{"id":5885,"date":"2017-08-10T14:16:17","date_gmt":"2017-08-10T20:16:17","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=5885"},"modified":"2017-08-14T11:30:02","modified_gmt":"2017-08-14T17:30:02","slug":"fto-08-10-2017-more-heavy-rainfall-in-short-term-then-big-pattern-change","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=5885","title":{"rendered":"FTO 08-10-2017: More Heavy Rainfall In Short Term, Then Big Pattern Change"},"content":{"rendered":"<p>Issue Date: Thursday, August 10, 2017<br>\nIssue Time: 2:20PM MDT<br>\nValid Dates: 8\/11-8\/25<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/threat_timeline-2.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-5888\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/threat_timeline-2.png\" alt=\"\" width=\"880\" height=\"127\"\/><\/a><\/p>\n<p>There is finally change towards a drier pattern on the horizon, but not before several more days of heavy rainfall and elevated\/high flood threat conditions will be endured. As shown in the northern hemisphere water vapor image, below, a surface high pressure is currently positioned over the northern Great Plains. The clockwise circulation around this high is transporting high moisture into eastern Colorado. At least one more such surface high pressure is expected to move southward over the next 72-120 hours, which will keep elevated moisture in place. Additionally, a strong jet remains overhead, which is supporting relatively cool temperatures at mid-levels (and surface), allowing for daily round of <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;scattered&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;25-40% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>scattered<\/span> to <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;numerous&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;40-60% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>numerous<\/span> showers and storms east of the <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;Continental Divide&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;the dividing line that separates the watersheds of the western and eastern United States; rivers west of the divide empty into the Pacific Ocean, while rivers east of the divide empty into the Atlantic Ocean or Gulf of Mexico&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>Continental Divide<\/span>.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/wv_markup-6.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-5889 size-full\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/wv_markup-6.png\" alt=\"\" width=\"565\" height=\"413\"\/><\/a><\/p>\n<p>Thus, the prolonged flood threat will continue through early next week, labeled as Event #1 for this Flood Threat Outlook. At this time, it appears that relatively <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> heavy rainfall, and flooding, will be the primary impact. However, the arrival of a new surface boundary on Sunday prompts a High threat, especially given that the region under threat appears to be the Southeast Plains. We cannot overstate the need to monitor the Arkansas River and its tributaries as they remain at elevated levels. The 40 day <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;trace&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;a descriptor used when precipitation occurs, but the amount is too small (less than 0.01&amp;quot;) to be measured by a weather instrument such as a rain gauge&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>trace<\/span> from the Las Animas USGS gage, below, shows that the river has been at significantly elevated levels since late July. Thus, it remains very vulnerable since even modest rainfall and runoff could cause flooding. At this time, we do not expect major riverine flooding within Colorado&rsquo;s borders, though stay tuned to daily Flood Threat Bulletins for a more detailed look.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/ark_river_las_animas.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-5886 size-full\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/ark_river_las_animas.png\" alt=\"\" width=\"576\" height=\"384\"\/><\/a><\/p>\n<p>After the middle of next week, we foresee a significant pattern change, as noted by the surface pressure anomaly maps below. Note the high pressure anomalies early in the period, which is supporting the moist easterly flow and heavy rainfall activity. By the middle of next week, a surface low pressure is expected to develop. This means generally <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;downsloping&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Refers to the winds that blow from higher elevations down towards lower elevations. As air parcels descend, they warm, which often results in rapid warming of areas near the higher terrains. It also promotes lower relative humidity values and stability, which prevents thunderstorm development.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>downsloping<\/span> low-level winds, also accompanied by a transport of relatively dry mid-level air from the Great Basin. Thus, we have only identified one precipitation event for this 15-day Outlook, which is described in more detail below.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/gfs_mslpanom_2panel.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-5887\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/gfs_mslpanom_2panel.png\" alt=\"\" width=\"698\" height=\"239\"\/><\/a><\/p>\n<h3><strong>Event #1: Friday (8\/11) through Wednesday (8\/16)<\/strong><\/h3>\n<p><span style=\"color: #ff6600;\"><strong>Prolonged Elevated\/<span style=\"color: #800000;\">High<\/span> Flood Threat <\/strong><\/span>for daily rounds of heavy rainfall east of the <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;Continental Divide&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;the dividing line that separates the watersheds of the western and eastern United States; rivers west of the divide empty into the Pacific Ocean, while rivers east of the divide empty into the Atlantic Ocean or Gulf of Mexico&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>Continental Divide<\/span>; Arkansas River basin will be vulnerable to minor riverine flooding<\/p>\n<p>With continued elevated moisture (<span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;PW&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;(Stands for: Precipitable Water) The total atmospheric water vapor contained in a vertical column of the atmosphere. It is typically measured in inches, and anomalously (deviation from normal) high values of precipitable water generally correlate to heavy rainfall potential.&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>PW<\/span> expected to stay at or above 1 inch east of the <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;Continental Divide&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;the dividing line that separates the watersheds of the western and eastern United States; rivers west of the divide empty into the Pacific Ocean, while rivers east of the divide empty into the Atlantic Ocean or Gulf of Mexico&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>Continental Divide<\/span>), daily rounds of <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;scattered&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;25-40% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>scattered<\/span> to <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;numerous&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;40-60% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>numerous<\/span> shower and thunderstorm activity are expected. Storms will form off the higher terrain first but then track eastward for at least several hours, especially over the Palmer and Raton Ridges. Max 1-hour rainfall up to 2.4 inches (east) and 1.9 inches (west) will be possible, supporting <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> <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>, small stream flooding and street flooding in urban areas. In addition, max 3-hour rainfall up to 3.1 inches (east) and 2.5 inches (west) will support mud flows and debris slides, especially in regions with saturated soils. In addition, the threat of <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> severe weather (mainly large hail) will exist especially towards the Kansas border.<\/p>\n<p>At this moment, Sunday appears to be the most vulnerable day, due to the expected <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;widespread&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;greater than 60% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>widespread<\/span> coverage of heavy rainfall in the Southeast Plains. The Arkansas River and its major tributaries will be in a particularly elevated risk of riverine flooding, especially towards the Kansas border.<\/p>\n<div style=\"position: relative;\"><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/FTO_20170810_e1.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-5947\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/FTO_20170810_e1.png\" alt=\"\" width=\"880\" height=\"498\"\/><\/a><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2015\/05\/Legend.png\"><img loading=\"lazy\" class=\"alignnone size-full wp-image-230\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2015\/05\/Legend.png\" alt=\"Legend\" width=\"94\" height=\"158\"\/><\/a><\/div>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Thursday, August 10, 2017 Issue Time: 2:20PM MDT Valid Dates: 8\/11-8\/25 There is finally change towards a drier pattern on the horizon, but not before several more days of heavy rainfall and elevated\/high flood threat conditions will be endured. As shown in the northern hemisphere water vapor image, below, a surface high pressure [&hellip;]<\/p>","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[3],"tags":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/5885"}],"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=5885"}],"version-history":[{"count":3,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/5885\/revisions"}],"predecessor-version":[{"id":5949,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/5885\/revisions\/5949"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5885"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5885"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5885"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}