{"id":14002,"date":"2021-05-24T14:41:45","date_gmt":"2021-05-24T20:41:45","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=14002"},"modified":"2021-05-27T08:29:08","modified_gmt":"2021-05-27T14:29:08","slug":"fto-05-24-2021-dry-with-a-warm-up-then-storms-return-for-memorial-day-weekend","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=14002","title":{"rendered":"FTO 05-24-2021: Dry with a Warm-Up Then Storms Return for Memorial Day Weekend"},"content":{"rendered":"<p>Issue Date: Monday,&nbsp;May, 24th, 2021<br>\nIssue Time: 2:40PM MDT<br>\nValid Dates:&nbsp;5\/25 &ndash; 6\/8<\/p>\n<p><img loading=\"lazy\" class=\"alignnone wp-image-14003\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524.png\" alt=\"\" width=\"880\" height=\"151\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524.png 1996w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524-300x51.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524-768x132.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524-1024x175.png 1024w\" sizes=\"(max-width: 880px) 100vw, 880px\"\/><\/p>\n<p>A chain of fairly fast-moving troughs and ridges will propagate across the state this next week. First, southwesterly and westerly flow aloft under a building ridge will help to keep the skies dry through Tuesday. On Wednesday, a weak <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> breaks up this ridge and pushes some mid-level energy across the state. Without much moisture accompanying this <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>, outside some <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> severe storms for the far eastern plains, it should remain dry. Then drying returns as another weak ridge builds overhead with very warm temperatures forecast. It should reach the upper 80Fs across the Southeast Plains and western valleys Friday into this weekend.<\/p>\n<p><img loading=\"lazy\" class=\"aligncenter wp-image-14004\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/wv_20210524-1.png\" alt=\"\" width=\"650\" height=\"431\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/wv_20210524-1.png 1594w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/wv_20210524-1-300x199.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/wv_20210524-1-768x510.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/wv_20210524-1-1024x680.png 1024w\" sizes=\"(max-width: 650px) 100vw, 650px\"\/><\/p>\n<p>Event #1 begins Memorial Day weekend with rainfall forecast first over the plains, and then back over the mountains\/adjacent plains. <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> looks again to be highest over eastern Colorado, and a rapid 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> on Sunday will warrant an Elevated flood threat. Models hinting at cooler temperatures behind a potentially strong cold front on Monday, which if this occurs, it should help temper rainfall rates with upslope flow. However, burn areas will need to be watched closely as precipitation chances will increase over the mountains. Monday\/Tuesday will be the best shot for measurable rainfall over the western mountains as winds aloft turn more southerly.<\/p>\n<p>After Tuesday, northwesterly flow aloft and building ridge to our north\/west will keep the state dry and help produce more seasonable temperatures. There&rsquo;s still plenty of changing factors for Event #2, but a broad troughing pattern should return unsettled weather for that period and perhaps further into the work week. At this time, there is No Apparent Flood threat.<\/p>\n<p><img loading=\"lazy\" class=\"aligncenter wp-image-14005\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/PW_20210524.png\" alt=\"\" width=\"880\" height=\"308\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/PW_20210524.png 2412w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/PW_20210524-300x105.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/PW_20210524-768x269.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/PW_20210524-1024x358.png 1024w\" sizes=\"(max-width: 880px) 100vw, 880px\"\/><\/p>\n<p><u>Streamflow<\/u><\/p>\n<p>Currently, there is a <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;flash flood&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;flash flooding can refer to usually dry areas becoming rapidly inundated with water, or rapid water level rises on streams, creeks, or rivers beyond flood stage; typically caused by heavy rainfall, but can also be caused by meltwater&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>Flash Flood<\/span> <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> for the Purgatoire River near Las Animas where a crest up to 9 feet is forecast tonight into Tuesday midday. On Saturday, after the 3+ inches of rainfall fell over the area, the Purgatorie River at Trinidad crested at 6.63 feet. This broke the previous record of 6.2 feet, but is still well below the Action stage (10.5 feet). The Cache La Poudre River at Greeley is also at or near Action stage today, so low land nuisance flooding is likely for the next couple of days.<\/p>\n<p>Warming temperatures throughout this week and into this weekend mean that runoff will likely increase. As discussed in pervious posts, this will mostly affect smaller creeks and streams over the eastern and northern mountains. You can see today&rsquo;s&nbsp;<span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;SWE&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;&amp;lt;strong&amp;gt;S&amp;lt;\/strong&amp;gt;now &amp;lt;strong&amp;gt;W&amp;lt;\/strong&amp;gt;ater &amp;lt;strong&amp;gt;E&amp;lt;\/strong&amp;gt;quivalent, the liquid water content of snowpack&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>SWE<\/span> and WY precipitation totals at SNOTEL sites across your water basin here: <span style=\"text-decoration: underline;\"><strong><a href=\"https:\/\/wcc.sc.egov.usda.gov\/reports\/UpdateReport.html?textReport=Colorado&amp;textRptKey=5&amp;textFormat=SNOTEL+Snow%2FPrecipitation+Update+Report&amp;StateList=5&amp;RegionList=Select+a+Region+or+Basin&amp;SpecialList=Select+a+Special+Report&amp;MonthList=May&amp;DayList=24&amp;YearList=2021&amp;FormatList=N0&amp;OutputFormatList=HTML&amp;textMonth=May&amp;textDay=24&amp;CompYearList=select+a+year\">NRCS<\/a><\/strong><\/span><\/p>\n<p>The cooler temperatures returning to start next week should help temper the flows and settle the snowpack at the higher elevations again. Not foreseeing any <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>, heavy rainfall this weekend over areas with potentially elevated flows right now, so there is No Apparent Threat.<\/p>\n<h3><strong>Event #1:<\/strong> <strong>Saturday<\/strong><strong> &ndash; <\/strong><strong>Tuesday<\/strong><strong> (5\/<\/strong><strong>29<\/strong><strong> &ndash; <\/strong><strong>6<\/strong><strong>\/1)<\/strong><\/h3>\n<p><span style=\"color: #ff6600;\"><strong>Elevated<\/strong><\/span><strong>\/<span style=\"color: #0000ff;\">No Apparent<\/span><\/strong><strong>&nbsp;<\/strong>flood threat as severe storms return to the eastern plains and upslope flow returns behind a cold front.<\/p>\n<p>Looks like more severe weather will be possible on both Saturday and Sunday across the eastern plains. Threats from the severe storms will include large hail, 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, local heavy rainfall and perhaps a couple tornadoes. Steering flows look to be a little bit slower than this last weekend, so there is an Elevated flood threat for Sunday when <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> should peak. The flood threat may need to be upgraded in Thursday&rsquo;s FTO for Saturday. On Monday, precipitation turns more stratiform and fills in over the mountains with cooler temperatures forecast for the holiday. Burn areas will need to be watched more closely on both Monday and Tuesday for embedded <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> or prolonged periods of rainfall.<br><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524_e1.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-14057\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524_e1.png\" alt=\"\" width=\"898\" height=\"608\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524_e1.png 898w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524_e1-300x203.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524_e1-768x520.png 768w\" sizes=\"(max-width: 898px) 100vw, 898px\"\/><\/a><\/p>\n<h3><strong>Event #2: <\/strong><strong>Saturday<\/strong><strong> &ndash; <\/strong><strong>Monday<\/strong><strong> (<\/strong><strong>6\/5<\/strong><strong> &ndash; <\/strong><strong>6\/7<\/strong><strong>)<\/strong><\/h3>\n<p><span style=\"color: #0000ff;\"><strong>No Apparent<\/strong><\/span>&nbsp;flood threat as a broad <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> brings stormy weather back into the forecast.<\/p>\n<p>Another weekend with storms is in the forecast to start the month of June. There&rsquo;s still plenty of uncertainty with the forecast, but a broad <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> will return rainfall chances to the state during this period. Currently this looks like an event favoring eastern Colorado again for the higher totals, but measurable precipitation over the western mountains will be likely as moisture is drawn up from the Pacific and Gulf of California. At this time there is No Apparent flood threat issued.<br><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524_e2.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-14058\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524_e2.png\" alt=\"\" width=\"897\" height=\"606\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524_e2.png 897w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524_e2-300x203.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2021\/05\/FTO_20210524_e2-768x519.png 768w\" sizes=\"(max-width: 897px) 100vw, 897px\"\/><\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Monday,&nbsp;May, 24th, 2021 Issue Time: 2:40PM MDT Valid Dates:&nbsp;5\/25 &ndash; 6\/8 A chain of fairly fast-moving troughs and ridges will propagate across the state this next week. First, southwesterly and westerly flow aloft under a building ridge will help to keep the skies dry through Tuesday. On Wednesday, a weak <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> breaks up [&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\/14002"}],"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=14002"}],"version-history":[{"count":4,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/14002\/revisions"}],"predecessor-version":[{"id":14060,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/14002\/revisions\/14060"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=14002"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14002"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14002"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}