Flash Flood Prediction Program

Time: 133 AM Fri June 30, 2023 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1’S HAVE BEEN ISSUED FOR PORTIONS OF THE DISTRICT UNTIL 4AM Message 1’s have been reissued for Arapahoe County, including Aurora, and Douglas County effective until 4am. A moderate late evening thunderstorm moved through northern portions of the District setting off and outflow boundary into Douglas County. This has initiated strong storm development in these late hours and will likely continue for southern portions of the District through the early morning hours. Storms have already produced over 1” of rainfall near the Lone Tree area, with storms continuing to move E/NE between 10-20mph at this time. Even with these speeds, quick heavy rainfall is expected under some of these storms as they continue eastward and out of the District by daybreak. STORM RAINFALL POTENTIAL AND DURATION: Typical thunderstorms have the potential to produce moderate to heavy rainfall of 0.20-0.40" total, in 10-30 minutes. Strong thunderstorms have the potential to produce moderate to heavy rainfall of 0.4-1.2" total, in 10-30 minutes. WORST CASE SCENARIO: Stationary or training of slow-moving thunderstorms have the potential to produce up to 2.0” total, in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 400 AM Current TO 330 AM Jefferson County 1 Current TO 400 AM Current TO 330 AM Broomfield County 1 Current TO 400 AM Current TO 330 AM Douglas County 1 Current TO 400 AM Current TO 330 AM Adams County 1 Current TO 400 AM Current TO 330 AM Denver County 1 Current TO 400 AM Current TO 330 AM DIA 1 Current TO 400 AM Current TO 330 AM Arapahoe County 1 Current TO 400 AM Current TO 330 AM the City of Aurora 1 Current TO 400 AM Current TO 330 AM Arvada 1 Current TO 400 AM Current TO 330 AM Wheat Ridge 1 Current TO 400 AM Current TO 330 AM Lakewood 1 Current TO 400 AM Current TO 330 AM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 400 AM FRI 0.2" (15%) to 0.4" (10%) to 1.2" (5%) NONE Arapahoe Current TO 400 AM FRI 0.2" (75%) to 0.4" (50%) to 1.2" (25%) ISSUED Boulder Current TO 400 AM FRI 0.2" (15%) to 0.4" (10%) to 1.2" (5%) NONE Broomfield Current TO 400 AM FRI 0.2" (15%) to 0.4" (10%) to 1.2" (5%) NONE Denver Current TO 400 AM FRI 0.2" (15%) to 0.4" (10%) to 1.2" (5%) NONE Douglas Current TO 400 AM FRI 0.2" (75%) to 0.4" (50%) to 1.2" (25%) ISSUED Jefferson Current TO 400 AM FRI 0.2" (15%) to 0.4" (10%) to 1.2" (5%) NONE Foothills above 6500ft       Boulder Current TO 400 AM FRI 0.2" (15%) to 0.4" (10%) to 1.2" (5%) NONE Douglas Current TO 400 AM FRI 0.2" (60%) to 0.4" (30%) to 1.2" (10%) ISSUED Jefferson Current TO 400 AM FRI 0.2" (15%) to 0.4" (10%) to 1.2" (5%) 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]