FTB 09-20-2021: Much Cooler Temperatures with Only Light Precipitation Forecast

Issue Date: Monday, September 20th, 2021
Issue Time: 9AM MDT

— Flooding is NOT expected today

A strong cold front moved through the state yesterday during the evening and overnight hours, which is very well defined in the 24-hour temperature change image below. So, it is a much cooler start to the day, and there’s even a dusting of snow over the highest peaks of the northern mountains. It looks like the snow line fell to just under 9K feet from CDOT cameras in the area. There are also some light showers over the Northeast Plains associated with the upper trough, which are expected to continue to weaken and move across the border over the next hour or so.

Today, much cooler high temperatures are forecast behind the front along with mostly stable conditions as high pressure begins to build across the state. There is still a chance for some light showers and snow over the northern mountains throughout the day and tonight, but only minimal accumulation is forecast. Additionally, some weak showers may develop over the Palmer Ridge/southern Front Range intersect and Southeast Plains this afternoon and evening associated with a wind speed maximum overhead. With only light precipitation forecast, flooding is NOT expected today.

Today’s Flood Threat Map

For more information on today’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.

Zone-Specific Forecasts:

Northwest Slope, Northern Mountains, Front Range, Grand Valley, San Juan Mountains, San Luis Valley, Central Mountains & Southwest Slope:

Some light snow and showers are possible over these mountain regions (north) this morning and later tonight. Minimal accumulation is forecast with isolated precipitation totals up to 0.15 inches possible. Clearing conditions this afternoon (west/south) will help produce very cold overnight temperatures. A Freeze Warning has been issued for the central Yampa and Colorado River Basins tonight where surface temperatures may drop to as low as 27F. A Freeze Watch has been issued for the San Luis Valley (below 8,500 ft) where lows may fall into the upper 20Fs and lower 30Fs, which could damage vegetation/crops.

Primetime: Ongoing to 2AM

Southeast Mountains, Northeast Plains, Southeast Plains, Urban Corridor, Raton Ridge & Palmer Ridge:

Light showers are expected to continue over the Northeast Plains for the next hour as the trough axis slides east. This afternoon, some additional weak showers may develop over the eastern Palmer Ridge/southern Urban Corridor as well as over the Southeast Mountains and Southeast Plains with upper level lift in the area. Isolated totals up to 0.20 inches may be possible, but most totals should remain under 0.10 inches. Flooding is NOT forecast today.

Primetime: 1PM to 10PM