FTB 06-26-2019: Weak Afternoon Thunderstorms Anticipated Over the Eastern Plains

Issue Date: Wednesday, June 26th, 2019
Issue Time: 10:05AM MDT

–Flooding is NOT expected today

Flow aloft over the state has turned to the southwest as the trough off the Pacific coast begins to deepen. Currently there is some cloud cover over the mountains and southwest corner of the state associated with some mid-level energy moving through the area. With shallow moisture in place again today, expecting these clouds to burn off after a couple hours of heating. Marked in green below is the dew point gradient. As noted the last couple of days, a very dry air mass remains over western Colorado. With a tightening pressure gradient aloft, surface winds will likely pick up to the 15-20 knot range along the western border today. This will increase fire danger, although critical fire weather is not anticipated until tomorrow. Some light showers may be possible over the southern San Juan Mountains this afternoon as the shortwave (marked in orange below) helps kick off some high-based, weak thunderstorms. The shortwave and diurnal flow will also help initiate some showers and weak thunderstorms over the eastern mountains with the main activity centered over the southern Front Range and Palmer Ridge. As storms move off the mountains into the adjacent plains, only light rainfall is anticipated. Threats also include brief gusty winds, similar to yesterday.

A lee trough is expected to setup over the Northeast Plains and will tighten the dew point gradient (dry line). This will produce some convergence for storm initiation over the eastern plains this afternoon in a north/south oriented line east of Highway 71. Better moisture will be located over Nebraska and Kansas, so the main threat for storms today will again be gusty winds, severe hail and moderate rainfall. Storm activity will move east of the border by early this evening. Therefore, flooding is not expected.

Another day with no riverine flooding expected as well. While a couple gages remain at Action stage, streamflow levels are predicted to decrease statewide. Thus, since no flooding was reported yesterday, there is no riverine flood threat issued today. For the most up to date information on the riverine flooding threat, follow your local NWS Weather Forecast Office.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. For Zone-Specific forecasts, scroll below the map.

Zone-Specific Forecasts:

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

High temperatures will continue to creep up a couple of degrees today with the 5880mb ridge pushing north thanks to warm air advection. Highs over the Southeast Plains will reach just under the 100°F mark. Feeling more like summer! For storms today, max 1-hour rain rates up to 0.15 inches (west) and 0.6 inches (east) will be possible under the stronger storms. Thus, brief gusty winds will also be possible again with Inverted-V soundings. Over the eastern plains, storms will be capable of producing stronger gusts (up to 50 mph), hail up to 1.5 inches and dangerous lightning. These threats should end by the early evening as activity moves east of the state. Flooding is not anticipated.

Primetime: 1PM to 9PM

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

Low dew points and increasing surface winds will escalate fire danger this afternoon. Critical fire weather is not anticipated until tomorrow, but be sure to use caution with any open flame. Surface winds in the 15-20 knot range are anticipated to mix to the surface with gusts between 30 and 35 knots possible by later this afternoon. Winds will then decrease overnight. High temperatures today will be similar to yesterday with an increase in afternoon cloud cover as the shortwave passes overhead. Very light showers may be possible over the southern San Juan Mountains, but the weak storms will likely only produce gusty winds and a drop or two of rain.

Primetime: 2PM to 7PM