Time: 216 PM Sat August 20, 2022 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 9:30 PM. - Slow storm motions and high moisture values at the surface and aloft will result in thunderstorms that develop this afternoon and evening having the potential to produce heavy rainfall that may result in excessive runoff and possibly flash flooding. - Cloud cover this morning may keep the stronger storms at bay but even weak to moderate storms will produce brief heavy rainfall should they develop. Best chances for thunderstorms will be from 3:30pm to 8:30pm, likely favoring the W and S areas of the District. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers will only produce a trace to 0.2" of rainfall in 10-30 minutes. Thunderstorms will have the potential to produce rainfall rates of 0.4-1.0" in 10-30 minutes. WORST CASE SCENARIO: A strong slower moving thunderstorm or anchored thunderstorm may result in up to 2.0" of heavy rain in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Arvada 1 Current TO 930 PM 330 PM TO 830 PM the City of Aurora 1 Current TO 930 PM 330 PM TO 830 PM Arapahoe County 1 Current TO 930 PM 330 PM TO 830 PM DIA 1 Current TO 930 PM 330 PM TO 830 PM Denver County 1 Current TO 930 PM 330 PM TO 830 PM Douglas County 1 Current TO 930 PM 330 PM TO 830 PM Adams County 1 Current TO 930 PM 330 PM TO 830 PM Broomfield County 1 Current TO 930 PM 330 PM TO 830 PM Jefferson County 1 Current TO 930 PM 330 PM TO 830 PM Boulder County 1 Current TO 930 PM 330 PM TO 830 PM Wheat Ridge 1 Current TO 930 PM 330 PM TO 830 PM Lakewood 1 Current TO 930 PM 330 PM TO 830 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 930 PM SAT 0.1" (70%) to 0.4" (40%) to 1.0" (15%) ISSUED Arapahoe Current TO 930 PM SAT 0.1" (80%) to 0.4" (50%) to 1.0" (20%) ISSUED Boulder Current TO 930 PM SAT 0.1" (80%) to 0.4" (50%) to 1.0" (20%) ISSUED Broomfield Current TO 930 PM SAT 0.1" (75%) to 0.4" (50%) to 1.0" (15%) ISSUED Denver Current TO 930 PM SAT 0.1" (75%) to 0.4" (50%) to 1.0" (15%) ISSUED Douglas Current TO 930 PM SAT 0.1" (80%) to 0.4" (50%) to 1.0" (20%) ISSUED Jefferson Current TO 930 PM SAT 0.1" (80%) to 0.4" (50%) to 1.0" (20%) ISSUED Foothills above 6500ft       Boulder Current TO 930 PM SAT 0.1" (95%) to 0.4" (60%) to 1.0" (30%) ISSUED Douglas Current TO 930 PM SAT 0.1" (95%) to 0.4" (60%) to 1.0" (30%) ISSUED Jefferson Current TO 930 PM SAT 0.1" (95%) to 0.4" (60%) to 1.0" (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]