Issue Date: Friday, July 8th, 2022
Issue Time: 10:35 AM MDT

— A LOW flood threat has been issued for portions of the Palmer Ridge, Northeast Plains, and Southeast Plains
— Fire-Burn Forecast Summary: 2 burn areas under LOW threat, click HERE for more info 

As a ridge of high pressure continues to build overhead today, subsidence and associated drying are expected across the state along with an increase in temperatures to several degrees above climatological average. A subtle shortwave is expected to move southeast across eastern Colorado and provide some added midlevel energy across the area later today. Over the eastern Northeast and Southeast Plains, residual moisture is expected to be suppressed in place due to the subsidence aloft. This afternoon, upslope flow is expected to steadily increase and reinforce or even increase moisture slightly over the Eastern Plains. This in conjunction with the aforementioned midlevel energy should provide weak convergence over the Palmer Ridge and Southeast Mountains. While some mixing out of boundary layer moisture is anticipated over the mountains and Urban Corridor, PW over 1 inch and dew points in the upper 50s to low 60s°F are forecast to remain in place across the Eastern Plains throughout the day, as shown in the visible satellite image below.

Given that instability is forecast to increase to 2700 to 3000 J/kg across eastern Colorado this afternoon, there should be enough dynamic lift for a few isolated storms to develop over the Palmer Ridge and Southeast Mountains initially, before moving off to the Northeast and Southeast Plains and Raton Ridge. These isolated storms will be capable of producing briefly heavy rainfall just above flood threshold over the eastern Palmer Ridge, as well as the far eastern Northeast and Southeast Plains, where soils are likely saturated as a result of the last two days of rainfall. As such, a LOW flood threat has been issued for the eastern Palmer Ridge, as well as portions of the Northeast and Southeast Plains where isolated 2 to 3-hour storm totals of up to 2 inches are possible.

Western Colorado is already under the influence of the drying trend as PW in Grand Junction this morning was measured to be only 0.48 inches, which is a stark decrease from yesterday’s value. Boundary layer moisture is forecast to continue to decrease rapidly throughout the day across the western half of the state, with dew points expected to drop from the upper 30s°F this morning to the teens and 20s°F by this afternoon. No meaningful precipitation is expected, therefore NO flooding is expected for western Colorado 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:

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

This morning, clear skies and pleasant temperatures are expected to quickly warm into the upper 80s to low 90s°F today. A few rounds of isolated storms are expected to develop initially over the Palmer Ridge and Southeast Mountains, and then propagate eastward onto the adjacent plains this afternoon. Storms that do form are expected to be brief in nature, though isolated heavy rainfall is possible with the more intense storms. Isolated 1 to 2-hour storm totals up to 1.5 inches are possible over the eastern Palmer Ridge, and 1.75 inches to isolated totals up to 2 inches are possible over a 1 to 2-hour period across the eastern Northeast and Southeast Plains; as such, a LOW flood threat has been issued for these zones.

Over the Southeast Mountains, isolated rain totals of 0.5 inches are possible, with 0.75 inches of rainfall possible over the Raton Ridge. A few isolated light showers are possible over the Front Range mountains as well, where max 1-hour rain rates up to 0.5 inches could occur with storms that may briefly intensify over the mountains. However, moisture is more negligible over these areas any storms that do form should be brief and relatively low in intensity. NO flooding is expected over these zones.

Primetime: 2PM to 9PM

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

A clear and sunny day is expected for the western half of the state today as any residual moisture should quickly mix out by early afternoon. Temperatures are expected to warm into the low to mid 90s°F for much of western Colorado today. Due to the influence of the high pressure and subsidence building over these zones, primarily dry and hot conditions are expected throughout the day, and no precipitation is forecast for these zones. Therefore, NO flooding is expected today.

Issue Date: Thursday, July 7th, 2022
Issue Time: 10AM MDT

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

Colorado will be under a transitioning synoptic pattern over the next 24-hours as a strong ridge begins to build overhead, which will bring some very hot temperatures back to the state this weekend. There has been a downtick in the available moisture due to the location of the High, which is helping to produce the clear skies seen in the visible satellite imagery below. There is some mid-level energy that’s combining with the residual moisture to produce some cloud cover and light rainfall over northwestern Colorado. However, the main moisture axis is marked by a green dashed line below, which is both south and east of the state.

Despite the overall decrease in moisture from yesterday, PW this morning at Denver and Grand Junction was still quite elevated at 0.9 and 0.85 inches, respectively. So, there is plenty of residual moisture for storms today, but with the building ridge promoting subsidence, storms should be more widely scattered to scattered in nature. Expecting the storms that develop to favor the high terrains with some spill over into the adjacent eastern plains as the weak mid-level energy over northwestern Colorado transitions eastward. As far as the flood threat, a drier surface layer over western Colorado and the mountains means that storms in these areas today should pose more of a wind than heavy rainfall threat with only moderate rainfall rates forecast under the stronger storm cores that develop. Over the adjacent eastern plains, surface moisture will be less likely to mix out, and with steering flows still on the lower end and extra convergence near the elevated ridges, isolated heavy rainfall will be possible. A LOW flood threat has been issued for this reason.

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:

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

Widely scattered storms are forecast to develop over the Front Range by early afternoon and then spill into the adjacent plains later this afternoon and evening. As they reach into the deeper moisture and instability out east, storms should become more scattered. Max 1-hour rain rates up to 0.75 inches west and 2 inches east will be possible. A LOW flood threat has been issued for areas near the elevated ridges. In addition to local, heavy rainfall, stronger thunderstorms may produce strong outflow winds and small hail with a couple severe thunderstorms possible further east. Thunder and rainfall may linger over the plains overnight, but the flood threat should end a couple of hours after the sun sets.

Primetime: 12PM to 6AM

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

Isolated to widely scattered storms are forecast today favoring the central and northern high terrains for accumulation. With less surface moisture than yesterday, stronger storms that develop will be capable of producing strong, but brief outflow winds. Isolated max 1-hour rain rates up to 0.75 inches over the north/central high terrains and Raton Ridge will be possible. Further south, rain rates up to 0.5 inches are forecast. Flooding is NOT expected today.

Primetime: 12PM to 8:30PM (west); 2PM to 11PM (east)

Issue Date: Wednesday, July 6th, 2022
Issue Time: 10:45AM MDT  

— A HIGH flood threat has been issued for portions of the Northeast & Southeast Plains
— A MODERATE flood threat has been issued for the Palmer Ridge and portions of the Urban Corridor and Front Range
— A LOW flood threat has been issued for portions of the Central Mountains, Northern Mountains, San Juan Mountains, Northwest Slope, Grand Valley and Southwest Slope
— Fire-Burn Forecast Summary: 2 burn areas under HIGH threat, 3 burn areas under a MODERATE threat, 4 burn areas under a LOW threat; click HERE for more info

This morning there are some ongoing showers and weak storms over the northern Front Range and Northeast Plains with plenty of monsoon moisture and some mid-level energy overhead. PW at Denver was measured at a walloping 1.14 inches, which is right around the maximum moving average for this time of year! This value increases over towards the eastern border to about 1.4-1.5 inches. Even over Grand Junction, PW was measured at 1 inch, which is just above the 90^th percentile. Both atmospheric profiles show plenty of surface moisture and a decent warm layer depth, which means storms should be very efficient at producing rainfall today. Another factor contributing to higher rainfall rates today will be slower steering flows under the ridging pattern. Storm movement should be clockwise across the state, so there will likely be a bit more of a northerly component to the steering flow over the far eastern plains due to the location of the High.

With a well-defined shortwave (orange “X”) also moving across the northern tier of the state, numerous storms are forecast to develop over this area by mid-afternoon. By later this afternoon and evening, the shortwave and ongoing storms should arrive to the adjacent eastern plains where there will be plenty of moisture (dew points were measured in the 60°Fs this morning), high instability and decent shear, so some severe storms are likely to develop along with upscale growth of the thunderstorms. A HIGH/MODERATE flood threat has been issued for today. Over the western and southern high terrains, storms should be more scattered in nature, but could still produce some small hail and strong outflow winds under the strong thunderstorms that develop along with local, heavy rainfall. A LOW flood threat has been issued. The heavy rainfall threat ends for most by this evening, but some thunderstorm activity may persist until about midnight over the eastern plains. 

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:

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

Scattered to numerous storms are forecast today with some severe storms possible over the adjacent eastern plains this afternoon and evening. In addition to the heavy rainfall threat, severe storms may produce large hail and damaging outflow winds. With slower storm motion, especially east, storms may linger for a couple hours. Isolated max 1-hour rain rates up to 1.4 inches (west) and 1.6 inches (adjacent plains) will be possible. This could cause isolated mud flows and debris slides over the steeper terrains as well as increased runoff, heavy ponding and road flooding over more impervious areas. A LOW/MODERTE flood threat has been issued through this evening. Over the far eastern plains, isolated storm totals between 3.5 and 4 inches will be possible under the stronger storm cores. This could cause rises in local creeks, road flooding and heavy field ponding. A HIGH flood threat has been issued with most storms winding down later this evening. A thunderstorm or two may linger into tonight.

Primetime: 1PM to 1AM

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

Scattered storms are forecast today with isolate max 1-hour rain rates up to 1.3 inches possible. The majority of the rainfall will likely fall in the first 30-minutes under the stronger thunderstorms that develop. This could cause isolated mud flows and debris slides over the steeper terrains as well as road flooding. Stronger thunderstorms may produce some brief outflow winds and small hail. A LOW flood threat has been issued.

Primetime: 12:30PM to 9:30PM

Southeast Mountains, Raton Ridge & San Luis Valley:

More isolated storms are forecast this afternoon for these areas south. Max 1-hour rain rates may reach up to 0.3 inches over the high terrains, but most storms are forecast to produce totals under 0.2 inches and brief windy conditions. The southern San Luis Valley may see a little rainfall, but more wind and cloud cover is forecast for the area. Flooding is NOT expected today.

Primetime: 2PM to 8PM

Issue Date: Tuesday, July 5^th, 2022
Issue Time: 9:40AM MDT

— A LOW flood threat has been issued for portions of the Central Mountains, San Juan Mountains, Southwest Slope, Southeast Mountains and Northeast Plains
— Fire-Burn Forecast Summary: 6 burn areas under MODERATE threat, 1 burn area under LOW threat; click HERE for more info

After a short lull, monsoon moisture has quickly re-entered Colorado from the south as shown in the visible satellite image below. Morning PW measured 0.99 inches at Grand Junction (up from 0.91 inches yesterday morning) and 0.76 inches at Denver (from 0.69 inches yesterday). Moreover, looking at the flow streamlines shows more moist air moving into western Colorado from AZ/NM where PW as high as 1.65 inches was noted at Tucson. Cloud cover along with scattered showers and even weak storms were already noted as of this morning, arising from elevated instability in association with a weak mid-level disturbance. This, along with normal elevated heating will drive numerous/widespread showers and storms over most of our high terrain today, with the highest coverage over central and southern regions. The big question mark regarding heavy rainfall potential will be instability. Cloud cover will undoubtedly reduce instability overall, but breaks in the clouds along with a gradual increase in moisture suggests localized instability up to 1,000 J/kg CAPE will be possible today. This, along with slow storm motion will support isolated heavy rainfall over mainly the 30-60 minute duration, warranting a LOW flood threat for most of the central/southern high terrain.

Further northeast, a mesoscale low pressure was noted over eastern Colorado today, which is expected to direct some moisture advection into the Northeast Plains. Widely scattered storms are expected this afternoon. With moderate instability expected, there will be a threat of large hail and damaging winds. With very slow storm motion, the threat of heavy rainfall will also exist. A LOW flood threat has been posted along the CO/KS/NE tri-border region.

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

Partly to mostly cloudy with numerous/widespread showers and thunderstorms expected this afternoon and evening. Highest coverage will be over the central and southern high terrain, and adjoining foothills. Max 30-minute rainfall up to 0.8 inches, with max 1-hour rainfall up to 1.2 inches warrants a LOW flood threat for most of the higher terrain for isolated flash flooding, debris slides and mud flows. Widespread rainfall exceeding 0.5 inches is expected by Wednesday morning.

Primetime: 11AM through 10PM

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

Mostly sunny to partly cloudy early then isolated to widely scattered showers and storms developing this afternoon. Highest coverage will be over the Northeast Plains, where severe weather in the form of large hail and damaging winds is also possible. Max 30-minute rainfall up to 1.8 inches and max 1-hour rainfall up to 2.5 inches warrants a LOW flood threat for parts of the Northeast Plains. Elsewhere, the shorter duration of the moderate/heavy rainfall should limit the flood threat.

Primetime: 1PM through 1AM