FTB 06-27-2015: Showers and Thunderstorms Will Favor the High Country

Issue Date: 6/27/2015
Issue Time: 9:47 AM

A LOW FLOOD THREAT IS FORECAST FOR PORTIONS OF THE SAN JUAN MOUNTAINS, SOUTHWEST SLOPE, SOUTHEAST MOUNTAINS, AND RATON RIDGE.

An upper-level ridge has set down roots across the Western US, centered over western Utah. The location of the high pressure center is important, as it will place Colorado under north-northwesterly flow aloft. This will keep storms mainly confined to the high country, with a slight chance of an isolated shower/thunderstorm to stray over adjacent lower elevations of the Urban Corridor (Pikes Peak region and south) and Southeast Plains.

WV_06272015

With upper-level ridging in place, isolated-to-scattered showers and thunderstorms will rely on daytime heating to initiate activity over the mountains. The favored terrain for scattered storms will be the San Juan Mountains and Southeast Mountains, with more isolated coverage over the mountains of the Front Range, Northern Mountains, Southwest Slope, and Central Mountains. Gusty outflow winds and lightning will be the main impacts of storm activity, along with brief moderate-to-heavy rain. Precipitable water is near average, and while some drying is expected today, there will still be enough available for maximum rain rates around 0.8-1.2 inches/hour over the San Juan Mountains and Southeast Mountains. Elsewhere over the high country, maximum rain rates will be 0.4-0.7 inches/hour.

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, Southeast Plains, Northeast Plains and Raton Ridge:

Partly sunny near the interface with the higher terrain, mostly sunny further east. A stray, isolated thunderstorm or two will move off of the higher terrain and over adjacent portions of the Urban Corridor (Pikes Peak region and south), Southeast Plains, and Raton Ridge. Otherwise, the rest of the area will stay dry and warm a few degrees over yesterday’s high temperatures.

Any thunderstorm activity will result in mainly gusty winds, lightning, and brief light-to-moderate rainfall. Maximum rain rates will be in the 0.25-0.5 inches/hour.

Timing: 1 PM – 8 PM

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

Isolated-to-scattered showers and thunderstorms will develop around lunchtime over the higher terrain of the Front Range, Northern Mountains, Central Mountains, San Juan Mountains, Southeast Mountains, and Southwest Slope. The best coverage will be across the San Juan Mountains and Southeast Mountains, as discussed above in the main discussion. A few weak thunderstorms will stray over lower elevations, with gusty outflow winds, lightning, and light-to-moderate rainfall being the main threats.

Maximum rain rates around 0.8-1.2 inches/hour over the San Juan Mountains and Southeast Mountains, and elsewhere over the high country will be 0.4-0.7 inches/hour.

Timing: Noon – 9 PM