Time: 342 PM Sat July 29, 2023 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- A GOOD CHANCE FOR AFTERNOON SHOWERS AND THUNDERSTORMS WITH A SLIGHT CHANCE SOME OF THOSE STORMS BECOME SEVERE Message 1’s have been issued for the entire District effective until 9pm. A few isolated storms have formed along the higher terrain west of the District and will move through the District over the next several hours before storm chances taper off after sundown. A boundary has also been set up along the eastern portion of the District which will likely be the focal point for stronger storm development heading into the evening with the potential some of the storms become severe. These severe storms will have strong winds, 60+ mph, hail up to 1.5". The best chance for storms will be from now through 8pm with a few lingering showers through 9pm. Storm motions will typically be from west to east between 15-20mph, which should help limit point rainfall amounts. However, storms that form along outflow boundaries have the potential to stall out and bring moderate to heavy rainfall for an extended period of time. These storms will likely have the best chance of heavy rainfall leading to LOW IMPACT FLOODING with both threats of a quick 0.5” in 10-15 minutes, and a chance for rainfall over 1” in some spots, favoring eastern portions of the District at this time. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers, weak thunderstorms will produce a 0.10-0.50” total in 10-30 minute. A moderate to strong thunderstorm will produce 0.50-1.50” total in 10-30 minutes. WORST CASE SCENARIO: A strong, anchored thunderstorm will have the potential to produce 2.50” in 60-75 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 900 PM Current TO 830 PM Jefferson County 1 Current TO 900 PM Current TO 830 PM Broomfield County 1 Current TO 900 PM Current TO 830 PM Douglas County 1 Current TO 900 PM Current TO 830 PM Adams County 1 Current TO 900 PM Current TO 830 PM Denver County 1 Current TO 900 PM Current TO 830 PM DIA 1 Current TO 900 PM Current TO 830 PM Arapahoe County 1 Current TO 900 PM Current TO 830 PM the City of Aurora 1 Current TO 900 PM Current TO 830 PM Arvada 1 Current TO 900 PM Current TO 830 PM Wheat Ridge 1 Current TO 900 PM Current TO 830 PM Lakewood 1 Current TO 900 PM Current TO 830 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 900 PM SAT 0.1" (75%) to 0.5" (50%) to 1.5" (25%) ISSUED Arapahoe Current TO 900 PM SAT 0.1" (75%) to 0.5" (50%) to 1.5" (25%) ISSUED Boulder Current TO 900 PM SAT 0.1" (75%) to 0.5" (50%) to 1.5" (25%) ISSUED Broomfield Current TO 900 PM SAT 0.1" (75%) to 0.5" (50%) to 1.5" (25%) ISSUED Denver Current TO 900 PM SAT 0.1" (75%) to 0.5" (50%) to 1.5" (25%) ISSUED Douglas Current TO 900 PM SAT 0.1" (75%) to 0.5" (50%) to 1.5" (25%) ISSUED Jefferson Current TO 900 PM SAT 0.1" (75%) to 0.5" (50%) to 1.5" (25%) ISSUED Foothills above 6500ft       Boulder Current TO 900 PM SAT 0.1" (75%) to 0.5" (50%) to 1.5" (25%) ISSUED Douglas Current TO 900 PM SAT 0.1" (75%) to 0.5" (50%) to 1.5" (25%) ISSUED Jefferson Current TO 900 PM SAT 0.1" (75%) to 0.5" (50%) to 1.5" (25%) 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]