FTB 09-28-2016: A Few Showers/Thunderstorms Return

Issue Date: 9/28/2016
Issue Time: 9:12 AM

NO FLOOD THREAT IS FORECAST.

The upper-level ridge that was largely responsible for the recent stretch of pleasant weather will remain in control of the forecast across eastern Colorado, keeping dry conditions present for another day. A few mid-/high-level clouds, mainly along/near the mountains, will be noted, but that’s it. On the other hand, changes are afoot for the High Country and Western Slope in the form of a slowly moving upper-level low. It is easy to pick out the low in the infrared imagery below, as well as the associated subtropical moisture plume. As the low lifts northward, mid- and upper-level moisture will stream into the state, bringing an increase of mid-/upper-level clouds to western regions.

ir_20160928

A few showers and isolated thunderstorms are expected across the Southwest Slope, San Juan Mountains, Grand Valley, and Central Mountains regions this afternoon and evening, with a couple spotty showers continuing overnight over the higher terrain. Rain rates are expected to remain well below flash flood thresholds, thanks in part to the low-levels remaining fairly dry. For more details, including rain rates and timing, please see the zone-specific forecast discussions below.

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, jump below the map.

Flood Threat Legend

Zone-Specific Forecasts

Urban Corridor, Palmer Ridge, Northeast Plains, Raton Ridge and Southeast Plains:

Mostly sunny skies and dry conditions will be the main weather story again today, leading to another pleasant late-September day. Highs over the eastern plains will be a few degrees cooler than yesterday, with other regions experiencing highs similar to those yesterday.

Front Range, Southeast Mountains, and San Luis Valley:

Dry conditions will be the main story again today, along with a slight increase of mid- and high-level clouds (as compared to yesterday). High temperatures will be similar to yesterday’s readings, as well.

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

Increasing clouds and dry for most, with a few showers/isolated thunderstorms expected across western Colorado. The higher terrain of the Southwest Slope and San Juan Mountains regions will see the most activity, relatively speaking, with only isolated showers/thunderstorms over the higher terrain of the Central Mountains. As the day turns to night, a few showers will spread to the Northwest Slope and western extents of the Northern Mountains regions.

Dry low-levels will subdue rainfall rates/totals, resulting in maximum rain rates of 0.15-0.30 inches/hour, with most rain rates checking in below 0.10 inches/hour.

Timing: Noon – 9 PM, with a relative minimum in activity between 9 PM and 2 AM, and then a slight uptick in the early morning hours as a weak disturbance lifts northward across the area from the south/southwest.