FTB 06-28-2020: Approaching Disturbance to Bring More Wind Than Rainfall

Issue Date: Sunday, June 28th, 2020
Issue Time: 8:55AM MDT

— Flooding is NOT expected today

An impressive disturbance was noted on visible satellite this morning, see below, with the upper level trough located over northern Oregon as of 8:30AM MDT. The accompanying surface low was located over the Great Basin, forcing some morning showers and even a few weak thunderstorms in northern Utah. This disturbance will not be in any particular hurry today and will slowly approach Colorado as it digs southeastward. However, cooler mid-level temperatures and some mid-level dynamics on the outskirts of the trough imply a higher coverage of showers and thunderstorms today over central and western Colorado.

While the PW at Grand Junction (0.68 inches) appears fairly elevated, an inspection of this morning’s sounding shows that the vast majority of the moisture lies well above the boundary layer. As such, any thunderstorms that do form this afternoon will be much more effective at producing gusty winds than rainfall. By this afternoon, an area of very strong mid-level winds is expected to approach western Colorado. This sets up an enhanced risk of wildfires since dry lightning will be possible, along with fairly low relative humidity. A Red Flag Warning and Wind Advisory have already been issued for the Northwest Slope, Grand Valley and Southwest Slope.

East of the Continental Divide, very warm weather will return today after a brief hiatus with temperatures up to 10F above normal. Isolated to widely scattered storms are possible later this afternoon, but rainfall will be limited and the main impact will be gusty winds.

Flooding is not expected today.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. If there is a threat, hover over the threat areas for more details, and click on burn areas to learn more about them. For Zone-Specific forecasts, scroll below the threat map.

Zone-Specific Forecasts:

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

Partly to mostly cloudy this morning, the scattered showers and thunderstorms, mainly over the higher terrain. Max 1-hour rainfall up to 0.4 inches possible. Flooding is not expected today.

Winds will pick up this afternoon, especially over the Northwest Slope with gusts above 60mph possible over the highest peaks. Furthermore, an elevated fire risk exists over the Grand Valley and Southwest Slope today due to the combination of wind speed and low relative humidity. Stay tuned to NWS forecasts and #COfire threat for updates.

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

Mostly sunny this morning then partly cloudy and hot with isolated to widely scattered showers and thunderstorms this afternoon. Coverage will be highest over the higher terrain extending northeast into the Northeast Plains. Max 1-hour rainfall up to 0.4 inches. Gusty winds, up to 45 mph, will accompany the strongest storms that do form. Flooding is not expected today.