{"id":18767,"date":"2021-05-17T17:41:27","date_gmt":"2021-05-17T22:41:27","guid":{"rendered":"https:\/\/inside.nssl.noaa.gov\/ewp\/?p=18767"},"modified":"2021-05-17T17:41:27","modified_gmt":"2021-05-17T22:41:27","slug":"ntda-threshold-vs-qc-suppression","status":"publish","type":"post","link":"https:\/\/inside.nssl.noaa.gov\/ewp\/2021\/05\/17\/ntda-threshold-vs-qc-suppression\/","title":{"rendered":"NTDA Threshold vs QC Suppression"},"content":{"rendered":"<p>A variety of non-meteorological returns seem to trigger the NTDA. In the attached image there are 3 NTDA icons within ~25 miles from the RDA. All have \u201cProb\u201d values less than 30%. There were other examples from earlier in the day where bad radials and elevated roadways caused detections. All of these were also less than 30% prob. So I can see why the default threshold for the NTDA is &gt;= 30%. I was assuming that the probability from the NTDA represents the actual probability of a tornado occurring based on the training cases. To me I would want the NTDA to pick up on anything that would be even a slight potential for a tornado. That way I could use it as SA or a first alert. I would be concerned if the NTDA was predicting a 22.7% probability of a tornado, like in the screen capture below. That to me means similar detections from the training cases produced a tornado about 1 out of 5 times. To see a non-meteorological return produce that high of values would lower my confidence in real returns. Rather than setting the threshold at &gt;=30% I think that filtering out the bad detections\u00a0 would make me trust the NTDA more.<\/p>\n<figure id=\"attachment_18768\" aria-describedby=\"caption-attachment-18768\" style=\"width: 660px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-content\/uploads\/sites\/22\/2021\/05\/ntda_low_end_probs_20210517_temp-e1621291231878.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-18768\" src=\"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-content\/uploads\/sites\/22\/2021\/05\/ntda_low_end_probs_20210517_temp-e1621291231878.png\" alt=\"\" width=\"660\" height=\"616\" srcset=\"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-content\/uploads\/sites\/22\/2021\/05\/ntda_low_end_probs_20210517_temp-e1621291231878.png 660w, https:\/\/inside.nssl.noaa.gov\/ewp\/wp-content\/uploads\/sites\/22\/2021\/05\/ntda_low_end_probs_20210517_temp-e1621291231878-600x560.png 600w\" sizes=\"auto, (max-width: 767px) 100vw, (max-width: 1200px) 60vw, 720px\" \/><\/a><figcaption id=\"caption-attachment-18768\" class=\"wp-caption-text\">Three NDTA detections from near the KLBB radar on non-meteorological returns.<\/figcaption><\/figure>\n<p>&#8211; Gerry Bertier<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A variety of non-meteorological returns seem to trigger the NTDA. In the attached image there are 3 NTDA icons within ~25 miles from the RDA. All have \u201cProb\u201d values less&#8230; <\/p>\n<p class=\"link-more\"><a href=\"https:\/\/inside.nssl.noaa.gov\/ewp\/2021\/05\/17\/ntda-threshold-vs-qc-suppression\/\" class=\"more-link\">Read more \u00bb<\/a><\/p>\n","protected":false},"author":139,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-18767","post","type-post","status-publish","format-standard","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-json\/wp\/v2\/posts\/18767","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-json\/wp\/v2\/users\/139"}],"replies":[{"embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-json\/wp\/v2\/comments?post=18767"}],"version-history":[{"count":1,"href":"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-json\/wp\/v2\/posts\/18767\/revisions"}],"predecessor-version":[{"id":18769,"href":"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-json\/wp\/v2\/posts\/18767\/revisions\/18769"}],"wp:attachment":[{"href":"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-json\/wp\/v2\/media?parent=18767"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-json\/wp\/v2\/categories?post=18767"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/ewp\/wp-json\/wp\/v2\/tags?post=18767"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}