Time: 517 PM Sat August 5, 2023 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- SHOWERS CURRENTLY OVER PORTIONS OF THE DISRTICT WITH AN APPROACHING GUST FRONT COULD PRODUCE RAPID STORM DEVELOPMENT OVER THE FEW HOURS The Denver metro was able to miss stronger storms so far today and this could continue, however, a gust front approaches from the east with an uptick in surface moisture. This uptick combined with good upper-level support in and and around the area will bring a chance for rapid storm development leading to localized heavy rainfall. Stronger storms will favor eastern portions of the District at this time. Showers and weak thunderstorms that have developed are currently moving fairly quick, between 25-30mph, although strong storms that form along outflow boundaries could stall out and produce a quick 0.5-1.0” in 10-30 minutes. The best chance for storms will be between now and 9pm, with a few off and on showers through the late evening. Note: if stronger storms are able to develop, there is potential for large hail 1+”, gusty winds 60mph, and frequent cloud-to-ground. STORM RAINFALL POTENTIAL AND DURATION: Typical showers/thunderstorms will produce a 0.05-0.25” total in 10 to 30 minutes. A moderate thunderstorm will produce 0.25” to 0.50” total in 10 to 30 minutes. A strong thunderstorm will produce 0.50” to 1.00” total in 10 to 30 minutes. WORST CASE SCENARIO: An anchored strong thunderstorm or training of thunderstorm cells has the potential to produce up to 1.75” in under 60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 900 PM Current TO 800 PM Jefferson County 1 Current TO 900 PM Current TO 800 PM Broomfield County 1 Current TO 900 PM Current TO 800 PM Douglas County 1 Current TO 900 PM Current TO 800 PM Adams County 1 Current TO 900 PM Current TO 800 PM Denver County 1 Current TO 900 PM Current TO 800 PM DIA 1 Current TO 900 PM Current TO 800 PM Arapahoe County 1 Current TO 900 PM Current TO 800 PM the City of Aurora 1 Current TO 900 PM Current TO 800 PM Arvada 1 Current TO 900 PM Current TO 800 PM Wheat Ridge 1 Current TO 900 PM Current TO 800 PM Lakewood 1 Current TO 900 PM Current TO 800 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 900 PM SAT 0.25" (50%) to 0.5" (25%) to 1" (15%) ISSUED Arapahoe Current TO 900 PM SAT 0.25" (50%) to 0.5" (25%) to 1" (15%) ISSUED Boulder Current TO 900 PM SAT 0.25" (50%) to 0.5" (25%) to 1" (15%) ISSUED Broomfield Current TO 900 PM SAT 0.25" (50%) to 0.5" (25%) to 1" (15%) ISSUED Denver Current TO 900 PM SAT 0.25" (50%) to 0.5" (25%) to 1" (15%) ISSUED Douglas Current TO 900 PM SAT 0.25" (50%) to 0.5" (25%) to 1" (15%) ISSUED Jefferson Current TO 900 PM SAT 0.25" (50%) to 0.5" (25%) to 1" (15%) ISSUED Foothills above 6500ft       Boulder Current TO 900 PM SAT 0.25" (50%) to 0.5" (25%) to 1" (15%) ISSUED Douglas Current TO 900 PM SAT 0.25" (50%) to 0.5" (25%) to 1" (15%) ISSUED Jefferson Current TO 900 PM SAT 0.25" (50%) to 0.5" (25%) to 1" (15%) 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]