Flash Flood Prediction Program

Time: 1159 AM Sat June 8, 2024 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1’S HAVE BEEN ISSUED EFFECTIVE UNTIL 8:00 PM Message 1’s have been issued for the entire District effective until 8:00pm as the threat for heavy rainfall with the potential for severe storms across the District this afternoon and early evening. The best chance for any shower/thunderstorm activity within the District will be between noon-8pm with a few lingering showers possible through 10pm. The best chance for heavy rainfall will be during the initial round of storms, with storm intensities decreasing into the evening hours. Storm motions will be west to east between 20-25mph which should also limit point rainfall amounts. However, outflow boundaries could produce erratic storm movement which will increase chances for brief heavy rainfall. Good upper-level support suggests at least a moderate chance for severe weather today, mainly for gusty winds 60+ mph and hail up to 1.0” in diameter likely favoring areas east of I-25. Severe storms will also contain isolated heavy rainfall with the largest threat being a quick 0.5” in 10-15min rather than any long-lasting heavy rainfall. Skies will clear this evening with dry conditions expected through the overnight as temperatures drop into the mid to upper 50s on the plains with upper 40s to around 50 degrees along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers and isolated thunderstorms will produce a 0.05-0.30” total in 10-30 minutes. A moderate to strong/severe shower/thunderstorm will produce 0.30-0.60” 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 1.20” total in under 60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Arvada 1 1200 PM TO 800 PM 100 PM TO 700 PM the City of Aurora 1 1200 PM TO 800 PM 100 PM TO 700 PM Denver County 1 1200 PM TO 800 PM 100 PM TO 700 PM Arapahoe County 1 1200 PM TO 800 PM 100 PM TO 700 PM DIA 1 1200 PM TO 800 PM 100 PM TO 700 PM Adams County 1 1200 PM TO 800 PM 100 PM TO 700 PM Douglas County 1 1200 PM TO 800 PM 100 PM TO 700 PM Broomfield County 1 1200 PM TO 800 PM 100 PM TO 700 PM Jefferson County 1 1200 PM TO 800 PM 100 PM TO 700 PM Boulder County 1 1200 PM TO 800 PM 100 PM TO 700 PM Wheat Ridge 1 1200 PM TO 800 PM 100 PM TO 700 PM Lakewood 1 1200 PM TO 800 PM 100 PM TO 700 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 1200 PM TO 800 PM 0.05" (90%) to 0.3" (60%) to 0.6" (30%) ISSUED Arapahoe 1200 PM TO 800 PM 0.05" (90%) to 0.3" (60%) to 0.6" (30%) ISSUED Boulder 1200 PM TO 800 PM 0.05" (90%) to 0.3" (60%) to 0.6" (30%) ISSUED Broomfield 1200 PM TO 800 PM 0.05" (90%) to 0.3" (60%) to 0.6" (30%) ISSUED Denver 1200 PM TO 800 PM 0.05" (90%) to 0.3" (60%) to 0.6" (30%) ISSUED Douglas 1200 PM TO 800 PM 0.05" (90%) to 0.3" (60%) to 0.6" (30%) ISSUED Jefferson 1200 PM TO 800 PM 0.05" (90%) to 0.3" (60%) to 0.6" (30%) ISSUED Foothills above 6500ft       Boulder 1200 PM TO 800 PM 0.05" (70%) to 0.3" (35%) to 0.6" (15%) ISSUED Douglas 1200 PM TO 800 PM 0.05" (70%) to 0.3" (35%) to 0.6" (15%) ISSUED Jefferson 1200 PM TO 800 PM 0.05" (70%) to 0.3" (35%) to 0.6" (15%) 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]