FTB 09-20-2017: Mostly Sunny with Continuing Downslope Winds

Issue Date: Wednesday, September 20, 2017
Issue Time: 10:35 AM MDT

— Flooding is NOT expected today

Currently, cooler temperatures after the passage of the cold front yesterday evening and a few clouds over the northwest corner of the state. The cold front dramatically cooled temperatures 15-20F yesterday and produced a lot of blowing dust during the evening. It also helped moisten the lower levels of the atmosphere a bit. This moistening helped produce light showers overnight in the northern high terrains and is responsible for the continued cloud cover this morning. Despite temperatures in the 40s and low 50s this morning, high temperatures will return to average this afternoon.

The trough to our northwest will begin to dig south today, and the jet stream will lift to our north. This should decrease wind speeds throughout the day, especially when compared to yesterday. Higher dew points and cooler temperatures will also give us a little relief from fire danger. However, windy conditions will still exist today, so use extra caution with open flames. Aloft, winds will shift from west to southwesterly as the day continues. Not much in the way of mid-level energy this afternoon, but models hint at a weak shortwave over the southwest corner of the state, which may help initiate some showers. Low dew points and mid-level drying will limit how much rainfall reaches the surface, but isolated totals up to 0.25 inches are possible. Elsewhere across the state, downsloping winds will keep skies clear and continue to promote atmospheric drying. Surface wind speeds will be highest today over the NW corner, mountain peaks and the Palmer Ridge. Isolated gusts are expected to be 35 mph over the lower elevations and up to 50 mph over the higher terrains. Flooding is not expected today.

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, scroll below the map.

Zone-Specific Forecasts:

Front Range, Urban Corridor, Northeast Plains, Palmer Ridge, Southeast Mountains, Raton Ridge, Southeast Plains:

Sunny throughout the day with increasing winds this afternoon, especially over the higher peaks and the Palmer Ridge. Downsloping winds will continue to promote atmospheric drying, so no rainfall is expected. No Red Flag Warning today, but gusty conditions could still easily spread fires and extra caution should be used with any open flame. Flooding is not expected today.

Primetime: 5PM to 10PM

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

Clouds over the northern mountains expected to clear later this morning. Gusty winds over the northwest corner of the state will decrease throughout the day as the jet lifts north. This afternoon some showers could develop over the San Juan Mountains with the arrival of a weak shortwave. However, mid-level drying and low surface dew points will limit how much rain reaches the surface. Isolated amounts up to 0.25 inches are possible. Flooding is not expected today.

Primetime: 4PM to 11PM