Issue Date: Friday, August 24th, 2018
Issue Time: 08:40AM MDT
— Flooding is NOT expected today
Visible satellite shows mostly clear skies with a little fog over southern Colorado to start the day. The smoke is also still here, which is heaviest over eastern Colorado along the Urban Corridor. Guidance shows the near-surface smoke increasing over this area quite a bit throughout the day. There is also an Air Quality Health Advisory this morning for northwestern Colorado.
Today the weak ridge over Utah will slide eastward as the next trough begins to dig south over the west coast. After the ridge passes, some upper-level energy on its back side will help promote some light showers and thunderstorms over western Colorado later this afternoon. Flow aloft will also become more southwesterly this afternoon after the ridge passes to the east. While the southwest flow will begin to increase the subtropical moisture overnight, low-level moisture for the storms this afternoon will be lacking. This translates to storms today likely producing gusty winds with limited rainfall totals. To the east, downsloping winds will continue to scour out any residual moisture under the ridge. This will make it quite difficult for any storms to fire over the higher terrains today.
Today’s Flood Threat Map
For more information on today’s flood threat, see the map below. For Zone-Specific forecasts, scroll below the map.
Zone-Specific Forecasts:
Grand Valley, Central Mountains, San Juan Mountains, San Luis Valley, Southwest Slope, Northern Mountains, Northwest Slope, Northeast Plains:
Weak showers and a possible thunderstorm or two this afternoon are possible over western CO as the trough digs in over the west coast. Flow will turn more southwesterly aloft this afternoon as well. This may help bring a little low-level moisture back, but the moderate monsoon surge won’t occur until tomorrow. Thus, storms today are not expected to be widespread in coverage. Max 1-hr rain rates up to 0.2 inches are possible with gusty outflow winds likely under the stronger cores. Flooding is not expected today.
Primetime: 2PM – 9PM
Southeast Plains, Raton Ridge, Southeast Mountains, Front Range, Palmer Ridge, Urban Corridor:
Downsloping winds and resulting subsidence will continue today, which will scour out most of the residual moisture under the ridge. Weak upslope flow may set up this afternoon, but this would only increase cloud cover over the higher terrains. High temperatures should bump up a couple degrees from yesterday. Visibility is expected to deteriorate throughout the day along the I-25 Corridor. The Front Range Air Quality forecast has an Action Day, which means air quality will once again be unhealthy for sensitive groups.
