Time: 607 PM Fri July 30, 2021 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S HAVE TRANSITIONED TO MESSAGE 2'S AND WILL REMAIN VALID UNTIL 9PM SATURDAY - Message 1's have transitioned to Message 2's at 6pm to coincide with the NWS Flash Flood Watch. Message 2's/NWS Flash Flood Watch will remain valid until 9:00pm Saturday. - Strong, slow moving thunderstorms have developed over the District this afternoon and are expected to persist well into the evening. Moisture levels are expected to be higher than at any point this season and storms that develop today and tomorrow will be very capable of producing heavy rainfall that will lead to excessive runoff and possibly flash flooding. - The greatest threat for heavy rain from thunderstorms will be through about 10pm or midnight then rain showers may be capable of producing up to 1"/hr or higher rainfall rates overnight absent of any thunder. STORM RAINFALL POTENTIAL AND DURATION: Weak thunderstorms will produce 0.2-0.6" in 10-30 minutes. Moderate to strong thunderstorms will have the potential to produce 0.6-1.8" of heavy rain in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm will have the potential to produce up to 3.5" in 45-60 minutes. Storms that persist beyond 60 minutes may produce locally higher amounts. COUNTY MESSAGE VALID TIMES PRIME TIME Denver County 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY Adams County 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY Douglas County 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY Lakewood 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY Broomfield County 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY Jefferson County 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY Boulder County 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY Wheat Ridge 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY Arvada 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY the City of Aurora 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY DIA 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY Arapahoe County 1 Current TO 900 PM SATURDAY Current TO 900 PM SATURDAY County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1159 PM FRI 0.2" (100%) to 0.6" (85%) to 1.8" (65%) ISSUED Arapahoe Current TO 1159 PM FRI 0.2" (100%) to 0.6" (85%) to 1.8" (65%) ISSUED Boulder Current TO 1159 PM FRI 0.2" (100%) to 0.6" (85%) to 1.8" (65%) ISSUED Broomfield Current TO 1159 PM FRI 0.2" (100%) to 0.6" (85%) to 1.8" (65%) ISSUED Denver Current TO 1159 PM FRI 0.2" (100%) to 0.6" (85%) to 1.8" (65%) ISSUED Douglas Current TO 1159 PM FRI 0.2" (100%) to 0.6" (85%) to 1.8" (65%) ISSUED Jefferson Current TO 1159 PM FRI 0.2" (100%) to 0.6" (85%) to 1.8" (65%) ISSUED Foothills above 6500ft       Boulder Current TO 1159 PM FRI 0.2" (100%) to 0.6" (85%) to 1.8" (65%) ISSUED Douglas Current TO 1159 PM FRI 0.2" (100%) to 0.6" (85%) to 1.8" (65%) ISSUED Jefferson Current TO 1159 PM FRI 0.2" (100%) to 0.6" (85%) to 1.8" (65%) 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]