FTB 06-07-2021: Hot with Scattered PM Storms East

Issue Date: Monday, June 7th, 2021
Issue Time: 9:00AM MDT

— Flooding is NOT expected today

Colorado continues to be sandwiched between two systems today. The Low to our east, is helping to produce more northernly flow over eastern Colorado. The trough over the Pacific Northwest and a cut off low off the California coast are aiding in more southwesterly flow aloft over western Colorado. Across central Colorado, the transition flow between the two systems is more westerly. With the ridge continuing to strengthen, expect another day with hot temperatures. The water vapor imagery below also shows some residual moisture over the area, more so east than west.

PW at Denver this morning was measured at 0.56 inches and over Grand Junction was measured at 0.50 inches. This indicates that the higher moisture accompanying yesterday’s front over eastern Colorado has already begun to mix out with the westerly flow. With southwest and westerly flow aloft forecast to continue today, the drier air mass marked below should be advected across the state (west to east), which will continue to decrease the available moisture. Decreasing this moisture should cause a downtick in storm coverage and intensity over the mountains that develop from the upslope flow. Additional scattered storm development is likely over the eastern, elevated ridges by mid-afternoon with southwesterly flow at the surface. These storms, and the storms that meander off the Front Range this evening, are expected produce lower rainfall totals in their storm cores when compared to yesterday. If stronger storms develop, the main threat will be strong outflow winds, lightning and only brief, heavy rainfall in the small storm cores. Therefore, flooding is NOT forecast 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:

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

It rapidly has transitioned from spring to summer. Today’s high temperatures will reach into the upper 80Fs and low 90Fs across the I-25 corridor. Mid 90Fs are forecast across portions the eastern plains. Over the mountains, valleys will reach into the low 80Fs.

As for rainfall, isolated (south) to scattered (north) storms will develop over the mountains this afternoon. With the dry air mixing in from the west, rain rates will be lower with some storms only producing virga. Isolated max 1-hour rain rates up to 0.25 inches (north) and 0.15 inches (south) will be possible. Storms that develop over the ridges will produce slightly higher rain rates, up to 0.45 inches per hour. If outflow boundaries can help break the cap and initiate some storms over the eastern border, max 1-hour rain rates up to 1.25 inches will be possible. The main threat from the stronger storms that develop will be brief, heavy rainfall, strong outflow winds and lightning. Small hail may also be possible. Flooding is NOT forecast.

Primetime: 1PM to 11PM

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

With the ridge continuing to strengthen and southwest flow pulling in a drier air mass, it’s going to be hot and dry day ahead. High temperatures over the valleys and NW/SW Slope will reach into the mid-90Fs. Over the mountain valleys, highs will be in the low to mid-80Fs. Isolated storms will be possible along and near the Continental Divide. However, storms will likely produce more cool outflow winds than measurable rainfall. Totals should remain around or just below 0.10 inches. Flooding is not forecast.

Primetime: 1PM to 8:30PM