Flash Flood Prediction Program

Time: 839 AM Mon May 22, 2023 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- SUNNY & HAZY WITH GENREALLY DRY CONDITIONS TODAY A weak ridge of high-pressure holds over the region today, likley leading to mild and dry conditions throughout the day. Hazy skies will remain in place as wildfire smoke from Canada continues to move into the region. Generally dry conditions are expected today, with a slight chance for a few high-based rain showers along the foothills and Palmer Divide this afternoon and early evening. Minimal, if any chances these showers make their way onto the plains as surface dewpoints expected to mix out into the upper 30’s to around 40 degrees this afternoon resulting in any foothills storms to mix out fairly quickly. Overnight lows will drop to around 50 degrees on the plains with mid 40’s along the foothills. Mild and dry conditions expected through the overnight and into Monday. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers will produce TR-0.05" in 10-30 minutes. A weak thunderstorm will have the potential to produce rainfall rates of 0.0.5-0.2" in 10-30 minutes. WORST CASE SCENARIO: A slow moving or stationary thunderstorm, or training of rain showers/thunderstorms may result in rainfall rates of up to 0.5" in 45-60 minutes. A LOOK AHEAD: A relatively weak disturbance moves into the region Tuesday afternoon, bringing a slightly better chance for scattered rain showers/isolated thunderstorms in the afternoon and evening, with a very slight chance for heavy rainfall at this time. A much better chance for widespread storms Wednesday with a good chance for moderate to heavy rainfall in the afternoon and evening leading to a good chance for some localized flooding. A slight chance some of these storms become severe, bringing gusty winds 60+mph and hail up to 1”. Similar conditions remain in place Thursday, however the threat for severe weather decreases significantly. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 700 PM Trace (5%) to 0.05" (1%) to 0.1" (0%) NONE Arapahoe 200 PM TO 700 PM Trace (5%) to 0.05" (1%) to 0.1" (0%) NONE Boulder 200 PM TO 700 PM Trace (5%) to 0.05" (1%) to 0.1" (0%) NONE Broomfield 200 PM TO 700 PM Trace (5%) to 0.05" (1%) to 0.1" (0%) NONE Denver 200 PM TO 700 PM Trace (5%) to 0.05" (1%) to 0.1" (0%) NONE Douglas 200 PM TO 700 PM Trace (5%) to 0.05" (1%) to 0.1" (0%) NONE Jefferson 200 PM TO 700 PM Trace (5%) to 0.05" (1%) to 0.1" (0%) NONE Foothills above 6500ft       Boulder 200 PM TO 700 PM Trace (20%) to 0.05" (10%) to 0.1" (5%) NONE Douglas 200 PM TO 700 PM Trace (20%) to 0.05" (10%) to 0.1" (5%) NONE Jefferson 200 PM TO 700 PM Trace (20%) to 0.05" (10%) to 0.1" (5%) NONE MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]