Time: 922 AM Sat June 29, 2024 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- Cooler today behind a cold front with another chance for showers and thunderstorms this afternoon and early evening. A cooling trend is in store for the District as a cold front pushed through overnight resulting in high temperatures only reaching the low 80s rather than into the 90s this afternoon. These cooler temperatures could either help or hurt our cause today as storms could very well stay suppressed bringing a better chance for typical showers and thunderstorms rather than any strong or severe storm potential. The best chance for impactful storms today will be between 3-8pm with a few lingering showers possible until 10/11pm. Storms today will move from the W/SW to the E/NE between 10-15mph with some erratic storm movement possible along outflow boundaries. A slightly better chance of storms with impactful rainfall along the foothills and Palmer Divide this afternoon and early evening as storms anchor along the higher terrain before moving onto the plains. The largest threat for moderate to brief heavy rainfall will be a quick 0.50” in 10-30 minutes rather than any longer lasting rainfall. Storm today may also contain some hail and gusty wind gusts up to 40mph. Skies will gradually clear overnight with temperatures dropping into the low 60 for the plains with mid to upper 50s along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers and thunderstorms will produce a trace to 0.25” total in 10-30 minutes. A moderate to strong thunderstorm will produce 0.25-0.50” total in 10-30 minutes. WORST CASE SCENARIO: A strong, stationary thunderstorm, or training of thunderstorm cells has the potential to produce up to 1.00” in 30-60 minutes. A LOOK AHEAD: The peak of monsoonal moisture transport into Colorado is expected to be tomorrow, with warmer temperatures reaching back into the low 90s and atmospheric moisture levels hovering around 175% of normal. Scattered to widespread thunderstorm activity, some potentially severe, is expected in multiple rounds throughout the afternoon and evening Sunday, and storms are expected to be some of the most rain-loaded of the season so far. With a solid chunk of moisture falling Sunday but a similar atmospheric setup, Monday will bring similar temperatures in the low 90s and a decrease in thunderstorm activity. Tuesday cools off by a few degrees due to the passing of a trough to the north, which initiates another round of afternoon thunderstorms with its passing. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 300 PM TO 1100 PM Trace (60%) to 0.25" (30%) to 0.5" (15%) LOW Arapahoe 300 PM TO 1100 PM Trace (60%) to 0.25" (30%) to 0.5" (15%) LOW Boulder 300 PM TO 1100 PM Trace (60%) to 0.25" (30%) to 0.5" (15%) LOW Broomfield 300 PM TO 1100 PM Trace (60%) to 0.25" (30%) to 0.5" (15%) LOW Denver 300 PM TO 1100 PM Trace (60%) to 0.25" (30%) to 0.5" (15%) LOW Douglas 300 PM TO 1100 PM Trace (60%) to 0.25" (30%) to 0.5" (15%) LOW Jefferson 300 PM TO 1100 PM Trace (60%) to 0.25" (30%) to 0.5" (15%) LOW Foothills above 6500ft       Boulder 200 PM TO 1000 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Douglas 200 PM TO 1000 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Jefferson 200 PM TO 1000 PM Trace (75%) to 0.25" (50%) to 0.5" (25%) 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]