Issue Date: Monday, May 3rd, 2021
Issue Time: 9:50AM MDT

— Flooding is NOT expected today

The surface observations from 8AM this morning show almost completely overcast conditions across the state (filled in circles) and much cooler temperatures behind yesterday’s cold front (red numbers). This is about a 20 to 30 degF drop from this weekend, so you know it must be springtime in Colorado. Precipitation continues over and near the higher terrains with the trough near the four corners region helping to produce orographic lift. The snowline has dropped slightly below the 7,000 ft contour along the Front Range, and precipitation over the mountains is falling as snow (* symbol).

Expect these conditions to continue today and expand in coverage this morning into early afternoon as the open trough moves east. Although there is plenty of moisture and lift available for widespread precipitation, limited instability means that rainfall at the lower elevations will be more wetting in nature rather than convective. This paired with snow at the high elevations means there is no flood threat issued today. The pulse-like showers and snowfall are expected to gradually come to an end by tomorrow morning.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. 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, Front Range, Southeast Mountains, Central Mountains & San Juan Mountains:

Quite a bit of wet and heavy snow is expected this afternoon as the base of the trough, or center of energy, moves east. Generally, snowfall accumulation will be in the 6-12 inch range with local higher totals possible. The Central Mountains look to get between 0.75 and 1.50 inch of precipitation, whereas the San Juan Mountains could see the same, but will be more isolated. Over the Front Range and Southeast Mountains, isolated totals up to 1.25 inches of precipitation are possible by morning. With precipitation falling as snow, flooding is not forecast. Tune into your local NWS for the latest on winter weather advisories and warnings.

Primetime: Ongoing to 2AM

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

A dreary day is ahead for areas along and near the mountains, so expect rain across these lower elevations. As the system continues to move slowly eastward into tonight, the shortwave looks to weaken. So, generally, only about a 0.20 to 0.40 inches of rain are expected over the eastern Raton/Palmer Ridge and far southeast corner of the state, but isolated totals up to 0.75 inches are possible. Isolated totals along the Urban Corridor and areas just east of the Southeast Mountains could be slightly higher in the 0.75 to 1 inch range, but generally expect totals in the 0.25 to 0.50 inch range. Due to the gradual nature of the rainfall, flooding is not expected. However, there may be some localized, light ponding due to compounding rainfall.

Primetime: Ongoing to Midnight

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

Fairly widespread rainfall will continue today for the lower elevations of the Northwest Slope and Grand Valley. Isolated totals around 0.40 inches will be possible and totals over the higher elevations could reach 1 inch. Isolated areas of lower elevations in the Southwest Slope may see up to 0.15 inches by morning, and the higher elevations could just under 0.50 inches. Flooding is not forecast due to the gradual nature of the rainfall.

Primetime: Ongoing to 10PM

Issue Date: Sunday, May 2nd, 2021
Issue Time: 10:15AM MDT

— A LOW flood threat has been issued for portions the Northeast Plains, Urban Corridor and Palmer Ridge

It’s going to be a true Colorado spring day with a potpourri of weather phenomenon across the state: sunshine, fire danger, rain and snow. Earlier this morning, there were some isolated light showers over the Northwest Slope and cloud cover over the eastern border associated with some energy moving through the upper-level flow. Today and into tomorrow, the trough to our west will deepen and slowly move into the four corners region. Between the lift from this strengthening system and a strong cold front returning low-level moisture, the stage will be set for widespread rainfall and snow (higher elevations) over the next couple of days.

The first round of rainfall this afternoon is expected to be more convective in nature with stronger storms forecast across the eastern half of Colorado from about Highway 50 to the northern border. The main threats from the severe storms that develop will be heavy rainfall, large hail and strong outflow winds. The largest flood threat from these storms looks to be confined to the Northeast Plains, but some heavy rainfall over the Palmer Ridge will also be possible. A Low flood threat has been issued for these regions.

Behind a strong cold front that drops south late this afternoon and evening moisture is expected to increase and upslope flow will begin to dominate the pattern. Precipitation is expected to become more stratiform in nature over the Front Range, Southeast Mountains, Urban Corridor and Palmer Ridge. Snow should initially be confined to the highest elevations but expect the snow line to drop quite a bit tonight into tomorrow morning. Additionally, as morning approaches, the precipitation should become more widespread over the mountains. Due to the more gradual nature of the rainfall, cross over from rain to snow and dry soils, no flood threat has been issued for the upslope flow component of the precipitation.

For the burn area forecast, please visit the Flood Burn Forecast tab at the top of the page.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below. 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:

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

Expect storms to begin to pop over the Front Range by midday and move into the adjacent plains by early afternoon. Severe storms will be possible over the Northeast Plains with thunderstorms also likely along the Urban Corridor and Palmer Ridge. The main threats from today’s stronger storms will be local heavy rainfall, hail and strong outflow winds. Larger hail and stronger winds will be possible with the severe storms that form over the eastern plains. A Low flood threat has been issued for the possibility of small stream flooding, field ponding and street flooding. Max 1 to 2 hour totals up to 1.1 inches (west) and up to 2.5 inches (east) are possible.

The rainfall becomes more stratiform tonight with the post-frontal upslope flow. With the snow line dropping, precipitation over the Front Range and Southeast Mountains should turn to snow around 7-8K feet. Tune into your local NWS office for the latest on winter weather advisories and warnings. Dry soils and more gradual rainfall will limit the flood threat overnight, so the flood threat has not been extended into the higher terrains. For the burn area forecast, please visit the Flood Burn Forecast tab at the top of the page.

Primetime: Noon to 10PM

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

More precipitation is finally in the forecast. This afternoon, expect precipitation in all zones just south of I-70 to the northern border. Max 1-hour rain rates up to 0.60 inches will be possible, so at this time flooding is not forecast. Precipitation is forecast to fill in overnight and into tomorrow morning over the mountain regions after the front moves south. The snow line will drop at that time as well, so flooding is not forecast. For the burn area forecast, please visit the Flood Burn Forecast tab at the top of the page.

Over the Southwest Slope and San Luis Valley, a Red Flag Warning has been issued. Please tune into your local NWS office for the latest on fire danger.

Primetime: Noon to 9PM

Issue Date: Saturday, May 1st, 2021
Issue Time: 9AM MDT

— Flooding is NOT expected today

The 2021 FTB season is officially under way! Welcome back, and we appreciate the opportunity to serve you this flood season.

The water vapor imagery shows Colorado pinched between two systems this morning (orange X’s). With the ridge still overhead for most of the day, warm temperatures are expected to continue statewide. As the system from the west approaches the state later today into tomorrow, more moisture and slight lift will become available. So, expect an increase in cloud cover from west to east throughout the day across the state. Soundings indicate that most of the moisture today will be located in the mid to upper levels of the atmosphere. This paired with the dry lower layer of the atmosphere indicates gusty outflow winds will be possible with the isolated storms that develop over the mountains this afternoon and evening. Although isolated accumulation will be possible this afternoon and overnight for the central and northern high terrains, the more widespread and measurable rainfall is not expected until tomorrow. Therefore, flooding is not forecast 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:

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

Warm temperatures will continue for another day before a change in the pattern tomorrow. The upper-level lift and moisture from the incoming system looks to be strongest over the Northwest Slope, Central Mountains and Northern Mountains. So, be expecting these areas to have more coverage of isolated storms than further south over the San Juan Mountains. Gusty outflow winds are more of a threat from the storms that develop than measurable rainfall this afternoon. Another round of light showers may move in overnight further north, so isolated totals just under 0.10 inches will be possible by tomorrow morning over the high terrains. A Red Flag Warning has been issued for portions of the western border today and tomorrow, so be sure to tune into NWS Grand Junction for more information about the fire danger.

Primetime: 3PM to 8PM

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

Another day with above average temperatures is expected. As the day continues, cloud cover will increase from the west and move eastward. Some isolated storms are possible over the mountains this afternoon, but accumulation will be unlikely underneath most storms due the dry boundary layer. Brief, gusty outflows winds will be possible with the stronger storms that develop. Light showers are possible over the Front Range overnight, so isolated totals around 0.05 inches are possible over the Front Range by morning. As storms move eastward off the mountains and into the Urban Corridor, they are expected dissipate quickly.  Flooding is not forecast.

Primetime: 3PM to 7PM

Spring is underway, which means the Flood Threat Bulletin is back! We’ll be returning to our daily posts starting this Saturday, May 1st. Additionally, the Flood Threat Outlook will continue to be issued weekly on Monday and Thursday, which will track the flood and precipitation potential across Colorado over the next 15 days.

New to this season, after a historical 2020 wildfire season, is the Fire Burn Forecast (FBF). The FBF will be issued daily for select, high-risk burn areas across Colorado’s high terrain. This standalone forecast will officially separate out the burn areas from the existing FTB product. The FBF table will track antecedent rainfall over the last 24 hours and whether or not flooding was reported over a given burn area. Reminder that you can report floods by going to the Report a Flood tab at the top of this site. The FBF will also have a daily forecast component (issued by 11AM), which will indicate the likelihood for excessive runoff, flash flooding, muds flows and/or debris slides over the next 24 hours. To learn more about the high-risk burn areas we’ll be forecasting for, head on over to the About the FTB page and scroll down to our interactive map.

We are looking forward to serving you for another flood season. To sign up and receive a daily notification of the flood threat to your inbox, please navigate to the Subscribe option above (or click here). You can also follow us on Twitter and Facebook for the latest flood updates.