Flash Flood Prediction Program

Time: 859 AM Sun May 12, 2024 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- Widespread scattered showers and thunderstorms this morning with afternoon and evening isolated showers/thunderstorms possible. An active weather pattern is upon the District this weekend with a round of widespread off and on showers this morning with a few imbedded thunderstorms. These showers have persisted this morning and will continue over the next several hours, slowly clearing out into the afternoon. As skies clear, a continued chance for a few isolated showers and possibly some more thunderstorms depending on how much we warm into the afternoon. Currently temperatures are expected to reach the mid to upper 60s, however, more sunshine will result in a better chance for thunderstorm activity this afternoon. Storm motions will shift from NE to SW to a more N to S orientation this afternoon with storm speeds between 10-15mph effectively limiting point rainfall amounts. If stronger storms develop, some slower storm motions will be possible as storms form along outflow boundaries, which could lead to some moderate to brief heavy rain bringing a LOW chance for Message 1s today. The best chance for thunderstorms will be between noon and 6pm with a few lingering showers possible into the later evening and overnight, although any threat of heavy rain will diminish this evening. A chance for a few lingering off and on showers overnight tonight with conditions clearing out tomorrow morning. Overnight lows will drop into the mid 40s. STORM RAINFALL POTENTIAL AND DURATION: Typical showers will produce rainfall rates of up to T-0.25” total in 15-30 minutes. Moderate showers or a thunderstorm will produce 0.25"-0.50" in 15-30 minutes. WORST CASE SCENARIO: Stronger showers/thunderstorms, or training of showers/thunderstorms will have the potential to produce up to 0.75” total rainfall 15-30 minutes. A LOOK AHEAD: This active pattern will hold throughout the week with storm chances every afternoon and evening. Tomorrow will likely be the least active day with only a slight chance of showers and possibly an isolated thunderstorm or two in the afternoon/evening. A better chance for impactful rainfall Wednesday and into Thursday with a slight chance for moderate to heavy rainfall both days. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 800 PM SUN Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Arapahoe Current TO 800 PM SUN Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Boulder Current TO 800 PM SUN Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Broomfield Current TO 800 PM SUN Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Denver Current TO 800 PM SUN Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Douglas Current TO 800 PM SUN Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Jefferson Current TO 800 PM SUN Trace (75%) to 0.25" (50%) to 0.5" (25%) LOW Foothills above 6500ft       Boulder Current TO 800 PM SUN Trace (90%) to 0.25" (60%) to 0.5" (30%) LOW Douglas Current TO 800 PM SUN Trace (90%) to 0.25" (60%) to 0.5" (30%) LOW Jefferson Current TO 800 PM SUN Trace (90%) to 0.25" (60%) to 0.5" (30%) 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]