{"id":4454,"date":"2017-05-11T15:06:23","date_gmt":"2017-05-11T21:06:23","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=4454"},"modified":"2017-05-15T13:01:41","modified_gmt":"2017-05-15T19:01:41","slug":"fto-05-11-2017-warm-and-dry-to-start-followed-by-multi-day-flood-threat","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=4454","title":{"rendered":"FTO 05-11-2017: Warm and Dry To Start, Followed By Multi-Day Flood Threat"},"content":{"rendered":"<p>Issue Date: May 11th, 2017<br>\nIssue Time: 3:05PM EDT<br>\nValid Dates: May 12 &ndash; May 26<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/05\/threat_timeline-1.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-4455\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/05\/threat_timeline-1.png\" alt=\"\" width=\"880\" height=\"111\"\/><\/a>This afternoon&rsquo;s water vapor imagery, below, continues to show a very active North Pacific <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;jet stream&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Relatively strong winds concentrated within a narrow stream in the atmosphere. General weather patterns are related closely to the position, strength and orientation of the jet stream.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>jet stream<\/span> that will continue to affect Colorado over the next 15 days. The first feature of note is the departing <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;cut-off low&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;an upper-level low pressure system that has been &amp;quot;cut off&rdquo; from the prevailing winds that steer weather systems; cut-off lows typically become stationary or move very slowly, bringing prolonged periods of unsettled weather&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>cut-off low<\/span>-pressure system that affected the state over the past 3 days. As this continues to move away, Colorado will be increasingly influenced by a moderate strength ridge that will provide several days of warm and dry conditions. Certainly a welcome change after a string of days with severe weather and heavy rainfall.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/05\/wv_markup-3.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-4456\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/05\/wv_markup-3.png\" alt=\"\" width=\"700\" height=\"453\"\/><\/a><\/p>\n<p>Turning our attention westwards, we see two low-pressure systems in the North Pacific, separated by a high pressure ridge. Despite the fact that the eastern feature is already entering the west coast of North America, it will be in no hurry to propagate eastward and will instead nearly stall out. Thereafter, guidance is in surprisingly good agreement that the two large-scale troughs will merge over the western US and thereafter begin to affect Colorado. This has been identified as Event #1. There is some uncertainty as to how long this event will affect the state and where exactly the low pressure will develop. However, an elevated flood threat appears likely.<\/p>\n<p>Thereafter, a more <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;zonal&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;refers to the east-west direction; usually used to describe atmospheric flow that roughly follows lines of latitude&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>zonal<\/span> flow will develop over western North America. Seasonally warm temperatures are expected and several weak disturbances may affect the state. However, the next organized precipitation event does not appear to be in the works until the latter part of the 15-day period, when another <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;trough&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;An elongated area of relatively low atmospheric pressure; the opposite of a ridge.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>trough<\/span> affects Colorado.<\/p>\n<p>Below we describe each of the two identified Events in more detail.<\/p>\n<h3><strong>Event #1: Thursday (5\/18) and Friday (5\/19)<\/strong><\/h3>\n<p><span style=\"color: #ff6600;\"><strong>Elevated Flood Threat<\/strong><\/span> as another <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;cut-off low&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;an upper-level low pressure system that has been &amp;quot;cut off&rdquo; from the prevailing winds that steer weather systems; cut-off lows typically become stationary or move very slowly, bringing prolonged periods of unsettled weather&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>cut-off low<\/span> pressure is likely to affect Colorado&rsquo;s weather<\/p>\n<p>Somewhat similar to the recent <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;cut-off low&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;an upper-level low pressure system that has been &amp;quot;cut off&rdquo; from the prevailing winds that steer weather systems; cut-off lows typically become stationary or move very slowly, bringing prolonged periods of unsettled weather&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>cut-off low<\/span> pressure, this event will begin in earnest on Thursday as the cut-off enters the state either from the west or southwest. Current guidance is in very good agreement about the chances of heavy rainfall both Thursday and Friday. On Thursday, as the disturbance first affects the state, at least one round of thunderstorms is expected across a wide swath of the state, with the possible exception of the far southeast. <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> will be possible along with hail, and gusty thunderstorm winds. Up to 1.5 inches of rainfall could fall, with the highest threat regions being the Palmer Ridge and into the Central Mountains. By Friday, as the system moves across the state, a deep easterly\/southeasterly moisture feed will likely result in another round of showers and thunderstorms. The focus region this time will be in the Front Range along the Wyoming border. <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>, debris slides and mud flows will be possible. It is possible that this event is upgraded to a High flood threat, so stay tuned.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/05\/FTO_20170511_e2.png\"><img loading=\"lazy\" class=\"size-full wp-image-4505 aligncenter\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/05\/FTO_20170511_e2.png\" alt=\"\" width=\"881\" height=\"498\"\/><\/a><\/p>\n<div id=\"FTOlegend\" align=\"right\"><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2015\/05\/Legend.png\"><img loading=\"lazy\" class=\"alignright wp-image-230 size-full\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2015\/05\/Legend.png\" alt=\"Legend\" width=\"94\" height=\"158\"\/><\/a><\/div>\n<h3><strong>Event #2: Thursday (5\/25) and Friday (5\/26)<\/strong><\/h3>\n<p><span style=\"color: #0000ff;\"><strong>No Anticipated Flood Threat<\/strong><\/span> at this time<\/p>\n<p>A more <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;zonal&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;refers to the east-west direction; usually used to describe atmospheric flow that roughly follows lines of latitude&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>zonal<\/span> flow will provide Colorado with seasonable weather after Event #1. At this time, it appears another large-scale <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;trough&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;An elongated area of relatively low atmospheric pressure; the opposite of a ridge.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>trough<\/span> may enter the west coast by Wednesday 5\/24. Thereafter, chances of <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> precipitation will increase as easterly winds bring in Gulf of Mexico moisture. The chances of rainfall exceeding 0.5 inches is uncertain at this time, so no precipitation map is provided.<\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: May 11th, 2017 Issue Time: 3:05PM EDT Valid Dates: May 12 &ndash; May 26 This afternoon&rsquo;s water vapor imagery, below, continues to show a very active North Pacific <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;jet stream&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Relatively strong winds concentrated within a narrow stream in the atmosphere. General weather patterns are related closely to the position, strength and orientation of the jet stream.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>jet stream<\/span> that will continue to affect Colorado over the next 15 days. The first feature of note is the departing <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;cut-off low&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;an upper-level low pressure system that has been &amp;quot;cut off&rdquo; from the prevailing winds that steer weather systems; cut-off lows typically become stationary or move very slowly, bringing prolonged periods of unsettled weather&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>cut-off low<\/span>-pressure system that [&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\/4454"}],"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=4454"}],"version-history":[{"count":5,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/4454\/revisions"}],"predecessor-version":[{"id":4506,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/4454\/revisions\/4506"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4454"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4454"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4454"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}