Issue Date: 9/14/2015
Issue Time: 10:05AM
— NO Flood Threat Today
Though it certainly may not feel like it outside, today’s weather map has “Fall Is Here” written all over it (see water vapor image below). A potent large-scale trough is entering the west coast of North America. The resulting dynamics will help develop a low-pressure circulation over the northern U.S. Rockies by later this afternoon. Meanwhile, a push of subtropical moisture is also noted over southern California. In fact, the eastern fringes of this have already made it into Colorado: the precipitable water has jumped from 0.4 inches yesterday to 0.8 inches this morning. Note that this moisture transport is from the west (as opposed to south or southwest), potentially signalling that the Southwest monsoon may be waning. Collectively, these factors will support a continuous, widespread light to moderate rainfall across the Continental Divide, and locations to the west. However, the fast steering winds (increasing to 35mph and higher) and unfavorable moisture profile (low-levels remain dry) will preclude the threat of heavy rainfall. Thus, we get an optimal result: beneficial widespread rainfall, but no flood threat.
Today’s Flood Threat Map
For more information on today’s flood threat, see the map below (hover over threat areas for more details). For Zone-Specific forecasts, jump below the map.
Zone Specific Forecasts
Front Range, Urban Corridor, Northeast Plains, Southeast Plains, Palmer Ridge, Raton Ridge, Southeast Mountains:
Partly to mostly sunny skies with several waves of high cloudiness streaming in throughout the day from the west. Continued warm with high temperatures 5-10F above normal. Showers and a weak thunderstorm will be possible above 8,000 feet over the Front Range, Palmer Ridge and Southeast Mountains. However, rainfall amounts will remain light, under 0.25 inches. Flooding is not expected.
Southwest Slope, San Juans, San Luis Valley, Central Mountains, Northern Mountains, Grand Valley, Northwest Slope, Southwest Slope:
Mostly cloudy skies with numerous rounds of showers and weak thunderstorms throughout the day and into the evening/overnight hours. Max 1-hour rainfall rates up to 0.6 inches will be possible. Thus, flooding is not expected. However, maximum 24-hour rainfall amounts could exceed 1 inch is localized regions.
