Issue Date: Tuesday, May 5th, 2020
Issue Time: 8:25AM MDT

— Flooding is NOT expected today

It’s a cooler start to the morning with a Frost Advisory in effect for the northern Front Range and Urban Corridor through 8AM. Currently, there is a disturbance over southern Colorado (orange “X”) that helped produce some overnight rainfall for the area. This is the same boundary that helped initiate the convection over the Palmer Ridge Monday afternoon. Expecting the disturbance to move eastward throughout the morning and clearing skies to fill in behind it.

Mild weather day ahead of us as the ridge begins to build over the state from the west and dry northwesterly flow drives the upper levels. A minor disturbance within the flow will likely help produce some cloud cover over the Southeast Mountains and Front Range, which will then be pushed into the adjacent plains for some afternoon and evening cloud cover. The only moisture available for storms is marginal, and is located over southern Colorado where the current disturbance is located. Over this area there may be some light rainfall later this afternoon into the evening along a convergence boundary. Gusty winds will likely accompany any storms that do form due to the storms being outflow driven. Once again, flooding is not anticipated.

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

Temperatures are back on the rise again today with highs in the 70Fs for the lower elevations and 50Fs for the mountain valleys. Best chance for rainfall this afternoon is over the southern border along the Raton Ridge and Southeast Plains. Storm totals up to 0.20 inches are possible with a lot of storms producing only very light rainfall. The main threats will be downburst winds as they will be outflow driven due to the large temperature and dew point spread. Elsewhere cloud cover will increase throughout the day with a sprinkle or two possible under the bases.

Primetime: 3PM to Midnight

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

With the ridge building north and decreasing surface winds, there will be a break (for a day) in critical fire weather. Some breezy conditions may be possible over the south, central mountains and San Luis Valley, so there is still some elevated fire danger in these parts. Temperatures will be increasing with highs in the 70Fs for the valleys and 50Fs for the mountain valleys.

Issue Date: Monday, May 4th, 2020
Issue Time: 8:10AM MDT

— Flooding is NOT expected today

Taking a look at the visible satellite imagery below, you can see a few lingering showers from the passing shortwave overnight into this morning. This is producing some snow at the highest elevations, although it does not appear to be sticking to any of the roads. The early morning thunderstorms over the far northeast border counties are moving into Nebraska at this time. Overall, expecting a mild day in regards to temperature with clearing conditions as a ridge starts to build overhead. Residual moisture and a passing shortwave to our north may allow for a couple stray, weak thunderstorms to form this afternoon over the Northeast Plains and Palmer Ridge. With quick storm motion to the southeast, dew points in the high 40Fs, and very dry mid-levels, flooding is not expected. Some gusty outflow winds will be possible with the storms that do form.

Fire conditions will also return with a jet streak over central Colorado. These high winds are expected to mix downwards throughout the day and will cause breezy conditions statewide with the southern half of Colorado reaching critical fire weather. Over the eastern plains and western low elevations, afternoon wind speeds will be in the 15 to 25 mph range with gusts possibly 10 to 20 mph higher. Higher gusts are possible over the mountain passes. For the San Luis Valley and Southeast Mountains there will also be low relative humidity; thus, a Red Flag Warning has been issued. Don’t be too surprised if a Red Flag Warning is also be issued for portions of southwest Colorado later this afternoon, so please be sure to tune into your local NWS office for the latest.

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:

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

Showers are starting to break up and move eastward at this time. Expect some showers to continue over the highest terrains through early afternoon before the ridge begins to build. A couple stray, weak thunderstorms are possible this afternoon over the Northeast Plains and Palmer Ridge. Accumulations will be less than 0.5 inches, so flooding is not expected. Strong outflow winds and gusts up to 35 mph are possible with the jet overhead.

Primetime: 1PM to 7PM

Northern Mountains & Northwest Slope:

Highlighting these areas in their own discussion due to flows in area rivers, streams and creek continue to remain elevated or at bankfull conditions. Areas to watch closely for lowland flooding are the Elkhead Creek, upper Elk River, upper Slater Fork and other small streams in the upper Yampa Basin. Showers are expected to thin out as the day conditions with a couple lingering showers over the Northern Mountains. Isolated totals up to 0.15 inches will be possible by tomorrow morning. As for temperatures, forecasting seasonal highs this afternoon.

Primetime: 8AM to 6PM

Grand Valley, Southwest Slope, San Luis Valley, San Juan Mountains, Central Mountains, Southeast Plains, Raton Ridge, Southeast Mountains:

Expecting spotty Red Flag Warning criteria to be met over these regions this afternoon as temperatures remain warmer than northern Colorado. This is also due to low relative humidity as dry air fills in behind the departing shortwave from the west. Gusts up to 50 mph can be expected over the high, mountain passes with winds in the 15 to 25 mph range over the lower elevations. A weak cool front is expected to push south over the Southeast Plains later this evening. This may produce a few sprinkles, but more likely, just some cloud cover. Be sure to tune into your local NWS office for the latest on the critical fire weather.

Issue Date: 5/3/2020
Issue Time: 8:00 AM

— NO FLOOD THREAT is forecast today

Northern Colorado and Southern Colorado are once again looking at two different weather stories today as the large-scale pattern has not changed much over the last 24-48 hours. Shown in the water vapor imagery below, west-southwest flow continues aloft, and embedded within this flow is a disturbance. This disturbance will travel across Wyoming today, but it will scrape across northern Colorado, providing the initiation for another round of afternoon/evening showers and thunderstorms for the following regions: Northwest Slope, Northern Mountains, Front Range, Urban Corridor, Northeast Plains, and Palmer Ridge. There will be fewer storms than yesterday thanks in part to the disturbance staying mainly north of the state. With that said, a couple will be strong-to-severe over the Urban Corridor, Palmer Ridge, and Northeast Plains regions, capable of producing hail up to 1 inch in diameter and wind gusts up to 65 mph.

For Southern Colorado, the story is much the same as the last few, with above-normal temperatures and dry and conditions expected. Elevated fire danger is a concern, with portions of the Grand Valley, Southwest Slope, San Juan Mountains, San Luis Valley, Southeast Mountains, Raton Ridge, and Southeast Plains regions. Please check with your local National Weather Service office for more information.

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

Northwest Slope and Northern Mountains:

Scattered showers/thunderstorms expected mainly this afternoon and evening, with the best coverage near the Wyoming border. A few showers/weak thunderstorms will continue into the overnight hours, with nearly all activity coming to an end by dawn tomorrow. Rain rates will generally be in the 0.1-0.3 inches/hour, with up to 0.2-0.5 inches/hour rain rates attending thunderstorms. Storm motions will be quickly to the east-northeast, so no flood threat is warranted.

Timing: Noon – 10 PM, with a few lingering showers/weak thunderstorms ending by dawn tomorrow.

NOTE: Minor lowland flooding from snowmelt may occur during the afternoon/evening hours tonight along low-lying areas of Elkhead Creek and Slater Fork Creek in Northeastern Moffat County and Northwestern Routt County.

Front Range, Urban Corridor, Palmer Ridge, and Northeast Plains:

Scattered showers/thunderstorms are expected once again this afternoon and evening, beginning around 1 PM over the Front Range, and spreading/developing eastward over the plains with time. A couple storms will be strong-to-marginally severe, capable of producing hail up to 1-inch in diameter and wind gusts up to 65 mph. Middling moisture below cloud bases will keep rain rates limited, especially over the Front Range and Urban Corridor, but slightly better moisture over the Northeast Plains and Palmer Ridge will be capable of producing heavier rainfall. Maximum rain rates are as follows:

Northeast Plains: 1-1.25 inches/hour
Palmer Ridge: 0.4-0.8 inches/hour
Urban Corridor: 0.3-0.6 inches/hour
Front Range: 0.2-0.4 inches/hour

Timing: 1 PM – 9 PM over the Front Range, with a few lingering showers/thunderstorms into the early morning hours; 2 PM – Midnight for the Urban Corridor, and Palmer Ridge, 2 PM – 3 AM for the Northeast Plains, with a couple lingering showers/storms until sunrise tomorrow.

Grand Valley, Central Mountains, Southwest Slope, San Juan Mountains, Southeast Mountains, San Luis Valley, Raton Ridge and Southeast Plains:

Hot and dry with gusty winds will be the main weather story, with elevated fire danger spread across the regions. Red Flag Warnings have been issued, so please check with your local National Weather Service office for more details.

Issue Date: 5/2/2020
Issue Time: 8:15 AM

— NO FLOOD THREAT is forecast today

It is a tale of two Colorado’s today, with the weather regimes split fairly nicely by Highway 50. South of Highway 50, it will be warm and dry, with elevated fire danger spread across the Southwest Slope, San Juan Mountains, San Luis Valley, Southeast Mountains, and Raton Ridge regions. Red Flag Warnings have been issued, so please check with your local National Weather Service office for more information.

Along and north of Highway 50, a mid-level disturbance (shown by the yellow line in the image above) and decent moisture will combine to produce scattered showers and thunderstorms, beginning around lunchtime. The best coverage of storms will be across the Northwest Slope, Northern Mountains, Front Range, Urban Corridor, and Northeast Plains, with more widely scattered coverage as you move southward. A couple storms may become marginally severe over the Front Range, Urban Corridor, Palmer Divide, and adjacent plains areas, producing hail up to 1 inch in diameter and strong wind gusts up to 60 mph. Showers and storms will move generally west-to-east, ending over the mountains around sunset, and diminishing/exiting the state overnight across the plains. For more specific timing details, please see the zone-specific forecasts below.

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

Northwest Slope, Northern Mountains, Grand Valley, Central Mountains, and Front Range:

Scattered showers and thunderstorms are expected, beginning around 11 AM, and continuing into the evening hours. Surface moisture values are above average for the date, and they will provide the fuel for a couple stronger storms. Rain rates will generally be in the 0.1-0.3 inches/hour range, with up to 0.4-0.6 inches/hour with stronger storms. Storm motions will be fairly quick from west-to-east, precluding the issuance of any flood threat.

Timing: 11 AM – 9 PM, with primetime between 2 PM and 7 PM

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

Scattered showers and thunderstorms are expected today, thanks to the combination of increased surface moisture and passing mid-level disturbance. The best coverage of storms will be along/north of I-70, with more widely scattered coverage to the south, becoming isolated across northern portions of the Southeast Plains.

A few storms will be on the strong-to-marginally severe side, mainly over the Front Range, Urban Corridor, and adjacent areas of the Palmer Ridge and Northeast Plains. The main threats from these stronger storms will be wind gusts up to 60 mph and hail up to 1 inch in diameter.

Rain rates will generally be in the 0.25 – 0.5 inches hour range, with the stronger storms producing rainfall up to 0.75 – 1.25 inches/hour. Storm motions will be fairly quick to the east, so no flood threat is warranted, but ponding in low-lying and/or poorly drained areas is expected under the stronger storms.

Timing: 1 PM – 10 PM for the Urban Corridor and Palmer Ridge, 2 PM – Midnight for the Plains.

Southwest Slope, San Juan Mountains, Southeast Mountains, San Luis Valley, and Raton Ridge:

Hot and dry with gusty winds will be the main weather story, with elevated fire danger spread across the regions. Red Flag Warnings have been issued, so please check with your local National Weather Service office for more details.