{"id":10403,"date":"2019-08-19T14:11:28","date_gmt":"2019-08-19T20:11:28","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=10403"},"modified":"2019-08-22T11:40:41","modified_gmt":"2019-08-22T17:40:41","slug":"fto-08-19-2019-elevated-flood-threat-for-the-next-two-days-before-the-drying-trend-begins","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=10403","title":{"rendered":"FTO 08-19-2019: Elevated Flood Threat for the Next Two Days Before the Drying Trend Begins"},"content":{"rendered":"<p>Issue Date: Monday, August 19th, 2019<br>\nIssue Time: 2:10PM MDT<br>\nValid Dates: 8\/20 &ndash; 9\/3<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/08\/FTO_20190819.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-10405\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/08\/FTO_20190819.png\" alt=\"\" width=\"880\" height=\"131\"\/><\/a><\/p>\n<p>Event #1 begins tomorrow, which is actually a semi-continuation of today&rsquo;s weather pattern. The 500mb ridge axis continues to build northward with the center of the high shifting slightly to the west. This will keep temperatures hot again with only some slight cooling indicated by models over the Urban Corridor. A surface low is expected to develop over the far eastern plains (possibly western Kansas), which will pull in high moisture on its east and north side as it wraps around the low in a counterclockwise manner. This should help return high <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> and <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 back to the Northeast Plains. The one question is the depth of this moisture, which will be better answered by tomorrow&rsquo;s FTB. Meanwhile, some mid-level energy will move across the state from Utah and Wyoming, which will trigger 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> activity over this moisture rich area. Expecting some <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 Tuesday along with some heavy rainfall due to slow steering winds. A cold front begins to move south over eastern Colorado on Wednesday morning. Post frontal upslope flow will return heavy rainfall chances to the mountains and immediate adjacent plains, which could cause some issues for recent burn areas over the Southeast Mountains. <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 begin to drop off Thursday and Friday as mid-level 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>, so the Elevated threat decreases at that time.<\/p>\n<p>Should be a quiet weather weekend with 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> to our west, east, and south. Tuesday into Wednesday, flow aloft becomes more northwesterly as high pressure begins to build off the Pacific Coast. Models showing a cold front dropping south, and with mid-level energy likely, heavy rainfall chances return. Unsure how deep this moisture return would be behind the front and strength of the steering flow (likely fairly fast), thus the hesitation to go above an Elevated flood threat at this time. Looks like some elevated moisture could sneak in over the southwest corner as well, so we&rsquo;ll keep an eye on this for the 416 burn area. Overall, Event #2 looks like it might give us a taste of fall.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/08\/wv_20190819.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-10404\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/08\/wv_20190819.png\" alt=\"\" width=\"675\" height=\"447\"\/><\/a><\/p>\n<p>Climatological <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 looks to decline as 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> begins to shut off for the season (red line). There is a strong moisture return for eastern Colorado during Event #1 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> values in the 90<sup>th<\/sup> percentile for this time of year. The forecast below indicates a strong easterly component to the low level winds for the high moisture to make it back to Denver tomorrow afternoon. Keep in mind <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> was measured at 0.52 inches in the soundings Monday morning. With slower steering winds forecast for tomorrow afternoon, storms over the Northeast Plains have the potential to drop a lot of rainfall. It also looks like there is potential for some overnight, heavy rainfall for the far northeast corner of the state if the <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;cap&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;The area where a parcel of air has negative buoyancy or sinks. The intensity of the cap is measured by its convective inhibition. If the cap is sufficiently large, it may prevent thunderstorms from forming at all.&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>cap<\/span> is broken. Please tune into the FTB tomorrow for the latest. After Wednesday, moisture looks to decline to below average with a very dry weekend ahead.<\/p>\n<p>To the west, the dry air seen in the water vapor imagery above continues to keep <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 well below average. On Tuesday\/Wednesday, <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> may increase over the southwest corner, so we&rsquo;ll be watching that closely. Not thinking there will be much fire weather danger until (perhaps) Event #2. For that event, models are currently placing the jet to our north, so that should keep <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;critical fire weather&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 especially conducive to the formation of wildfires; typically strong winds, low relative humidity, and atmospheric instability&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>critical fire weather<\/span> out of the forecast. However, if this feature sags south at all, there may be a brief window where 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> could be issued. Of course this forecast is for mid to end of next week, so a lot can still change in the details.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/08\/PW_20190819.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-10406\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/08\/PW_20190819.png\" alt=\"\" width=\"880\" height=\"304\"\/><\/a><\/p>\n<h3><strong>Event #1: <\/strong><strong>Tuesday<\/strong><strong> (8\/<\/strong><strong>20<\/strong><strong>) &ndash; <\/strong><strong>Friday<\/strong><strong> (8\/<\/strong><strong>23<\/strong><strong>)<\/strong><\/h3>\n<p><span style=\"color: #ff6600;\"><strong>Elevated Threat<\/strong><\/span><strong><span style=\"color: #0000ff;\">\/No Apparent Threat<\/span><\/strong><em> for a surface low pulling in high moisture over the Northeast Plains and mixing with mid-level energy rotating around the ridge from Utah and Wyoming.<\/em><\/p>\n<p>Looking to be another hot one tomorrow with the ridge well in place over the state. A lee&nbsp;cyclone&nbsp;looks to pull in higher moisture to the Northeast Plains. Further south over the eastern plains, better moisture looks to be over Kansas, so the potential flood threat area will be on the smaller side. Northeast Plain&rsquo;s moisture paired with mid-level energy rotating around the high means there is a chance for some heavy rainfall, but only if the waves are timed correctly and moisture isn&rsquo;t mixed out. A 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> would also be likely in this scenario, which would be capable of producing large hail (best guess is 1.75 inches at this time), strong winds and heavy rainfall. Some models indicting storms will continue over the far northeast corner of the state overnight with the low level jet (possibly) kicking in to provide lift. Wednesday, post frontal upslope flow will return the heavy rainfall threat to the mountains. With rain rates likely greater than 0.5 inches, there is the potential for flooding issues over the Spring Creek burn area. Of course this is only if storms track over the scar, so details will be clearer on Wednesday morning. The threat decreases Thursday into Friday with measurable rainfall mainly projected for the eastern mountains and immediate adjacent plains.<\/p>\n<div style=\"position: relative;\"><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/08\/FTO_20190819_e1.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-10452\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/08\/FTO_20190819_e1.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>\n<p>&nbsp;<\/p>\n<h3><strong>Event #2: Tuesday (8\/2<\/strong><strong>7<\/strong><strong>) &ndash; T<\/strong><strong>hursday<\/strong><strong> (8\/2<\/strong><strong>9<\/strong><strong>)<\/strong><\/h3>\n<p><span style=\"color: #ff6600;\"><strong>Elevated Threat<\/strong><\/span><strong><span style=\"color: #ff6600;\">\/<\/span><span style=\"color: #0000ff;\">No Apparent Threat<\/span><\/strong><em> as we potentially get our first taste of fall.<\/em><\/p>\n<p>Flow aloft switches back to the northwest for this event, which will send a strong cold front through the state sometime on Tuesday or Wednesday. The GFS is indicating much below average temperatures behind the front at this time, which will feel a lot like fall. There will likely be a quick return of moisture behind the front, which could cause some <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> storms over the eastern plains.&nbsp; This will only come to fruition if the front passes during peak heating. The reality is, this is probably looking more like an eastern mountains, plus San Juan Mountain, event with some rainfall spilling over into the immediate adjacent plains. Only time will tell if those mid to upper 60&deg;Fs high temperatures verify behind the front on Wednesday. Personally, I&rsquo;m looking forward to it.<\/p>\n<div style=\"position: relative;\"><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/08\/FTO_20190819_e2.png\"><img loading=\"lazy\" class=\"alignnone wp-image-10453\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/08\/FTO_20190819_e2.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>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Monday, August 19th, 2019 Issue Time: 2:10PM MDT Valid Dates: 8\/20 &ndash; 9\/3 Event #1 begins tomorrow, which is actually a semi-continuation of today&rsquo;s weather pattern. The 500mb ridge axis continues to build northward with the center of the high shifting slightly to the west. This will keep temperatures hot again with only [&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\/10403"}],"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=10403"}],"version-history":[{"count":4,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/10403\/revisions"}],"predecessor-version":[{"id":10455,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/10403\/revisions\/10455"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10403"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10403"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10403"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}