Flash Flood Prediction Program

Time: 212 PM Fri August 23, 2024 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1’S HAVE BEEN ISSUED EFFECTIVE UNTIL 7:00 PM Storms have started to initiate along the foothills and will start moving into the District over the next hour. Temperatures today reached the mid to upper 80s, combined with dew points in the low to mid 50s, storms today could potentially produce moderate to brief heavy rainfall. Storm motions will be from west to east, generally between 10-15mph with some erratic storm movement possibly along outflow boundaries. These outflow storms will likely have the most potential for heavy rainfall with a quick 0.5” in 10-20 minutes rather than any long-lasting rainfall. Storms may also contain hail up to 1.0”, frequent cloud-to-ground lightning and gusty winds up to 60mph. One round of showers and thunderstorms with moderate to heavy rainfall is expected today, with skies likely clearing out by sundown. A slight chance for a few overnight showers as temperatures drop into the low 60s on the plains with mid to upper 50s along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers/thunderstorms will produce a 0.05-0.30" total in 10-30 minutes. A moderate to strong thunderstorm will produce rainfall rates of 0.30”-0.70” total in 10-30 minutes. WORST CASE SCENARIO: A slow-moving stationary thunderstorm, training of thunderstorms cells or a large thunderstorm complex may result in up to 1.40” total rain in under 60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Broomfield County 1 Current TO 700 PM 230 PM TO 630 PM Jefferson County 1 Current TO 700 PM 230 PM TO 630 PM Boulder County 1 Current TO 700 PM 230 PM TO 630 PM Douglas County 1 Current TO 700 PM 230 PM TO 630 PM Adams County 1 Current TO 700 PM 230 PM TO 630 PM Denver County 1 Current TO 700 PM 230 PM TO 630 PM DIA 1 Current TO 700 PM 230 PM TO 630 PM Arapahoe County 1 Current TO 700 PM 230 PM TO 630 PM the City of Aurora 1 Current TO 700 PM 230 PM TO 630 PM Arvada 1 Current TO 700 PM 230 PM TO 630 PM Wheat Ridge 1 Current TO 700 PM 230 PM TO 630 PM Lakewood 1 Current TO 700 PM 230 PM TO 630 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 700 PM FRI 0.05" (75%) to 0.3" (50%) to 0.7" (25%) ISSUED Arapahoe Current TO 700 PM FRI 0.05" (75%) to 0.3" (50%) to 0.7" (25%) ISSUED Boulder Current TO 700 PM FRI 0.05" (75%) to 0.3" (50%) to 0.7" (25%) ISSUED Broomfield Current TO 700 PM FRI 0.05" (75%) to 0.3" (50%) to 0.7" (25%) ISSUED Denver Current TO 700 PM FRI 0.05" (75%) to 0.3" (50%) to 0.7" (25%) ISSUED Douglas Current TO 700 PM FRI 0.05" (80%) to 0.3" (60%) to 0.7" (30%) ISSUED Jefferson Current TO 700 PM FRI 0.05" (80%) to 0.3" (60%) to 0.7" (30%) ISSUED Foothills above 6500ft       Boulder Current TO 700 PM FRI 0.05" (80%) to 0.3" (60%) to 0.7" (30%) ISSUED Douglas Current TO 700 PM FRI 0.05" (80%) to 0.3" (60%) to 0.7" (30%) ISSUED Jefferson Current TO 700 PM FRI 0.05" (80%) to 0.3" (60%) to 0.7" (30%) 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]