FTB 09-26-2021: Scattered Storms Return to Southwest Colorado

Issue Date: Sunday, September 26th, 2021
Issue Time: 9:10AM MDT

— Flooding is NOT expected today

Finally, there’s a change in the weather pattern today. The cutoff Low, from a few days back, will start to meander to the northeast and center itself on the New Mexico/Arizona border by tomorrow morning. There’s a good lump of monsoon moisture being circulated around the Low, which can be seen by the white/green shades in the water vapor imagery below. This moisture plume is expected to continue to move into the far southwest corner of the state and help spark some scattered afternoon and evening storms over the high terrains in the area.

Soundings out of Flagstaff and Albuquerque show robust moisture throughout the atmospheric column, so that likely means more widespread coverage of rainfall with a couple weak thunderstorms possible over the southwest corner. With the dryness of the air mass overhead from the few days, it’s likely that it will take a bit to moisten the boundary layer. Slower steering flows should help do this, so anticipating an increase in rainfall rates and accumulations by early this evening. Rainfall rates should remain just under flood threat criteria and dry soils are expected to absorb much of the rainfall and subsequent runoff. So, outside of nuisance road and low-lying area ponding, flooding is NOT expected.

Elsewhere, dry northwest and westerly flow aloft is forecast, which should keep precipitation chances near zero and allow temperatures to continue to rise. Afternoon high temperatures will make today feel more like summer than fall. High clouds will likely develop as the moisture plume moves northeast this afternoon into 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:

Southeast Mountains, San Juan Mountains & Southwest Slope:

Scattered storms will return to the southwest high terrains this afternoon and evening with a couple high-based showers possible over the Southeast Mountains. Accumulations over the Southeast Mountains should remain under 0.15 inches. Over the high terrains of the Southwest Slope and San Juan Mountains, max 1-hour rain rates up to 0.80 inches per hour and isolated accumulations up to up to 0.90 inches will be possible. In addition to moderate rainfall, storms may produce some strong outflow winds and small hail. Outside of nuisance ponding, flooding is NOT expected. Storms should end as instability drops off with the setting sun.
Primetime: 2PM to 9:30PM

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

Anticipate an increase in mid and high cloud cover (south to north) this afternoon and into tomorrow, but today should remain dry. Afternoon high temperatures will likely reach into the mid to upper 80Fs for the Grand Valley and upper 70Fs for the mountain valleys. Flooding/rainfall is NOT expected.

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

It’s going to be a hot day ahead with highs reaching into the upper 80Fs (adjacent plains) and 90Fs (eastern plains). Mountain valley locations will likely reach the 80F marker. High cloud cover is anticipated to move in this afternoon and overnight associated with the moisture plume to our southwest. Rainfall is not forecast, so there is NO flood threat issued.

FTB 09-25-2021: Heating Up with Dry Conditions Continuing

Issue Date: Saturday, September 25th, 2021
Issue Time: 8:50AM MDT

— Flooding is NOT expected today

High pressure will continue to build across the state today with the ridge axis sliding overhead by this evening. This will help to produce warmer temperatures with highs today generally running 7F to 12F above normal. The visible satellite imagery below shows no clouds over the state, which exemplifies the dryness of the air mass. PW was measured just above 0.40 inches at Denver and Grand Junction this morning, which means that it will be too dry, once again, for any rainfall to develop. Breezy conditions are forecast over the eastern plains through early afternoon, and westerly/northwesterly surface winds are forecast to pick up over the mountains by this afternoon (north/central). This may elevate fire weather conditions for a brief window this afternoon into this evening.

Over the far southwest corner of the image below, monsoon moisture has started to move counterclockwise around an upper-level Low. This is the same disturbance that cut itself off from the main flow a couple days back. This moisture plume is expected to stay south of the border today, although some mid and high level clouds will likely move into the southwest corner of the state overnight. With only some broken cloud cover forecast over the southern high terrains by later this afternoon, flooding is NOT expected.

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:

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

It’s going to be a hot day by late September standards. Highs across the lower elevations will reach into the mid to upper 80Fs with mid to upper 70Fs for the mountain valleys. Outside of some afternoon cloud cover over the southern Front Range and Southeast Mountains, it should be clear day ahead. So, NO flood threat is issued. Breezy conditions are forecast over the far eastern plains through early afternoon with south and southwesterly winds reaching between 10 and 18 mph. By this afternoon, westerly and northwesterly winds will pick up over the Front Range reaching between 10 and 15 mph. This may cause elevated localized fire weather conditions.

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

Highs today will reach into the upper 80Fs for the Grand Valley and into the 80Fs for other valley locations. Mountain valleys could reach into the mid 70Fs. No rainfall is forecast today, although some mid and upper level cloud cover is expected to move into the southwest corner of the state overnight. This should help keep overnight low temperatures a little warmer for the region. Breezy afternoon conditions should be anticipated over portions of the Northern/Central Mountains and Northwest Slope where surface winds could gust up to 30 mph (Northern Mountains). With the dry air overhead, this will likely elevate local fire weather conditions. Flooding is NOT forecast today.

FTB 09-24-2021: Mild Weather Continues with Slightly Cooler Temperatures East

Issue Date: Friday, September 24th, 2021
Issue Time: 9:50AM MDT

— Flooding is NOT expected today

Subsidence and building high pressure should bring another day of mild weather to the state. Marked in the water vapor imagery below (blue) is the cold front that started to move through during the early morning hours. Not much moisture return behind the front, and with PW remaining under 0.50 inches and an increase in dry, northwesterly flow aloft, only cloud cover is forecast over the northern tier of the state. There should be plenty of sunshine elsewhere, so another beautiful day ahead. Surface winds are expected to turn easterly over the eastern portion of the state throughout the day, so slightly cooler temperatures on the magnitude of ~5 degF are forecast. High temperatures are forecast to be around the same as yesterday over western Colorado, so still above average. Without any rainfall anticipated, there is NO flood threat 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:

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

High should reach the into the upper 70Fs and 80Fs today over the lower elevations with upper 60Fs and low 70Fs for the mountain towns. Outside of some cloud cover over the northwest corner of the state and Front Range this evening, it should be clear day. Flooding is NOT expected.

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

The shortwave from yesterday has already moved into southern Utah this morning. So, there will be a mix of northwesterly and more easterly flow aloft today. With PW remaining around 0.40 inches, rainfall is not anticipated, so there is NO flood threat issued. A few high clouds may be possible over the San Juan Mountains late this afternoon/evening with some upper level moisture. High temperatures should reach into the 80Fs for the valley locations and low 70Fs for the mountain towns.

FTB 09-23-2021: Increasing Clouds And Warm; A Few Rain/Snow Showers Possible Late

Issue Date: Thursday, September 23rd, 2021
Issue Time: 9:15AM MDT

— Flooding is NOT expected today

As shown in the visible satellite image, below, a pronounced disturbance is currently moving into the Central Rockies from the northwest. Although it will produce mainly an increase in clouds for Colorado today, it is expected to cut off from the main steering flow by tomorrow. In turn, depending on what exactly transpires with it over the next 3-7 days, it could lead to some more interesting weather for us in the days ahead (see this afternoon’s Outlook for more info).

For today, expect slightly above normal afternoon temperatures along with partly to mostly cloudy skies by afternoon. Isolated, higher-elevation rain and snow showers are possible this evening and into the early overnight hours as some mid-level moisture gets pushed upslope over our Rockies. But very little precipitation accumulation is expected. Thus, there is NO flood threat 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, Northern Mountains, Central Mountains, San Juan Mountains and Southeast Mountains:

Becoming mostly cloudy and seasonably warm with temperatures a few degrees above normal. Isolated rain and snow showers are possible over the higher terrain, mainly above 9,000 feet later this evening and into the early overnight hours. A lucky location could get 0.1 inch of accumulation. Flooding is NOT expected today.

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

Becoming partly cloudy and warm with high temperatures of 5-10F above normal expected. Breezy conditions are expected for the Northeast Plains later this afternoon as a dry cool front moves southward. However, precipitation and flooding are NOT expected today.

Northwest Slope, Grand Valley, Southwest Slope and San Luis Valley:

Becoming partly cloudy and seasonably warm today with temperatures a few degrees above normal. Flooding is NOT expected today.