comments
19990307 Good Case. Poor low-level moisture relative to EML. One hail report around 12z n-cntrl TX.
19990331 Good Case . Poor low-level moisture relative to EML. No svr.
19990407 Good Case. Failure unknown. Tstms developed between 01-02z near the TX/NM border sw of LBB along dryline and nwrn edge of richer low-level moisture return. Vertical shear was supportive of supercells, but initial instability appeared marginal and T/Td spreads were likely around 30 F. Through 04z, tstms rapidly moved/developed newd through the south plains into low rolling plains and ern pnhdl with embedded left-moving storms observed as well as one right-moving cell along the srn end of the broken line. By this time, dewpoints had increased into the lower/mid 60s with T/Td spreads below 10 F. However, given the rapid weakening and eventual dissipation between 04-06z, it appears that capping may have become an issue.
20000320 Good Case. Poor low-level moisture relative to EML. No svr.
20000429 Storms initiated over the low rolling plains of TX around 23z invof of warm or stationary boundary. Severeal storm splits were observed through 01z and a boundary was identified moving swwd through the sern TX pnhdl and s plains. Between 03-05z, large cyclonic supercells evolved over Kent, Stonewall and Haskell counties, producing hail up to 3″ in diameter. Earlier, hail up to 3.5″ in diameter was reported in Motley county.
20000516 Storms initiated along dryline around 00z over cntrl/ern TX pnhdl within a hot, deeply mixed CBL with T/Td spreads of around 50 F. Storms moved into a cooler and progressively more moist air mass over wrn OK, but modification of 00z OUN sounding suggested environment was strongly capped. Storms quickly weakened and eventually dissipated between 00-03z. Farther n, two supercells formed in upslope flow regime over sern WY. A brief tornado (F0) report sern WY at 01z, with storms weakening thereafter as storms moved into lower elevations with more convective inhibition.
20010310 Tstms developed along cold front from swrn KS into the TX pnhdl between 22-23z. Storms evolved into messy convective modes with considerable outflow. Apparent negatives were weak convective instability, anafrontal structure, potentially excessive cold pool generation and no well defined increase in LLJ.
20010405 Despite a rather weak cap and moderate/strong instability, no storms developed along dryline or stalling boundary across KS. Severe storms with hail and wind were confined to the lower MO valley where LLJ focused stronger convergence along the front.
20010409 Tstms initiated around 21z along stationary or warm front near the KS/OK border. Storms increased in coverage through 03z while shifting across ern KS into MO. Secondary initiation occurred along the boundary over n-cntrl OK about 0330z, including the development of a supercell. The storm appeared to remain very near to the boundary, exhibiting persistent midlevel rotation, but not an organized signature at 0.5 degrees. Modification of 00z OUN and 12z LMN soundings suggested that a cap existed, but was not overly strong with MLCIN of generally less than 100 J/kg.
20010502 Tstms developed around 21z along ne-sw oriented cold front across the TX pnhdl into south plains as well as along the dryline over the Permian Basin. With the exception of a nearly stationary storm cluster over the sern pnhdl, storms had trouble sustaining themselves. Issues appeared to be anafrontal airflow along cold front and marginal deep-layer shear across the warm sector. The two tornado reports we brief dirt whirls.
20020313 Poor low-level moisture relative to EML. No storms.
20020323 Poor low-level moisture relative to EML. No storms, but strong nocturnal response.
20020415 Isolated tstms initiated around 21z over the Trans-Pecos region along dryline within deeply-mixed boundary layer with T/Td spreads of around 50 F. Diurnal storms dissipated by 03z with no apparent indication of supercell development. Additional nocturnal storms developed over the lower Rio Grande valley into cntrl TX in advance of a low latitude impulse lifting newd from nrn Mexico. No other nocturnal storm development occurred. Deep-layer shear was marginal across OK, decreasing with nwd extent.
20020418 Tstms initiated along stalled front over cntrl KS between 21-22z, e of dryline triple point. The initial storms generated an outflow boundary which slowly sagged s of the synoptic front. the most intense storm, a supercell, evolved over Marion county between 03-04z, displaying a hook and 3-D overhang. Low-level velocity signature was modest. This storm formed to the n of outflow boundary by 30-40 miles so it is possible that it may have been slightly elevated. Modifying 00z OUN sounding suggests that capping may have been an issue for any truly surface-based storm.
20020420 Anticipated tornado day (15% sig). Shallow surface front over wrn TX never eroded due to persistent elevated storms. Some elevated severe KS.
20020426 Good Case. Nocturnal storms wrn TX and nern OK/sern KS. Except for surface-based storms over the TX Big Bend, a shallow frontal zone was slow to erode with the majority of tstms remaining elevated. Day before a substantial severe/tornado event lower OH valley.
20020515 Questionable case due to ill-defined upstream trough and weak low-level response.Wind and hail late afternoon into night KS.
20030316 OK Case. No svr. Day before cntrl/srn plains event (Gotebo, OK – 3/17)
20030403 Good Case. Isolated, diurnal supercell developed along dryline over swrn OK. It produced svr hail into cntrl OK. Day before tornado outbreak cntrl plains into mid south
20030405 Questionable null case due to the brief tornadoes and equal intensity diurnal storms. Multiple supercells nrn TX. Diurnal storm tracked from e of LBB to the Metroplex with a number of brief (F0) tornadoes reported. A second supercell formed after 00z e of SPS and tracked toward PRX.
Day before big svr event Ozark plateau into lower MS valley.
20040326 Good Case. Diurnal storms initiated around 2230z along the dryline near the nern nm/nwrn TX pnhdl border before dissipating by 0130z. Elevated storms develop around 06z over nwrn ok into cntrl KS. Day before cntrl/srn plains event (Kingman,KS – 3/27)
20040419 Good Case. Diurnal storms (including supercells) ern NM/wrn TX. Diurnal storms dissipated over the TX S plains. Over the nrn TX pnhdl into OK pnhdl, storms intensified after 01z with sig hail being reported. Day before tornado outbreak IL/IND.
20040521 Questionable null case due to NEB/IA tornado reports. Diurnal storms (supercells), but dissipation during the evening presumably due to the cap. Day before cntrl plains outbreak (Hallam, NEB – 5/22)
20050404 Good Case. No storms. Air mass remained capped. Day before cntrl/srn plains svr episode
20050409 Good Case. No diurnal storms. Air mass remained capped. Elevated, nocturnal storms NEB and from the TX pnhdl into cntrl KS. Day before cntrl/srn plains svr episode
20050420 Good Case. Diurnal storms TX pnhdl into swrn KS. Another cluster of svr storms moved across nern CO. The strongest storm was a supercell near CDS. Sig hail, but no tornadoes in smooth log. Day before a severe wx episode from the mid MO valley into the cntrl low plains and Ozark plateau.
20060329 Good Case. No diurnal storms; short wave trough passed through cntrl conus early in the day. Nocturnal storms late wrn/cntrl KS. Day before a severe wx episode from the mid MO valley into srn plains.
20060405 Good Case. Air mass capped; no duirnal storms. No nocturnal storms either. Day before a severe wx episode cntrl/srn plains (4/6).
20060423 Good Case. Diurnal storms along dryline wrn KS into the TX pnhdl. Nocturnal storms KS. Day before a severe wx episode OK (El Reno – 4/24).
20070412 Good Case. Diurnal storms along dryline the TX pnhdl into TX s plains. Storms persisted ewd into wrn OK. Very marginal moisture. Storms may have become elevated by evening. Day before a severe wx episode TX (4/13).
20071013 Good Case. new
20080407 Good Case. Diurnal storms (supercells) including a tornado near Electra, TX. Storms persisted through the evening, but mode issues.
20080416 Good Case. No diurnal storms due to limited moisture. Elevated storms developed by late evening n of warm front.
20090930 Good Case. Diurnal storms initiated along dryline between 20-21z over the TX pnhdl and swrn KS. A few supercells evolved with the longest-lived one tracking from the e-cntrl TX pnhdl into wrn OK. The storms dissipated by 01z, apparently due to the cap. Elevated storms then developed overnight in NEB/KS.