Time: 105 PM Mon August 15, 2022 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S AND 2'S ISSUED FOR THE DISTRICT - Message 1's have been issued for Adams, Arapahoe, Broomfield and Denver Counties and will be valid until midnight tonight. Message 2's (NWS Flood/Flash Flood Watch) have been issued for Boulder, Douglas and Jefferson Counties and will also be valid until midnight. Although Message 1's and 2's are issued for differing Counties the threat level for heavy rainfall is elevated all areas within the District. - Thunderstorms are beginning to develop over the higher terrain to the W and upper level steering winds will push these storms eastward as the afternoon progresses. Numerous showers and thunderstorms or multiple rounds of showers and thunderstorms are expected into the evening. Moderate to strong thunderstorms will be very capable of producing heavy rainfall. - The greatest threats for extended periods of heavy rainfall today will be from training of thunderstorm cells or a large, slower moving thunderstorm. The first or second round of storms will most likely be the strongest of the day but subsequent storms will be very efficient rainfall producers and even weak thunderstorms will be capable of producing heavy rain into the evening. STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce rainfall rates of 0.3-0.8" in 10-30 minutes. Strong thunderstorms will have the potential to produce heavy rainfall rates of 0.8-2.2" in 10-30 minutes. WORST CASE SCENARIO: Training of thunderstorm cells or a large/slower moving thunderstorm may produce up to 3.5" of rain in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Lakewood 2 100 PM TO 1159 PM 200 PM TO 1000 PM Wheat Ridge 2 100 PM TO 1159 PM 200 PM TO 1000 PM the City of Aurora 1 100 PM TO 1159 PM 200 PM TO 1000 PM Arapahoe County 1 100 PM TO 1159 PM 200 PM TO 1000 PM Denver County 1 100 PM TO 1159 PM 200 PM TO 1000 PM DIA 1 100 PM TO 1159 PM 200 PM TO 1000 PM Douglas County 2 100 PM TO 1159 PM 200 PM TO 1000 PM Adams County 1 100 PM TO 1159 PM 200 PM TO 1000 PM Broomfield County 1 100 PM TO 1159 PM 200 PM TO 1000 PM Boulder County 2 100 PM TO 1159 PM 200 PM TO 1000 PM Jefferson County 2 100 PM TO 1159 PM 200 PM TO 1000 PM Arvada 2 100 PM TO 1159 PM 200 PM TO 1000 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 1159 PM 0.5" (75%) to 1.3" (50%) to 2.0" (25%) ISSUED Arapahoe 200 PM TO 1159 PM 0.5" (90%) to 1.3" (60%) to 2.0" (30%) ISSUED Boulder 200 PM TO 1159 PM 0.5" (80%) to 1.3" (60%) to 2.0" (30%) ISSUED Broomfield 200 PM TO 1159 PM 0.5" (75%) to 1.3" (50%) to 2.0" (25%) ISSUED Denver 200 PM TO 1159 PM 0.5" (80%) to 1.3" (60%) to 2.0" (30%) ISSUED Douglas 200 PM TO 1159 PM 0.5" (90%) to 1.3" (60%) to 2.0" (30%) ISSUED Jefferson 200 PM TO 1159 PM 0.5" (90%) to 1.3" (60%) to 2.0" (30%) ISSUED Foothills above 6500ft       Boulder Current TO 1159 PM MON 0.5" (95%) to 1.3" (65%) to 2.0" (30%) ISSUED Douglas Current TO 1159 PM MON 0.5" (95%) to 1.3" (65%) to 2.0" (30%) ISSUED Jefferson Current TO 1159 PM MON 0.5" (95%) to 1.3" (65%) to 2.0" (30%) 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]