Time: 830 PM Thu May 18, 2023 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S WILL BE ALLOWED TO EXPIRE AT 9PM Message 1’s will be allowed to expire at 9:00 PM as the threat of heavy rainfall has come to an end. A few lingering light, to briefly moderate rain showers continue to impact portions of the District currently, however the threat of heavy rainfall has ended for the evening. The best chance for continued light shower activity will be from now through midnight, with the best chance for precipitation along the foothills through the rest of the evening. A slight chance for a few lingering off and on rain showers through daybreak tomorrow, with minimal additional rainfall expected at this time. Overnight lows will drop to around 50 degrees, with mid to upper 40’s along the foothills. The chance for rains showers continues tomorrow, with isolated thunderstorms in the afternoon, although the threat for heavy rainfall will be minimal at best. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers will produce a trace to 0.1” in 10-30 minutes. A moderate rain shower could produce 0.1-0.3” in 10-30 minutes. WORST CASE SCENARIO: A slower moving rain shower, isolated thunderstorm, or training of rain showers could potentially produce 0.3-0.8” in under 60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 900 PM Current TO 900 PM Jefferson County 1 Current TO 900 PM Current TO 900 PM Broomfield County 1 Current TO 900 PM Current TO 900 PM Douglas County 1 Current TO 900 PM Current TO 900 PM Adams County 1 Current TO 900 PM Current TO 900 PM Denver County 1 Current TO 900 PM Current TO 900 PM DIA 1 Current TO 900 PM Current TO 900 PM Arapahoe County 1 Current TO 900 PM Current TO 900 PM the City of Aurora 1 Current TO 900 PM Current TO 900 PM Arvada 1 Current TO 900 PM Current TO 900 PM Wheat Ridge 1 Current TO 900 PM Current TO 900 PM Lakewood 1 Current TO 900 PM Current TO 900 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 200 AM FRI Trace (60%) to 0.1" (30%) to 0.3" (10%) ISSUED Arapahoe Current TO 200 AM FRI Trace (60%) to 0.1" (30%) to 0.3" (10%) ISSUED Boulder Current TO 200 AM FRI Trace (60%) to 0.1" (30%) to 0.3" (10%) ISSUED Broomfield Current TO 200 AM FRI Trace (60%) to 0.1" (30%) to 0.3" (10%) ISSUED Denver Current TO 200 AM FRI Trace (60%) to 0.1" (30%) to 0.3" (10%) ISSUED Douglas Current TO 200 AM FRI Trace (60%) to 0.1" (30%) to 0.3" (10%) ISSUED Jefferson Current TO 200 AM FRI Trace (60%) to 0.1" (30%) to 0.3" (10%) ISSUED Foothills above 6500ft       Boulder Current TO 200 AM FRI Trace (80%) to 0.1" (40%) to 0.3" (20%) ISSUED Douglas Current TO 200 AM FRI Trace (80%) to 0.1" (40%) to 0.3" (20%) ISSUED Jefferson Current TO 200 AM FRI Trace (80%) to 0.1" (40%) to 0.3" (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]