Time: 1129 AM Thu June 1, 2023 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S ISSUED FOR THE ENTIRE DISTRICT Message 1’s have been issued for the entire District and will be valid until 9:00pm this evening. Storm have initiated along the higher terrain at this time and should move into the District in the next hour or two. Currently temperatures have been fairly suppressed with upper 50’s to low 60’s across the District. These cooler temperatures could help limit storm strength heading into this afternoon, however, with this approaching disturbance, combined with dew points currently in the low 50’s, there will be a good chance for moderate to heavy rainfall this afternoon and evening even out of weak to moderate thunderstorms. The best chance for showers and thunderstorms will be from 1-9pm with lingering rain showers possible through midnight. Storm motions today will continue from the S/SW to N/NE for the most part, with additional storms likely forming along outflow boundaries. These outflow storms will likely have the highest chance of bringing localized heavy rainfall as the storm movements will be non-existent at times. There will be multiple rounds of storms possible today as well, however the initial round should have highest chance for impactful rain showers, with additional rounds likely becoming much weaker into the evening hours. STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce 0.1-0.3” of rain in 10-30 minutes. Strong thunderstorms will have the potential to produce rainfall rates of 0.3-0.8” in 10-30 minutes. WORST CASE SCENARIO: A nearly stationary strong thunderstorm may result in up to 1.6” of rain in 45-75 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 1200 PM TO 900 PM 100 PM TO 830 PM Jefferson County 1 1200 PM TO 900 PM 100 PM TO 830 PM Broomfield County 1 1200 PM TO 900 PM 100 PM TO 830 PM Douglas County 1 1200 PM TO 900 PM 100 PM TO 830 PM Adams County 1 1200 PM TO 900 PM 100 PM TO 830 PM Denver County 1 1200 PM TO 900 PM 100 PM TO 830 PM DIA 1 1200 PM TO 900 PM 100 PM TO 830 PM Arapahoe County 1 1200 PM TO 900 PM 100 PM TO 830 PM the City of Aurora 1 1200 PM TO 900 PM 100 PM TO 830 PM Arvada 1 1200 PM TO 900 PM 100 PM TO 830 PM Wheat Ridge 1 1200 PM TO 900 PM 100 PM TO 830 PM Lakewood 1 1200 PM TO 900 PM 100 PM TO 830 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 1200 PM TO 900 PM 0.1" (90%) to 0.3" (60%) to 0.8" (20%) ISSUED Arapahoe 1200 PM TO 900 PM 0.1" (90%) to 0.3" (60%) to 0.8" (20%) ISSUED Boulder 1200 PM TO 900 PM 0.1" (90%) to 0.3" (60%) to 0.8" (20%) ISSUED Broomfield 1200 PM TO 900 PM 0.1" (90%) to 0.3" (60%) to 0.8" (20%) ISSUED Denver 1200 PM TO 900 PM 0.1" (90%) to 0.3" (60%) to 0.8" (20%) ISSUED Douglas 1200 PM TO 900 PM 0.1" (90%) to 0.3" (60%) to 0.8" (20%) ISSUED Jefferson 1200 PM TO 900 PM 0.1" (90%) to 0.3" (60%) to 0.8" (20%) ISSUED Foothills above 6500ft       Boulder 1200 PM TO 900 PM 0.1" (90%) to 0.3" (80%) to 0.8" (40%) ISSUED Douglas 1200 PM TO 900 PM 0.1" (90%) to 0.3" (80%) to 0.8" (40%) ISSUED Jefferson 1200 PM TO 900 PM 0.1" (90%) to 0.3" (80%) to 0.8" (40%) 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]