Time: 1149 PM Fri July 23, 2021 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S WILL BE ALLOWED TO EXPIRE AT MIDNIGHT/ADDITIONAL RAIN SHOWERS CONTINUE INTO SATURDAY MORNING - Message 1's will be allowed to expire at midnight as the threat for heavy rainfall has come to an end. - Additional isolated to widely scattered rain showers will continue likely overnight and may linger into Saturday morning. Wetting rains can be expected under the more persistent showers and will produce minor runoff. Excessive runoff from heavy rainfall is no longer expected. - Cooler Saturday with highs in the 80's over the plains. Isolated to widely scattered rain showers early Saturday morning give way to a chance for thunderstorms before noon. Strong thunderstorms if they develop will be capable of producing heavy rainfall that may lead to excessive runoff and possibly flash flooding. STORM RAINFALL POTENTIAL AND DURATION: Rain showers will produce rainfall rates of a trace to 0.2" in 30-60 minutes. Persistent rain showers will have the potential to produce 0.2-0.4" in 30-60 minutes. WORST CASE SCENARIO: A weak to moderate thunderstorm is able to develop with the potential to produce brief heavy rainfall of 0.3-0.8" in 10-30 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 1159 PM Current TO 1159 PM Jefferson County 1 Current TO 1159 PM Current TO 1159 PM Broomfield County 1 Current TO 1159 PM Current TO 1159 PM Douglas County 1 Current TO 1159 PM Current TO 1159 PM Adams County 1 Current TO 1159 PM Current TO 1159 PM Denver County 1 Current TO 1159 PM Current TO 1159 PM DIA 1 Current TO 1159 PM Current TO 1159 PM Arapahoe County 1 Current TO 1159 PM Current TO 1159 PM the City of Aurora 1 Current TO 1159 PM Current TO 1159 PM Arvada 1 Current TO 1159 PM Current TO 1159 PM Wheat Ridge 1 Current TO 1159 PM Current TO 1159 PM Lakewood 1 Current TO 1159 PM Current TO 1159 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 60-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1000 AM SAT Trace (80%) to 0.2" (40%) to 0.4" (10%) NONE Arapahoe Current TO 1000 AM SAT Trace (60%) to 0.2" (30%) to 0.4" (5%) NONE Boulder Current TO 1000 AM SAT Trace (100%) to 0.2" (50%) to 0.4" (15%) NONE Broomfield Current TO 1000 AM SAT Trace (90%) to 0.2" (40%) to 0.4" (10%) NONE Denver Current TO 1000 AM SAT Trace (60%) to 0.2" (30%) to 0.4" (5%) NONE Douglas Current TO 1000 AM SAT Trace (60%) to 0.2" (30%) to 0.4" (5%) NONE Jefferson Current TO 1000 AM SAT Trace (80%) to 0.2" (40%) to 0.4" (10%) NONE Foothills above 6500ft       Boulder Current TO 1000 AM SAT Trace (100%) to 0.2" (40%) to 0.4" (10%) NONE Douglas Current TO 1000 AM SAT Trace (100%) to 0.2" (40%) to 0.4" (10%) NONE Jefferson Current TO 1000 AM SAT Trace (100%) to 0.2" (40%) to 0.4" (10%) NONE MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]