Flash Flood Prediction Program

Time: 858 PM Wed May 31, 2023 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S WILL BE ALLOWED TO EXPIRE AT 10PM Message 1’s will be allowed to expire at 10pm as the threat of heavy rainfall has ended for the day. A few showers persist over the District at this time, however, the threat of heavy rainfall has come to an end. These showers and a weak thunderstorm or two will last for the next few hours favoring areas W of I-25 over the foothills, before gradually clearing into the overnight. Storm motions continue to be south to north, with areas along the foothills and west of I25 having the best chance for rain showers through the rest of the evening. Not much change in the overall pattern heading into tomorrow with another good chance for widespread afternoon/eve rain showers and thunderstorms. There will continue to be a chance of severe weather under stronger storms, mainly for gusty winds and hail up to an inch. These strong thunderstorms will likely contain pockets of heavy rainfall which could lead to isolated flash flooding. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers will produce a TR-0.2” in 10-30 minutes. A moderate rain shower, or a weak thunderstorm could produce 0.2-0.4” in 10-30 minutes. WORST CASE SCENARIO: A moderate to strong thunderstorm has the potential to produce 0.4-0.8” in up to 60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 1000 PM Current TO 900 PM Jefferson County 1 Current TO 1000 PM Current TO 900 PM Broomfield County 1 Current TO 1000 PM Current TO 900 PM Douglas County 1 Current TO 1000 PM Current TO 900 PM Adams County 1 Current TO 1000 PM Current TO 900 PM Denver County 1 Current TO 1000 PM Current TO 900 PM DIA 1 Current TO 1000 PM Current TO 900 PM Arapahoe County 1 Current TO 1000 PM Current TO 900 PM the City of Aurora 1 Current TO 1000 PM Current TO 900 PM Arvada 1 Current TO 1000 PM Current TO 900 PM Wheat Ridge 1 Current TO 1000 PM Current TO 900 PM Lakewood 1 Current TO 1000 PM Current TO 900 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1159 PM WED Trace (50%) to 0.2" (20%) to 0.4" (10%) NONE Arapahoe Current TO 1159 PM WED Trace (50%) to 0.2" (20%) to 0.4" (10%) NONE Boulder Current TO 1159 PM WED Trace (85%) to 0.2" (40%) to 0.4" (10%) NONE Broomfield Current TO 1159 PM WED Trace (65%) to 0.2" (30%) to 0.4" (10%) NONE Denver Current TO 1159 PM WED Trace (50%) to 0.2" (20%) to 0.4" (10%) NONE Douglas Current TO 1159 PM WED Trace (50%) to 0.2" (20%) to 0.4" (10%) NONE Jefferson Current TO 1159 PM WED Trace (80%) to 0.2" (40%) to 0.4" (10%) NONE Foothills above 6500ft       Boulder Current TO 1159 PM WED Trace (95%) to 0.2" (60%) to 0.4" (20%) NONE Douglas Current TO 1159 PM WED Trace (95%) to 0.2" (60%) to 0.4" (20%) NONE Jefferson Current TO 1159 PM WED Trace (95%) to 0.2" (60%) to 0.4" (20%) NONE MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]