Issue Date: Thursday, August 25^th, 2022
Issue Time: 10:50AM MDT

— A LOW flood threat has been posted for parts of the Front Range, Northern Mountains, Central Mountains, Grand Valley, San Juan Mountains and Southeast Mountains
— Fire-Burn Forecast Summary: 5 burn areas under MODERATE threat; 3 areas under LOW threat; click HERE for more info

This morning’s visible satellite imagery, below, shows that a couple of features will bring a notable uptick in heavy rainfall chances mainly over our higher terrain. First, a strong but small disturbance over Wyoming will provide synoptic-scale lift to our Central and Northern Mountain zones, resulting in scattered to numerous showers and storms. Further south and west, Grand Junction’s PW has increased from 0.77 to 0.89 inches, with values likely approaching 1 inch over the southwest part of the state. Although synoptic-scale lift will be weaker over southwest Colorado, the diurnal upslope circulation combined with an increase in monsoonal moisture will be enough to cause scattered to numerous showers and storms here as well. The flood threat today will be primarily earlier in the afternoon as plenty of sunshine should generated CAPE of up to 900 J/kg. This will support the threat of heavy rainfall at predominantly the 30-60 minute duration. Thus, a LOW flood threat has been posted for a large part of our higher terrain today. Later in the evening, upscale growth of storms should transition rainfall intensity into the (mighty welcome) light to moderate variety.

Further east, the Platteville morning PW of 0.62 inches is down further from yesterday morning’s 0.71 inches. Boundary layer moisture looks less favorable for heavy rainfall potential. Nonetheless, with the strong forcing described above, a few storms will likely make it off the higher terrain, especially from the Palmer Ridge northward. However, they are expected to pose more of a gusty wind threat along with brief moderate rainfall potential. Thus, flooding is not expected here.

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:

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

Becoming mostly cloudy with scattered to numerous showers and storms developing by early afternoon. Max 30-min/60-min rain rates up to 0.9/1.3 inches, respectively, warrant a LOW flood threat for most of the higher terrain. Primary hazards will be flash flooding along with debris slides and mud flows over steeper terrain. Light to moderate rainfall should continue into the late evening hours and lucky locations could receive up to 2.0 inches of total rainfall by Friday morning.

Primetime: 1PM to 9PM

Northeast Plains, Southeast Plains, Urban Corridor, Palmer Ridge & Raton Ridge:

Mostly sunny and seasonably hot through early afternoon, then partly cloudy with isolated to widely scattered showers and storms. Best coverage will be closer to the foothills, especially from Colorado Springs northward to the WY border. Max 30-min rain rates up to 0.6 inches are possible, but flooding is NOT expected today. However, gusty winds up to 50mph could accompany the strongest storm cores.

Primetime: 3PM to 9PM

Issue Date: Wednesday, August 24th, 2022
Issue Time: 10:10 AM MDT

— Flooding is NOT expected today
— Fire-Burn Forecast Summary: 3 burn areas under LOW threat, click HERE for more info 

The upper High continues to build over western Utah this morning and advect dry air into the state today from the north. Column moisture has decreased slightly across western Colorado from yesterday, with Grand Junction measuring a PW value of 0.77 inches this morning. Surface dew points in the low to mid-40s°F this morning further indicate drying of the boundary layer air as well. Still, weak energy circling around the high is expected to move through western Colorado and trigger isolated to widely scattered storm development along and west of the Continental Divide beginning early afternoon.

Given the forecast drying of both surface and column moisture today, storms are expected to remain confined to the higher elevations similarly to prior days. Slightly higher surface moisture may remain in place over the far southwest where dewpoints are currently in the low 50s°F, and it is here that the highest likelihood for heavy rainfall is expected this afternoon. But with limited instability forecast to reach between 800-1200 J/kg of CAPE over the southwest, along with decreasing column moisture, storm cores are expected to be small and produce only light to moderate rain rates. Flooding is NOT expected today.

Further east, a there has been a slight moistening in Platteville compared to yesterday with a PW value of 0.71 inches measured this morning. However, continued mixing out of boundary layer moisture is expected, and with no instability forecast, eastern Colorado is expected to remain dry and NO flooding is 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:

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

Stray high clouds are noted across the Northwest Slope this morning, otherwise skies are mostly clear across western Colorado. As the weak impulse approaches this afternoon, isolated to widely scattered southward-moving storms are anticipated across mainly higher elevations. Over the Northern and Central Mountains, an isolated storm or two may produce 30-minute rain rates up to 0.4 inches. Over the San Juan Mountains and eastern Southwest Slope, isolated 30 to 45-minute rain rates up to 0.8 inches are possible. Storms should remain confined to the higher elevations and although some runoff may occur, flooding is NOT expected today.

Primetime: 1PM to 10PM

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

Clear skies and warmer temperatures (relative to the last few days) are forecast for eastern Colorado today. Storms are expected to remain confined to the higher elevations west of the Continental Divide, while eastern Colorado is expected to remain dry. Therefore flooding is NOT expected today.

Issue Date: Tuesday, August 23rd, 2022
Issue Time: 10:35 AM MDT

— Flooding is NOT expected today
— Fire-Burn Forecast Summary: 3 burn areas under LOW threat; click HERE for more info 

As the high pressure to the west continues to build, associated subsidence is pushing into Colorado from the north. A disturbance in the flow is currently located in central Colorado, and a secondary disturbance is located further north over Wyoming (both marked by the “X’s” in the water vapor image below); both of which are forecast to move southward throughout the state with the northerly flow today. These weak impulses should provide some subtle midlevel energy to trigger widely scattered storms in the higher elevations mainly along and west of the Continental Divide this afternoon.

Column moisture is continuing to trend downward from prior days, with Grand Junction measuring a PW value of 0.8 inches and Platteville measuring PW of 0.66 inches this morning, both notably decreased from yesterday. Additionally, surface dewpoints in the upper 30s to mid-40s°F (northwest) and upper 40s to low 50s°F (south and east) show a decrease in boundary layer moisture as well. What moisture remains this morning is forecast to mix out beginning early afternoon with the dry air intrusion moving in from the north. While a few isolated to widely scattered storms may develop over the mountains, the northern storms are expected to produce mainly gusty winds, along with a brief shower or two with low rain rates given low forecast instability and meager moisture.

Meanwhile across the southwestern portions of the state, instability may reach values between 800-1200 J/kg of CAPE this afternoon. With slightly greater boundary layer moisture forecast over these areas and enhanced uplift from terrain, initially convective storms may produce locally heavy downpours. But given the decreasing moisture throughout the day, the window for heavy rainfall should be limited to only 30 to 45 minutes before storms weaken in intensity. Therefore, NO flooding is 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:

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

As patchy early morning fog in parts of central and southwest Colorado continues to erode this morning, some high mountain clouds are beginning to build. By early afternoon, widely scattered storm development is anticipated over the high terrain along and west of the Continental Divide. Echoing the pattern of prior days, these storm cores should remain small. The greatest heavy rainfall chances exist over portions of southwestern Colorado where isolated 30-minute rain rates up to 0.6 inches and 45-minute rain rates up to 0.8 inches are possible, specifically over the western San Juan Mountains and eastern Southwest Slope. Some runoff may occur over steeper terrain but NO flooding is expected today.

Primetime: 1PM to 10PM

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

Skies are mostly clear this morning across eastern Colorado. This afternoon, an isolated to a few widely scattered storms may develop over the mountains, with an additional storm or two possible over the Palmer and Raton Ridges. Given the forecast meager moisture and instability, these storms should produce primarily gusty winds, with max 30-minute rain rates up to 0.4 inches and 45-minute rain rates up to 0.6 inches possible over the mountains and ridges. NO flooding is expected today.

Primetime: 3PM to 9PM

Issue Date: Monday, August 22nd, 2022
Issue Time: 9:30AM MDT

— A LOW flood threat has been issued for the Central Mountains, San Juan Mountains, Southeast Mountains and portions of the Front Range and Raton Ridge
— Fire-Burn Forecast Summary: 2 burn areas under MODERATE threat; click HERE for more info

There is some fog, cloud cover and morning showers over the state this morning associated with the upper-level Low that is helping to generate lift in a moisture rich environment. The Low will continue to slowly track southward throughout the day with building High pressure filling in behind it. As it does so, it should promote enhanced lift out in front of it over the high terrain. Monsoon moisture is still in place over the state with PW at Grand Junction measured at 0.98 inches. There is some drier air has begun to work its way in from the north, and PW at Platteville has dropped to 0.83 inches. This drier air in tandem with building high pressure, should help to keep that area mostly dry today with only isolated mountain storms expected. Better moisture and lift are forecast south of I-70, which will be the focal point for another round of scattered to numerous mountain storms this afternoon and evening.

Similar to the last couple of days, where there are breaks in cloud cover behind this first round of showers and associated cloud cover, isolated, stronger storms are likely to develop. With cooler temperatures forecast (limited instability), the more intense rainfall from these thunderstorms should occur in the first 30 minutes to hour. Slow steering flows to the southeast will also promote higher accumulations under the small storm cores, so a LOW 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, Central Mountains, Southeast Mountains, Raton Ridge, San Juan Mountains & San Luis Valley:

Scattered to numerous afternoon and evening storms are forecast today with more intense thunderstorms likely to develop in areas with breaks in cloud cover. Max 30-minute/1-hour rain rates up to 1.1/1.75 inches will be possible, but since stronger storm cores should be relatively small and isolated, only a LOW flood threat has been issued. Storms should mostly stick to the high terrain with some spillover possible into the western Raton Ridge and San Luis Valley. In addition to local, heavy rainfall, thunderstorms may produce small hail and strong outflow winds. Flood threats include mud flows, debris slides, road flooding and ponding in low-lying areas. The flood threat should end early this evening with some light rainfall likely lingering through midnight over the southern mountains.

Primetime: 1:30PM to Midnight

Urban Corridor, Palmer Ridge, Southwest Slope, Southeast Plains, Northwest Slope, Northern Mountains, Grand Valley & Northeast Plains:

Afternoon high temperatures should still be below a couple of degrees below average today, although it will be warmer when compared to yesterday. Isolated storms may develop over high terrain with residual moisture, but totals should remain under 0.2 inches. Other areas should see plenty of sunshine and dry conditions. Flooding is NOT expected.

Primetime: 1:30PM to 9PM