Issue Date: Tuesday, July 12th, 2022
Issue Time: 9:50AM MDT

— A LOW flood threat has been issued for the Southeast Mountains, Raton Ridge and portions of the Palmer Ridge, Urban Corridor, Front Range, San Juan Mountains and Southwest Slope
— Fire-Burn Forecast Summary: 3 burn areas under LOW threat; click HERE for more info

This morning skies are mostly clear across the state thanks to the advection of a drier air mass from the north. There is a small disturbance just west of Colorado (orange “X” below) creating some morning cloud cover with the residual moisture. However, the morning sounding at Grand Junction indicates that this moisture is mostly located around 500mb with the dry boundary layer remaining. PW was measured at 0.75 inches with values increasing towards the southern border, closer to the moisture plume. There was no sounding again at Denver this morning, but it’s likely that PW is around the same as Grand Junction with values estimated around an inch over the far eastern plains. So, while there has been a reduction in the available moisture, there is still plenty left for scattered to numerous storms to develop this afternoon again.

The ridge will continue to build northward today, which will place Colorado under northwesterly flow aloft and help increase afternoon temperatures. Diurnal flow and perhaps some weak mid-level lift will help initiate storms over the high terrains by early afternoon. More activity is forecast over the Front Range and Central Mountains today with some storm activity likely over the adjacent, Northeast Plains as storms roll off the Cheyenne Ridge and mountains. Further south, closer to the moisture plume, storms should be more numerous again. Storm motion should be marginally faster than yesterday and paired with the slight downtick in moisture, this should reduce the flood threat when compared to yesterday. However, isolated thunderstorms over the elevated ridges and southern mountains may still be able to produce local, heavy rainfall under the stronger cores that develop in areas of higher instability. With soils likely saturated from yesterday over the Southeast Mountains and Raton Ridge, there is an increased threat for flooding over the area, mostly regarding runoff. A LOW flood threat has been issued. Scroll down for more details.

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:

Raton Ridge, Palmer Ridge, Southeast Mountains, Southeast Plains, San Luis Valley, Southwest Slope & San Juan Mountains:

Scattered to numerous storms are forecast today with isolated heavy rainfall possible under the stronger thunderstorms that develop. Small hail and outflow winds may also accompany these stronger storms. Over eastern Colorado, isolated max 1-hour rain rates up to 1.75 inches will be possible. This could cause mud flows and debris slides over steeper terrains and increased runoff and road flooding, especially if storms track over saturated soils. The far eastern plains look to stay dry. Over western Colorado, there should be an uptick in storm coverage today over the high terrains. Isolated max 1-hour rain rates up to 1.5 inches will be possible with training storms or storms that anchor to an area. This could cause isolated mud flows and debris slides as well as road flooding across the steeper terrains. A LOW flood threat has been issued.
Primetime: 11AM to 10PM

Front Range, Central Mountains, Northern Mountains, Northwest Slope, Grand Valley, Northeast Plains & Urban Corridor:

Storms should be widely scattered (west) to scattered (east) today with max 1-hour rain rates up to 0.4 inches possible over the western high terrains and mountains. A few storms will likely produce some strong outflow winds with the drier surface layer. The Urban Corridor will likely stay dry with downscoping winds forecast. A couple stronger thunderstorms may be possible over the Northeast Plains as storms roll off the mountains and Cheyenne Ridge into higher moisture. Additional storms may develop from their outflow boundaries. Small hail and wind along with max 1-hour rain rates up to 1.5 inches will be possible. Flooding is NOT expected.
Primetime: 12:30PM to 11PM

Issue Date: Monday, July 11th, 2022
Issue Time: 9:45AM MDT

— A MODERATE flood threat has been issued for the Raton Ridge and portions of the Southeast Plains
— A LOW flood threat has been issued for the Southeast Mountains and portions of the Front Range, Central Mountains, San Luis Valley, San Juan Mountains and Urban Corridor
— Fire-Burn Forecast Summary: 1 burn area under MODERATE threat, 1 burn area under LOW threat; click HERE for more info

There’s a bit of a change in the weather pattern today as shown in the water vapor imagery below. At the mid-levels, the 500mb High will start to rebuild back to the west, which should help to transition the flow aloft over the state from more westerly to northwesterly over the course of the day. At the surface, a disturbance to our east (orange “X”) is creating a northerly wind surge over the eastern plains this morning. This is helping to produce cooler morning temperatures as well as an increase in cloud cover behind it over northwest Colorado. This stabilizing air mass should help confine rainfall activity to the southern Front Range and south today.

 

As far as moisture, PW at Grand Junction was measured at 0.92 inches with dew points in the upper 40°Fs and low 50°Fs noted across the lower elevations in southern Colorado. As the front and associated lift push south, scattered storms are forecast to develop over the central and southern high terrains. Moisture over central Colorado and the western valleys should continue to be limited at the surface, which will limit the flood threat over the area. However, higher moisture over portions of the southern San Juan Mountains, Southeast Mountains, San Luis Valley and immediate adjacent eastern plains paired with extra lift from the boundary will return the flood threat to the area. A LOW flood threat has been issued. Longer duration rainfall, expanding thunderstorm coverage and higher dew points over the immediate adjacent plains along the elevated Raton Ridge could cause widespread heavy rainfall through this evening, so a MODERATE flood threat has been issued for this area.

Flood related threats today include the possibility for isolated mud flows and debris slides over steeper terrains along with road flooding, field ponding and rises in local streams and creeks possible (east) under the stronger storm cores that develop. The heavy rainfall looks to wind down after about midnight, but some light rainfall may linger over and near the Raton Ridge through early tomorrow morning.

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:

Raton Ridge, Front Range, Central Mountains, Southeast Mountains, Southeast Plains, San Luis Valley, & San Juan Mountains:

Scattered to numerous thunderstorms are forecast for these zones today. Northwesterly steering flows by later this afternoon should produce some spill over into the adjacent plains favoring the elevated ridges, especially south, for rainfall accumulation. Over the southern San Juan Mountains, scattered storms may produce 1-hour rain rates up to 1.1 inches, and for the Southeast Mountains, 2 to 3-hour totals up to 2.25 inches will be possible. This could cause isolated mud flows and debris slides as well as road flooding. A LOW flood threat has been issued.

Longer duration, heavy rainfall is forecast for the Raton Ridge through about midnight, although some lighter rainfall could linger into the early morning hours. Max 1-hour rain rates up to 1.9 inches and storm totals just under 3 inches will be possible. This could cause road and arroyo flooding, field ponding as well as rises on local streams/creeks. A MODERATE threat has been issued. A couple severe thunderstorms are also possible over the eastern Raton Ridge area along the front late this afternoon into the evening hours, so some hail and strong outflow winds may accompany those if they develop. 

Primetime: 12PM to 9PM (west); 12PM to Midnight (east)

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

It should be relatively quiet on the rainfall front over these zones today with drier and/or stable conditions forecast. Some isolated, light precipitation will be possible over the high terrains west, but rainfall amounts should remain under 0.1 inches. Better rainfall chances will be over the elevated regions of the Southeast Slope where totals up to 0.5 inches will be possible. Flooding is NOT expected. The more northern zones, especially east, should have a nice break from the heat.

Primetime: 12PM to 8PM

Issue Date: Sunday, July 10^th, 2022
Issue Time: 8:45AM MDT

— Flooding is NOT expected today

Compared to yesterday morning, a much busier weather map is noted over Colorado today as shown in the water vapor image, below. The main feature continues to be a strong upper-level ridge, now centered just to our east. Clockwise circulation along with subsidence will continue to hamper convection today, though mainly over southeast Colorado. An increase in moisture over western Colorado (Grand Junction PW at 0.74 inches compared to ~0.50 inches yesterday), combined with more active synoptic scale dynamics coming in from the north will support scattered shower and storm activity this afternoon and evening across most of the state. This will be welcome news given that very hot afternoon temperatures are expected once again. The good news today is that cloud cover should bring down temperatures quicker by early evening.

Focusing on details, mid-level clouds are already noted over parts of western Colorado as modest monsoon moisture has moved into the state. However, PW is expected to top in the 0.5 – 0.8 inch range as the much higher moisture will be suppressed well south over southern New Mexico and Arizona. With some mid-level cooling associated with a jet stream and cool front to our north, we expect much higher storm coverage today compared to Saturday. However, the combination of limited boundary layer moisture and notably faster steering flow will still act to suppress rainfall accumulation. While short-term moderate intensity downpours are still expected under the strongest storm cores, flooding is NOT expected today. However, gusty storm winds are expected basically statewide this afternoon and evening as storms increase in coverage.

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, Urban Corridor, Palmer Ridge, Southeast Mountains, Raton Ridge, Northern Mountains, Central Mountains, Grand Valley, San Juan Mountains, Southwest Slope, San Luis Valley & Northwest Slope:

Becoming partly to mostly cloudy and continued hot with isolated to scattered showers and storms expected this afternoon. Highest coverage will be over the southern and central higher terrain. Max 30-minute rainfall up to 0.5 inches possible along with max 1-hour rainfall up to 0.7 inches. Gusty winds of 30-50 mph or even higher with the strongest cells. Flooding is NOT expected today.

Primetime: 11AM to 8PM

Northeast Plains & Southeast Plains:

Becoming partly cloudy and very hot with isolated to widely scattered storms expected later this afternoon and evening. Highest coverage will be over the Northeast Plains with minimal coverage further south. Max 30-minute rainfall up to 0.9 inches with max 1-hour rainfall up to 1.2 inches. Nuisance street and field ponding is possible but flooding is NOT expected today.

Very gusty winds exceeding 60mph are possible later this afternoon as storms could form a larger complex as they move across the Northeast Plains.

Primetime: 2PM to 11PM

Issue Date: Saturday, July 9th, 2022
Issue Time: 8:50AM MDT

— Flooding is NOT expected today

After a prolonged stretch of fairly active weather featuring heavy rainfall somewhere in the state, a quieter day is on tap for most of Colorado. As shown in the water vapor image, below, a strong upper-level ridge is centered directly over Colorado this morning. The ridge has intensified over the past 24 hours with mid-level temperatures rising 4-6F. This implies stronger subsidence is expected today with an increase in afternoon high temperatures to near record territory. Moisture has decreased notably statewide with this morning’s PW at Grand Junction coming in at 0.48 inches, while Denver’s PW is estimated at 0.6 – 0.7 inches (sounding not available). With the aforementioned subsidence and no import of fresh moisture, expect a further decrease in storm coverage today. Nonetheless, with plenty of sunshine, the deep boundary layer this afternoon will be just unstable enough to produce some isolated storms over the Palmer Ridge, Southeast Mountains, Raton Ridge and San Juan Mountains. Most storms will produce very little precipitation with gusty winds being the more notable “threat”. However, right along the NM border along the Raton Ridge, a brief moderate/heavy downpour is possible. But aside from some nuisance ponding, 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, Southeast Mountains, San Juan Mountains, Southeast Plains, Palmer Ridge, Southeast Mountains & Raton Ridge:

Mostly sunny early then partly cloudy and hot with isolated thunderstorms possible this afternoon and evening. Max 30-minute rainfall 0.5 inches (north) and 0.7 inches (south). Gusty winds will be possible with the strongest cells, but flooding is NOT expected today.

Primetime: 1PM to 8PM

Northern Mountains, Front Range, Urban Corridor, Grand Valley, Southwest Slope, San Luis Valley & Northwest Slope:

Mostly sunny and hot today with near record high temperatures expected. An isolated weak storm cannot be ruled out over the higher terrain of the Front Range, but max 30-minute rainfall is expected to stay below 0.3 inches. Thus, flooding is NOT expected today.

Primetime: 2PM to 8PM