FTB 05-02-2021: Low Flood Threat Issued for the Palmer Ridge and Northeast Plains

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

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