{"id":10028,"date":"2019-07-25T14:35:40","date_gmt":"2019-07-25T20:35:40","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=10028"},"modified":"2019-07-29T11:42:27","modified_gmt":"2019-07-29T17:42:27","slug":"fto-07-25-2019-heavy-rainfall-and-widespread-thunderstorm-activity-anticipated-to-start-this-weekend","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=10028","title":{"rendered":"FTO 07-25-2019: Heavy Rainfall and Widespread Thunderstorm Activity Anticipated to Start this Weekend"},"content":{"rendered":"<p>Issue Date: Thursday, July 25th, 2019<br>\nIssue Time: 2:50PM MDT<br>\nValid Dates: 7\/26 &ndash; 8\/9<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/07\/FTO_20190725.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-10029\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/07\/FTO_20190725.png\" alt=\"\" width=\"880\" height=\"132\"\/><\/a><\/p>\n<p>There is an Elevated\/High flood threat to start this FTO, which is due to the location of the subtropical high tomorrow and then incoming upper level low on Saturday (Event #1). While most of eastern Colorado will begin to dry out tomorrow with flow aloft from the northwest, the Elevated flood threat continues for the southwest high terrains where flow aloft remains more westerly. Three days of rain over this area has likely saturated parts of the soil, so expecting an increase in runoff from storms tomorrow afternoon. On Saturday, the incoming <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> (marked below) pushes towards the east and shifts the ridge with it. Meanwhile, the subtropical high moves into California\/Arizona\/southern Nevada, which will eject a fairly strong <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> over the state for 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> thunderstorm coverage and possibly an overnight <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;MCS&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;(Stands for: Mesoscale Convective System) A complex of thunderstorms that produces a large, contiguous area of precipitation on the order of 100 km or more in the horizontal scale and normally persist for several hours or more.&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>MCS<\/span> on the plains. There is a break in the heavy rainfall threat from Sunday into Tuesday, although there will likely be enough residual moisture for <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 to trigger over the mountains each afternoon. A passing cold front on Saturday night\/early Sunday morning is expected to reduce highs 2-5&deg;F over eastern Colorado on Sunday and Monday.<\/p>\n<p>The next northward <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 begins on Wednesday, and an Elevated flood threat will be issued for Event #2. The ridge begins to build back to the north with the center of the subtropical high centered somewhere near the Colorado\/New Mexico\/Texas Panhandle. There will likely be several shortwaves rotating around the high, which will cause the increased threat level as the next <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> pushes the ridge axis east. Decreased steering winds under the high will cause storms over the higher terrains to produce more rainfall as well. In this classic <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> setup, flooding may be possible each afternoon, although the area of the threat is anticipated to change day to day. The ridge looks to break down with the high moving west sometime to start that next week, resulting in a break&nbsp;for the heavy rainfall threat.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/07\/wv_20190725.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-10030\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/07\/wv_20190725.png\" alt=\"\" width=\"675\" height=\"495\"\/><\/a><\/p>\n<p>Reaching that point in the season where <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 are climatologically peaking, which means the above average values shown below are very impressive. Slight decrease in moisture over eastern Colorado tomorrow with flow aloft changing to the northwest and pushing in a little drier air from the north. Doesn&rsquo;t take long for the values to increase again on Saturday night with south and southeast winds at the surface pulling in high moisture. To the west, above average moisture is forecast for western Colorado through Saturday. This will keep the flood threat around, especially with multiple days of rainfall in a row. <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> drops statewide as the high builds over the southern Colorado border Sunday through Tuesday. Moisture then looks to return to more seasonal values mid-next week with the strengthening high pressure, associated building ridge and slight eastward placement of the ridge axis.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/07\/PW_20190725.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-10031\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/07\/PW_20190725.png\" alt=\"\" width=\"880\" height=\"303\"\/><\/a><\/p>\n<h3><strong>Event #1: <\/strong><strong>Friday<\/strong><strong> (7\/2<\/strong><strong>6<\/strong><strong>) &ndash; <\/strong><strong>Sunday<\/strong><strong> (7\/2<\/strong><strong>8<\/strong><strong>)<\/strong><\/h3>\n<p><span style=\"color: #ff0000;\"><strong>High<\/strong><\/span><strong>\/<span style=\"color: #ff6600;\">Elevated Threat<\/span>&nbsp;<\/strong><em>as a <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> combines with a <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> moisture surge. &nbsp;<\/em><\/p>\n<p>A strong lee <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> looks to set up on Saturday, which will provide ample lift for afternoon storms in a moisture rich environment across the state. Best instability right now looks to be over the southern high terrains\/Raton Ridge and the Northeast Plains\/Palmer Ridge. Won&rsquo;t be surprised if there are couple <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;severe thunderstorms&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Thunderstorms that produce a tornado, winds of at least 58 mph (50 kts) and\/or hail at least 1&amp;quot; in diameter.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>severe thunderstorms<\/span> on Saturday across the plains with the main threats being large hail (up to 1.5 inches), heavy rainfall and gusty winds. Storms on Friday and Saturday will be problematic if they track over recent burn areas. Watching the 416\/Spring Creek burn area on Friday and all recent burn areas listed on the help page on Saturday. A passing cold front overnight on Saturday and decrease in moisture should keep afternoon storm activity more quiet on Sunday. <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> showers will be likely over the higher terrains in the afternoon with residual moisture over the area.<\/p>\n<div style=\"position: relative;\"><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/07\/FTO_20190725_e1.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-10072\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/07\/FTO_20190725_e1.png\" alt=\"\" width=\"880\" height=\"498\"\/><\/a><\/div>\n<p><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><\/p>\n<p>&nbsp;<\/p>\n<h3><strong>Event #2: <\/strong><strong>Monday<\/strong><strong> (7\/2<\/strong><strong>9<\/strong><strong>) &ndash; <\/strong><strong>Sunday<\/strong><strong> (<\/strong><strong>8\/4<\/strong><strong>)<\/strong><\/h3>\n<p><strong><span style=\"color: #ff6600;\">Elevated Threat<\/span>\/<\/strong><span style=\"color: #0000ff;\"><strong>No Apparent Threat<\/strong><\/span><em> break in rainfall to start the week before the next <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> moisture surge occurs.<\/em><\/p>\n<p>The ridge begins to build back to the north on Monday and Tuesday, which should suppress a lot of afternoon storm activity. The highest <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 are expected to be south of the state, though there looks to be enough moisture for a couple light afternoon showers or weak thunderstorms over the high terrains over eastern Colorado. By Wednesday, the building ridge will pull more moisture up from the south and slight eastward movement of the ridge axis, will pull the high <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 into the state. This will increase the heavy rainfall threat into the weekend. Details will likely change, but for now just wanted to mention moderate confidence for increased storminess. Afternoon shortwaves, similar to this current event, will likely rotate around the high, which may have an impact on rainfall duration and spatial coverage if they are timed with peak instability.<\/p>\n<div style=\"position: relative;\"><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/07\/FTO_20190725_e2.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-10073\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/07\/FTO_20190725_e2.png\" alt=\"\" width=\"880\" height=\"496\"\/><\/a><\/div>\n<p><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><\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Thursday, July 25th, 2019 Issue Time: 2:50PM MDT Valid Dates: 7\/26 &ndash; 8\/9 There is an Elevated\/High flood threat to start this FTO, which is due to the location of the subtropical high tomorrow and then incoming upper level low on Saturday (Event #1). While most of eastern Colorado will begin to dry [&hellip;]<\/p>","protected":false},"author":8,"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\/10028"}],"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=10028"}],"version-history":[{"count":3,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/10028\/revisions"}],"predecessor-version":[{"id":10075,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/10028\/revisions\/10075"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10028"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10028"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10028"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}