{"id":{"repo_id":"creighton","oai_identifier":"oai:cdr.creighton.edu:10504/6118"},"canonical_url":"https://search.dev.ndltd.org/etd/creighton/oai:cdr.creighton.edu:10504/6118","repository":{"repo_id":"creighton","name":"Creighton University","base_url":"https://cdr.creighton.edu/server/oai/request"},"display":{"title":"The Association of Strong Near-Surface Wind Shear Profiles with Enhanced Probabilities of Significant Severe Weather and Tornado Events.","abstract":"On several significant tornado days, a distinct combination of near surface (< 1 km AGL) speed and directional shear has been noted in pre-tornadic vertical wind profiles. This combination consists of intense speed shear followed by intense directional shear between the surface and 1 km AGL, which appears as a sickle-shape on a hodograph. A composite sickle-shaped hodograph was constructed using several notable tornado outbreak days. The composite hodograph was used to examine the historical upper-air database for the 1995-2004 period in order to determine the relative frequency of the sickle-shape. Furthermore, the occurrence of the sickle-shape was related to severe weather documented within spatial and temporal proximity of the sounding site. Over the 10-year dataset, the sickle-shape was found to occur at most 4% of the time. It was also found that the sickle-shape occurs less than 0.5% of the time in the presence of minimally supportive kinematics and thermodynamics. On those days when the sickle-shape was accompanied by minimally supportive kinematics and thermodynamics (0-6 km AGL shear ≥ 20 m s-1 and CAPE ≥ 500 J kg-1), it was found that severe weather and tornadoes were more likely to be observed in proximity to the sounding site. The results show that the presence of the sickle-shaped hodograph and minimally supportive thermodynamics and kinematics is related to an increased likelihood of tornadic and significantly tornadic events.","abstract_html":"On several significant tornado days, a distinct combination of near surface (&lt; 1 km AGL) speed and directional shear has been noted in pre-tornadic vertical wind profiles. This combination consists of intense speed shear followed by intense directional shear between the surface and 1 km AGL, which appears as a sickle-shape on a hodograph. A composite sickle-shaped hodograph was constructed using several notable tornado outbreak days. The composite hodograph was used to examine the historical upper-air database for the 1995-2004 period in order to determine the relative frequency of the sickle-shape. Furthermore, the occurrence of the sickle-shape was related to severe weather documented within spatial and temporal proximity of the sounding site. Over the 10-year dataset, the sickle-shape was found to occur at most 4% of the time. It was also found that the sickle-shape occurs less than 0.5% of the time in the presence of minimally supportive kinematics and thermodynamics. On those days when the sickle-shape was accompanied by minimally supportive kinematics and thermodynamics (0-6 km AGL shear ≥ 20 m s-1 and CAPE ≥ 500 J kg-1), it was found that severe weather and tornadoes were more likely to be observed in proximity to the sounding site. The results show that the presence of the sickle-shaped hodograph and minimally supportive thermodynamics and kinematics is related to an increased likelihood of tornadic and significantly tornadic events.","abstract_has_math":false,"creators":["Ludwig, Stephanie L."],"institution":"Creighton University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Martinelli, Jason"],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010-05-03","date_published":"2010-05-03","updated_at":"2026-07-24T01:50:02Z","subjects":[],"languages":["en_US"],"rights":["copyright Stephanie L. Ludwig"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10504/6118","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Martinelli, Jason"]},{"key":"dc:creator","label":"Author","values":["Ludwig, Stephanie L."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2010-05-18T22:53:37Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2010-05-18T22:53:37Z"]},{"key":"dc:date.issued","label":"Date","values":["2010-05-03"]},{"key":"dc:publisher","label":"Institution","values":["Creighton University"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]},{"key":"dc:rights","label":"Dc Rights","values":["copyright Stephanie L. Ludwig"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["Ludwig_creighton.edu_0339M_10011.pdf"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10504/6118"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["On several significant tornado days, a distinct combination of near surface (< 1 km AGL) speed and directional shear has been noted in pre-tornadic vertical wind profiles. This combination consists of intense speed shear followed by intense directional shear between the surface and 1 km AGL, which appears as a sickle-shape on a hodograph. A composite sickle-shaped hodograph was constructed using several notable tornado outbreak days. The composite hodograph was used to examine the historical upper-air database for the 1995-2004 period in order to determine the relative frequency of the sickle-shape. Furthermore, the occurrence of the sickle-shape was related to severe weather documented within spatial and temporal proximity of the sounding site. Over the 10-year dataset, the sickle-shape was found to occur at most 4% of the time. It was also found that the sickle-shape occurs less than 0.5% of the time in the presence of minimally supportive kinematics and thermodynamics. On those days when the sickle-shape was accompanied by minimally supportive kinematics and thermodynamics (0-6 km AGL shear ≥ 20 m s-1 and CAPE ≥ 500 J kg-1), it was found that severe weather and tornadoes were more likely to be observed in proximity to the sounding site. The results show that the presence of the sickle-shaped hodograph and minimally supportive thermodynamics and kinematics is related to an increased likelihood of tornadic and significantly tornadic events."]},{"key":"dc:title","label":"Title","values":["The Association of Strong Near-Surface Wind Shear Profiles with Enhanced Probabilities of Significant Severe Weather and Tornado Events."]}]}],"canonical_facts":{"dc:contributor.advisor":["Martinelli, Jason"],"dc:creator":["Ludwig, Stephanie L."],"dc:date.accessioned":["2010-05-18T22:53:37Z"],"dc:date.available":["2010-05-18T22:53:37Z"],"dc:date.issued":["2010-05-03"],"dc:description.abstract":["On several significant tornado days, a distinct combination of near surface (< 1 km AGL) speed and directional shear has been noted in pre-tornadic vertical wind profiles. This combination consists of intense speed shear followed by intense directional shear between the surface and 1 km AGL, which appears as a sickle-shape on a hodograph. A composite sickle-shaped hodograph was constructed using several notable tornado outbreak days. The composite hodograph was used to examine the historical upper-air database for the 1995-2004 period in order to determine the relative frequency of the sickle-shape. Furthermore, the occurrence of the sickle-shape was related to severe weather documented within spatial and temporal proximity of the sounding site. Over the 10-year dataset, the sickle-shape was found to occur at most 4% of the time. It was also found that the sickle-shape occurs less than 0.5% of the time in the presence of minimally supportive kinematics and thermodynamics. On those days when the sickle-shape was accompanied by minimally supportive kinematics and thermodynamics (0-6 km AGL shear ≥ 20 m s-1 and CAPE ≥ 500 J kg-1), it was found that severe weather and tornadoes were more likely to be observed in proximity to the sounding site. The results show that the presence of the sickle-shaped hodograph and minimally supportive thermodynamics and kinematics is related to an increased likelihood of tornadic and significantly tornadic events."],"dc:identifier.other":["Ludwig_creighton.edu_0339M_10011.pdf"],"dc:identifier.uri":["http://hdl.handle.net/10504/6118"],"dc:language.iso":["en_US"],"dc:publisher":["Creighton University"],"dc:rights":["copyright Stephanie L. Ludwig"],"dc:title":["The Association of Strong Near-Surface Wind Shear Profiles with Enhanced Probabilities of Significant Severe Weather and Tornado Events."],"dc:type":["Thesis"]},"updated_at":"2026-07-24T01:50:02Z"}