FTB 09-09-2019: Mostly Dry Start to the Week after a Wet Weekend

Issue Date: Monday, September 9th, 2019
Issue Time: 10:20AM MDT

–Flooding is NOT expected today

The shortwave trough that provided widespread precipitation yesterday has moved over central Great Plains (“X” below). This system has left behind high surface moisture, which has created a large region of fog over the eastern plains and Urban Corridor this morning. This surface moisture is expected to mix out as zonal flow of dry air makes its way over Colorado from the west. This advection of dry air and subsidence behind the trough will keep most of the state dry and sunny today. There is a slight chance for precipitation over the far eastern plains this afternoon associated with a dryline set up (dashed orange line below). Chances of precipitation are on the low end, but a couple storms maybe produce isolated areas of rainfall up to 0.75 inches along the Colorado/Kansas border this afternoon. Additional storms are possible over the Northeast Plains and northern Urban Corridor overnight due to a low level jet streak passing over Wyoming. This will provide upper level support in a moderate moisture environment. Flooding is not forecast 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, Northern Mountains, Northwest Slope, Northeast Plains, Palmer Ridge, Southeast Plains:

Expecting a 3°F to 5°F temperature increase from yesterday with a building ridge and mostly sunny skies. There is a slight (10%-20%) chance of some weak thunderstorms over the northern mountain ranges this afternoon from upslope flow of residual surface moisture, but cloud cover and maybe some brief wind is more likely with the low dew points. Isolated totals up to 0.1 inches may be possible for the stronger storms. The highest chance (30%-40%) for isolated thunderstorms today is over the far eastern plains to the east of the dryline over Prowers and Baca County. Max 1-hour rainfall rates up to 0.75 inches are forecast for the stronger storms. There is an additional chance for a few isolated storms overnight for the Northeast Plains and northern Urban Corridor due to a low level jet streak passing over Wyoming. Max 1-hour rainfall rates up to 0.5 inches are forecast for these storms. Flooding is not forecast today.

Primetime: 1PM to 3AM

Grand Valley, Central Mountains, Southwest Slope, San Juan Mountains, San Luis Valley, Southeast Mountains, Raton Ridge:

Storms are very unlikely today with dry air and building high pressure over the area. Expecting high temperatures to increase 3°F to 5°F from yesterday with dew points dropping into the teens and single digits. Wind gusts will remain well below critical fire weather, but caution is still needed with open flames due to the drying out vegetation over the last month or so. Sustained winds between 10 and 15 mph with gusts up to 20 mph are possible out of the west/southwest near the Continental Divide. Flooding is not forecast today.