Time: 611 PM Mon May 17, 2021 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S CONTINUE VALID FOR THE DISTRICT - Message 1's will continue valid for the entire District until 10:00pm this evening. The threat for heavy thunderstorm rainfall is diminishing but moderate to heavy rainfall continues possible over the next few hours. - The strongest thunderstorms have recently diminished with a more widespread light to moderate rain now ongoing from roughly I-25 westward. A wetting rain will continue into the evening with lighter rainfall rates that what were observed earlier today. Runoff from rain showers into the evening may result in smaller creeks and streams running high. - Best chances for additional showers and weak thunderstorms will be through 10pm this evening. Additional light rain showers continue likely overnight with an uptick in rain showers possible by mid-morning Tuesday. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce 0.1-0.4" in 10-30 minutes. Moderate to strong thunderstorms. Moderate to strong thunderstorms will have the potential to produce 0.4-0.9" in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm becomes stationary producing an extended period of heavy rainfall with up to 1.5" in 60 minutes or less. COUNTY MESSAGE VALID TIMES PRIME TIME Wheat Ridge 1 Current TO 1000 PM Current TO 900 PM Lakewood 1 Current TO 1000 PM Current TO 900 PM Denver County 1 Current TO 1000 PM Current TO 900 PM DIA 1 Current TO 1000 PM Current TO 900 PM Arapahoe County 1 Current TO 1000 PM Current TO 900 PM the City of Aurora 1 Current TO 1000 PM Current TO 900 PM Arvada 1 Current TO 1000 PM Current TO 900 PM Adams County 1 Current TO 1000 PM Current TO 900 PM Douglas County 1 Current TO 1000 PM Current TO 900 PM Broomfield County 1 Current TO 1000 PM Current TO 900 PM Jefferson County 1 Current TO 1000 PM Current TO 900 PM Boulder County 1 Current TO 1000 PM Current TO 900 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1000 PM MON 0.1" (80%) to 0.4" (40%) to 0.9" (10%) ISSUED Arapahoe Current TO 1000 PM MON 0.1" (80%) to 0.4" (40%) to 0.9" (10%) ISSUED Boulder Current TO 1000 PM MON 0.1" (95%) to 0.4" (40%) to 0.9" (10%) ISSUED Broomfield Current TO 1000 PM MON 0.1" (95%) to 0.4" (40%) to 0.9" (10%) ISSUED Denver Current TO 1000 PM MON 0.1" (95%) to 0.4" (40%) to 0.9" (10%) ISSUED Douglas Current TO 1000 PM MON 0.1" (90%) to 0.4" (40%) to 0.9" (10%) ISSUED Jefferson Current TO 1000 PM MON 0.1" (95%) to 0.4" (40%) to 0.9" (10%) ISSUED Foothills above 6500ft       Boulder Current TO 1000 PM MON 0.1" (100%) to 0.4" (50%) to 0.9" (10%) ISSUED Douglas Current TO 1000 PM MON 0.1" (100%) to 0.4" (50%) to 0.9" (10%) ISSUED Jefferson Current TO 1000 PM MON 0.1" (100%) to 0.4" (50%) to 0.9" (10%) 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]