Issue Date: Saturday, August 13th, 2022
Issue Time: 10:40 AM MDT
— A LOW flood threat has been issued for the Northwest Slope, Northern Mountains, Front Range, Central Mountains, San Juan Mountains, and Southwest Slope
— Fire-Burn Forecast Summary: 1 burn area under HIGH threat, 3 burn areas under MODERATE threat, 2 burn areas under LOW threat; click HERE for more info
The broad, high-pressure ridge center is located over southwestern Kansas this morning and should slowly begin a slight southeastward track later this afternoon. There is an upper-level disturbance located over central Colorado that is expected to track north to northeast throughout the day and provide some added energy for storm development this afternoon. As upper-level flow shifts more westerly, modest moisture transport over the northern portions of the state is expected, while drier air moves in over the south and east. This morning, Grand Junction measured a PW value of 1.03 inches, only a slight increase from yesterday, and Platteville record a PW value of 0.89 inches, indicating sufficient column moisture. Surface moisture is modest with dew points in the mid-40s°F to low 50s°F for most of the state. Some mixing out of surface moisture is expected statewide, although moisture pooling is anticipated over north-central Colorado due to increasing upslope flow from the east and westerly flow aloft.
This afternoon, scattered storm development is expected primarily over the higher terrain from north-central Colorado, extending south along and west of the Continental Divide, with storms expected to move east-northeastward at about 10 to 15mph. Some training of storms is possible due to the west to southwesterly flow. By mid-afternoon, instability over north-central Colorado is forecast to reach values of 1500-2000 J/kg of CAPE, and in the presence of forecast dew points in the mid-50s°F and increased convergence over the mountains, isolated heavy rainfall will be possible with the stronger storms. Further to the southwest, slightly drier air is expected along with lesser instability, though likely sufficient for isolated heavy downpours and possible storm training this afternoon which could lead to higher storm totals. A LOW flood threat has been issued for portions of western Colorado through this evening. Eastern Colorado is expected to remain largely dry and hot except for the potential for an isolated storm or two over the Cheyenne Ridge near the Wyoming border later this afternoon.
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:
Northwest Slope, Northern Mountains, Front Range, Central Mountains, & Grand Valley:
A few weak early showers are dissipating over the Northwest Slope this morning, though a cloud deck remains over the far northwest corner of the state; otherwise, mostly clear skies further east should allow ample instability for scattered storm development beginning early afternoon. This development should remain confined to the higher terrain and move east to northeastward, with a few rounds of training storms possible. Isolated 1-hour rain rates up to 1.25 inches and storm totals up to 1.75 inches are possible. A LOW flood threat has been issued for portions of the Front Range, Northern Mountains, Central Mountains, and far eastern Northwest Slope. Excessive runoff, mud flows, and debris slides will be possible especially with storms that train over the steeper terrain over a couple hour period.
Primetime: 1PM to 10PM
Southwest Slope, San Juan Mountains, San Luis Valley, & Southeast Mountains:
While lesser instability and moisture is forecast over the southwest portions of the state, clouds are beginning to build over the high terrains already this morning. By the noon hour, widely scattered storm development is likely over the mountains primarily, moving northward. Training storms are possible here as well given the more southerly wind component. Max 30-minute rain rates up to 0.9 inches and 1-to-2-hour storm totals up to 1.5 inches are possible. A LOW flood threat has been issued for portions of the San Juan Mountains and eastern Southwest Slope. Excessive runoff, mud flows, and debris slides will be possible especially with storms that train over the steeper terrain over a couple hour period.
Primetime: 12PM to 9PM
Urban Corridor, Northeast Plains, Palmer Ridge, Southeast Plains, & Raton Ridge:
This morning, skies are clear and warm temperatures are expected to rise quickly into the low to mid-90s°F this afternoon. Under great influence from subsidence from the ridge and high dewpoint depressions, storms are not expected for most of the eastern half of the state. That said, a few isolated storms are possible over the northern Urban Corridor and the northern Northeast Plains border counties. These storms may produce 30-minute rain rates up to .04 inches, but flooding is NOT expected today given nearly nonexistent instability forecast for the Northeast Plains.
