Flash Flood Prediction Program

Time: 546 PM Mon August 22, 2022 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S CONTINUE VALID FOR PORTIONS OF THE DISTRICT - Message 1's continue valid for Adams, Arapahoe, Denver, Douglas and Jefferson Counties until 8:30 PM. - Isolated weak to moderate thunderstorms have develop along a wind convergence line that extended from Douglas County northeastward into Arapahoe and Adams Counties. These initial storms has produced a weak outflow boundary pushing back to the west and has initiated a weak storm over Denver and additional storms may develop into the evening. - Most storms will be weak but a moderate to briefly strong thunderstorm will be capable of producing heavy rainfall. Best chances for thunderstorms will be over the next 60-90 minutes and Message 1's are expected to be allowed to expire this evening. STORM RAINFALL POTENTIAL AND DURATION: Weak thunderstorms will produce 0.1-0.3" in 10-30 minutes. Moderate to strong thunderstorms will be capable of producing heavy rainfall rates of 0.3-0.8" in 10-30 minutes. WORST CASE SCENARIO: A nearly stationary strong thunderstorm will have the potential to produce up to 1.5" of rain in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Lakewood 1 100 PM TO 830 PM 200 PM TO 730 PM Wheat Ridge 1 100 PM TO 830 PM 200 PM TO 730 PM Arvada 1 100 PM TO 830 PM 200 PM TO 730 PM Jefferson County 1 100 PM TO 830 PM 200 PM TO 730 PM the City of Aurora 1 100 PM TO 830 PM 200 PM TO 730 PM Arapahoe County 1 100 PM TO 830 PM 200 PM TO 730 PM DIA 1 100 PM TO 830 PM 200 PM TO 730 PM Denver County 1 100 PM TO 830 PM 200 PM TO 730 PM Adams County 1 100 PM TO 830 PM 200 PM TO 730 PM Douglas County 1 100 PM TO 830 PM 200 PM TO 730 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 830 PM MON Trace (50%) to 0.3" (20%) to 0.8" (5%) ISSUED Arapahoe Current TO 830 PM MON Trace (60%) to 0.3" (30%) to 0.8" (10%) ISSUED Boulder Current TO 830 PM MON Trace (50%) to 0.3" (20%) to 0.8" (5%) LOW Broomfield Current TO 830 PM MON Trace (50%) to 0.3" (20%) to 0.8" (5%) LOW Denver Current TO 830 PM MON Trace (75%) to 0.3" (40%) to 0.8" (15%) ISSUED Douglas Current TO 830 PM MON Trace (75%) to 0.3" (40%) to 0.9" (15%) ISSUED Jefferson Current TO 830 PM MON Trace (60%) to 0.3" (30%) to 0.9" (10%) ISSUED Foothills above 6500ft       Boulder Current TO 830 PM MON Trace (60%) to 0.3" (30%) to 0.8" (10%) LOW Douglas Current TO 830 PM MON Trace (60%) to 0.3" (30%) to 0.8" (10%) ISSUED Jefferson Current TO 830 PM MON Trace (60%) to 0.3" (30%) to 0.8" (10%) 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]