Time: 319 PM Fri September 3, 2021 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S CONTINUE VALID FOR THE ENTIRE DISTRICT - Message 1's will continue valid until 8pm although the threat for heavy rainfall is diminishing now that the main area of thunderstorms has pushed eastward. - Additional isolated rain showers and weak to moderate thunderstorms remain possible over the next few hours but but the strength of storms is expected to be less intense than earlier today, however a stronger storm cannot be completely ruled out. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.2" of rainfall in 10-30 minutes. Moderate thunderstorms will have the potential to produce heavy rainfall of 0.2-0.6" in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm is able to develop with the potential to produce heavy rainfall of 0.5-1.5" in 10-30 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 800 PM Current TO 700 PM Jefferson County 1 Current TO 800 PM Current TO 700 PM Broomfield County 1 Current TO 800 PM Current TO 700 PM Douglas County 1 Current TO 800 PM Current TO 700 PM Adams County 1 Current TO 800 PM Current TO 700 PM Denver County 1 Current TO 800 PM Current TO 700 PM DIA 1 Current TO 800 PM Current TO 700 PM Arapahoe County 1 Current TO 800 PM Current TO 700 PM the City of Aurora 1 Current TO 800 PM Current TO 700 PM Arvada 1 Current TO 800 PM Current TO 700 PM Wheat Ridge 1 Current TO 800 PM Current TO 700 PM Lakewood 1 Current TO 800 PM Current TO 700 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 800 PM FRI Trace (60%) to 0.2" (30%) to 0.6" (10%) ISSUED Arapahoe Current TO 800 PM FRI Trace (80%) to 0.2" (40%) to 0.6" (20%) ISSUED Boulder Current TO 800 PM FRI Trace (60%) to 0.2" (30%) to 0.6" (10%) ISSUED Broomfield Current TO 800 PM FRI Trace (60%) to 0.2" (30%) to 0.6" (10%) ISSUED Denver Current TO 800 PM FRI Trace (60%) to 0.2" (30%) to 0.6" (10%) ISSUED Douglas Current TO 800 PM FRI Trace (90%) to 0.2" (50%) to 0.6" (30%) ISSUED Jefferson Current TO 800 PM FRI Trace (80%) to 0.2" (40%) to 0.6" (20%) ISSUED Foothills above 6500ft       Boulder Current TO 800 PM FRI Trace (80%) to 0.2" (40%) to 0.6" (15%) ISSUED Douglas Current TO 800 PM FRI Trace (90%) to 0.2" (50%) to 0.6" (30%) ISSUED Jefferson Current TO 800 PM FRI Trace (80%) to 0.2" (40%) to 0.6" (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]