{"id":3442,"date":"2016-08-15T14:12:41","date_gmt":"2016-08-15T20:12:41","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=3442"},"modified":"2016-08-15T14:12:41","modified_gmt":"2016-08-15T20:12:41","slug":"fto-08-15-2016-elevated-flood-threat-this-weekend","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=3442","title":{"rendered":"FTO 08-15-2016: Elevated Flood Threat This Weekend"},"content":{"rendered":"

Issue Date: 8\/15\/2016
\nIssue Time: 2:08 PM<\/p>\n

\"Threat_Timeline_20160815\"<\/a><\/p>\n

Prior to Event #1, upper-level troughing will continue the process of deepening over the West Coast. This will bring southwest flow aloft back to Colorado, allowing for a slight uptick in moisture. Embedded in this flow will be a few weak disturbances, resulting in increasing clouds and storm coverage, especially over\/near the higher terrain. Drier low-levels will keep rain rates below flash flood<\/span> thresholds, with the main impacts being gusty winds and lightning. All of this will set the stage for Event #1.<\/p>\n

The circulation underneath the purple “#1” on the water vapor image below will drop southward out of Canada, helping to deepen the upper-level trough<\/span> along the west coast, and begin its transition eastward across the region. This will push a series of cool fronts across Colorado, establish upslope flow in their wake, and reintroducing good low-level moisture. Areas over and near the mountains\/preferred terrain of the Raton Ridge\/Palmer Ridge will be favored for more widespread<\/span> showers and thunderstorms, while scattered<\/span> coverage is expected over the plains. The airmass will gradually dry out beginning on Sunday, but northwest flow aloft will keep isolated<\/span>-to-scattered<\/span> showers\/thunderstorms in the forecast over\/near the higher terrain, with the steering flow taking a few over the plains.<\/p>\n

\"WV_20160815\"<\/a><\/p>\n

Event #2 looks to be a quick-hitting event, with a fairly transient mid-\/upper-level disturbance being ejected by the longwave trough<\/span> marked by the purple line\/”#2” in the water vapor image. In the mid- and upper-levels, moisture will be fairly lacking across Colorado, but southerly surface flow across the far eastern plains will provide a pool of good low-level moisture. A dry-line\/convergence boundary will exist on the western edge of the moisture thanks to westerly flow off of the mountains, providing a focus for a few stronger storms to develop. Drier air over the mountains will attempt to squash convection<\/span>, but a few isolated<\/span> thunderstorms will develop, resulting in mainly gusty winds and lightning. Unfortunately, model performance continues to be poor in the extended time frame, so this situation will need more monitoring before a flood threat designation will be given. For now, it will remain “No Apparent Flood Threat.”<\/p>\n

Event #1: Friday (08-19-2016) and Sunday (08-21-2016)<\/strong><\/h3>\n

Elevated Flood Threat<\/span> due to Upslope Flow and Deeper Moisture<\/em><\/p>\n

A low pressure circulation will drop southward out of Canada, helping to deepen the upper-level trough<\/span> along the west coast. Shortly thereafter, the trough<\/span> will begin to swing eastward across the region, pushing a series of cool fronts through Colorado. Behind the cool fronts, upslope flow will reintroduce good low-level moisture. Areas over and near the mountains\/preferred terrain of the Raton Ridge\/Palmer Ridge will be favored for more widespread<\/span> showers and thunderstorms, while scattered<\/span> coverage is expected over the plains.<\/p>\n