Time: 138 PM Fri June 21, 2024 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1’S HAVE BEEN ISSUED EFFECTIVE UNTIL 8:00 PM Message 1’s have been issued for the entire District effective until 8:00pm for the threat of heavy rainfall with a slight chance for severe storms across the District this afternoon and evening. Storms have initiated along the higher terrain and are expected to move into the District over the next hour. Similar to yesterday storms will move from WSW to ENE between 10-15mph, with erratic storm movement likely along outflow boundaries. These outflow storms will likely have the highest potential for heavy rainfall today as they anchor in place. Storms may also contain large hail up to 1.0” and gusty winds up to 60mph. Dew points are also still elevated, in the mid to upper 50s and will likely help fuel moderate to heavy rainfall leading to some localized flooding. A couple of rounds of storms will be possibly today, likely decreasing in strength as the evening progresses with off and on showers possible through the overnight. Overnight temperatures will drop to around 60 degrees on the plains with low to mid 50s along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers and thunderstorms will produce a 0.10-0.50” total in 10-30 minutes. A moderate to strong shower/thunderstorm will produce 0.50-0.80" total in 10-30 minutes. WORST CASE SCENARIO: Strong stationary thunderstorms, or training of thunderstorm cells could have the potential to produce up to 1.60” total in 30-60 minutes or less. COUNTY MESSAGE VALID TIMES PRIME TIME Lakewood 1 Current TO 800 PM Current TO 730 PM Arvada 1 Current TO 800 PM Current TO 730 PM Wheat Ridge 1 Current TO 800 PM Current TO 730 PM Arapahoe County 1 Current TO 800 PM Current TO 730 PM the City of Aurora 1 Current TO 800 PM Current TO 730 PM DIA 1 Current TO 800 PM Current TO 730 PM Denver County 1 Current TO 800 PM Current TO 730 PM Adams County 1 Current TO 800 PM Current TO 730 PM Broomfield County 1 Current TO 800 PM Current TO 730 PM Douglas County 1 Current TO 800 PM Current TO 730 PM Jefferson County 1 Current TO 800 PM Current TO 730 PM Boulder County 1 Current TO 800 PM Current TO 730 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 800 PM FRI 0.1" (80%) to 0.5" (60%) to 0.8" (30%) ISSUED Arapahoe Current TO 800 PM FRI 0.1" (80%) to 0.5" (60%) to 0.8" (30%) ISSUED Boulder Current TO 800 PM FRI 0.1" (75%) to 0.5" (50%) to 0.8" (25%) ISSUED Broomfield Current TO 800 PM FRI 0.1" (75%) to 0.5" (50%) to 0.8" (25%) ISSUED Denver Current TO 800 PM FRI 0.1" (80%) to 0.5" (60%) to 0.8" (30%) ISSUED Douglas Current TO 800 PM FRI 0.1" (75%) to 0.5" (50%) to 0.8" (25%) ISSUED Jefferson Current TO 800 PM FRI 0.1" (75%) to 0.5" (50%) to 0.8" (25%) ISSUED Foothills above 6500ft       Boulder Current TO 800 PM FRI 0.1" (75%) to 0.5" (50%) to 0.8" (25%) ISSUED Douglas Current TO 800 PM FRI 0.1" (75%) to 0.5" (50%) to 0.8" (25%) ISSUED Jefferson Current TO 800 PM FRI 0.1" (75%) to 0.5" (50%) to 0.8" (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]