Time: 1201 PM Thu June 29, 2023 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1’S HAVE BEEN ISSUED FOR THE ENTIRE DISTRICT Message 1’s have been issued for the entire District effective until 1159pm. A few isolated storms are starting to initiate along the foothills currently and will continue to build over the next hour or two before moving into the District. Multiple rounds of strong to severe storms will be possible today with a good chance for heavy rainfall leading to localized flooding through the afternoon and evening. Typical storm movements will be from W/SW to E/NE between 5-10mph. Some erratic storm movements will be possible as storms form and stall out along outflow boundaries. These storms will likely have the highest chance of producing longer lasting heavy rainfall. Storms today will have the potential to produce both a quick 0.5” in 10 minutes as well as over 1” per hour rainfall if a storm stalls out for an extended time, or training of thunderstorms cells. Storm intensities should diminish after midnight tonight. However, if the heavy rainfall threat persists past midnight, Message 1’s may need to be extended. STORM RAINFALL POTENTIAL AND DURATION: Typical thunderstorms have the potential to produce moderate to heavy rainfall of 0.25-0.50" total, in 10-30 minutes. Strong thunderstorms have the potential to produce moderate to heavy rainfall of 0.5-1.5" total, in 10-30 minutes. WORST CASE SCENARIO: Stationary or training of slow-moving thunderstorms have the potential to produce up to 2.4” total, in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Denver County 1 100 PM TO 1159 PM 100 PM TO 1159 PM Adams County 1 100 PM TO 1159 PM 100 PM TO 1159 PM Douglas County 1 100 PM TO 1159 PM 100 PM TO 1159 PM Broomfield County 1 100 PM TO 1159 PM 100 PM TO 1159 PM Jefferson County 1 100 PM TO 1159 PM 100 PM TO 1159 PM Boulder County 1 100 PM TO 1159 PM 100 PM TO 1159 PM DIA 1 100 PM TO 1159 PM 100 PM TO 1159 PM Arapahoe County 1 100 PM TO 1159 PM 100 PM TO 1159 PM the City of Aurora 1 100 PM TO 1159 PM 100 PM TO 1159 PM Arvada 1 100 PM TO 1159 PM 100 PM TO 1159 PM Wheat Ridge 1 100 PM TO 1159 PM 100 PM TO 1159 PM Lakewood 1 100 PM TO 1159 PM 100 PM TO 1159 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 100 PM TO 1159 PM 0.25" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Arapahoe 100 PM TO 1159 PM 0.25" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Boulder 100 PM TO 1159 PM 0.25" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Broomfield 100 PM TO 1159 PM 0.25" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Denver 100 PM TO 1159 PM 0.25" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Douglas 100 PM TO 1159 PM 0.25" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Jefferson 100 PM TO 1159 PM 0.25" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Foothills above 6500ft       Boulder 100 PM TO 1159 PM 0.25" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Douglas 100 PM TO 1159 PM 0.25" (90%) to 0.5" (60%) to 1.5" (30%) ISSUED Jefferson 100 PM TO 1159 PM 0.25" (90%) to 0.5" (60%) to 1.5" (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]