{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/117827"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/117827","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Characterizing the role of blocking in frontal precipitation enhancement near and upstream of the Olympic Mountains","abstract":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-04-12 without embargo terms","abstract_html":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-04-12 without embargo terms","abstract_has_math":false,"creators":["James, Scott Gregory"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Atmospheric Sciences","degree_department":null,"school":null,"contributors":["Hence, Deanna"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-12","date_published":"2022-12","updated_at":"2026-07-22T22:24:56Z","subjects":["Atmospheric Science","Mountain Meteorology","Wrf Simulation","Radar Meteorology"],"languages":["en","eng"],"rights":["Copyright 2022 Scott James"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/117827","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Hence, Deanna"]},{"key":"dc:creator","label":"Author","values":["James, Scott Gregory"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-12","2022-12-07"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Atmospheric Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Atmospheric Science","Mountain Meteorology","Wrf Simulation","Radar Meteorology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2022 Scott James"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/117827"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-04-12 without embargo terms","The student, Scott James, accepted the attached license on 2022-12-02 at 12:41.","The student, Scott James, submitted this Thesis for approval on 2022-12-02 at 12:49.","This Thesis was approved for publication on 2022-12-07 at 08:47.","DSpace SAF Submission Ingestion Package generated from Vireo submission #18741 on 2023-04-12 at 07:37:30","Analysis of OLYMPEX observations and high-resolution Weather Research and Forecasting (WRF) simulations upstream of the Olympic mountains from 17 December 2015 investigate low-level blocking’s role in precipitation distributions before and during a frontal passage near the Olympic Peninsula. Low-level blocking by stable air ahead of a front can modify precipitation distributions by frontal deformation, slowing, splitting, or merging. Observed coastal sounding-derived vertical stability profiles indicate high levels of low-level stability (~7.5 K km-1) and significant vertical wind shear (dU/dz= 0.025 s-1), which showed little change while the front propagated northeastward and stalled as the stable air mass likely dammed against the terrain. The resulting Froude number was sufficiently low ( 1) and the front well within the Rossby radius of deformation as the front bowed around the peninsula. Radial velocity from the NPOL radar and simulated wind fields indicate strong down-valley flow coupled with a frontal jet also contributed to long-lasting Kelvin-Helmholtz (KH) waves extending offshore. Simulated surface precipitation accumulation distributions divided the event into five regions upstream of NPOL and into timeframes relative to the fronts position. Results indicate that pre-warm frontal precipitation accumulations decrease with distance upstream of the coast with the highest accumulations present over the terrain. During the WF period, accumulations are highest far upstream of the coast before decreasing in a middle region and then increasing over the terrain. These results indicate that upstream precipitation enhancement upstream is an indirect effect of the terrain influencing the frontal shape and propagation, which resulted in enhanced near front precipitation accumulations."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Characterizing the role of blocking in frontal precipitation enhancement near and upstream of the Olympic Mountains"]}]}],"canonical_facts":{"dc:contributor":["Hence, Deanna"],"dc:creator":["James, Scott Gregory"],"dc:date":["2022-12","2022-12-07"],"dc:description":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-04-12 without embargo terms","The student, Scott James, accepted the attached license on 2022-12-02 at 12:41.","The student, Scott James, submitted this Thesis for approval on 2022-12-02 at 12:49.","This Thesis was approved for publication on 2022-12-07 at 08:47.","DSpace SAF Submission Ingestion Package generated from Vireo submission #18741 on 2023-04-12 at 07:37:30","Analysis of OLYMPEX observations and high-resolution Weather Research and Forecasting (WRF) simulations upstream of the Olympic mountains from 17 December 2015 investigate low-level blocking’s role in precipitation distributions before and during a frontal passage near the Olympic Peninsula. Low-level blocking by stable air ahead of a front can modify precipitation distributions by frontal deformation, slowing, splitting, or merging. Observed coastal sounding-derived vertical stability profiles indicate high levels of low-level stability (~7.5 K km-1) and significant vertical wind shear (dU/dz= 0.025 s-1), which showed little change while the front propagated northeastward and stalled as the stable air mass likely dammed against the terrain. The resulting Froude number was sufficiently low ( 1) and the front well within the Rossby radius of deformation as the front bowed around the peninsula. Radial velocity from the NPOL radar and simulated wind fields indicate strong down-valley flow coupled with a frontal jet also contributed to long-lasting Kelvin-Helmholtz (KH) waves extending offshore. Simulated surface precipitation accumulation distributions divided the event into five regions upstream of NPOL and into timeframes relative to the fronts position. Results indicate that pre-warm frontal precipitation accumulations decrease with distance upstream of the coast with the highest accumulations present over the terrain. During the WF period, accumulations are highest far upstream of the coast before decreasing in a middle region and then increasing over the terrain. These results indicate that upstream precipitation enhancement upstream is an indirect effect of the terrain influencing the frontal shape and propagation, which resulted in enhanced near front precipitation accumulations."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/117827"],"dc:language":["en","eng"],"dc:rights":["Copyright 2022 Scott James"],"dc:subject":["Atmospheric Science","Mountain Meteorology","Wrf Simulation","Radar Meteorology"],"dc:title":["Characterizing the role of blocking in frontal precipitation enhancement near and upstream of the Olympic Mountains"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Atmospheric Sciences"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:56Z"}