{"id":15392,"date":"2021-08-05T14:47:28","date_gmt":"2021-08-05T20:47:28","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=15392"},"modified":"2021-08-09T13:05:55","modified_gmt":"2021-08-09T19:05:55","slug":"fto-08-05-2021-long-awaited-break-from-heavy-rainfall-has-arrived","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=15392","title":{"rendered":"FTO 08-05-2021: Long-Awaited Break From Heavy Rainfall Has Arrived"},"content":{"rendered":"<p>Issue Date: Thursday,&nbsp;August 5th, 2021<br>\nIssue Time: 2:50PM MDT<br>\nValid Dates:&nbsp;8\/6 &ndash; 8\/20<\/p>\n<p><img loading=\"lazy\" class=\"aligncenter wp-image-15393\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/FTO_20210805.png\" alt=\"\" width=\"880\" height=\"124\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/FTO_20210805.png 2406w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/FTO_20210805-300x42.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/FTO_20210805-768x108.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/FTO_20210805-1024x144.png 1024w\" sizes=\"(max-width: 880px) 100vw, 880px\"\/><\/p>\n<p>Finally, we&rsquo;ve reached the long-awaited break in heavy rainfall activity as the axis of the ridge moves into an unfavorable position for a subtropical moisture surge over the state. Tomorrow, a quick-moving <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> (orange &ldquo;X&rdquo;) moves across our northern border. As it passes, it should help spark some <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 over the mountains, which will likely spill into the adjacent plains by the afternoon and evening hours. However, with the dry west and northwesterly flow aloft over the state and not much surface moisture associated with the <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>, the storms are not expected to produce a flood threat but more of a wind threat. The&nbsp;increase afternoon cloud cover and very modest rainfall for limited&nbsp;areas will be a nice break from the heat as high temperatures will run ~5 to 8 degF above average.<\/p>\n<p><img loading=\"lazy\" class=\"aligncenter wp-image-15394\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/wv_20210805.png\" alt=\"\" width=\"650\" height=\"448\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/wv_20210805.png 1322w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/wv_20210805-300x207.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/wv_20210805-768x530.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/wv_20210805-1024x706.png 1024w\" sizes=\"(max-width: 650px) 100vw, 650px\"\/><\/p>\n<p>After Event #1, it should be fairly quiet the rest of the week with <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> below normal for this time of year. Some showers and weak storms may still be possible over the mountains with the residual moisture, but it&rsquo;s more likely we&rsquo;ll only see afternoon, fair weather cumulus clouds and plenty of <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>. Taking a look at the red solid lines below, you can see that we&rsquo;ve started our downward trend in the long-term normal for <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>. That doesn&rsquo;t mean the heavy rainfall threat is over for the season, but climatologically over the next week or so, we typically see our <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> season begin to wind down. The plumes do hint at a slight rise in <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> by the end of end of next week, but the separation in the gray lines still show a lot of uncertainty in this forecast. The upward trend in <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> indicates that this will be&nbsp;the next opportunity for a moisture surge not this weekend, but next weekend. An Elevated flood threat has been issued for this event, but it is very likely that the forecast could change given the uncertainty this far out. Be sure to tune into the FTO next week to keep tabs on the changes for Event #2.<\/p>\n<p><img loading=\"lazy\" class=\"aligncenter wp-image-15395\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/PW_20210805.png\" alt=\"\" width=\"880\" height=\"308\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/PW_20210805.png 2122w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/PW_20210805-300x105.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/PW_20210805-768x269.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/PW_20210805-1024x358.png 1024w\" sizes=\"(max-width: 880px) 100vw, 880px\"\/><\/p>\n<p>Below is the near surface smoke from the HRRR model with ongoing fires marked by the red dots. There is already some relatively thick near-surface smoke over the I-25 Corridor and eastern foothills with the integrated smoke (full atmospheric column) showing even higher concentrations (not pictured). The&nbsp;<span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;advection&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;The process of transport of an atmospheric property, typically temperature or moisture in our FTB discussions, by the wind. &amp;quot;Strong&rdquo; or &amp;quot;weak&rdquo; advection refers to the rate of change of the advected property&amp;#039;s value at a given point.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>advection<\/span> of smoke with the northwest&nbsp;flow is impacting visibility quite a bit today, and the air quality alert continues.&nbsp;So, the&nbsp;big &ldquo;weather&rdquo; feature over the next couple of days will be the wildfire smoke increasing across&nbsp;the state as the flow becomes 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> with the approaching <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>.&nbsp;Expect that big plume of near surface&nbsp;smoke (pink\/red shades below) to arrive to western Colorado by tomorrow evening and eastern Colorado by Saturday morning. So although a dry and warm weekend is ahead, anticipate limited visibly.<\/p>\n<p><img loading=\"lazy\" class=\"aligncenter wp-image-15396\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/Smoke_20210805.png\" alt=\"\" width=\"880\" height=\"528\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/Smoke_20210805.png 1492w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/Smoke_20210805-300x180.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/Smoke_20210805-768x461.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/08\/Smoke_20210805-1024x615.png 1024w\" sizes=\"(max-width: 880px) 100vw, 880px\"\/><\/p>\n<p>Keep scrolling below to read a few more&nbsp;details about the events for this FTO.<\/p>\n<h3><strong>Event #1:<\/strong><strong> Friday (8\/<\/strong><strong>5<\/strong><strong>)<\/strong><\/h3>\n<h4><span style=\"color: #0000ff;\"><strong>No Apparent<\/strong><\/span> <strong>threat as scattered storms will likely develop over the mountains and produce more of a wind than heavy rainfall threat.<\/strong><\/h4>\n<p>No map has been drawn below to the one-day event likely producing precipitation totals under 0.50 inches. <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 develop by early afternoon over the mountains and spill into the adjacent plains by late afternoon. Due to the drier air, storms will likely dissipate rather quickly and could produce some 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. The increased mid-level lift from the vorticity maximum will help support this wind threat over the mountains as well. The tightening surface gradient is also forecast to produce&nbsp;higher surface winds over the Northwest Slope. Paired with low <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> (relative humidity) over the area there is an increase in fire danger over that region. So, a <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;Red Flag&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;weather conditions are extremely conducive to burning and wildfires&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>Red Flag<\/span> <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;Warning&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 warning is issued when a specific weather event is imminent or occurring&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>Warning<\/span> has been issued. Flooding is NOT expected with this event.<\/p>\n<h3><strong>Event #2: <\/strong><strong>Thursday<\/strong><strong> &ndash; <\/strong><strong>Sunday<\/strong><strong> (<\/strong><strong>8\/12<\/strong><strong> &ndash; <\/strong><strong>8\/15<\/strong><strong>)<\/strong><\/h3>\n<h4><strong>Next shot at a moderate monsoon moisture surge<\/strong><strong>, so a<\/strong><strong>n<\/strong> <span style=\"color: #ff6600;\"><strong>Elevated <\/strong><\/span><strong>flood threat<\/strong><strong> is issued.<\/strong><\/h4>\n<p>Quite a bit of uncertainty in an event this far out, and details will inevitably change. Between the northwesterly flow pushing disturbances through the state and a more active Pacific (hurricane season), there is a chance for an increase in moisture over the area. Extra dynamics could also be at play with mid-level energy likely moving through the flow during this period, so an Elevated flood threat has been issued. Chosen not to draw any maps due to the uncertainty of the forecast, but just wanted to look ahead to the next potential rainfall event.<\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Thursday,&nbsp;August 5th, 2021 Issue Time: 2:50PM MDT Valid Dates:&nbsp;8\/6 &ndash; 8\/20 Finally, we&rsquo;ve reached the long-awaited break in heavy rainfall activity as the axis of the ridge moves into an unfavorable position for a subtropical moisture surge over the state. Tomorrow, a quick-moving <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> (orange &ldquo;X&rdquo;) moves across our northern border. As it [&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\/15392"}],"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=15392"}],"version-history":[{"count":2,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/15392\/revisions"}],"predecessor-version":[{"id":15447,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/15392\/revisions\/15447"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=15392"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=15392"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=15392"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}