Flash Flood Prediction Program

Time: 1149 PM Fri June 25, 2021 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGES WILL BE ALLOWED TO EXPIRE AT MIDNIGHT/ADDITIONAL RAIN SHOWERS CONTINUE OVERNIGHT - Message 1's will be allowed to expire at midnight as the threat for heavy rainfall from thunderstorms has ended for the day. Additional rain showers will continue likely overnight into Saturday morning. - Now that temperatures are firmly in the 50's the threat for thunderstorms has diminished with precipitation for the remainder of the overnight period expected to fall as general rain showers. Rainfall rates from light to moderate rain showers will typically range from 0.05-0.30" in 30-60 minutes. A persistent moderate rainfall may result in higher rainfall rates. - Many areas of the District has reported between 1-2" or more of rain today. Additional rain showers overnight will continue to produce runoff as the ground is becoming saturated and some creeks/streams will continue to run high into Saturday morning. Thunderstorms are likely to develop by midday Saturday and will once again be very capable of producing heavy rainfall. STORM RAINFALL POTENTIAL AND DURATION: Light to moderate rain showers will produce rainfall rates of 0.05-0.30" in 30-60 minutes. Heavy non-thunderstorm rain may result in rainfall rates of 0.3-0.8" in 30-60 minutes. WORST CASE SCENARIO: Although unlikely, if a thunderstorm were to develop it would have the potential to produce heavy rainfall of 0.5-1.5" in 15-45 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 1159 PM 1230 PM TO 1130 PM Jefferson County 1 Current TO 1159 PM 1230 PM TO 1130 PM Broomfield County 1 Current TO 1159 PM 1230 PM TO 1130 PM Douglas County 1 Current TO 1159 PM 1230 PM TO 1130 PM Adams County 1 Current TO 1159 PM 1230 PM TO 1130 PM Denver County 1 Current TO 1159 PM 1230 PM TO 1130 PM DIA 1 Current TO 1159 PM 1230 PM TO 1130 PM Arapahoe County 1 Current TO 1159 PM 1230 PM TO 1130 PM the City of Aurora 1 Current TO 1159 PM 1230 PM TO 1130 PM Arvada 1 Current TO 1159 PM 1230 PM TO 1130 PM Wheat Ridge 1 Current TO 1159 PM 1230 PM TO 1130 PM Lakewood 1 Current TO 1159 PM 1230 PM TO 1130 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 60-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 900 AM SAT 0.1" (100%) to 0.3" (75%) to 0.6" (25%) ISSUED Arapahoe Current TO 900 AM SAT 0.1" (100%) to 0.3" (75%) to 0.6" (25%) ISSUED Boulder Current TO 900 AM SAT 0.1" (100%) to 0.3" (75%) to 0.6" (25%) ISSUED Broomfield Current TO 900 AM SAT 0.1" (100%) to 0.3" (75%) to 0.6" (25%) ISSUED Denver Current TO 900 AM SAT 0.1" (100%) to 0.3" (75%) to 0.6" (25%) ISSUED Douglas Current TO 900 AM SAT 0.1" (100%) to 0.3" (75%) to 0.6" (25%) ISSUED Jefferson Current TO 900 AM SAT 0.1" (100%) to 0.3" (75%) to 0.6" (25%) ISSUED Foothills above 6500ft       Boulder Current TO 900 AM SAT 0.1" (100%) to 0.3" (75%) to 0.6" (25%) ISSUED Douglas Current TO 900 AM SAT 0.1" (100%) to 0.3" (75%) to 0.6" (25%) ISSUED Jefferson Current TO 900 AM SAT 0.1" (100%) to 0.3" (75%) to 0.6" (25%) 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]