{"id":9042,"date":"2019-05-20T09:14:09","date_gmt":"2019-05-20T15:14:09","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=9042"},"modified":"2019-05-20T09:14:09","modified_gmt":"2019-05-20T15:14:09","slug":"ftb-05-20-2019-heavy-rainfall-with-snow-over-the-higher-terrains-through-tuesday","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=9042","title":{"rendered":"FTB 05-20-2019: Heavy Rainfall with Snow over the Higher Terrains through Tuesday"},"content":{"rendered":"<p>Issue Date: Monday, May 20th, 2019<br>\nIssue Time: 9:30AM MDT<\/p>\n<p><em>&ndash;Flooding is <strong>NOT<\/strong> expected today<\/em><\/p>\n<p>The upper closed low that is currently over the Nevada\/Utah border will start to move to the southeast today, which will bring cool and wet weather statewide. By tomorrow morning it will be positioned over the southeast Colorado\/New Mexico border&nbsp;and bring&nbsp;snow&nbsp;to the lower elevations. With an incoming jet, ample low level moisture with southwesterly flow and plenty of mid-level ascent, expect precipitation to continue throughout today and into tomorrow. Currently, surface maps are indicating heavy snowfall and rain over the southwest corner of the state and moderate snow over the Central Mountains. With southwest flow increasing throughout the day, highest snow accumulations are expected to be over 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>, with all of the higher terrains receiving some snow accumulation through tomorrow morning. Over the southeast Plains in Baca and Powers Counties, showers continue from a wave of storms that moved through the Southeast Plains overnight.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/05\/wv_20190520.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-9043\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/05\/wv_20190520.png\" alt=\"\" width=\"600\" height=\"424\"\/><\/a><\/p>\n<p>For today, expect an uptick in <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> showers and snow (&gt; 9K ft). For western Colorado, storm motion will have more of a southerly component during the day, but as the low moves into the southwest corner tonight, storms will wrap around it counterclockwise giving more of a northerly component to the motion. Expecting all zones to get some precipitation with snow levels dropping to 7K ft overnight. Overnight, precipitation should be confined to the mountains, and snow accumulations are expected to be highest over the San Juan Mountains by tomorrow morning.<\/p>\n<p>To the east, the heaviest precipitation over the next 24-hours is expected along a line from Pueblo County to eastern Weld\/western Logan Counties as upslope flow and a boundary set up. 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> with hail are possible with these storms this afternoon, but tonight temperatures drop off significantly. This means there will likely be snow over the Cheyenne and Palmer Ridges by morning with the snow level around 6K feet. There is an outside chance of snow within the Urban Corridor as well, so be sure to bring in outdoor plants or cover them overnight. As the low moves into the southeast corner of the state tonight, <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;downsloping&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Refers to the winds that blow from higher elevations down towards lower elevations. As air parcels descend, they warm, which often results in rapid warming of areas near the higher terrains. It also promotes lower relative humidity values and stability, which prevents thunderstorm development.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>downsloping<\/span> winds to the south should decrease precipitation activity over the Southeast Plains and Raton Ridge. As mentioned, favorable upper level dynamics will keep activity going through the night over the Southeast Mountains, Front Range and Urban Corridor.<\/p>\n<p>Interesting flood forecast as the main threat will occur this afternoon over the Palmer Ridge. Max 1-hr rain rates hover around flood threat criteria if stronger (severe) thunderstorms are able to develop with <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 upper 40&deg;Fs to low 50&deg;Fs. However, dry soils and green vegetation decrease the chance for <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> flooding. At this time, going with no flood threat, but should the threat increase enough to warrant a Low threat, a PM update will be issued.<\/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. For Zone-Specific forecasts, scroll below the map.<br><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/05\/FTB_No_Flood_Threat_2019.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-8803\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2019\/05\/FTB_No_Flood_Threat_2019.png\" alt=\"\" width=\"880\" height=\"580\"\/><\/a><\/p>\n<h3><strong>Zone-Specific Forecasts:<\/strong><\/h3>\n<h4><\/h4>\n<h4><strong>Raton Ridge, Southeast Plains, Urban Corridor, Palmer Ridge, Northeast Plains:<\/strong><\/h4>\n<p>Upper dynamics, increased low level moisture and a boundary will help form a line of thunderstorms this afternoon over the adjacent plains around the Palmer Ridge\/Southeast Plains intersect. There is a possibility for some severe storms in this area with hail up to 1.25 inches. Max 1-hr rain rates up to 1.5 inches are possible with 3-hour totals just under 2 inches. Expecting showers to become 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> as an <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;MCS&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;(Stands for: Mesoscale Convective System) A complex of thunderstorms that produces a large, contiguous area of precipitation on the order of 100 km or more in the horizontal scale and normally persist for several hours or more.&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>MCS<\/span> quickly forms with the upper air support and moist <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;boundary layer&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;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&amp;lt;br \/&amp;gt;&amp;lt;p&amp;gt;&amp;lt;span style=&amp;quot;color: #ffffff;&amp;quot;&amp;gt;The lower portion of the atmosphere that is directly influenced by the earth&amp;#039;s surface. Primarily, the boundary layer is driven by solar heating during the day and radiational cooling at night.&amp;lt;\/span&amp;gt;&amp;lt;\/p&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>boundary layer<\/span>. Max 1-hr rain rates will drop to 0.3 to 0.7 inches when this occurs. Storms will have northerly motion throughout the day with decreasing rainfall from south to north this afternoon as the low moves into the southeast corner of the state. Snow levels drop off tonight, so ongoing, overnight storms will likely cross over into snow by morning over the Palmer and Cheyenne Ridges. There is a slight chance for snow across the Urban Corridor by morning as well. Flooding is not forecast.<\/p>\n<p>Primetime: 11AM to Tuesday morning<\/p>\n<h4><strong>Northwest Slope, Grand Valley, Southwest Slope, San Luis Valley:<\/strong><\/h4>\n<p>Southwest flow and the approaching low will pull multiple bands of rainfall with a couple thunderstorms across the lower elevations this morning into this afternoon, so expect an increase in storms throughout the day. Storm motion will be south to north this afternoon and switch to more northerly overnight as the low moves into the area. Since moisture decreases to the north, the highest 24-hr totals are forecast over the Southwest Slope where <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> totals up to 0.7 inches could accumulate. Over the Grand Valley totals up to 0.3 inches are possible. Rainfall is also likely over the Northwest Slop with totals remaining under 0.1 inches.<\/p>\n<p>Primetime: Ongoing to Tuesday morning<\/p>\n<h4><strong>Front Range, Northern Mountains, Southeast Mountains, San Juan Mountains, Central Mountains:<\/strong><\/h4>\n<p>Snow level may drop throughout the day some, but for the most part, expecting all precipitation to fall as snow above ~9K ft. Expecting coverage of the precipitation to pick up throughout the day as the low begins to approach and southwest flow increases. The highest 24-hour snow accumulations are expected along 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> where totals could reach 10-12 inches. More general totals in the 4-8 inch range are forecast for other areas.<\/p>\n<p>Primetime: Ongoing to Tuesday morning<\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Monday, May 20th, 2019 Issue Time: 9:30AM MDT &ndash;Flooding is NOT expected today The upper closed low that is currently over the Nevada\/Utah border will start to move to the southeast today, which will bring cool and wet weather statewide. By tomorrow morning it will be positioned over the southeast Colorado\/New Mexico border&nbsp;and [&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\/9042"}],"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=9042"}],"version-history":[{"count":1,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/9042\/revisions"}],"predecessor-version":[{"id":9044,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/9042\/revisions\/9044"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9042"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9042"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9042"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}