Flash Flood Prediction Program

Time: 829 AM Wed June 14, 2023 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- WARMER AND SUNNY TODAY WITH A SLIGHT CHANCE FOR AFTERNOON SHOWERS/ISOLATED THUNDERTORMS Westerly upper-level flow will dry things out for the most part today. Mostly sunny and mild conditions this morning, with a slight chance of a few isolated rain showers/thunderstorms this afternoon and early evening. Storms will likely initiate along the higher terrain by midday today. The best chance for storm activity in the District will be between 2-8pm. However, rain showers will generally be hit or miss, with most areas likely remaining dry. Moisture at the surface has decreased today, bringing a much less chance for heavy rainfall, although a quick 0.5” in 10-30 minutes cannot be completely ruled out today, leading to a LOW chance for Message 1’s this afternoon. This also coincides with the elevated rainfall this season, likely resulting in any rainfall to produce some minor flooding/standing water in the usual trouble spots, with creeks and streams also rising quickly with any precipitation in the area. Storms will subside into the evening with clearing skies through the overnight. Lows will drop into the low to mid 40’s for the plains with mid to upper 40’s for the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers will produce a trace to 0.25” total, in 10-30 minutes. A weak to moderate thunderstorm will produce 0.25-0.50” total in 10-30 minutes. WORST CASE SCENARIO: A stronger thunderstorm, or training of moderate showers/thunderstorms will have the potential to produce 1.0” total in 45-60 minutes. A LOOK AHEAD: An uptick in moisture, combined with a disturbance that will move overhead tomorrow, will result in a better chance for widespread rain showers and thunderstorms. These storm chances will likely initiate in the late morning hours tomorrow, with multiple rounds of showers and thunderstorms through the afternoon and into the evening. A good chance some of these showers will produce heavy rainfall throughout the day tomorrow. Not much chance in the overall pattern for Friday, with another good chance for active weather in the afternoon and early evening. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 800 PM Trace (40%) to 0.25" (20%) to 0.5" (10%) LOW Arapahoe 200 PM TO 800 PM Trace (40%) to 0.25" (20%) to 0.5" (10%) LOW Boulder 200 PM TO 800 PM Trace (40%) to 0.25" (20%) to 0.5" (10%) LOW Broomfield 200 PM TO 800 PM Trace (40%) to 0.25" (20%) to 0.5" (10%) LOW Denver 200 PM TO 800 PM Trace (40%) to 0.25" (20%) to 0.5" (10%) LOW Douglas 200 PM TO 800 PM Trace (40%) to 0.25" (20%) to 0.5" (10%) LOW Jefferson 200 PM TO 800 PM Trace (40%) to 0.25" (20%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder 200 PM TO 800 PM Trace (50%) to 0.25" (25%) to 0.5" (15%) LOW Douglas 200 PM TO 800 PM Trace (50%) to 0.25" (25%) to 0.5" (15%) LOW Jefferson 200 PM TO 800 PM Trace (50%) to 0.25" (25%) to 0.5" (15%) 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]