Issue Date: 5/6/2018
Issue Time: 7:35 AM

NO FLOOD THREAT IS FORECAST TODAY.

The high pressure ridge that we discussed yesterday continues to control the weather across Colorado, but it is beginning to have its authority challenged by an encroaching low-pressure system coming onshore the Pacific Northwest. From this low-pressure system is an ejecting, weak disturbance, accompanied by an increase in mid-/upper-level moisture (whites/greens in the water vapor image below). This disturbance will ripple through the high-pressure ridge today, providing support for isolated showers/thunderstorms this afternoon and evening. However, scant moisture in the low-levels will keep storms from producing much more than gusty winds, lightning, and plenty of virga, with only isolated areas of wetting rainfall. The best chance to see these wetting rains will be over the Front Range, Urban Corridor, Northeast Plains, Palmer, Ridge, and Southeast Plains, where low-level moisture will be best (relatively speaking).

For more information on the locations most likely to see this activity, please see the zone-specific forecast discussions below.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below (hover over threat areas for more details). For Zone-Specific forecasts, jump below the map.

Zone-Specific Forecasts

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

Most locations will remain dry today, but isolated, high-based thunderstorms will rumble during the afternoon and evening hours. Much of the rainfall will evaporate before reaching the ground, dotting the skies with streaks of virga. Brief periods of wetting rain will attend the stronger storms, with the best chances from Highway 50 northward. The main threat from any thunderstorm activity will be lightning and gusty winds, with maximum rain rates of 0.01-0.3 inches/hour being the best that they can muster.

Timing: 1 PM – 8 PM over the Front Range, 2 PM – 10 PM over the other regions

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

Warm and dry will be the name of the weather game for most today, with bubbling cumulus clouds during the afternoon/evening dotting the skies over the high country. A few isolated, high-based showers/weak thunderstorms are expected over the higher elevations, but nothing much to write home about in the way of rainfall due to dry lower levels. Virga, lightning, and gusty winds will be the main impacts, with maximum rain rates in the 0.05-0.15 inches/hour range.

Timing: Noon – 8 PM

Issue Date: 5/5/2018
Issue Time: 7:15 AM

NO FLOOD THREAT IS FORECAST TODAY.

Today’s weather will provide a great start to the weekend as the warming trend of yesterday continues today. The high pressure ridge that we discussed yesterday continues to control the weather across Colorado, keeping most areas dry. However, there is a bit of mid- and upper-level moisture riding the ridge, which will push across Colorado accompanied by a weak disturbance this afternoon, providing a brief shot of isolated showers/thunderstorms. Low-level moisture is lacking, so most of this activity will result in nothing more than a sprinkle and gusty winds. The main threat will be cloud-to-ground lightning, so remember that if thunder roars, go indoors. For more information on the locations most likely to see this activity, please see the zone-specific forecast discussions below.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below (hover over threat areas for more details). For Zone-Specific forecasts, jump below the map.

Zone-Specific Forecasts

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

The warming trend continues, and most locations will remain dry today. The best chance to see isolated, high-based showers/thunderstorms will be across the Urban Corridor and Northeast Plains, where moisture is best (relatively speaking). One or two isolated, high-based thunderstorms cannot be ruled out across the Palmer Ridge, Southeast Plains, and Raton Ridge, but the chance of occurrence for these regions is <15%. The main threat from any thunderstorm activity will be lightning and gusty winds – very little rainfall is expected. Maximum rain rates of 0.05-0.15 will the most the strongest among them can muster.

Timing: 1 PM – 9 PM

Northern Mountains, Front Range, Central Mountains, and Southeast Mountains:

Most areas will remain dry today, but an isolated shower/thunderstorm or two is expected across the area, mainly for the Northern Mountains and Front Range. For the Central Mountains and Southeast Mountains, moisture will remain too low, but virga should accompany the bubbling, high-based afternoon clouds. Any rainfall will be light, with maximum rain rates of around 0.05 inches/hour under the best thunderstorms.

Timing: Noon – 8 PM

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

Warm and dry is the name of the game today, with a few streaks of virga attending the high-based cumulus clouds that will bubble up during the afternoon hours over the higher elevations.

Issue Date: 5/4/2018
Issue Time: 7:45 AM

NO FLOOD THREAT IS FORECAST TODAY.

There will not be much to write home about with regards to today’s weather forecast. As you can see in this morning’s visible satellite image, a few clouds remain over the mountains, but otherwise it’s a clear morning across the state. High pressure is building in from the west, which will allow drier air from the northwest to move in. However, with the amount of moisture that has fallen the last couple of days, there will be enough residual moisture to muster isolated-to-widely scattered showers/weak thunderstorms over the mountains. The best coverage, relatively speaking will be over the San Juan Mountains and Southeast Mountains, with more isolated activity across the higher elevations elsewhere across the state. For lower elevations, including mountain valleys, Urban Corridor, Palmer Ridge, and the plains, dry conditions will prevail with temperatures warming 10-20 degrees over yesterday’s highs.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below (hover over threat areas for more details). For Zone-Specific forecasts, jump below the map.

Zone-Specific Forecasts

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

Drier and warmer, with abundant sunshine. Not much to say other than a beautiful day is expected. A stray, high-based shower briefly moving off the mountains and overhead cannot be ruled out for areas immediately adjacent to the mountains, like the far western portions of the Urban Corridor, Southeast Plains, and Raton Ridge. Rainfall from any such activity will be barely enough to wet the pavement, with rain rates less than 0.1 inches/hour.

Timing: 2 PM – 9 PM

Northern Mountains, Northwest Slope, Front Range, Southeast Mountains, Central Mountains, San Juan Mountains, Grand Valley, San Luis Valley, and Southwest Slope:

Isolated-to-widely scattered showers/thunderstorms are expected for the higher elevations, as orographic effects, sunshine, and residual moisture combine to create meager precipitation. Snow levels will be around 12000 feet, with accumulations in the trace-to-1 inch range. Rain rates below 12000 feet will be in the 0.05-0.15 inches/hour range for most locations, with maximum rain rates in the 0.15-0.25 inches/hour range over the Southeast Mountains and San Juan Mountains regions.

For lower mountain valleys, including the San Luis Valley and the lower elevations of the Grand Valley region, dry and warmer conditions are expected to prevail.

Timing: 11 AM – 9 PM

Issue Date: 5/3/2018
Issue Time: 8:10 AM

NO FLOOD THREAT IS FORECAST TODAY.

The 700 mb low feature (highlighted in the water vapor image below) is the one to watch today, as it slowly exits the state towards southwest Nebraska. Wraparound moisture from the north/northwest will be pulled across the state, eventually pushing out the dry air over Southeast Colorado, paving the way for all regions to see at least a little bit of rainfall (below 8000 feet) and snowfall (above 8000 feet) today. This is welcome news for a state that is struggling with the emergence of drought. Unfortunately, those areas of southern Colorado where drought is the worst will receive the least amount of rainfall today, as areas along and north of I-70 receive the lion’s share.

Generally speaking, most activity will be of the “garden-variety shower” nature, with a few thunderstorms mixing in during the afternoon and evening hours. Showers/storms will begin to diminish during the late evening/early nighttime hours, with the high country hanging on to showers the longest due to orographic effects. All activity should come to an end between 11 PM and 2 AM. For more details on rate rates and timing, please see the zone specific forecast discussions below.

Today’s Flood Threat Map

For more information on today’s flood threat, see the map below (hover over threat areas for more details). For Zone-Specific forecasts, jump below the map.

Zone-Specific Forecasts

Urban Corridor, Palmer Ridge, and Northeast Plains:

Scattered showers and a few thunderstorms are expected through today and into the evening, diminishing after sunset and coming to an end around Midnight. Heads up for some minor street/field ponding that may arise in poorly drained areas. Rain rates will generally be in the 0.1-0.2 inches/hour range, with maximum rain rates as follows:

Urban Corridor: 0.25-0.5 inches/hour
Palmer Ridge: 0.3-0.6 inches/hour
Northeast Plains: 0.6-1.0 inches/hour

Timing: 11 AM – Midnight

Raton Ridge and Southeast Plains:

Isolated-to-scattered showers and thunderstorms are expected to begin around lunchtime for northern portions of the Southeast Plains, eventually spreading south over the rest of the Southeast Plains and Raton Ridge regions. Most activity will be in the form of light showers, but a few thunderstorms will mix in bringing periods of moderate rainfall to a few locations. Not everyone will receive rain today, but any little bit helps. Maximum rain rates are as follows:

Raton Ridge: 0.1-0.25 inches/hour
Southeast Plains: 0.4-0.6 inches/hour

Timing: Noon – 1 AM

Northern Mountains, Northwest Slope, Front Range, Southeast Mountains, Central Mountains, San Juan Mountains, Grand Valley, San Luis Valley, and Southwest Slope:

Scattered showers/thunderstorms are expected to continue, increasing in coverage through the afternoon hours, and diminishing as the sun sets. Snow will the dominant precipitation type down to 8000-8500 feet, with rain expected below that. Periods of heavy snow in the highest elevations will lead to an additional 5-10 inches of snow in some locations, with a few locally higher amounts. Rainfall below 8000 feet will generally be light, with rain rates typically in the 0.05-0.15 inches/hour range, maxing out around 0.25 inches/hour under thunderstorms.

Timing: 11 AM – 2 AM