Flash Flood Prediction Program

Time: 420 PM Sun June 13, 2021 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S ISSUED FOR THE ENTIRE DISTRICT - Message 1's have been issued for the entire District and will remain valid until 9:30pm this evening. - Thunderstorms are beginning to initialize along a wind convergence line that extends from roughly Arvada to Parker currently. With ample surface moisture in place storms that develop through the remainder of the afternoon may become strong with the potential to produce heavy rainfall that may lead to excessive runoff and possibly flash flooding. - Upper level steering winds from NW to SE at around 15mph will keep heavy rainfall relatively brief from most storms. Training of thunderstorm cells or strong thunderstorms that stall along surface wind convergence boundaries will pose a risk for an extended period of heavy rainfall. STORM RAINFALL POTENTIAL AND DURATION: Moderate to strong thunderstorms will have the potential to produce 0.3-0.9" of rain in 10-30 minutes. WORST CASE SCENARIO: Strong/slow moving thunderstorms or training of thunderstorm cells have the potential to produce up to 1.8" in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME the City of Aurora 1 Current TO 930 PM 430 PM TO 830 PM Arapahoe County 1 Current TO 930 PM 430 PM TO 830 PM DIA 1 Current TO 930 PM 430 PM TO 830 PM Denver County 1 Current TO 930 PM 430 PM TO 830 PM Adams County 1 Current TO 930 PM 430 PM TO 830 PM Douglas County 1 Current TO 930 PM 430 PM TO 830 PM Broomfield County 1 Current TO 930 PM 430 PM TO 830 PM Jefferson County 1 Current TO 930 PM 430 PM TO 830 PM Boulder County 1 Current TO 930 PM 430 PM TO 830 PM Arvada 1 Current TO 930 PM 430 PM TO 830 PM Wheat Ridge 1 Current TO 930 PM 430 PM TO 830 PM Lakewood 1 Current TO 930 PM 430 PM TO 830 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 930 PM SUN 0.1" (75%) to 0.3" (50%) to 0.8" (20%) ISSUED Arapahoe Current TO 930 PM SUN 0.1" (100%) to 0.3" (75%) to 0.8" (40%) ISSUED Boulder Current TO 930 PM SUN 0.1" (75%) to 0.3" (50%) to 0.8" (20%) ISSUED Broomfield Current TO 930 PM SUN 0.1" (75%) to 0.3" (50%) to 0.8" (20%) ISSUED Denver Current TO 930 PM SUN 0.1" (100%) to 0.3" (75%) to 0.8" (40%) ISSUED Douglas Current TO 930 PM SUN 0.1" (100%) to 0.3" (75%) to 0.8" (40%) ISSUED Jefferson Current TO 930 PM SUN 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Foothills above 6500ft       Boulder Current TO 930 PM SUN 0.1" (80%) to 0.3" (50%) to 0.8" (15%) ISSUED Douglas Current TO 930 PM SUN 0.1" (80%) to 0.3" (50%) to 0.8" (15%) ISSUED Jefferson Current TO 930 PM SUN 0.1" (80%) to 0.3" (50%) to 0.8" (15%) 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]