Issue Date: Friday, July 2nd, 2021
Issue Time: 9:40AM MDT
— A LOW flood threat has been issued for the Southeast Mountains, Raton Ridge and portions of the Front Range, Central Mountains, Urban Corridor and Palmer Ridge
The visible satellite imagery below is showing pockets of fog and cloud cover across the eastern plains and in some of the mountain valleys this morning. It is more widespread over the adjacent eastern plains with the dew points in the upper 50Fs to low 60Fs range. The upper Low from yesterday is currently over northern Wyoming, and it will continue to pull northward throughout the day while the High and associated ridge begins to reestablish itself back over the southwest US.
While moisture is about the same over western Colorado (PW at 0.93 inches), it has dropped slightly over eastern Colorado (PW at 0.87 inches). This is still quite elevated, and with lower-end steering flow forecast again under the building ridge, the scattered storms that develop (east) will again be capable of local heavy rainfall this afternoon and evening. Guidance is indicating that the westerly steering flows over eastern Colorado will be slightly higher in magnitude than yesterday. This in tandem with the more scattered nature of the rainfall today, will help to limit the heavy rainfall threat.
There are also no noticeable shortwaves moving through the flow this afternoon, so this will support the heavy downpours to be more scattered in nature. As the west and northwest steering flow drive the storms into the adjacent eastern plains this afternoon, they are expected to have a better chance of producing higher rain rates further south. Outflow boundaries may trigger some additional convection further east, so the Low has been extended due to the elevated moisture in the area.
The mountains, particularly the southern Front Range/northern Southeast Mountains have seen a lot of rainfall over the last 48-hours. Saturated soils and another round of heavy rainfall producing storms this afternoon will increase the runoff, debris flow and local stream flood threat. A Low flood threat has been issued for this reason. Over western Colorado, storm motion will be slightly faster, storm cores a bit smaller, and a larger spread in dew point/temperature will cause rainfall rates to less efficient, so no flood threat has been issued.
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:
Front Range, Palmer Ridge, Southeast Mountains, Central Mountains, Raton Ridge & Urban Corridor:
Storms are expected to begin by midday again with more scattered coverage than widespread coverage (when compared to yesterday). Over the southern Front Range and Southeast Mountains, max 1-hour rain rates up to 1.10 inches will be possible. Over the northern Front Range and Central Mountains max 1-hour rain rates up to 0.75 inches will be possible. Over the adjacent plains, max 1-hr rain rates up to 1.50 inches (north) and 1.75 inches (south) will be possible. A Low Flood threat has been issued. Flood threats over the steeper terrains include excess runoff into local streams, mud flows and debris slides. Over the adjacent plains, road, local stream, and field ponding will be possible. The heavy rainfall threat is expected to end soon after sundown.
Primetime: Noon to 10PM
Northeast Plains & Southeast Plains:
No rainfall is anticipated for the far eastern plains today, but a couple outflow boundaries back to the west could trigger some storms over these regions late this afternoon and evening. Max 1-hour rain rates up to 1.75 inches would be possible with slightly higher storm totals further south. A Low flood threat has been issued for road, field and local stream flooding.
Primetime: 4:30PM to 11PM
Northern Mountains, San Luis Valley, San Juan Mountains, Grand Valley, Northwest Slope & Southwest Slope:
Scattered storms will develop over the elevated plateaus and mountains this afternoon with best coverage anticipated closer the Continental Divide. Max 1-hour rain rates up to 0.50 inches (south) and 0.30 inches (north) will be possible. Flooding is NOT expected today.
Primetime: Noon to 9PM
