FTB 08-17-2017: Isolated Severe Weather Possible Southeast, But Drying For Most

Issue Date: Thursday, August 17, 2017
Issue Time: 9AM MDT

Flooding is NOT expected today

This morning’s water vapor image, below, shows a weak trough is currently positioned over Colorado. Westerly flow has advected drier air across most of the state, with the biggest impact seen at lower levels. This morning’s Precipitable Water values were in the 0.5 – 0.9 inch range, with the highest values being limited to the far southeast corner of the state. Mid-level moisture was noted across the state, organized by a jet streak positioned along the NM border. Despite the clouds, there will be enough sunshine this morning to generate light to moderate instability especially over the southeast quadrant of the state. Isolated to scattered showers and weak thunderstorms are expected this afternoon over the Palmer Ridge and plains to the south and east. Rainfall rates will be well below flood threat levels, and thus flooding is not expected today.

In the far southeast corner of the state, strong to severe thunderstorms will be possible during the late afternoon and evening. The biggest impact from these will be large hail, gusty winds and an isolated tornado. With westerly steering winds of 25mph+, rain rates should be limited to 1.2 inches per hour or less, which is below flash flood guidance.

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, Palmer Ridge, Northeast Plains, Southeast Mountains, Raton Ridge, Southeast Plains:

Isolated to scattered showers and weak thunderstorms developing by early afternoon, lasting through sunset (except 9PM in the far southeast). Highest coverage will be over the Palmer Ridge and Southeast Plains. Strong to severe thunderstorms are possible in the far southeast regions towards the OK and KS border. Max 1-hour rainfall up to 1.2 inches (southeast) and 0.6 inches (west). Hail up to 1.25 inches, gusty winds up to 65 mph and isolated tornadoes will be possible with the strongest storms in the southeast corner of the state. However, flooding is not expected today.

Primetime: 1PM to 9PM

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

Partly cloudy early with isolated showers and a weak thunderstorm possible this afternoon. Highest coverage will be over the Central Mountains and San Juans. Max 1-hour rainfall up to 0.4 inches is possible. Flooding is not expected today.

Primetime: 12PM to 7:30PM