Time: 1249 PM Mon August 19, 2024 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1’S HAVE BEEN ISSUED EFFECTIVE UNTIL 9:30 PM A couple of thunderstorms have developed along the higher terrain foothills and Palmer Divide and are expected to slowly move into the District over the next hour or two. Temperature have reached the mid to upper 80s already despite the cloud cover this morning, combined with dew points around 50 degrees, with pockets of mid 50s, should provide enough heat and moisture for moderate to heavy rainfall today. Typical storms motions will be from the SW to NE between 10-15mph, which could help limit some point rainfall amounts. However, additional storms will likely develop along outflow boundaries today, leading to an increased chance of heavy rainfall with localized flooding this afternoon and early evening. The best chance for shower/thunderstorm activity will be in the next hour, lasting until sundown before skies gradually start to clear into the later evening. Storms today may also contain gusty winds, up to 60mph and medium to large hail up to 1.0” with severe storms possible, favoring areas east of I-25 and out on the eastern plains. Overnight conditions will be mild and dry as temperatures drop into the low 60s on the plains with mid to upper 50s along the foothills. Conditions dry out tomorrow with high temperatures jumping back into the 90s. STORM RAINFALL POTENTIAL AND DURATION: Typical showers/thunderstorms will produce a 0.30-0.80" total in 10-30 minutes. A moderate to strong thunderstorm will produce rainfall rates of 0.80”-1.50” total in 10- 30 minutes. WORST CASE SCENARIO: A slow-moving thunderstorm, training of thunderstorms cells or a large thunderstorm complex may result in up to 2.25” total rain in 60-90 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 930 PM 100 PM TO 900 PM Jefferson County 1 Current TO 930 PM 100 PM TO 900 PM Broomfield County 1 Current TO 930 PM 100 PM TO 900 PM Douglas County 1 Current TO 930 PM 100 PM TO 900 PM Adams County 1 Current TO 930 PM 100 PM TO 900 PM Denver County 1 Current TO 930 PM 100 PM TO 900 PM DIA 1 Current TO 930 PM 100 PM TO 900 PM Arapahoe County 1 Current TO 930 PM 100 PM TO 900 PM the City of Aurora 1 Current TO 930 PM 100 PM TO 900 PM Arvada 1 Current TO 930 PM 100 PM TO 900 PM Wheat Ridge 1 Current TO 930 PM 100 PM TO 900 PM Lakewood 1 Current TO 930 PM 100 PM TO 900 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 930 PM MON 0.3" (75%) to 0.8" (50%) to 1.5" (25%) ISSUED Arapahoe Current TO 930 PM MON 0.3" (75%) to 0.8" (50%) to 1.5" (25%) ISSUED Boulder Current TO 930 PM MON 0.3" (60%) to 0.8" (30%) to 1.5" (15%) ISSUED Broomfield Current TO 930 PM MON 0.3" (60%) to 0.8" (30%) to 1.5" (15%) ISSUED Denver Current TO 930 PM MON 0.3" (75%) to 0.8" (50%) to 1.5" (25%) ISSUED Douglas Current TO 930 PM MON 0.3" (75%) to 0.8" (50%) to 1.5" (25%) ISSUED Jefferson Current TO 930 PM MON 0.3" (60%) to 0.8" (30%) to 1.5" (15%) ISSUED Foothills above 6500ft       Boulder Current TO 930 PM MON 0.3" (60%) to 0.8" (40%) to 1.5" (20%) ISSUED Douglas Current TO 930 PM MON 0.3" (60%) to 0.8" (40%) to 1.5" (20%) ISSUED Jefferson Current TO 930 PM MON 0.3" (60%) to 0.8" (40%) to 1.5" (20%) ISSUED MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]