{"id":14095,"date":"2021-05-29T10:26:27","date_gmt":"2021-05-29T16:26:27","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=14095"},"modified":"2021-05-30T09:17:39","modified_gmt":"2021-05-30T15:17:39","slug":"spm-05-29-2021-isolated-severe-storms-over-raton-ridge-otherwise-warm-and-pleasant-friday-for-most","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=14095","title":{"rendered":"SPM 05-29-2021: Isolated Severe Storms Over Raton Ridge, Otherwise Warm and Pleasant Friday For Most"},"content":{"rendered":"<p>Issue Date: Saturday, May 29, 2021<br>\nIssue Time: 10:15 am MDT<\/p>\n<h3>Summary<\/h3>\n<p>With a transient ridge overhead, sunshine was aplenty for most of Colorado on Friday, along with slightly above normal temperatures. However, in typical Colorado fashion, our unique summer circulation (that is driven strongly by heating over the higher terrain) was able to generate <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;isolated&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;less than 10% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>isolated<\/span> thunderstorms, a few that were severe, over the Raton Ridge, Palmer Ridge and parts of the Northeast Plains.<\/p>\n<p>By far the most impressive storms were located over the Raton Ridge, and trekked once again over the Purgatoire River basin. This region is one of the most poorly observed areas of the state, which manifested itself in a huge discrepancy in estimate rainfall rates. Both Stage IV and MRMS guidance estimated that over 2 inches of rainfall occurred in the small Trinchera Creek tributary of the Purgatoire. However, the MetStorm product shown below estimates less than 0.5 inches fell in the 24-hour period (it also estimates max 1-hour intensity of 0.5-1.0 inch; it is common for the 1-hour estimate to be higher than the 24-hour in these situations since the 1-hour is strongly biased towards the more uncertain radar-only estimates). Perhaps the verdict lies in the streamflow. A USGS gage located on the Purgatoire River just downstream of the confluence with Trinchera Creek noted only a ~15 c.f.s. rise in streamflow, shown below. Keep in mind this is the same gauge that rose above 5,000 c.f.s. with the recent rain. With this limited increase in flow yesterday, it is very hard to imagine that anywhere near 2.0 inches of rain actually fell. The most likely outcome was hail contamination causing a spike in the radar estimated rainfall, with actual rainfall likely in the 0.5-1.0 inch range possible.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/purga_trinchera.png\"><img loading=\"lazy\" class=\"aligncenter  wp-image-14102\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/purga_trinchera-1024x501.png\" alt=\"\" width=\"854\" height=\"418\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/purga_trinchera-1024x501.png 1024w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/purga_trinchera-300x147.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/purga_trinchera-768x376.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/purga_trinchera.png 1771w\" sizes=\"(max-width: 854px) 100vw, 854px\"\/><\/a><\/p>\n<p>&nbsp;<\/p>\n<h4 class=\"collapseomatic \" id=\"id6a1c6aac31d7d\" tabindex=\"0\" title=\"Click Here For Map Overview\">Click Here For Map Overview<\/h4><div id=\"target-id6a1c6aac31d7d\" class=\"collapseomatic_content \">\nThe map below shows radar-estimated, rainfall gage-adjusted Quantitative Precipitation Estimates (<span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;QPE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;strong&amp;gt;Q&amp;lt;\/strong&amp;gt;uantitative &amp;lt;strong&amp;gt;P&amp;lt;\/strong&amp;gt;recipitation &amp;lt;strong&amp;gt;E&amp;lt;\/strong&amp;gt;stimate; an estimate of the amount of precipitation that has fallen at a particular location or across a region based on several different data sources, such as radar or satellite; QPE is often calculated using remotely-sensed data sources&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>QPE<\/span>) across Colorado. The map is updated daily during the operational season (May 1 &ndash; Sep 30) by 11AM. The following six layers are currently available: 24-hour, 48-hour and 72-hour total precipitation, as well as maximum 1-hour, 2-hour and 6-hour precipitation over the past 24 hour period (to estimate where <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;flash flooding&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;!-- wp:paragraph {&amp;quot;textColor&amp;quot;:&amp;quot;white&amp;quot;} --&amp;gt;\n&amp;lt;p class=&amp;quot;has-white-color has-text-color&amp;quot;&amp;gt;flash flooding can refer to usually dry areas becoming rapidly inundated with water, or rapid water level rises on streams, creeks, or rivers beyond flood stage; typically caused by heavy rainfall, but can also be caused by meltwater&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>flash flooding<\/span> may have occurred). The accumulation ending time is 7AM of the date shown in the bottom right corner. Also shown optionally are vulnerable fire burn areas (post 2012), which are updated throughout the season to include new, vulnerable burn areas. The home button in the top left corner resets the map to the original zoom.\n<p><span style=\"color: #ff0000;\">Note: The 24-hour, 48-hour and 72-hour total precipitation do not contain bias corrections today due to errors in the <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;CoCoRaHS&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;!-- wp:paragraph {&amp;quot;textColor&amp;quot;:&amp;quot;white&amp;quot;} --&amp;gt;\n&amp;lt;p class=&amp;quot;has-white-color has-text-color&amp;quot;&amp;gt;&amp;lt;strong&amp;gt;Co&amp;lt;\/strong&amp;gt;mmunity &amp;lt;strong&amp;gt;Co&amp;lt;\/strong&amp;gt;llaborative &amp;lt;strong&amp;gt;Ra&amp;lt;\/strong&amp;gt;in, &amp;lt;strong&amp;gt;H&amp;lt;\/strong&amp;gt;ail, and &amp;lt;strong&amp;gt;S&amp;lt;\/strong&amp;gt;now Network, a volunteer network of precipitation observers across the country&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>CoCoRaHS<\/span> data. This means there may be underestimations in <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;QPE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;strong&amp;gt;Q&amp;lt;\/strong&amp;gt;uantitative &amp;lt;strong&amp;gt;P&amp;lt;\/strong&amp;gt;recipitation &amp;lt;strong&amp;gt;E&amp;lt;\/strong&amp;gt;stimate; an estimate of the amount of precipitation that has fallen at a particular location or across a region based on several different data sources, such as radar or satellite; QPE is often calculated using remotely-sensed data sources&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>QPE<\/span> over the southwest and southeast corners of the state. <\/span><\/p>\n<\/div>\n<a href=\"http:\/\/www.dewberry-hydromet.com\/STP\/Snapshots\/SPM\/SPM_20210529_snap.png\"><img loading=\"lazy\" class=\"alignnone wp-image-13558 size-full\" src=\"http:\/\/www.dewberry-hydromet.com\/STP\/Snapshots\/SPM\/SPM_20210529_snap.png\" alt=\"\" width=\"906\" height=\"617\"\/><\/a>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Saturday, May 29, 2021 Issue Time: 10:15 am MDT Summary With a transient ridge overhead, sunshine was aplenty for most of Colorado on Friday, along with slightly above normal temperatures. However, in typical Colorado fashion, our unique summer circulation (that is driven strongly by heating over the higher terrain) was able to generate [&hellip;]<\/p>","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[4],"tags":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/14095"}],"collection":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=14095"}],"version-history":[{"count":3,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/14095\/revisions"}],"predecessor-version":[{"id":14110,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/14095\/revisions\/14110"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=14095"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14095"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14095"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}