{"id":11706,"date":"2020-05-30T09:56:14","date_gmt":"2020-05-30T15:56:14","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=11706"},"modified":"2020-05-31T07:51:26","modified_gmt":"2020-05-31T13:51:26","slug":"ftb-05-30-2020-heavy-rainfall-forecast-for-the-mountains-urban-corridor","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=11706","title":{"rendered":"FTB 05-30-2020: Heavy Rainfall Forecast for the Mountains &#038; Urban Corridor"},"content":{"rendered":"<p>Issue Date: Saturday, May 30th, 2020<br>\nIssue Time: 10AM MDT<\/p>\n<p><em>&mdash; A <strong>MODERATE<\/strong> flood threat has been issued for the Front Range, Urban Corridor, Palmer Ridge, Northeast Plains and 416 burn area<\/em><\/p>\n<p><em>&mdash; A <strong>LOW<\/strong> flood threat has been issued for the Northern Mountains, Central Mountains, San Juan Mountains, Southeast Mountains, portions of the Northwest Slope. This includes the Spring Creek, Deckers, and Lake Christine burn areas.<\/em><\/p>\n<p>Same general pattern as yesterday with a few minor differences, which will be pointed out in the water vapor imagery below. There looks to still be plenty of moisture trapped underneath the ridging pattern, which is defined by the yellow line. <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> in the soundings this morning was measured at 0.80 inches and 0.75 inches at Grand Junction and Denver, respectively, which means there is actually a slight uptick since yesterday. In the image, you can also see a surface low over the eastern plains as indicated by the blue arrows (surface flow). This will help reinforce and slightly increase surface moisture on its eastern and northern side (northeast Colorado). <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;dew points&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;The temperature to which a given air parcel must be cooled (at constant pressure and water vapor content) in order for saturation to occur.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>Dew points<\/span> are forecast in the 50Fs, which is pretty juicy for Colorado.<\/p>\n<p>Today, the 500mb low off the coast of California will start to move northward up the coast. While this feature is well to our west, there will likely be some enhanced lift over the state out in front of it, which will help storms that fire over the mountains this afternoon be more <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> than yesterday. Additionally, as the low starts to move towards the Pacific Northwest, the axis of the ridge will start to shift eastward. This will place the state under southwest flow loft today. This should allow storms that form (from the southwest to northeast over the mountains) to push into the adjacent plains this afternoon favoring the Palmer Ridge and Urban Corridor for accumulations. With storm motion slower than yesterday, paired with increasing moisture and trailing\/pulsing storms, the flood threat increases.<\/p>\n<p><img loading=\"lazy\" class=\"size-full wp-image-11707 aligncenter\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/05\/wv_20200530.png\" alt=\"\" width=\"620\" height=\"444\"\/><\/p>\n<p>A Low flood threat for the majority of the mountain areas, which includes the aforementioned burn areas above. A Moderate flood threat has been issued for the Front Range, Urban Corridor and Palmer Ridge as rain rates will increase in the moisture rich environment along a tongue of convergence and instability. <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> 24-hour totals over the San Juan Mountains will likely reach 1-inch with the multiple rounds of rainfall through tomorrow morning, so for caution, a Moderate flood threat has been issued for the 416 burn area. Threats over all burn areas include <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>, mud flows and debris slides.<\/p>\n<h3><strong>Today&rsquo;s Flood Threat Map<\/strong><\/h3>\n<p>For more information on today&rsquo;s flood threat, see the map below. If there is a threat, hover over the threat areas for more details, and click on burn areas to learn more about them. For Zone-Specific forecasts, scroll below the threat map.<\/p>\n<p><img loading=\"lazy\" class=\"aligncenter wp-image-11712\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/05\/FTB_20200530_snap.png\" alt=\"\" width=\"880\" height=\"597\"\/><\/p>\n<h3><strong>Zone-Specific Forecasts:<\/strong><\/h3>\n<h4><strong>Front Range, Urban Corridor, Palmer Ridge, &amp; Northeast Plains:<\/strong><\/h4>\n<p>Nearly stationary storms this afternoon will increase the chances for flooding over the Front Range. Other threats include severe hail and strong <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;outflow&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;A cool pool of air that results when a thunderstorm downdraft reaches the surface and spreads horizontally.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>outflow<\/span> gusts. Max 1-hour rain rates up to 1 inch will be possible with <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> storm totals up just over 1.50 inches by morning. This could cause local flooding issues such as mud flows, debris slides, field ponding and local stream <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>.<\/p>\n<p>As storms move off the mountains, moisture increases, but the hail threat likely decreases somewhat. However, small hail will still be possible. With nearly stationary storms, very heavy, local rainfall is forecast. Guidance is indicating that the greatest threat for flooding will be from 3PM to 8PM. Max 1-hour rain rates up to 1.50 inches will be possible under the storm cores with <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> storm totals up to 1.90 inches possible. This would cause street flooding, field ponding and local stream\/gulch <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>. Storms are expected to start dissipating around midnight.<\/p>\n<p>Primetime: 12PM to 2AM<\/p>\n<h4><strong>Southeast Mountains, San Juan Mountains,<\/strong> <strong>Northwest Slope, Northern Mountains, Central Mountains, Grand Valley, Southwest Slope, &amp; San Luis Valley:<\/strong><\/h4>\n<p>Although there was an <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;Inverted-V&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Refers to the shape of the lower levels of an atmospheric profile. The shape of the &amp;quot;Inverted V&rdquo; is the result of dry air below cloud level, which promotes strong winds and evaporation of precipitation before reaching the surface.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>inverted-V<\/span> sounding west of the <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;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\"}]'>Divide<\/span> (indicating strong winds with storms again), the lower atmosphere and multiple rounds of rainfall will increase totals for these regions as the <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;boundary layer&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;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&amp;lt;br \/&amp;gt;&amp;lt;p&amp;gt;&amp;lt;span style=&amp;quot;color: #ffffff;&amp;quot;&amp;gt;The lower portion of the atmosphere that is directly influenced by the earth&amp;#039;s surface. Primarily, the boundary layer is driven by solar heating during the day and radiational cooling at night.&amp;lt;\/span&amp;gt;&amp;lt;\/p&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>boundary layer<\/span> moistens. <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> max 1-hour rain rates up to 0.60 inches will be possible with 24-hour totals up to 1-inch over the San Juan Mountains along with gusty <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;outflow&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;A cool pool of air that results when a thunderstorm downdraft reaches the surface and spreads horizontally.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>outflow<\/span> winds. Thus, a Low flood threat has been issued for the Deckers, Spring Creek, and Lake Christine burn areas. A Moderate Threat has been issued for the 416 burn area.<\/p>\n<p>With 1-2 hour rain rates around 0.75 inches, a Low flood threat has been issued for other mountainous regions. Lower elevations over western Colorado and the San Luis Valley will likely get in on the rain action as well with instability rotating around the ridge. Totals between 0.15 and 0.25 inches are the most likely with strong <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;outflow&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;A cool pool of air that results when a thunderstorm downdraft reaches the surface and spreads horizontally.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>outflow<\/span> winds (40-50 mph).<\/p>\n<p>Primetime: 12PM to 6AM<\/p>\n<h4><strong>Raton Ridge<\/strong><strong> &amp;<\/strong><strong> Southeast Plains<\/strong><strong>: <\/strong><\/h4>\n<p>Due to storm motions, not thinking there will be much rainfall threat over these areas today with the eastern Raton Ridge receiving the majority of the rainfall. Max 1-hour rain rates up to 0.50 inches will be possible. A couple overnight storms may be possible over the Southeast Plains, but lower moisture will reduce spatial coverage and totals. <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> totals just under 0.50 inches by morning seem reasonable.<\/p>\n<p>Primetime: 12:30PM to 3AM<\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Saturday, May 30th, 2020 Issue Time: 10AM MDT &mdash; A MODERATE flood threat has been issued for the Front Range, Urban Corridor, Palmer Ridge, Northeast Plains and 416 burn area &mdash; A LOW flood threat has been issued for the Northern Mountains, Central Mountains, San Juan Mountains, Southeast Mountains, portions of the Northwest [&hellip;]<\/p>","protected":false},"author":8,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[6],"tags":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/11706"}],"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\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=11706"}],"version-history":[{"count":2,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/11706\/revisions"}],"predecessor-version":[{"id":11713,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/11706\/revisions\/11713"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=11706"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11706"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11706"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}