Flash Flood Prediction Program

Time: 430 PM Wed July 20, 2022 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S ISSUED FOR THE ENTIRE DISTRICT - Message 1's have been issued for the entire District and will be valid until 8:00pm this evening. - An outflow boundary from storms to the S of the District is progressing northward through the District at this time and may act to energize and slow down or briefly anchor storms that are moving into the District from the NW. Stronger thunderstorms will have the potential to produce brief heavy rainfall that may lead to excessive runoff roadways. - Typical thunderstorms will move form WNW to ESE at 15-20mph. 1-2 rounds of thunderstorms is expected through 7 or 8pm. After 8pm the stronger storms are expected to have moved east of the District. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.2" of moisture. Moderate thunderstorms will have the potential to produce rainfall rates of 0.4-1.0" in 10-30 minutes. WORST CASE SCENARIO: A slower moving thunderstorm or briefly anchored thunderstorm will have the potential to produce up to 1.4" of heavy rain in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Arapahoe County 1 Current TO 800 PM Current TO 700 PM Denver County 1 Current TO 800 PM 500 PM TO 700 PM DIA 1 Current TO 800 PM 500 PM TO 700 PM Douglas County 1 Current TO 800 PM Current TO 700 PM Adams County 1 Current TO 800 PM 500 PM TO 700 PM Broomfield County 1 Current TO 800 PM 500 PM TO 700 PM Jefferson County 1 Current TO 800 PM Current TO 700 PM Boulder County 1 Current TO 800 PM Current TO 700 PM the City of Aurora 1 Current TO 800 PM 500 PM TO 700 PM Arvada 1 Current TO 800 PM 500 PM TO 700 PM Wheat Ridge 1 Current TO 800 PM 500 PM TO 700 PM Lakewood 1 Current TO 800 PM 500 PM TO 700 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 800 PM WED 0.1" (90%) to 0.4" (60%) to 1.0" (20%) ISSUED Arapahoe Current TO 800 PM WED 0.1" (90%) to 0.4" (60%) to 1.0" (20%) ISSUED Boulder Current TO 800 PM WED 0.1" (90%) to 0.4" (60%) to 1.0" (20%) ISSUED Broomfield Current TO 800 PM WED 0.1" (90%) to 0.4" (60%) to 1.0" (20%) ISSUED Denver Current TO 800 PM WED 0.1" (90%) to 0.4" (60%) to 1.0" (20%) ISSUED Douglas Current TO 800 PM WED 0.1" (90%) to 0.4" (60%) to 1.0" (20%) ISSUED Jefferson Current TO 800 PM WED 0.1" (90%) to 0.4" (60%) to 1.0" (20%) ISSUED Foothills above 6500ft       Boulder Current TO 800 PM WED 0.1" (100%) to 0.4" (65%) to 1.0" (20%) ISSUED Douglas Current TO 800 PM WED 0.1" (95%) to 0.4" (60%) to 1.0" (20%) ISSUED Jefferson Current TO 800 PM WED 0.1" (100%) to 0.4" (65%) to 1.0" (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]