FTB 09-15-2020: Mild Weather Continues

Issue Date: Tuesday, September 15th, 2020
Issue Time: 8:50AM MDT

— Flooding is NOT expected today

Below is the visible satellite imagery and Hurricane Sally pops out over the Gulf of Mexico. Sally should be making landfall by early this afternoon, and will bring with her life-threatening storm surge and major flooding. Over Colorado, the ridge is holding steady and building to the northwest a bit. This is pulling in smoke from fires across the western US (gray hue), and the HRRR smoke continues to show an increase in near surface smoke along and just south of the northern border today. PW was measured at 0.38 and 0.45 inches at Grand Junction and Denver, respectively. So, it’s quite dry, which can also be seen by the 50F dew point line both south and east of the state (dashed green). Further drying of the atmosphere is expected today, so other than some cloud cover building over the mountains this afternoon with residual mid-level moisture, it should be another clear and warm day. Flooding is not forecast.

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:

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

Cloud cover is forecast again this afternoon over the mountains, and it looks to be better in coverage further south over the climatologically favored San Juan Mountains. A few sprinkles may be possible, but the more likely scenario is just cloud cover like we saw on Sunday with the very dry surface layer. Brief gusty winds may also be possible under the virga showers. High temperatures will continue to be 4 to 10F above normal with 80Fs for the valleys and 70Fs for the mountain valleys. Expect an increase in smoke over the Northwest Slope and northern Mountains from the ongoing fires.

Palmer Ridge, Raton Ridge, Southeast Mountains, Front Range, San Luis Valley, Urban Corridor, Northeast Plains, & Southeast Plains:

Afternoon temperatures will be similar to yesterday, and a few degrees uptick over the southeast corner is possible. So high temperatures remain well above average for mid-September. Some scattered cloud cover is expected again this afternoon over the mountains and Palmer Ridge, but rainfall is not forecast. Also expecting an increase in near surface smoke from the western US fires, which could lower air quality some by later in the day. This will mostly be across the northern border and south, and especially affect the Front Range and Urban Corridor.