{"id":6941,"date":"2018-05-23T07:43:36","date_gmt":"2018-05-23T13:43:36","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=6941"},"modified":"2018-05-23T07:43:36","modified_gmt":"2018-05-23T13:43:36","slug":"ftb-05-23-2018-warming-and-drying-trend-begins-but-thunderstorms-wont-let-go-easily","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=6941","title":{"rendered":"FTB 05-23-2018: Warming and Drying Trend Begins, but Thunderstorms Won\u2019t Let Go Easily"},"content":{"rendered":"<p>Issue Date: 5\/23\/2018<br>\nIssue Time: 7:45 AM<\/p>\n<p><em>NO FLOOD THREAT IS FORECAST TODAY.<\/em><\/p>\n<p><span style=\"color: #ff0000;\"><em>NOTE: THE ANNUAL FLUSH OF CHERRY CREEK WILL OCCUR TODAY. 1300 CFS WILL BE RELEASED FROM CHERRY CREEK DAM, POTENTIALLY CAUSING BIKE PATH AND STREAM CROSSING CLOSURES ALONG THE CHERRY CREEK TRAIL.<\/em><\/span><\/p>\n<p>The upper-level low that was centered over the Great Basin yesterday has weakened and is lifting off to the northeast, as denoted by the red &ldquo;L&rdquo; in the water vapor image below. As it does so, it will place Colorado under drier, southwesterly flow aloft (orange arrow), which will suppress thunderstorm development across much of the Colorado High Country. The exception to this rule will be a few <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> thunderstorms north of I-70, thanks being nearer the broad upper-level support provided by the decaying upper-level low and a weak <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> expected to pass overhead during the afternoon hours.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2018\/05\/WV_20180523.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-6942\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2018\/05\/WV_20180523.png\" alt=\"\" width=\"880\" height=\"637\"\/><\/a><\/p>\n<p>East of the mountains, <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> afternoon\/evening thunderstorms are expected thanks to the presence of convergence along a surface 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>\/<span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;dryline&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;A low-level, small-scale boundary that separates dry air from moist air. Storms develop along it because the dry air (behind the boundary) is less dense than the moisture-rich air (ahead of the boundary). Typically, it advances eastward during the afternoon and retreats westward at night.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>dryline<\/span>. The drier, southwesterly flow aloft will mix down into the low-levels and scour out the moisture, much like across western Colorado, but thanks to low-level easterly flow east of the <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;dryline&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;A low-level, small-scale boundary that separates dry air from moist air. Storms develop along it because the dry air (behind the boundary) is less dense than the moisture-rich air (ahead of the boundary). Typically, it advances eastward during the afternoon and retreats westward at night.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>dryline<\/span>, some moisture will be able to hang on. Due to the expected surface wind fields, the best opportunity for <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> thunderstorms will be east of a line from Cheyenne-Fort Collins-Boulder-Castle Rock-Limon-La Junta-Trinidad. For more specifics on rain rates and timing, please see the zone-specific forecast discussions below.<\/p>\n<h3><strong>Today&rsquo;s Flood Threat Map<\/strong><\/h3>\n<p>For more information on today&rsquo;s flood threat, see the map below (hover over threat areas for more details). For Zone-Specific forecasts, jump below the map.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/no_threat.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-6157\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2017\/08\/no_threat.png\" alt=\"\" width=\"880\" height=\"580\"\/><\/a><\/p>\n<div><img loading=\"lazy\" class=\"alignright wp-image-135\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2015\/04\/floodthreat_legend2.png\" alt=\"Flood Threat Legend\" width=\"275\" height=\"71\"\/><\/div>\n<h3><strong>Zone-Specific Forecasts<\/strong><\/h3>\n<h4><strong>Front Range, Urban Corridor, Northeast Plains, Southeast Plains, Palmer Ridge, and Raton Ridge:<\/strong><\/h4>\n<p><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>-to-<span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;widely scattered&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;10-25% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>widely scattered<\/span> thunderstorms are expected to rumble during the afternoon\/evening hours, breaking up the otherwise mostly sunny, dry, and warm day across the area. A few storms will be on the strong-to-severe side, producing hail, strong winds, and periods of moderate-to-heavy rainfall. Due to the risk of small hail, be on the lookout for street\/field ponding where hail accumulates and clogs drainage. Maximum rain fall rates will be as follows:<\/p>\n<p>Front Range: 0.2-0.4 inches\/hour<br>\nUrban Corridor, Palmer Ridge, and Raton Ridge: 0.4-0.8 inches\/hour<br>\nNortheast Plains and Southeast Plains: 1.0-1.35 inches\/hour<\/p>\n<p>Timing for Front Range: 11 AM &ndash; 7 PM<br>\nTiming for Urban Corridor and Palmer Ridge: Noon &ndash; 8 PM<br>\nTiming for Northeast Plains, Southeast Plains, and Raton Ridge: 1 PM &ndash; 11 PM<\/p>\n<h4><strong>Northwest Slope and Northern Mountains:<\/strong><\/h4>\n<p><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>-to-<span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;widely scattered&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;10-25% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>widely scattered<\/span> showers\/thunderstorms are expected to begin during the late morning hours, continuing into the late evening hours. The higher terrain has the best chance at any wetting rainfall, while lower valleys will feel the gusty winds and notice a sprinkle or two with 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> to go around. Rainfall rates will generally remain low, with maximum rates of 0.2-0.4 inches\/hour.<\/p>\n<p>Timing: 10 AM &ndash; 8 PM<\/p>\n<h4><strong>Central Mountains, Grand Valley, Southwest Slope, San Juan Mountains, Southeast Mountains, San Luis Valley:<\/strong><\/h4>\n<p>A warming and drying trend begins as drier, southwesterly flow aloft invades the region. Cumulus clouds will bubble over the higher terrain in the afternoon\/evening warmth, resulting in streaks 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> and perhaps a sprinkle or two over the higher terrain of the Central Mountains and Grand Valley. Otherwise, dry conditions will prevail.<\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: 5\/23\/2018 Issue Time: 7:45 AM NO FLOOD THREAT IS FORECAST TODAY. NOTE: THE ANNUAL FLUSH OF CHERRY CREEK WILL OCCUR TODAY. 1300 CFS WILL BE RELEASED FROM CHERRY CREEK DAM, POTENTIALLY CAUSING BIKE PATH AND STREAM CROSSING CLOSURES ALONG THE CHERRY CREEK TRAIL. The upper-level low that was centered over the Great Basin [&hellip;]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[6],"tags":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/6941"}],"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\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6941"}],"version-history":[{"count":1,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/6941\/revisions"}],"predecessor-version":[{"id":6943,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/6941\/revisions\/6943"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6941"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6941"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6941"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}