{"id":6999,"date":"2018-05-27T08:31:38","date_gmt":"2018-05-27T14:31:38","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=6999"},"modified":"2018-05-28T07:29:43","modified_gmt":"2018-05-28T13:29:43","slug":"ftb-05-27-2018-strong-to-severe-storms-return-to-eastern-colorado","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=6999","title":{"rendered":"FTB 05-27-2018: Strong-to-Severe Storms Return to Eastern Colorado"},"content":{"rendered":"<p>Issue Date: 5\/27\/2018<br>\nIssue Time: 8:35 AM<\/p>\n<p><em>A LOW FLOOD THREAT IS FORECAST TODAY FOR PORTIONS OF THE NORTHEAST PLAINS, SOUTHEAST PLAINS, URBAN CORRIDOR, FRONT RANGE, AND PALMER RIDGE.<\/em><\/p>\n<p>Today&rsquo;s forecast across Colorado will be defined by those with access to moisture and those without access to moisture. In the surface plot shown below, a thick green line has been drawn to denote the location of the 45&deg;F dewpoint contour. To the right of the line, ample moisture is already in place to fuel a fairly active strong-to-<span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;severe thunderstorm&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 thunderstorm<\/span> day. Strong instability and &ldquo;good enough&rdquo; <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;shear&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Local variation of the wind, either in the horizontal or vertical direction.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>shear<\/span> will coincide with this low-level moisture, which will promote quickly strengthening thunderstorms capable of producing large hail (up to 1.5&rdquo; diameter), strong winds (up to 70-80 mph), an <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> tornado or two, and periods of heavy rainfall. <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> values will push to near, or exceed, 1 inch across the far eastern plains by this evening, so that makes our ears perk up with regards to <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;flash flooding&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 flooding<\/span> concerns. Storm motions should keep storms moving quickly enough to avoid <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;flash flooding&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 flooding<\/span>, but the possibility of <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;training&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Continuous or repeated rainfall over the same region&nbsp;in a relatively short time span. Training thunderstorms can produce very high rainfall totals and cause flash flooding.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>training<\/span> thunderstorms is enough to warrant a low flood threat. Portions of the Front Range, Urban Corridor, and Palmer Ridge are also included in the low flood threat due to easterly flow likely pushing the 45&deg;F dewpoint line back into the area during the afternoon\/evening hours, providing enough moisture for a quick 0.5&rdquo;\/30 min rainfall &ndash; this is enough to cause street flooding in urban areas.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2018\/05\/SFC_20180527.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-7000 size-full\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2018\/05\/SFC_20180527.png\" alt=\"\" width=\"675\" height=\"589\"\/><\/a><\/p>\n<p>To the left of the green line (not including the Urban Corridor\/Front Range for reasons described above), mainly dry conditions will win out. The exception to this rule will be across the higher terrain of the Northwest Slope and Northern Mountains where enough moisture will sneak into the state from the north to work with orographic support and result in <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> showers\/weak thunderstorms.<\/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<div style=\"position: relative;\"><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2018\/05\/FTB_20180527_snap.png\"><img loading=\"lazy\" class=\"alignnone wp-image-7004\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2018\/05\/FTB_20180527_snap.png\" alt=\"\" width=\"880\" height=\"495\"\/><\/a><\/div>\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>Strong <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;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> thunderstorms will rumble this afternoon\/evening, with a few reaching severe thresholds. The main threats will be large hail (up to 1.5&rdquo; diameter), strong winds (up to 70-80 mph), and periods of heavy rainfall, with the potential for an <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> tornado or two. The Raton Ridge will remain mostly dry, but an <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> thunderstorm or two will result in gusty winds, dangerous lightning, and a brief period of light rainfall.<\/p>\n<p><span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;training&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Continuous or repeated rainfall over the same region&nbsp;in a relatively short time span. Training thunderstorms can produce very high rainfall totals and cause flash flooding.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>Training<\/span> storms over the Northeast Plains and quick bursts of heavy rain over urban areas and steep(er) terrain of the Front Range are the driving forces behind today&rsquo;s low flood threat. Maximum rain rates are as follows:<\/p>\n<p>Front Range, Urban Corridor, and Palmer Ridge: 0.4-0.6 inches\/30 minutes<br>\nNortheast Plains and Southeast Plains: 1.5-2.0 inches\/hour<br>\nRaton Ridge: 0.15-0.3 inches\/hour<\/p>\n<p>Timing: Noon &ndash; 10 PM, with an <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> storm or two rumbling until midnight<\/p>\n<h4><strong>Northwest Slope, Northern Mountains, Central Mountains, Grand Valley, Southwest Slope, San Juan Mountains, Southeast Mountains, San Luis Valley:<\/strong><\/h4>\n<p>Dry and warm, though temperatures will be a few degrees cooler than yesterday. The exception to the dry rule will be over the higher terrain of the Northwest Slope and Northern Mountains where enough low-level moisture will be in place to fuel orographically-forced showers\/weak thunderstorms. Rain rates will be low, with maximum rates of 0.15-0.25 inches\/hour<\/p>\n<p>Timing: Noon &ndash; Midnight<\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: 5\/27\/2018 Issue Time: 8:35 AM A LOW FLOOD THREAT IS FORECAST TODAY FOR PORTIONS OF THE NORTHEAST PLAINS, SOUTHEAST PLAINS, URBAN CORRIDOR, FRONT RANGE, AND PALMER RIDGE. Today&rsquo;s forecast across Colorado will be defined by those with access to moisture and those without access to moisture. In the surface plot shown below, a [&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\/6999"}],"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=6999"}],"version-history":[{"count":2,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/6999\/revisions"}],"predecessor-version":[{"id":7005,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/6999\/revisions\/7005"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6999"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6999"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6999"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}