Flash Flood Prediction Program

Time: 952 PM Fri July 23, 2021 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S HAVE BEEN EXTENDED UNTIL MIDNIGHT - Message 1's will will be extended until midnight as rain showers and weak to possibly moderate thunderstorms continue possible over the next couple hours. - Rain showers and weak thunderstorms are ongoing, mainly W of Hwy 76 at this time. Rain showers and weak thunderstorms are expected to continue into the evening with chances for thunderstorms diminishing after midnight. - With a moist airmass in place even weak to moderate thunderstorms will be capable of producing heavy rainfall that may lead to excessive runoff. Beyond midnight additional rain showers are expected to continue into Saturday morning. STORM RAINFALL POTENTIAL AND DURATION: Rain showers will produce 0.1-0.3" in 30-60 minutes. Weak to moderate thunderstorms will have the potential to produce rainfall rates of 0.3-0.8" in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm develops with the potential to produce 0.4-1.2" of heavy rain in 10-30 minutes and up to 1.8" in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 1159 PM Current TO 1130 PM Jefferson County 1 Current TO 1159 PM Current TO 1130 PM Broomfield County 1 Current TO 1159 PM Current TO 1130 PM Douglas County 1 Current TO 1159 PM Current TO 1130 PM Adams County 1 Current TO 1159 PM Current TO 1130 PM Denver County 1 Current TO 1159 PM Current TO 1130 PM DIA 1 Current TO 1159 PM Current TO 1130 PM Arapahoe County 1 Current TO 1159 PM Current TO 1130 PM the City of Aurora 1 Current TO 1159 PM Current TO 1130 PM Arvada 1 Current TO 1159 PM Current TO 1130 PM Wheat Ridge 1 Current TO 1159 PM Current TO 1130 PM Lakewood 1 Current TO 1159 PM Current TO 1130 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1159 PM FRI 0.1" (80%) to 0.3" (50%) to 0.8" (20%) ISSUED Arapahoe Current TO 1159 PM FRI 0.1" (80%) to 0.3" (50%) to 0.8" (20%) ISSUED Boulder Current TO 1159 PM FRI 0.1" (80%) to 0.3" (50%) to 0.8" (20%) ISSUED Broomfield Current TO 1159 PM FRI 0.1" (80%) to 0.3" (50%) to 0.8" (20%) ISSUED Denver Current TO 1159 PM FRI 0.1" (75%) to 0.3" (40%) to 0.8" (15%) ISSUED Douglas Current TO 1159 PM FRI 0.1" (75%) to 0.3" (40%) to 0.8" (15%) ISSUED Jefferson Current TO 1159 PM FRI 0.1" (80%) to 0.3" (50%) to 0.8" (20%) ISSUED Foothills above 6500ft       Boulder Current TO 1159 PM FRI 0.1" (80%) to 0.3" (50%) to 0.8" (20%) ISSUED Douglas Current TO 1159 PM FRI 0.1" (80%) to 0.3" (50%) to 0.8" (20%) ISSUED Jefferson Current TO 1159 PM FRI 0.1" (80%) to 0.3" (50%) 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]