Time: 554 PM Tue May 9, 2023 Forecaster: Justin Brooks ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S ISSUED FOR THE ENTIRE DISTRICT Message 1's have been issued for the entire District and will be valid until 2:00 AM tomorrow morning. Persistent easterly surface level flow, combined with an incoming upper-level disturbance has initiated a line of thunderstorms through the District at this time. These storms have rapidly developed and will be capable of heavy rainfall, which could produce localized flooding. The best chance for storms will be from now through 8pm with another round of overnight rain showers possible between 10pm and 2am. Off and on rain shower chances will continue overnight and into daybreak Wednesday, however, the threat for heavy rainfall should diminish after 2am. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce 0.1-0.4" of rain in 30-60 minutes. Moderate to strong thunderstorms will have the potential to produce rainfall rates of 0.4-0.8" in 10-30 minutes. WORST CASE SCENARIO: Training of thunderstorm cells or a slower moving thunderstorm may result in up to 1.5" of rain in 60 minutes or less. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM Jefferson County 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM Broomfield County 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM Douglas County 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM Adams County 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM Denver County 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM DIA 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM Arapahoe County 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM the City of Aurora 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM Arvada 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM Wheat Ridge 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM Lakewood 1 Current TO 200 AM WEDNESDAY Current TO 1159 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 200 AM WED 0.1" (75%) to 0.4" (50%) to 0.8" (20%) ISSUED Arapahoe Current TO 200 AM WED 0.1" (75%) to 0.4" (50%) to 0.8" (20%) ISSUED Boulder Current TO 200 AM WED 0.1" (75%) to 0.4" (50%) to 0.8" (20%) ISSUED Broomfield Current TO 200 AM WED 0.1" (75%) to 0.4" (50%) to 0.8" (20%) ISSUED Denver Current TO 200 AM WED 0.1" (75%) to 0.4" (50%) to 0.8" (20%) ISSUED Douglas Current TO 200 AM WED 0.1" (75%) to 0.4" (50%) to 0.8" (20%) ISSUED Jefferson Current TO 200 AM WED 0.1" (75%) to 0.4" (50%) to 0.8" (20%) ISSUED Foothills above 6500ft       Boulder Current TO 200 AM WED 0.1" (50%) to 0.4" (30%) to 0.8" (10%) ISSUED Douglas Current TO 200 AM WED 0.1" (50%) to 0.4" (30%) to 0.8" (10%) ISSUED Jefferson Current TO 200 AM WED 0.1" (50%) to 0.4" (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]