Flash Flood Prediction Program

Time: 247 PM Sun May 2, 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 District until 8:00pm and may need to be extended to 10pm... - A round of showers and thunderstorms moved through the District earlier with just a few isolated/weak rain showers currently. Another round or two of showers and thunderstorms are likely through the afternoon/early evening with stronger storms still capable of producing brief heavy rainfall and hail. - A widespread "wetting" rain is still expected to fill in this evening sometime between 7-10pm. If the front end of these showers are moderate to heavy in intensity then messages may need to be extended until 10pm for the threat of 1.00"/hour or more rainfall rates. Most likely these showers will result in rain rates of 0.10-0.60"/hr. As the evening progresses rainfall rates will lessen into the 0.05-0.20"/hr rate range overnight with rain changing over to snow in the Front Range foothills. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce 0.1-0.3" in 10-30 minutes. Moderate to strong thunderstorms will have the potential to produce 0.3-0.8" in 10-30 minutes. WORST CASE SCENARIO: Training of moderate/strong thunderstorm cells may result in up to 1.4" of rain in 60-90 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 800 PM 1100 AM TO 700 PM Jefferson County 1 Current TO 800 PM 1100 AM TO 700 PM Broomfield County 1 Current TO 800 PM 1100 AM TO 700 PM Douglas County 1 Current TO 800 PM 1100 AM TO 700 PM Adams County 1 Current TO 800 PM 1100 AM TO 700 PM Denver County 1 Current TO 800 PM 1100 AM TO 700 PM DIA 1 Current TO 800 PM 1100 AM TO 700 PM Arapahoe County 1 Current TO 800 PM 1100 AM TO 700 PM the City of Aurora 1 Current TO 800 PM 1100 AM TO 700 PM Arvada 1 Current TO 800 PM 1100 AM TO 700 PM Wheat Ridge 1 Current TO 800 PM 1100 AM TO 700 PM Lakewood 1 Current TO 800 PM 1100 AM TO 700 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 1100 AM TO 800 PM Trace (95%) to 0.3" (65%) to 0.8" (15%) ISSUED Arapahoe 1100 AM TO 800 PM Trace (95%) to 0.3" (65%) to 0.8" (15%) ISSUED Boulder 1100 AM TO 800 PM Trace (95%) to 0.3" (65%) to 0.8" (15%) ISSUED Broomfield 1100 AM TO 800 PM Trace (95%) to 0.3" (65%) to 0.8" (15%) ISSUED Denver 1100 AM TO 800 PM Trace (95%) to 0.3" (65%) to 0.8" (15%) ISSUED Douglas 1100 AM TO 800 PM Trace (95%) to 0.3" (65%) to 0.8" (15%) ISSUED Jefferson 1100 AM TO 800 PM Trace (95%) to 0.3" (65%) to 0.8" (15%) ISSUED Foothills above 6500ft       Boulder 1100 AM TO 800 PM Trace (100%) to 0.3" (65%) to 0.8" (15%) ISSUED Douglas 1100 AM TO 800 PM Trace (100%) to 0.3" (65%) to 0.8" (15%) ISSUED Jefferson 1100 AM TO 800 PM Trace (100%) to 0.3" (65%) 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]