Time: 233 PM Wed July 26, 2023 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 8:30 PM this evening. Thunderstorms have developed to the N and S of the District and are producing rain cooled outflow boundaries which may collide over the District and produce new storms over the next few hours. Typical weak to moderate thunderstorms will produce light to brief moderate rainfall and gusty winds. Stronger storms may form along the outflow boundaries or outflow boundary collision and will move more slowly initially before being carried away by upper level steering winds. Strong, slower moving thunderstorms will be capable of producing extended periods of heavy rainfall that may lead to excessive runoff. Thunderstorms will generally move from W to E or WSW to ENE at 20-25mph. 1-2 rounds of thunderstorms is expected into the evening. Strong thunderstorms may also contain large hail. STORM RAINFALL POTENTIAL AND DURATION: Moderate to strong thunderstorms will have the potential to produce rainfall rates of 0.4-0.9” in 10-30 minutes. WORST CASE SCENARIO: A slower moving strong thunderstorm or training of thunderstorm cells may result in up to 1.4" of rain in 45-75 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 830 PM 300 PM TO 730 PM Jefferson County 1 Current TO 830 PM 300 PM TO 730 PM Broomfield County 1 Current TO 830 PM 300 PM TO 730 PM Douglas County 1 Current TO 830 PM 300 PM TO 730 PM Adams County 1 Current TO 830 PM 300 PM TO 730 PM Denver County 1 Current TO 830 PM 300 PM TO 730 PM DIA 1 Current TO 830 PM 300 PM TO 730 PM Arapahoe County 1 Current TO 830 PM 300 PM TO 730 PM the City of Aurora 1 Current TO 830 PM 300 PM TO 730 PM Arvada 1 Current TO 830 PM 300 PM TO 730 PM Wheat Ridge 1 Current TO 830 PM 300 PM TO 730 PM Lakewood 1 Current TO 830 PM 300 PM TO 730 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 830 PM WED 0.1" (80%) to 0.4" (50%) to 0.9" (20%) ISSUED Arapahoe Current TO 830 PM WED 0.1" (80%) to 0.4" (50%) to 0.9" (20%) ISSUED Boulder Current TO 830 PM WED 0.1" (80%) to 0.4" (50%) to 0.9" (20%) ISSUED Broomfield Current TO 830 PM WED 0.1" (80%) to 0.4" (50%) to 0.9" (20%) ISSUED Denver Current TO 830 PM WED 0.1" (80%) to 0.4" (50%) to 0.9" (20%) ISSUED Douglas Current TO 830 PM WED 0.1" (80%) to 0.4" (50%) to 0.9" (20%) ISSUED Jefferson Current TO 830 PM WED 0.1" (80%) to 0.4" (50%) to 0.9" (20%) ISSUED Foothills above 6500ft       Boulder Current TO 830 PM WED 0.1" (80%) to 0.4" (50%) to 0.9" (20%) ISSUED Douglas Current TO 830 PM WED 0.1" (80%) to 0.4" (50%) to 0.9" (20%) ISSUED Jefferson Current TO 830 PM WED 0.1" (80%) to 0.4" (50%) to 0.9" (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]