Flash Flood Prediction Program

Time: 237 PM Wed July 14, 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 be valid until 10:00pm this evening. - Temperatures have remained on the cool side today over the District hindering thunderstorm development up to this point but an approaching upper level disturbance is expected override the lack of heat and generate showers and thunderstorms later this afternoon and evening. The strength of the storms remains in question but even a moderate thunderstorm will have the potential to produce brief heavy rainfall. 1-2 rounds of showers and thunderstorms are expected through 10pm. - Individual thunderstorms will move from NW to SE at around 15mph. A briefly anchored strong thunderstorm or slower moving large thunderstorm will contain the greatest potential to produce long duration heavy rainfall that may lead to excessive runoff and possibly flash flooding. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce 0.1-0.5" in 10-30 minutes. Moderate to strong thunderstorms will have the potential to produce 0.5-1.3" in 10-30 minutes. WORST CASE SCENARIO: A briefly anchored thunderstorm or slower moving large thunderstorm may result in up to 2.5" of heavy rain in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 1000 PM 330 PM TO 930 PM Jefferson County 1 Current TO 1000 PM 330 PM TO 930 PM Broomfield County 1 Current TO 1000 PM 330 PM TO 930 PM Douglas County 1 Current TO 1000 PM 330 PM TO 930 PM Adams County 1 Current TO 1000 PM 330 PM TO 930 PM Denver County 1 Current TO 1000 PM 330 PM TO 930 PM DIA 1 Current TO 1000 PM 330 PM TO 930 PM Arapahoe County 1 Current TO 1000 PM 330 PM TO 930 PM the City of Aurora 1 Current TO 1000 PM 330 PM TO 930 PM Arvada 1 Current TO 1000 PM 330 PM TO 930 PM Wheat Ridge 1 Current TO 1000 PM 330 PM TO 930 PM Lakewood 1 Current TO 1000 PM 330 PM TO 930 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 330 PM TO 1000 PM 0.1" (80%) to 0.5" (40%) to 1.3" (20%) ISSUED Arapahoe 330 PM TO 1000 PM 0.1" (80%) to 0.5" (40%) to 1.3" (20%) ISSUED Broomfield 330 PM TO 1000 PM 0.1" (80%) to 0.5" (40%) to 1.3" (20%) ISSUED Denver 330 PM TO 1000 PM 0.1" (80%) to 0.5" (40%) to 1.3" (20%) ISSUED Boulder 300 PM TO 1000 PM 0.1" (90%) to 0.5" (50%) to 1.3" (25%) ISSUED Douglas 300 PM TO 1000 PM 0.1" (90%) to 0.5" (50%) to 1.3" (25%) ISSUED Jefferson 300 PM TO 1000 PM 0.1" (90%) to 0.5" (50%) to 1.3" (25%) ISSUED Foothills above 6500ft       Boulder Current TO 1000 PM WED 0.1" (100%) to 0.5" (60%) to 1.3" (30%) ISSUED Douglas Current TO 1000 PM WED 0.1" (100%) to 0.5" (60%) to 1.3" (30%) ISSUED Jefferson Current TO 1000 PM WED 0.1" (100%) to 0.5" (60%) to 1.3" (30%) 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]