FTB 06-29-2016: Another Period of Showers/Thunderstorms On Tap

Issue Date: 6/29/2016
Issue Time: 10:12 AM

A LOW FLOOD THREAT IS ISSUED FOR PORTIONS OF NORTHEAST PLAINS, PALMER RIDGE, FRONT RANGE, URBAN CORRIDOR, SOUTHEAST PLAINS, SOUTHWEST SLOPE, GRAND VALLEY, AND SAN JUAN MOUNTAINS.

Current water vapor analysis shows the (slightly weakening) mid-/upper-level ridge still in place across the region today. Underneath the ridge, sufficient mid-level moisture remains across the state, while monsoonal moisture continues to seep into Colorado from the west/southwest. Embedded within the flow is a weak disturbance that will pivot out of Utah this morning and into Colorado this afternoon/evening. The disturbance will provide the support for more widespread showers/thunderstorms today across the High Country, as well as another day of scattered thunderstorms across eastern Colorado.

Across eastern Colorado, the concern for strong/severe storms exists again today, mainly across the Northeast Plains, Palmer Ridge, and northern/eastern extents of the Southeast Plains. The Urban Corridor has a lesser chance of getting in on the strong/severe storms, but the potential extends to those regions, as well. Generally speaking, the best coverage of showers/storms will be along/near the higher terrain, as well as over the preferred terrain of the Palmer Ridge, Cheyenne Ridge, and Raton Ridge, while the strongest storms will be further east where instability/moisture/wind shear will be best.

WV_20160629

From the Front Range/Southeast Mountains and westward, scattered-to-widespread showers and thunderstorms are expected this afternoon and evening, with a few showers lingering into the overnight hours. The main threats from these storms will be gusty winds and lightning, but locally heavy rainfall is a concern over southwestern Colorado where moisture will be best, thus the issuance of the low flood threat.

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

Scattered showers and thunderstorms are expected to begin this afternoon, continuing into the evening and overnight hours. Ingredients are favorable for the production of isolated strong/severe thunderstorms during the afternoon hours, with the main threats being hail and strong winds, as well as locally heavy rainfall.

The main event looks to come after 8 PM tonight in the form of a thunderstorm complex rolling in from WY/NE and into northeast Colorado. Much like yesterday’s strong storms, this complex will follow much of the same path, producing large hail, strong/damaging winds and heavy rain.

Timing: 1 PM – 1 AM, with lingering showers/thunderstorms along/south of the Palmer Ridge into the early morning hours

Front Range and Southeast Mountains:

Scattered showers/thunderstorms are expected, beginning around lunchtime and continuing into the evening and nighttime hours. Isolated showers/weak thunderstorms will continue into the early morning hours. The Front Range will have the potential to see one or two strong/severe storms this afternoon/evening, producing strong winds, small hail, and dangerous lightning. Locally heavy rainfall is also a threat, thus the inclusion of the Front Range in the low flood threat. Maximum rain rates will be 1.0-1.6 inches/hour for the Front Range, and 0.6-0.8 inches/hour for the Southeast Mountains.

Timing: 11 AM – 10 PM, with a few lingering into the early morning

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

Scattered-to-widespread showers/thunderstorms are expected, beginning around 11 AM and continuing into the evening hours. Overnight, showers/weak thunderstorms will become more isolated, but a few will linger into tomorrow morning. Generally speaking, the main threats from thunderstorms will be gusty winds, dangerous lightning, and small hail, but locally heavy rainfall is possible across southwestern Colorado. Maximum rain rates are as follows:

Northwest Slope, Northern Mountains, and Central Mountains: 0.4-0.8 inches/hour
San Luis Valley: 0.6-1.0 inches/hour
Grand Valley: 0.8-1.2 inches/hour
Southwest Slope and San Juan Mountains: 1.0-1.6 inches/hour

Timing: 11 AM – 10 PM, with isolated showers/weak thunderstorms continuing into tomorrow morning