{"id":3160,"date":"2016-07-21T10:47:02","date_gmt":"2016-07-21T16:47:02","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=3160"},"modified":"2016-07-21T10:47:02","modified_gmt":"2016-07-21T16:47:02","slug":"ftb-07-21-2016-after-4-days-monsoon-spigot-backs-off-slowly","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=3160","title":{"rendered":"FTB 07-21-2016: After 4 days, monsoon spigot backs off; slowly"},"content":{"rendered":"

Issue Date: Thursday, July 21st, 2016
\nIssue Time: 10:42AM MDT<\/p>\n

— LOW<\/strong> flood threat for parts of Central Mountains, Northern Mountains, Grand Valley, San Juans and Southwest Slope
\n— LOW<\/strong> flood threat for parts of Front Range and Palmer Ridge<\/em><\/p>\n

This morning’s water vapor image, below, appears quite similar to yesterday’s. At face value. However, important details emerge upon closer inspection. The most notable difference in the past 24-hours is the ridge centered southeast of Colorado will bulge out noticeably to the west. The main implication of this is essentially turning off the monsoon<\/span> spigot. That said, plenty of residual moisture remains this morning so heavy rainfall storms will be had once again. However, parts of the far southwest will see some notable upper-level drying. Thus, the main region for heavy rainfall storms will shift northward today and roughly straddle the I-70 corridor of the western slope. The second important difference today is that the steering flow will all but cease to exist as the ridge axis moves almost directly overhead. Regarding heavy rainfall, this has a pro and con component. On the one hand, a lack of storm motion will allow for very heavy short-term rainfall at a given location. On the other hand, lack of shear<\/span> means that downdrafts and updrafts will have a hard time separating. The ultimate effect of this is that today we are looking for sub-hourly heavy rainfall that could lead to isolated<\/span> flood problems. Lastly, antecedent rainfall amounts of 2-3 inches in the past 72 hours suggest runoff will be more effective today. In all, a Low flood threat captures these factors.<\/p>\n

A severe storm cannot be ruled out across the far eastern parts of the state in the early to late evening. However, odds are slim and hail up to 1 inch and wind up to 55mph should be the bigger threat compared to heavy rainfall. Given the very low odds, a flood threat is not warranted in this region today.<\/p>\n

 \"wv_markup\"<\/a>Today’s Flood Threat Map<\/strong><\/h3>\n

For more information on today’s flood threat, see the map below (hover over threat areas for more details). For Zone-Specific forecasts, scroll below the map.<\/p>\n