{"id":12122,"date":"2020-07-02T09:11:36","date_gmt":"2020-07-02T15:11:36","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=12122"},"modified":"2020-07-02T09:11:36","modified_gmt":"2020-07-02T15:11:36","slug":"ftb-07-02-2020-low-level-moisture-returns-to-eastern-colorado-setting-the-stage-for-afternoon-thunderstorms","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=12122","title":{"rendered":"FTB 07-02-2020: Low-Level Moisture Returns to Eastern Colorado Setting the Stage for Afternoon Thunderstorms"},"content":{"rendered":"<p>Issue Date: Thursday, July 2nd, 2020<br>\nIssue Time: 9:10AM MDT<\/p>\n<p><em>&mdash; Flooding is <strong>NOT<\/strong> expected today<\/em><\/p>\n<p>The image below shows very different air masses present east and 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>. Clear conditions over western Colorado indicate that a very dry air mass is still in place, which is confirmed by the Grand Junction sounding this morning that measured <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> at 0.32 inches. This means outside of some <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> clouds over the mountains this afternoon, it will be too dry for any rainfall. So, expect increasing high temperatures as the ridge builds to the northwest without much relief from the heat.<\/p>\n<p>Over eastern Colorado, southwest surface flow has returned low-level moisture to the area, which can be seen by the cloud cover and fog over the eastern plains. Currently, 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> (&gt; 50F) are to the east of the dashed, green line below. Weak southwesterly flow aloft this afternoon and a developing lee <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 help to mix out this superficial surface moisture from west to east. So, low-level moisture over the Front Range looks to be limited, but some weak, upslope storms will still be possible over the southern Southeast Mountains. The main hazard from these storms will be gusty <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 with only light rainfall forecast.<\/p>\n<p>Over the eastern plains, a moisture boundary sets up, so 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> should develop along that dry line this afternoon. The best instability will quickly erode into Kansas and Nebraska, but the severe storms that initially develop will be capable of producing large hail with strong, damaging <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 being the main threat shortly thereafter. Due to the better moisture continuing to mix out to the east through the late afternoon\/early evening (especially over the Southeast Plains), local, heavy rainfall will be limited in coverage. Therefore, there is no flood threat issued, but storms that form over the Northeast Plains border counties will still be capable of dropping up to 1.40 inches of rain in their cores &ndash; if the moisture can hang on.<\/p>\n<p><img loading=\"lazy\" class=\"size-full wp-image-12123 aligncenter\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/vis_20200702.png\" alt=\"\" width=\"623\" height=\"441\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/vis_20200702.png 623w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/vis_20200702-300x212.png 300w\" sizes=\"(max-width: 623px) 100vw, 623px\"\/><\/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. If there is a threat, hover over the threat areas for more details, and click on burn areas to learn more about them. For Zone-Specific forecasts, scroll below the threat map.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/04\/FTB_No_Flood_Threat_2020.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-11243\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/04\/FTB_No_Flood_Threat_2020.png\" alt=\"\" width=\"717\" height=\"537\"\/><\/a><\/p>\n<h3><strong>Zone-Specific Forecasts:<\/strong><\/h3>\n<h4><strong>Southeast Plains, Northeast Plains, &amp; Palmer Ridge:<\/strong><\/h4>\n<p>High temperatures will continue to rise a few degrees this afternoon. It will also feel relatively muggy with the 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> in the area, which will increase the heat index. Storms are expected to develop along a&nbsp;moisture boundary this afternoon and move to the northeast. 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> are possible. Initially, storms will be capable of producing very large hail with the wind threat increasing as moisture continues to mix out to the east. Local, heavy rainfall up to 1.40 inches will be possible over the Northeast Plains (border counties) if the surface moisture can hang on. The coverage of the heavy rainfall will be limited, so there is no flood threat issued.&nbsp;Further south, max 1-hour rain rates around 0.75 inches will be possible. Storms should exit the state by 7PM or so. Lingering, light showers may be possible over the Southeast Plains tonight.<\/p>\n<p>Primetime: 1PM to 7PM<\/p>\n<h4><strong>San Juan Mountains, Front Range, San Luis Valley,<\/strong> <strong>Urban Corridor,<\/strong> <strong>Southeast Mountains,<\/strong><strong> &amp;<\/strong><strong> Raton Ridge<\/strong><strong>: <\/strong><\/h4>\n<p>Since the moisture will be mixing out to the east today, only some weak storms are forecast for these mountains&rsquo; zones with the diurnal flow pattern. Moisture will be a little better further south and with some disturbances moving through the flow, some light rainfall will be possible. Max 1-hour rain rates up to 0.20 inches will be possible over the southern Southeast Mountains, but the main threat from storms will be gusty <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. Totals will decrease over the Front Range and San Juan Mountains with max totals under 0.10 inches. <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> will cause some windy conditions as storms create <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;outflow boundaries&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;A surface boundary formed by the horizontal spreading of thunderstorm-cooled air. Outflow boundaries may intersect with each other or with other features (fronts, dry line, low-level jet) and initiate new convection. Brief strong winds are possible with outflow boundaries, and they can also persist for more than 24 hours.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>outflow boundaries<\/span>.<\/p>\n<p>Primetime: 1PM to 8:30PM<\/p>\n<h4><strong>Central Mountains, Northern Mountains, Northwest Slope, Grand Valley, &amp; Southwest Slope:<\/strong><\/h4>\n<p>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> remains in place for portions of the Northwest Slope today. Southwest winds&nbsp;are expected in the 15 to 20 mph range with gusts up to 30 mph. With&nbsp;relative humidity in the teens, elevated fire danger is expected. High temperatures will also increase a couple of degrees this afternoon when compared to yesterday. With little to no cloud cover expected, be sure to stay hydrated with any outdoor activities.<\/p>\n<p>&nbsp;<\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Thursday, July 2nd, 2020 Issue Time: 9:10AM MDT &mdash; Flooding is NOT expected today The image below shows very different air masses present east and 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>. Clear conditions over western Colorado indicate that a very dry air mass is still in place, which is confirmed by the Grand Junction [&hellip;]<\/p>","protected":false},"author":8,"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\/12122"}],"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=12122"}],"version-history":[{"count":1,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/12122\/revisions"}],"predecessor-version":[{"id":12124,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/12122\/revisions\/12124"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=12122"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=12122"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=12122"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}