Time: 1207 PM Sat May 29, 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 10pm this evening. - Thunderstorms are beginning to initiate over the higher terrain to the W of the District currently. Upper level steering winds from W to E at around 20mph will push the storms eastward onto the plains as the afternoon progresses. As the storms move onto the lower elevations they will encounter a moist airmass and be capable of producing heavy rainfall. Multiple rounds (1-3) of thunderstorms are expected into the evening. - Training of thunderstorm cells or a large, slower moving thunderstorm will produce the greatest risk for extended periods of heavy rainfall that may lead to excessive runoff and possibly flash flooding. Most storms will move fast enough from W to E to keep the heavy rainfall relatively brief. STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce 0.1-0.3" of rain in 10-30 minutes. Strong thunderstorms will have the potential to produce 0.3-0.8" in 10-30 minutes. WORST CASE SCENARIO: Training of thunderstorm cells or a large/slower moving thunderstorm may result in up to 1.6" of rain in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Lakewood 1 Current TO 1000 PM 100 PM TO 900 PM Wheat Ridge 1 Current TO 1000 PM 100 PM TO 900 PM Arvada 1 Current TO 1000 PM 100 PM TO 900 PM the City of Aurora 1 Current TO 1000 PM 100 PM TO 900 PM Arapahoe County 1 Current TO 1000 PM 100 PM TO 900 PM Denver County 1 Current TO 1000 PM 100 PM TO 900 PM DIA 1 Current TO 1000 PM 100 PM TO 900 PM Adams County 1 Current TO 1000 PM 100 PM TO 900 PM Douglas County 1 Current TO 1000 PM 100 PM TO 900 PM Jefferson County 1 Current TO 1000 PM 100 PM TO 900 PM Broomfield County 1 Current TO 1000 PM 100 PM TO 900 PM Boulder County 1 Current TO 1000 PM 100 PM TO 900 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 100 PM TO 1000 PM 0.1" (85%) to 0.3" (60%) to 0.8" (30%) ISSUED Arapahoe 100 PM TO 1000 PM 0.1" (85%) to 0.3" (60%) to 0.8" (30%) ISSUED Boulder 100 PM TO 1000 PM 0.1" (85%) to 0.3" (60%) to 0.8" (30%) ISSUED Broomfield 100 PM TO 1000 PM 0.1" (85%) to 0.3" (60%) to 0.8" (30%) ISSUED Denver 100 PM TO 1000 PM 0.1" (85%) to 0.3" (60%) to 0.8" (30%) ISSUED Douglas 100 PM TO 1000 PM 0.1" (85%) to 0.3" (60%) to 0.8" (30%) ISSUED Jefferson 100 PM TO 1000 PM 0.1" (85%) to 0.3" (60%) to 0.8" (30%) ISSUED Foothills above 6500ft       Boulder Current TO 1000 PM SAT 0.1" (95%) to 0.3" (60%) to 0.8" (20%) ISSUED Douglas Current TO 1000 PM SAT 0.1" (95%) to 0.3" (60%) to 0.8" (20%) ISSUED Jefferson Current TO 1000 PM SAT 0.1" (95%) to 0.3" (60%) to 0.8" (20%) 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]