FTB 08-26-2017: Isolated Mountain & Far Eastern Plains Storms

Issue Date: 8/26/2017
Issue Time: 9:00 AM


The big weather story across the country is Harvey, currently a Category 1 hurricane that is expected to meander slowly across Texas. Here at home, however, a mainly dry day is on tap, with only a few isolated storms over the mountains and far eastern plains. In the water vapor imagery below, I have denoted the presence of the mid/upper high pressure centered over the Great Basin. This high pressure ridge will strengthen and expand over the region today, lowering our precipitation chances and keeping our temperatures near or just above average for this time of year. Enough moisture will be present over the high country for orographic effects to produce isolated showers/weak thunderstorms over the mountains during the afternoon and evening hours, with the preferred regions being the San Juan Mountains, Southwest Slope, Front Range, and Southeast Mountains.

Also denoted on the water vapor image is the presence of a mid-level disturbance, which will rotate around the periphery of the high pressure ridge, scraping by the far eastern plains during the afternoon and evening hours. Most of the thunderstorm activity associated with this disturbance will remain in Nebraska and Kansas, but a couple isolated thunderstorms cannot be ruled out for the Northeast and Southeast Plains, mainly east of a line from Sterling to Las Animas. For more details on 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, Raton Ridge, Northeast Plains, and Southeast Plains:

Mainly dry and mostly sunny conditions will prevail for the majority of the area throughout the day today, with a slight chance for a mountain shower drifting overhead locations adjacent to the mountains and the risk for isolated strong-to-severe thunderstorms over the far eastern plains. The main threat from those thunderstorms will be strong winds and hail, with brief periods of moderate-to-heavy rainfall. Rain rates are as follows:

Urban Corridor, Palmer Ridge, and Raton Ridge: 0.05-0.15 inches/hour
Northeast Plains and Southeast Plains: 0.6-1.2 inches/hour

Timing: 1 PM – 9 PM

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

Mainly dry and mostly sunny conditions will be the name of the game for most areas today. Increasing clouds near/over the higher terrain are expected this afternoon/evening as orographic effects work on residual moisture to develop isolated mountain showers/weak thunderstorms. Preferred regions for this activity will be the San Juan Mountains, Southwest Slope, Front Range, and Southeast Mountains. Rain rates will remain well below flash flood thresholds with maximum rates of 0.15-0.35 inches/hour.

Timing: 11 AM – 9 PM