FTB 06-29-2017: Cooler With Scattered Storms (Some Severe), But No Flood Threat

Issue Date: Thursday, June 29th, 2017
Issue Time: 10:40AM MDT

— Flooding is NOT expected today
Elevated fire danger continues for western Colorado

A bit of change is in the air this morning, as hinted by the water vapor image below. The upper-level trough that entered the US Pacific Northwest 48 hours ago is situated over the Continental Divide this morning. It is bringing with it seasonably strong dynamics that will provide large-scale upward motion across Colorado throughout this afternoon and evening. The limiting factor regarding the heavy rainfall threat, however, is once again the lack of low level moisture. Although dew point temperatures this morning are as high as the mid-50s F in eastern Colorado, this is an illusion as this moisture is quite shallow. With another deep boundary layer expected today (courtesy of the June sun + clear skies), expect most of the meaningful moisture to “mix out” leaving a few clouds and isolated showers and a weak thunderstorm for most.

The one exception will be in the Southeast Plains, where a stationary frontal boundary combined with another fresh cool front arriving this afternoon will act as a weak focal point for storm activity. Much like the past two afternoons, severe weather (gusty winds and hail) will likely be the main impact. Isolated short-term heavy rainfall, while likely, is not anticipated to exceed flood threat intensity. Thus, no flood threat is expected today.

Out west, the elevated fire danger continues today, and will be further exacerbated by dry lightning that could accompany any weak storms that manage to form.

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, scroll below the map.

Zone-Specific Forecasts:

Northeast Plains, Southeast Plains:

Partly cloudy with scattered thunderstorms likely after noon, lasting into the late evening for far eastern areas. Max 30 minute rainfall up to 1.1 inch and max 1-hour rainfall up to 1.5 inches will be just under flood threat intensity; thus no threat is issued. However, severe weather will be likely, including hail up to 1.75 inches and gusty winds up to 75 mph.

Primetime: 2PM to Midnight (near Kansas border)

Southeast Plains, Palmer Ridge, Southeast Mountains, Raton Ridge, Urban Corridor, Front Range:

Sunny early then partly cloudy with isolated to scattered showers and weak thunderstorms possible during the afternoon. Max 30-minute rainfall 0.6 inches. Flooding is not expected today.

Primetime: 1PM to 8PM

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

Mostly sunny and cooler today. An isolated shower or weak thunderstorm cannot be ruled out over higher terrain. Max 1-hour rainfall up to 0.2 inches. Gusty winds and dry lightning will be more of a threat than rainfall. An elevated fire danger continues to exist today, with a Red Flag warning in effect for most of the area. Please stay tuned to local National Weather Service offices for updates.

Primetime: 11AM to 7PM