Time: 1001 AM Tue June 11, 2024 Forecaster: Laura Smith ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- Slight chances for isolated afternoon to evening showers and thunderstorms Drier air aloft is moving into Colorado from the northwest today as warmer surface conditions continue to build into the region from the south. Afternoon highs will reach the mid to upper 80s, dew points in the upper 40s to low 50s, and precipitable water (PWAT) values around 0.85”. These temperatures and moisture values favor heavy rainfall across the District, but a drying mid-level and weak upper-level flow will discourage organized convection. Due to these conflicting forces, there is still some uncertainty about the rainfall forecast today. However, heavy precipitation is still possible if afternoon orographic convection sufficiently erodes the capping inversion. If this scenario resolves, isolated storms are possible across the District, with the best chances south of i-70. Storm motions will be from west to east around 10 mph. Storms will begin clearing by the early evening, with precipitation concluding by the mid to late evening. STORM RAINFALL POTENTIAL AND DURATION: Typical showers could produce 0.25”-0.50” total in 15-30 minutes. Stronger storms have the potential to produce 0.50-0.75” in 15-30 minutes. WORST CASE SCENARIO: Stronger, slow-moving storms may produce moderate to briefly heavy rainfall up to 1.50” in 60 minutes. A LOOK AHEAD: Tomorrow will be exceptionally hot as a ridge of highs pressure advances north. Afternoon temperatures will soar into the mid 90s under sunny skies. Thursday will be similar as sweltering conditions persist. Highs will once again reach the mid 90s under sunny skies, followed by slight chances for isolated afternoon to evening showers and thunderstorms. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 800 PM 0.25" (15%) to 0.5" (10%) to 0.75" (5%) LOW Arapahoe 200 PM TO 800 PM 0.25" (20%) to 0.5" (15%) to 0.75" (10%) LOW Boulder 200 PM TO 800 PM 0.25" (15%) to 0.5" (10%) to 0.75" (5%) LOW Broomfield 200 PM TO 800 PM 0.25" (15%) to 0.5" (10%) to 0.75" (5%) LOW Denver 200 PM TO 800 PM 0.25" (20%) to 0.5" (15%) to 0.75" (10%) LOW Douglas 200 PM TO 800 PM 0.25" (20%) to 0.5" (15%) to 0.75" (10%) LOW Jefferson 200 PM TO 800 PM 0.25" (20%) to 0.5" (15%) to 0.75" (10%) LOW Foothills above 6500ft       Boulder 200 PM TO 700 PM 0.25" (15%) to 0.5" (10%) to 0.75" (5%) LOW Douglas 200 PM TO 800 PM 0.25" (20%) to 0.5" (15%) to 0.75" (10%) LOW Jefferson 200 PM TO 800 PM 0.25" (20%) to 0.5" (15%) to 0.75" (10%) LOW MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]