FTB 09-28-2020: Sunshine will Help with Below Average Temperatures & Wind Continues

Issue Date: Monday, September 28th, 2020
Issue Time: 9:10AM MDT

— Flooding is NOT expected today

A highly amplified pattern has set up over the US bringing strong north and northwesterly flow aloft to the state. There’s a well-defined jet streak edging into Colorado, which is marked below. This feature will push eastward throughout the day as the High builds to our west. That means another day with windy conditions, and those winds are expected to expand into the eastern plains. Since there are much cooler temperatures behind the cold front that passed through yesterday, the elevated fire danger will be confined to the plains and northern Front Range near the ongoing fires where relative humidity values will become quite low.

There is some upper level cloud cover and likely a little fog/light rain over south, central Colorado to start the day. It is very dry elsewhere, and PW has dropped to 0.22 and 0.28 inches in Grand Junction and Denver, respectively. Additionally, increased subsidence will nearly nix rainfall chances. So outside of some very light showers in the area with cloud cover this morning, it should remain dry. 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:

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

Despite cooler temperatures, relative humidity will be quite low this afternoon. So, elevated fire danger is forecast for the eastern plains and northern Front Range for northerly winds in the 17 to 23 mph range (gusts up to 25-30 mph). Higher gusts will be possible along the Continental Divide this evening. Due to dryness and sinking motion behind the trough, rainfall is not forecast. If rainfall is generated in the area of cloud cover this morning, totals will remain below 0.08 inches. High temperatures are expected to be 10-15F below normal, so quite chilly but the increasing sunshine will help. Classic Colorado fall day is ahead.

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

It will be windy over these regions as well, although a bit more spotty than over eastern Colorado. Isolated gusts up to 25 mph will be possible with wind speeds in the 15 to 20 mph range over along the western border and near the Continental Divide. High temperatures will be 8 to 12F below normal (north) and 3-6F below normal (south). No rainfall is forecast due to increasing heights and very low moisture. A Freeze Watch is in place for the Central/Northern Mountains and portions of the Northwest Slope tonight. The SLV could also see freezing conditions early tomorrow morning, and frost is forecast for the lower Arkansas River valley.