{"id":10886,"date":"2019-09-19T08:32:09","date_gmt":"2019-09-19T14:32:09","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=10886"},"modified":"2019-09-20T07:37:13","modified_gmt":"2019-09-20T13:37:13","slug":"ftb-09-19-2019-rainfall-for-the-mountains-as-the-trough-approaches-from-the-west","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=10886","title":{"rendered":"FTB 09-19-2019: Rainfall for the Mountains as the Trough Approaches from the West"},"content":{"rendered":"<p>Issue Date: Thursday, September 19th, 2019<br>\nIssue Time: 8:30AM MDT<\/p>\n<p><em>&mdash; A <strong>LOW <\/strong>flood threat has been issued for the 416\/Burro burn area<\/em><\/p>\n<p>Average to slightly above average low temperatures overnight across the state. There&rsquo;s some dense, early morning fog being reported over the eastern plains near Limon out to the Kansas border (6:30AM MDT). This should quickly burn off with a little sunlight as the moisture is confined just to the surface. <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> at Denver and Grand Junction was measured at 0.52 and 0.58 inches, respectively in this morning&rsquo;s sounding. So not much change from yesterday. Expecting these values to increase over the next 24-hours from south to north, first over western Colorado with some really high values over eastern Colorado by tomorrow afternoon. This moisture surge has to do with the approaching low to our west. As the feature moves eastward and digs south throughout the day, upper level flow will turn from southwesterly to more southerly. This will allow a few disturbances to move through the flow and start to create a subtropical moisture surge (albeit weak).<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/09\/wv_20190919.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-10887\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/09\/wv_20190919.png\" alt=\"\" width=\"600\" height=\"493\"\/><\/a><\/p>\n<p>One of today&rsquo;s disturbances is marked over Utah with the &ldquo;X&rdquo;. This feature will first move east this morning, and then it will pull northwards throughout the afternoon. Not expecting much rainfall with this feature due to the low <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> values, but an increase in cloud cover should mark its location throughout the day. It may help spark some weak afternoon <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;convection&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Refers to vertical atmospheric motion driven by buoyancy, i.e., warm air is less dense than cool air, and therefore rises. One of the primary drivers of thunderstorm development, especially during monsoon season.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>convection<\/span> over the northern high terrains near and along 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> with the diurnal flow, but more <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;virga&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Wisps or streaks of precipitation falling out of a cloud that evaporate before reaching the surface. Virga can cause strong, but short-lived, localized winds (dry microburst).&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>virga<\/span> than measurable rainfall is forecast. Over the eastern plains, along the CO\/KS border, additional thunderstorms may be possible this afternoon. The latest model runs are keeping the stronger storms to the east of the border, but there is a good chance for an <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 or two initiating along the line of convergence over southeast Colorado (weak <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;dryline&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;A low-level, small-scale boundary that separates dry air from moist air. Storms develop along it because the dry air (behind the boundary) is less dense than the moisture-rich air (ahead of the boundary). Typically, it advances eastward during the afternoon and retreats westward at night.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>dryline<\/span>). Not expecting flooding from these storms due to the <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> nature and the quick storm motion to the northeast.<\/p>\n<p>Another disturbance moves from south to north this evening, which starts over western Colorado. With the increasing <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> throughout the day, expecting some weak showers over the south Central and San Juan Mountains to begin later this evening. Storms will be capable of producing totals up to 0.9 inches over a 2-3 hour period over the San Juans (earlier timing of the moisture surge), so a Low flood threat has been issued for the 416 burn area. Rain rates should be gradual enough they won&rsquo;t cause issues elsewhere. The coverage should expand over the high terrains overnight as the feature moves north. Some weak showers may also be possible over the Raton Ridge\/southern Southeast Plains associated with another <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;shortwave&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;A disturbance in the mid or upper part of the atmosphere which induces upward motion ahead of it.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>shortwave<\/span> tomorrow morning. As it moves north throughout the morning, expect more cloud cover than measurable rainfall. Despite the <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> rounds of rainfall across the state (today, tonight, and tomorrow morning), flooding outside of the 416 burn scar, is not anticipated.<\/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. For Zone-Specific forecasts, scroll below the map.<\/p>\n<div style=\"position: relative;\"><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/09\/FTB_20190919_snap.png\"><img loading=\"lazy\" class=\"alignnone size-full wp-image-10905\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/09\/FTB_20190919_snap.png\" alt=\"\" width=\"880\" height=\"550\"\/><\/a><\/div>\n<div><img loading=\"lazy\" class=\"alignright wp-image-135\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2015\/04\/floodthreat_legend2.png\" alt=\"Flood Threat Legend\" width=\"275\" height=\"71\"\/><\/div>\n<p>&nbsp;<\/p>\n<h3><strong>Zone-Specific Forecasts:<\/strong><\/h3>\n<h4><strong>Central Mountains, Northern Mountains, San Juan Mountains, Northwest Slope, Grand Valley, Southwest Slope, San Luis Valley:<\/strong><\/h4>\n<p>Very <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 0.75 inches with totals up to 0.9 inches by morning are possible over the San Juan Mountains with totals decreasing to 0.5 inches over the Central Mountains. The 1-hour rain rates are reduced to 0.35 inches as you move north into the Northern Mountains and Northwest Slope. Most of the rainfall will be along and near 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> this afternoon and evening with some <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> activity over the higher elevations of the North\/Southwest Slopes. Lowest elevations should stay dry today minus the southern tier Southwest Slope and San Luis Valley. <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 up to 0.25 inches will be possible by morning. Thunderstorms this afternoon will again be capable of producing some 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, but they should not be quite as strong as yesterday and Tuesday. If storms continues to track over the 416 burn area tonight, <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> of local streams, debris slides and mud flows will be possible due to the moisture surge arriving. A Low flood threat has been issued for this reason.<\/p>\n<p>Primetime: 6PM to 5AM<\/p>\n<h4><strong>Front Range, Southeast Mountains, Urban Corridor, Raton Ridge, Palmer Ridge, Southeast Plains, Northeast Plains:<\/strong><\/h4>\n<p>Some afternoon <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;convection&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Refers to vertical atmospheric motion driven by buoyancy, i.e., warm air is less dense than cool air, and therefore rises. One of the primary drivers of thunderstorm development, especially during monsoon season.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>convection<\/span> will be possible over the Front Range near 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>, but accumulations should stay low (up to 0.25 inches). Overnight <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;convection&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Refers to vertical atmospheric motion driven by buoyancy, i.e., warm air is less dense than cool air, and therefore rises. One of the primary drivers of thunderstorm development, especially during monsoon season.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>convection<\/span> along 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> may cause totals up to 0.4 inches over the Front Range by morning. Additional thunderstorms over the Southeast Plains this afternoon could have rain rates up to 1.1 inches with large hail and strong winds also possible. As showers move across the southern border early tomorrow morning, max 1-hour rain rates up to 0.5 inches will be possible. Flooding is not forecast due to the low intensity of storms and quick storm motion of the stronger storms to the NE this afternoon.<\/p>\n<p>Primetime: 4PM to 7AM<\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Thursday, September 19th, 2019 Issue Time: 8:30AM MDT &mdash; A LOW flood threat has been issued for the 416\/Burro burn area Average to slightly above average low temperatures overnight across the state. There&rsquo;s some dense, early morning fog being reported over the eastern plains near Limon out to the Kansas border (6:30AM MDT). [&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\/10886"}],"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=10886"}],"version-history":[{"count":4,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/10886\/revisions"}],"predecessor-version":[{"id":10906,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/10886\/revisions\/10906"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10886"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10886"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10886"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}