{"id":5950,"date":"2017-08-14T14:47:56","date_gmt":"2017-08-14T20:47:56","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=5950"},"modified":"2017-08-17T14:31:16","modified_gmt":"2017-08-17T20:31:16","slug":"fto-08-14-2017-drying-persists-in-the-short-term-but-possible-monsoon-surge-next-week","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=5950","title":{"rendered":"FTO 08-14-2017: Drying Persists In The Short-Term, But Possible Monsoon Surge Next Week"},"content":{"rendered":"<p>Issue Date: Monday, August 14, 2017<br>\nIssue Time: 3PM MDT<br>\nValid Dates: 8\/15-8\/29<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/threat_timeline-3.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-5952\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/threat_timeline-3.png\" alt=\"\" width=\"880\" height=\"119\"\/><\/a><\/p>\n<p>As shown in the water vapor image, below, a dynamic &ldquo;high-amplitude&rdquo; pattern is currently found across the eastern North Pacific and western parts of North America. A strong low-pressure <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> is currently entering the US west coast, supported mainly by the <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;jet stream&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Relatively strong winds concentrated within a narrow stream in the atmosphere. General weather patterns are related closely to the position, strength and orientation of the jet stream.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>jet stream<\/span> though moisture return is not all that impressive. As this disturbances makes it to Colorado, we expect an increase in shower and thunderstorm coverage over the next 48 hours. However, with fast steering winds, and marginal low-level moisture, flooding is not currently expected with this event (Event #1).<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/wv_markup-7.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-5953\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/wv_markup-7.png\" alt=\"\" width=\"676\" height=\"421\"\/><\/a><\/p>\n<p>Thereafter, large-scale drying is expected as a 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> flow brings in drier air from the west. As shown in the forecasted <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;precipitable water&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;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\"}]'>Precipitable Water<\/span> (<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>) plumes, below, this drying will be more marked west of 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>. For example, Grand Junction&rsquo;s <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> is forecasted to dip as low as 0.4 inches by Thursday 8\/17, which is substantially below normal. East of 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>, moisture as measured by the entire atmospheric column will be close to seasonal averages, but persistent and modestly strong westerly steering winds will provide for general <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;downsloping&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Refers to the winds that blow from higher elevations down towards lower elevations. As air parcels descend, they warm, which often results in rapid warming of areas near the higher terrains. It also promotes lower relative humidity values and stability, which prevents thunderstorm development.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>downsloping<\/span> (drying) conditions, limiting heavy rainfall chances and actually precipitation, in general.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/gefs_pw_plumes.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-5951\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/gefs_pw_plumes.png\" alt=\"\" width=\"800\" height=\"277\"\/><\/a><\/p>\n<p>Looking farther out, given that we are still in the midst of the <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, it is no surprise to see guidance suggesting the development of another large-scale moisture surge by early next week. At this time, this surge appears to be too brief in duration, with only marginal moisture. Thus, we label it as Event #2, but no flood threat is currently foreseen.<\/p>\n<p>Each of the two identified events are described in more detail below.<\/p>\n<h3><strong>Event #1: Tuesday (8\/15) and Wednesday (8\/16)<\/strong><\/h3>\n<p><span style=\"color: #0000ff;\"><strong>No Apparent Flood Threat <\/strong><\/span>but <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> to <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> showers and weak thunderstorms are expected<\/p>\n<p>The disturbance currently entering the west coast will provide <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> to <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> shower and thunderstorm activity both Tuesday and Wednesday across most of the state. However, with fast storm steering winds, above 30mph, and marginal moisture (<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 stay below 1 inch except for far eastern areas), only light to moderate rainfall amounts are expected. Generally, most locations will see up to 0.5 inches over this 48-hour period. However, <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> parts of the eastern Plains may see up to 1.5 inches (especially under the strongest storms). Flooding is not expected at this time. However, severe weather, notably large hail and gusty straight-line winds, may accompany the strongest storms.<\/p>\n<div style=\"position: relative;\"><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/20170814_e1-old.png\"><img loading=\"lazy\" class=\"alignnone wp-image-5985\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/20170814_e1-old.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<h3><strong>Event #2: Sunday (8\/20) through Tuesday (8\/22)<\/strong><\/h3>\n<p><span style=\"color: #0000ff;\"><strong>No Apparent Flood Threat <\/strong><\/span>at this time as <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 likely to enter western Colorado<\/p>\n<p>The main uncertainty with this event is the extent of moisture return. Current guidance suggests <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> up to 0.8-0.9 inches could enter far southwest Colorado. If this comes to fruition, a low-grade flood threat could arise in the climatologically favored parts of the San Juans, Sawatch, Elk ranges, Grand Mesa and Roan Cliffs. However, there is currently too much uncertainty to warrant an Elevated flood threat. Thus, while enhanced precipitation chances and coverage is likely, totals are expected to remain below 1 inch. Stay tuned to this Thursday&rsquo;s Outlook for an update.<\/p>\n<div style=\"position: relative;\"><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/20170814_e2-old.png\"><img loading=\"lazy\" class=\"alignnone wp-image-5987\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/20170814_e2-old.png\" alt=\"\" width=\"880\" height=\"500\"\/><\/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: Monday, August 14, 2017 Issue Time: 3PM MDT Valid Dates: 8\/15-8\/29 As shown in the water vapor image, below, a dynamic &ldquo;high-amplitude&rdquo; pattern is currently found across the eastern North Pacific and western parts of North America. A strong low-pressure <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> is currently entering the US west coast, supported mainly by the jet [&hellip;]<\/p>","protected":false},"author":4,"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\/5950"}],"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\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5950"}],"version-history":[{"count":4,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/5950\/revisions"}],"predecessor-version":[{"id":5988,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/5950\/revisions\/5988"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5950"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5950"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5950"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}