Time: 331 PM Sun August 6, 2023 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1’S HAVE BEEN ISSUED EFFECTIVE UNTIL 9:00 PM Message 1’s have been issued effective until 9pm as there is a threat of heavy rainfall. Storms have initiated along northern portions of the District today and will be moving quickly eastward through the afternoon and evening. Dew points at this time are not exceptionally high, in the upper 40’s to low 50’s. However, strong upper-level support is near the District, and out towards the eastern plains where strong to severe storms are likely. Temperatures have remained fairly cool, although there is at least a chance for moderate to brief heavy rainfall within the District this afternoon and early evening. The best chance will be from now until 9pm with a few lingering storms through midnight tonight. A slight chance a storm could become severe inside the District, mainly for gusty winds and hail up to 1”. Storm motions will generally be from west to east between 15-25mph with some erratic storm movements possible along gust fronts. These storms will have the best chance of producing longer lasting heavy rainfall. STORM RAINFALL POTENTIAL AND DURATION: Typical showers/thunderstorms will produce a 0.05-0.25” total in 10 to 30 minutes. A moderate to strong thunderstorm will produce 0.25” to 0.50” total in 10 to 30 minutes. A strong to severe thunderstorm will produce 0.50” to 1.00” total in 10 to 30 minutes. WORST CASE SCENARIO: An anchored strong thunderstorm or training of thunderstorm cells has the potential to produce up to 1.5” in under 60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 900 PM Current TO 830 PM Jefferson County 1 Current TO 900 PM Current TO 830 PM Broomfield County 1 Current TO 900 PM Current TO 830 PM Douglas County 1 Current TO 900 PM Current TO 830 PM Adams County 1 Current TO 900 PM Current TO 830 PM Denver County 1 Current TO 900 PM Current TO 830 PM DIA 1 Current TO 900 PM Current TO 830 PM Arapahoe County 1 Current TO 900 PM Current TO 830 PM the City of Aurora 1 Current TO 900 PM Current TO 830 PM Arvada 1 Current TO 900 PM Current TO 830 PM Wheat Ridge 1 Current TO 900 PM Current TO 830 PM Lakewood 1 Current TO 900 PM Current TO 830 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 900 PM SUN 0.05" (75%) to 0.25" (50%) to 0.5" (25%) ISSUED Arapahoe Current TO 900 PM SUN 0.05" (75%) to 0.25" (50%) to 0.5" (25%) ISSUED Boulder Current TO 900 PM SUN 0.05" (75%) to 0.25" (50%) to 0.5" (25%) ISSUED Broomfield Current TO 900 PM SUN 0.05" (75%) to 0.25" (50%) to 0.5" (25%) ISSUED Denver Current TO 900 PM SUN 0.05" (75%) to 0.25" (50%) to 0.5" (25%) ISSUED Douglas Current TO 900 PM SUN 0.05" (75%) to 0.25" (50%) to 0.5" (25%) ISSUED Jefferson Current TO 900 PM SUN 0.05" (75%) to 0.25" (50%) to 0.5" (25%) ISSUED Foothills above 6500ft       Boulder Current TO 900 PM SUN 0.05" (75%) to 0.25" (50%) to 0.5" (25%) ISSUED Douglas Current TO 900 PM SUN 0.05" (75%) to 0.25" (50%) to 0.5" (25%) ISSUED Jefferson Current TO 900 PM SUN 0.05" (75%) to 0.25" (50%) to 0.5" (25%) ISSUED MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]