Time: 846 AM Wed July 14, 2021 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- COOL AGAIN TODAY WITH A GOOD CHANCE FOR AFTERNOON & EVENING RAIN SHOWERS/THUNDERSTORMS - Cloudy and cool to start the day with partly cloudy to cloudy skies continuing throughout the day. High temperatures will reach the upper 70's to low 80's on the plains with low to mid 70's along the foothills. Elevated surface moisture is in place from a persistent influx of low-level moisture from the N/NE through the overnight and into this morning will increase the chances for heavy rainfall this afternoon and evening. - Although temperatures are rather cool today, an upper-level disturbance will initiate storms over the higher terrain by midday today. These storms will move into the District between 1-3pm this afternoon. Storm motions will be relatively fast between 10-15mph from west to east initially which will help limit some point rainfall amounts, however storms that form along outflow boundaries will likely move slowly and or erratically today leading to a good chance for isolated heavy rainfall. Storms also have a slight chance of becoming severe with strong winds and large hail. Best chance for storms in the District will be until sunset, with a slight chance for lingering rain showers/isolated thunderstorms until 10pm before skies start to gradually clear through the overnight. - Overnight will be generally mild as any rainfall chances taper off completely before midnight. Temperatures will drop into the low to mid 60's for most of the plains areas with mid to upper 50's along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce 0.1-0.4" of rainfall. Strong thunderstorms will have the potential to produce 0.4-1.2" in 10-30 minutes. WORST CASE SCENARIO: A nearly stationary strong thunderstorm may result in up to 2.4" of heavy rain in 45-75 minutes. A LOOK AHEAD: Afternoon/early evening rain showers and isolated thunderstorms will remain in play through the weekend. Temperatures will begin to warm tomorrow as high-pressure starts to slowly build back over the region. A bit drier air begins to move into the region tomorrow as well, which will decrease chances for heavy rainfall. Similar conditions Friday with a good chance for afternoon rain showers/isolated thunderstorms. Again, since the high-pressure ridge is building back, this will limit the potential for heavy rainfall, however, slow storms motions could create pockets of brief heavy rain. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 900 PM 0.1" (80%) to 0.4" (50%) to 1.2" (25%) HIGH Arapahoe 200 PM TO 900 PM 0.1" (80%) to 0.4" (50%) to 1.2" (25%) HIGH Boulder 200 PM TO 900 PM 0.1" (80%) to 0.4" (50%) to 1.2" (25%) HIGH Broomfield 200 PM TO 900 PM 0.1" (80%) to 0.4" (50%) to 1.2" (25%) HIGH Denver 200 PM TO 900 PM 0.1" (80%) to 0.4" (50%) to 1.2" (25%) HIGH Douglas 200 PM TO 900 PM 0.1" (80%) to 0.4" (50%) to 1.2" (25%) HIGH Jefferson 200 PM TO 900 PM 0.1" (80%) to 0.4" (50%) to 1.2" (25%) HIGH Foothills above 6500ft       Boulder 200 PM TO 900 PM 0.1" (80%) to 0.4" (40%) to 1.2" (20%) HIGH Douglas 200 PM TO 900 PM 0.1" (80%) to 0.4" (40%) to 1.2" (20%) HIGH Jefferson 200 PM TO 900 PM 0.1" (80%) to 0.4" (40%) to 1.2" (20%) HIGH MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]