{"id":19840,"date":"2022-09-19T15:03:05","date_gmt":"2022-09-19T21:03:05","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=19840"},"modified":"2022-09-22T09:41:58","modified_gmt":"2022-09-22T15:41:58","slug":"fto-09-19-2022-the-monsoon-event-begins","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=19840","title":{"rendered":"FTO 09-19-2022: The Late Season Monsoon Event Begins"},"content":{"rendered":"<p style=\"font-weight: 400;\">Issue Date: Monday,&nbsp;September 19th, 2022<br>\nIssue Time:&nbsp;3PM MDT<br>\nValid Dates:&nbsp;9\/20 &ndash; 10\/4<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-19841\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919-300x39.png\" alt=\"\" width=\"880\" height=\"116\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919-300x39.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919-1024x134.png 1024w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919-768x101.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919-1536x202.png 1536w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919-2048x269.png 2048w\" sizes=\"(max-width: 880px) 100vw, 880px\"\/><\/a><\/p>\n<p style=\"font-weight: 400;\">An active rainfall pattern is forecast to start this week with a subtropical moisture plume arriving to Colorado by tomorrow morning. As moisture from Tropical Cyclone Madeline moves northwards, it will be picked up and pulled into the state by the southwest flow created from the <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;cutoff 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\"}]'>cutoff Low<\/span> off the coast of California and High pressure center over Texas\/Oklahoma (Event #1). Embedded in this plume will likely be some small disturbances causing extra lift, which could help produce some localized <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>. Additionally, a <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> to our north is expected to track eastward, which will drop a cold front through the state late on Tuesday into Wednesday morning ending the late season hot streak. This also may mean that portions of the eastern plains get wet on Wednesday and Thursday. Enhanced convergence along a developing surface boundary is expected to help increase rainfall totals and rainfall rates over the state with a peak in storm activity forecast for Wednesday. By Friday morning, the <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;cutoff 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\"}]'>cutoff Low<\/span> should be north of the state and lift from it will continue to track eastward. Behind the Low, dry westerly flow is expected to take over, which should aid in quickly reducing the chance for precipitation on Friday.<\/p>\n<p style=\"font-weight: 400;\">Event #2 will likely begin on Saturday evening and last through Sunday midday when another cold front is forecast to drop through the state. There are still a few differences between models and individual runs for this event, but currently, more stratiform rainfall is forecast for the eastern plains. For this reason, there is No Apparent threat issued at this time.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/wv_20220919.jpg\"><img loading=\"lazy\" class=\"aligncenter wp-image-19842\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/wv_20220919-300x195.jpg\" alt=\"\" width=\"700\" height=\"454\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/wv_20220919-300x195.jpg 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/wv_20220919-1024x664.jpg 1024w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/wv_20220919-768x498.jpg 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/wv_20220919.jpg 1480w\" sizes=\"(max-width: 700px) 100vw, 700px\"\/><\/a><\/p>\n<p style=\"font-weight: 400;\">Once the moisture plume for Event #1 is overhead, the GEFS suggests that <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> will be running near the maximum moving average or slightly above for late September. That translates to <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 around or just above 1 inch, which is highly correlated to chase for heavy rainfall. While there may be some stronger storms that develop during the afternoons in areas that receive some breaks in cloud cover, the real threat for Event #1 will be from the longer duration rainfall and excessive runoff. Highest total for the event are anticipated to be over the southwest high terrain, but totals over 1.5 inches could also occur over portions of the west-central high terrain. A low-end High flood threat has been issued on Wednesday with an Elevated flood threat issued for both Tuesday and Wednesday.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/PW_20220919.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-19843\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/PW_20220919-300x105.png\" alt=\"\" width=\"880\" height=\"307\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/PW_20220919-300x105.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/PW_20220919-1024x357.png 1024w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/PW_20220919-768x268.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/PW_20220919-1536x536.png 1536w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/PW_20220919-2048x714.png 2048w\" sizes=\"(max-width: 880px) 100vw, 880px\"\/><\/a><\/p>\n<p>Scroll down to read more about the two events highlighted in today&rsquo;s FTO.<\/p>\n<h3><strong>Event #1:<\/strong> <strong>Tuesday<\/strong><strong> &ndash; <\/strong><strong>Friday<\/strong><strong> (9\/<\/strong><strong>20<\/strong><strong> &ndash; 9\/2<\/strong><strong>3<\/strong><strong>)<\/strong><\/h3>\n<p style=\"font-weight: 400;\"><strong>Late season <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;monsoon&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;a seasonal wind that brings moisture and rain to the region into which it blows; there is also a dry phase to monsoons, but popular usage refers only to the wet phase; these winds occur in many places around the world, and where they occur they are responsible for a majority of that location&rsquo;s annual precipitation&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>monsoon<\/span> surge to cause heavy rainfall over the central and south portions of western Colorado; <span style=\"color: #ff0000;\">High<\/span> flood threat issued.<\/strong><\/p>\n<p style=\"font-weight: 400;\">On Tuesday, <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> storms should mostly be located over the central and south high terrain of western Colorado. With drier low-levels and the likely limited instability, rain rates should only to be of moderate intensity. However, <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;training&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Continuous or repeated rainfall over the same region&nbsp;in a relatively short time span. Training thunderstorms can produce very high rainfall totals and cause flash flooding.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>training<\/span> storms may push localized 3-hour totals close to 1.75 inches. For this reason, a low-end Elevated flood threat has been issued. Heading into Wednesday, 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> rainfall is forecast for central and southwest Colorado where moisture and dynamics will be maximized. <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> 3-hour rain rates up to 2.25 inches and 24-hour totals up to 3 inches may be possible, so a High flood threat has been issued. By Thursday, max 3-hour rain rates will likely fall between 1 and 1.5 inches, but saturated soils will likely cause excessive runoff. For this reason, an Elevated flood threat has been issued. Rises in local streams, creeks and rivers should be anticipated over the next few days as well as ponding in low-lying areas. Over steeper terrain, <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> mud flows and debris slides may be possible. As far as storm totals, about 30% of the EPS members (50 total) are suggesting totals at or exceeding 3 inches in Durango, so it&rsquo;s going to get wet. Not surprisingly, <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;NWS&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;National Weather Service&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>NWS<\/span> Grand Junction issued a Flood <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;Watch&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;a weather watch is issued when conditions are favorable for a specific weather event to occur&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>Watch<\/span> earlier today. Be sure to tune into the daily FTB for the latest details and daily flood forecast.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919_e1-1.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-19885\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919_e1-1-300x203.png\" alt=\"\" width=\"880\" height=\"596\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919_e1-1-300x203.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919_e1-1-1024x693.png 1024w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919_e1-1-768x520.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919_e1-1-1536x1040.png 1536w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2022\/09\/FTO_20220919_e1-1.png 1776w\" sizes=\"(max-width: 880px) 100vw, 880px\"\/><\/a><\/p>\n<h3><strong>Event #2: <\/strong><strong>Saturday<\/strong><strong> &ndash; <\/strong><strong>Sunday<\/strong><strong> (9\/<\/strong><strong>24<\/strong><strong> &ndash; 9\/2<\/strong><strong>5<\/strong><strong>)<\/strong><\/h3>\n<p style=\"font-weight: 400;\"><strong>It looks like another cold front may drop through the state during this period, but there is <span style=\"color: #0000ff;\">No Apparent<\/span> flood threat issued. <\/strong><\/p>\n<p style=\"font-weight: 400;\">Currently guidance is predicting this cold front to move through Saturday night into Sunday morning. With limited instability during the overnight hours, only stratiform, <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> storms are expected for the eastern plains. Rain rates should remain under 0.5 inches per hour, so no precipitation map has been drawn.<\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Monday,&nbsp;September 19th, 2022 Issue Time:&nbsp;3PM MDT Valid Dates:&nbsp;9\/20 &ndash; 10\/4 An active rainfall pattern is forecast to start this week with a subtropical moisture plume arriving to Colorado by tomorrow morning. As moisture from Tropical Cyclone Madeline moves northwards, it will be picked up and pulled into the state by the southwest flow [&hellip;]<\/p>","protected":false},"author":8,"featured_media":0,"comment_status":"closed","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\/19840"}],"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=19840"}],"version-history":[{"count":13,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/19840\/revisions"}],"predecessor-version":[{"id":19886,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/19840\/revisions\/19886"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=19840"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=19840"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=19840"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}