Issue Date: 9/6/2016
Issue Time: 9:40 AM
A LOW FLOOD THREAT IS FORECAST TODAY FOR PORTIONS OF THE RATON RIDGE, SOUTHEAST PLAINS, NORTHEAST PLAINS, AND PALMER RIDGE REGIONS.
Mid-level moisture will return to the state today as a result of both the upper-trough (shown in yellow lines/arrows) sliding east and Hurricane Newton’s (circled in black) moist plume rotating across southeast Colorado. In the low-levels, better moisture will exist across eastern Colorado thanks to upslope flow behind a surface front transporting central plains moisture into the area. Additionally, good instability and wind shear will provide the necessary ingredients for a couple storms to become strong-to-marginally severe over the Plains/Palmer Ridge, with the main threats being strong winds and large hail. In the upper-levels, the right rear entrance of a jet streak will provide weak support for showers/thunderstorms, which will help bring about more coverage than previous days.
Overall, the High Country and Western Slope will remain mainly quiet today, with a few isolated-to-widely scattered showers/weak thunderstorms over the higher terrain of the San Juan Mountains, Southeast Mountains, and Front Range. Further east over the lower elevations, isolated-to-scattered showers and garden-variety thunderstorms will dot the area, with a couple strong/severe thunderstorms mixed in. Storms will remain mainly high-based, but one or two may become rooted near the surface, which would pose a low-end, low flood threat. Generally speaking, rainfall rates from most activity will be well below flash flood thresholds. For more information, 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.
Zone-Specific Forecasts
Urban Corridor, Northeast Plains, Palmer Ridge, Southeast Plains and Raton Ridge:
The main weather impact today will be the increase in clouds across the area and slightly cooler temperatures behind the passing surface front. A few isolated-to-scattered showers/thunderstorms are expected, with the best chance of occurrence along/near the Palmer Ridge and across the far Southeast Plains and Raton Ridge (where Hurricane Newton’s moist plume exists). A couple strong/severe storms will mix in with the otherwise garden variety activity, and these storms are the ones that pose the low-end, low flood threat. Maximum rain rates are as follows:
Urban Corridor: 0.4-0.6 inches/hour
Palmer Ridge and Raton Ridge: 0.6-1.0 inches/hour
Northeast Plains: 1.2-1.6 inches/hour
Southeast Plains: 1.5-2.0 inches/hour
Timing: Noon – Midnight
Front Range, Southeast Mountains, Northern Mountains, Northwest Slope, San Juan Mountains, Southwest Slope, San Luis Valley, Central Mountains, and Grand Valley:
Breezy conditions will be the name of the game for most, with dry weather expected as low-level relative humidity values remain in the 10-20% range. Red Flag Warnings exist for portions of the Northwest Slope, Grand Valley, Southwest Slope, and Central Mountains regions. The return of some mid-level moisture, combined with marginal low-level moisture and weak support aloft, will allow for a couple isolated showers over the higher terrain of the San Juan Mountains, Southeast Mountains, and Front Range. Don’t expect much in the way of rainfall, as sprinkles and a brief light shower will be all the environment can muster.
Timing: 11 AM – 9 PM
