Time: 906 AM Sun June 30, 2024 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- Warmer today with another chance for afternoon and evening showers/isolated thunderstorms Once again, very little change to the overall pattern will bring similar conditions as yesterday across the District. Due to late evening precipitation yesterday, dew points currently in the upper 50s to around 60 and will result in an increased chance for moderate to brief heavy rainfall today. Temperatures will reach the low 90s this afternoon with partly cloudy skies. There will be a chance for a couple of rounds of storms today, the first this afternoon, likely between 2-5pm and another late round between 7pm-10pm. A few lingering showers will be possible during the overnight, although the largest threat for moderate to heavy rainfall will be during the initial round and possibly into the later evening. A very slight chance storms become severe today, mainly for areas east of the District, with gusty winds up to 60mph and hail up to 1.0” in diameter. Initial storm development will occur by midday along the higher elevations and move into the District during the early afternoon. Storm motions will generally be between 10-20mph which should help limit point rainfall amounts. However, stronger storms could produce outflow boundaries, likely resulting in some erratic storm movement leading to a better chance of isolated moderate to heavy rainfall. The largest threat today will most likely be a quick 0.50-1.00” in 10-30 minutes, rather than any long-lasting rainfall. Storms will lose intensity into the evening hours with isolated showers possible between 7pm-10pm, although a few embedded thunderstorms cannot be completely ruled out. A few lingering showers overnight as temperatures decrease into the low to mid 60s on the plains with upper 50s to around 60 degrees along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers and isolated thunderstorms will produce a 0.10-0.50” total in 10-30 minutes. A moderate to strong shower/thunderstorm will produce 0.50-1.00” total in 10-30 minutes. WORST CASE SCENARIO: A strong, stationary thunderstorm, or training of thunderstorm cells will have the potential to produce up to 2.00” total in 30-60 minutes. A LOOK AHEAD: Tomorrow will start to dry out at the surface with more typical dew points in the upper 30s to low 40s in the afternoon. A chance for afternoon showers and isolated thunderstorms will be possible, although with decreased dew points, high-based storms will be possible with minimal rainfall expected at this time. Tuesday will be similar with another chance for high-based afternoon and evening showers/isolated thunderstorms with minimal precipitation as most struggle to reach the surface during peak daytime heating. This will likely result in gusty sprinkles rather than any meaningful rainfall. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 1159 PM 0.1" (70%) to 0.5" (35%) to 1" (15%) MOD Arapahoe 200 PM TO 1159 PM 0.1" (70%) to 0.5" (35%) to 1" (15%) MOD Boulder 200 PM TO 1159 PM 0.1" (60%) to 0.5" (30%) to 1" (15%) MOD Broomfield 200 PM TO 1159 PM 0.1" (60%) to 0.5" (30%) to 1" (15%) MOD Denver 200 PM TO 1159 PM 0.1" (70%) to 0.5" (35%) to 1" (15%) MOD Douglas 200 PM TO 1159 PM 0.1" (60%) to 0.5" (30%) to 1" (15%) MOD Jefferson 200 PM TO 1159 PM 0.1" (60%) to 0.5" (30%) to 1" (15%) MOD Foothills above 6500ft       Boulder 200 PM TO 1159 PM 0.1" (60%) to 0.5" (30%) to 1" (15%) MOD Douglas 200 PM TO 1159 PM 0.1" (60%) to 0.5" (30%) to 1" (15%) MOD Jefferson 200 PM TO 1159 PM 0.1" (60%) to 0.5" (30%) to 1" (15%) MOD MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]