Issue Date: 5/2/2015
Issue Time: 10:00 AM
NO FLOOD THREAT IS FORECAST.
Surface high pressure has settled in (albeit briefly) across Colorado, while an upper-level ridge slowly builds overhead. Clouds have mainly cleared from areas east of the mountains, while still in place across much of the High Country. The clearing skies will allow for a warm up in temperatures to values that haven’t been observed in recent days, although still below average for this time of year. The daytime heating will kick off isolated showers/thunderstorms across the High Country this afternoon/evening, mainly south of I-70. Instability values will remain fairly low, however, and any thunderstorms will be of the garden variety.
Northerly steering flow will keep the thunderstorms over the mountains, and it will be difficult for any to leak over the Urban Corridor or adjacent plains. It cannot be ruled out entirely, but it is unlikely. Rain rates will vary across the regions, but will remain below flood threat thresholds in each. Specifics on rain rates will be given in the zone-specific forecast discussion below.
Unfortunately, the surface high pressure will be short lived as a weak frontal surge will move into northeastern Colorado between 3 and 5 PM, bringing spotty, light precipitation with it. The weak front will race southward across the eastern third of the state, exiting the Southeast Plains region by tomorrow morning. The main area of light precipitation will remain across eastern portions of the Northeast Plains, Palmer Ridge, and Southeast Plains, but an isolated shower or two will work back into the Urban corridor, western portions of the Southeast Plains adjacent to the mountains, and Raton Ridge.
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, Southeast Plains, Palmer Ridge, Raton Ridge, and Northeast Plains:
Drying and warming today, before a weak frontal surge moves through eastern third of Colorado beginning later this afternoon/early evening. The frontal surge will bring increasing clouds, gusty northerly winds, and isolated light showers before exiting the state tomorrow morning. Rain rates will be low (0.1-0.2 inches/hour), so no flood threat is expected. Temperatures will closer to average, although still on the cool side for the date.
Northern Mountains, Northwest Slope, Grand Valley, and Front Range:
Isolated showers/weak thunderstorms are expected to develop around lunchtime, diminishing between 7 and 9 PM. Light rain (snow for the higher peaks) will be the result, along with cool, gusty winds. Maximum rain rates will be 0.1-0.2 inches/hour. Temperatures will continue to be a little cooler than normal, but will be warmer than yesterday.
Central Mountains, Southeast Mountains, San Juan Mountains, Southwest Slope, and San Luis Valley:
Isolated showers/garden-variety thunderstorms are expected to develop after 11 AM, and then diminish between 7 and 10 PM. Light rain (snow for the higher peaks) will be the main result, along with cool, gusty winds. The favored areas will be the higher terrain of the San Juan Mountains, Southwest Slope, and Central Mountains regions. Maximum rain rates will be slightly higher than other regions, coming in at 0.2-0.5 inches/hour. Just as the other regions, temperatures will be warmer than yesterday, but still below average for this time of year.
