Time: 433 PM Wed July 5, 2023 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S HAVE BEEN ISSUED FOR THE ENTIRE DISTRICT Message 1’s have been issued for the entire District and will be valid until 10:00 PM. Cool temperatures have suppressed thunderstorm activity over the District so far today but stronger storms have developed to the W/SW of the District and with abundant moisture in place should these storms survive they will be capable of producing brief heavy rainfall. With the ground at or near saturation for many areas of the District due to rainfall yesterday it may not take as much rain today to produce excessive runoff and possibly flash flooding. Typical thunderstorms will move from W to E at around 20mph with stronger storms potentially moving more slowly or erratically along outflow boundaries. A large thunderstorm or training of thunderstorm cells will be the likely culprit for extended periods of heavy rainfall. Strong thunderstorms may also contain large hail. Best chances for thunderstorms will be through 10:00 PM. Should thunderstorm activity linger past 10:00 PM Message 1’s may need to be extended. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce 0.1-0.5” of rain. Moderate to strong thunderstorms will have the potential to produce rainfall rates of 0.5-1.5” in 10-30 minutes. WORST CASE SCENARIO: A large thunderstorm or training of thunderstorm cells may result in up to 2.3” of rain in 45-75 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 1000 PM Current TO 900 PM Jefferson County 1 Current TO 1000 PM Current TO 900 PM Broomfield County 1 Current TO 1000 PM Current TO 900 PM Douglas County 1 Current TO 1000 PM Current TO 900 PM Adams County 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 Wheat Ridge 1 Current TO 1000 PM Current TO 900 PM Lakewood 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 WED 0.1" (80%) to 0.5" (40%) to 1.5" (10%) ISSUED Arapahoe Current TO 1000 PM WED 0.1" (80%) to 0.5" (40%) to 1.5" (10%) ISSUED Boulder Current TO 1000 PM WED 0.1" (80%) to 0.5" (40%) to 1.5" (10%) ISSUED Broomfield Current TO 1000 PM WED 0.1" (80%) to 0.5" (40%) to 1.5" (10%) ISSUED Denver Current TO 1000 PM WED 0.1" (80%) to 0.5" (40%) to 1.5" (10%) ISSUED Douglas Current TO 1000 PM WED 0.1" (80%) to 0.5" (40%) to 1.5" (10%) ISSUED Jefferson Current TO 1000 PM WED 0.1" (80%) to 0.5" (40%) to 1.5" (10%) ISSUED Foothills above 6500ft       Boulder Current TO 1000 PM WED 0.1" (90%) to 0.5" (50%) to 1.5" (20%) ISSUED Douglas Current TO 1000 PM WED 0.1" (90%) to 0.5" (50%) to 1.5" (20%) ISSUED Jefferson Current TO 1000 PM WED 0.1" (90%) to 0.5" (50%) to 1.5" (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]