Time: 832 PM Thu July 29, 2021 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S CONITINUE VALID UNTIL 10PM FOR PORTIONS OF THE DISTRICT - Message 1's will continue valid over NW portions of the District until 10pm although the threat for heavy rainfall is diminishing. - A warm layer of air aloft has kept any moderate to strong storm development at bay despite moisture levels rising significantly from this morning as the 6pm sounding in Denver yielded 1.09" of precipitable water. A surface wind convergence line still exists over NW portions of the District but is is now washing out and reducing storm chances. - There is still a slight chance for a stronger, slow moving thunderstorm to develop but now that temperatures are backing off as the sun sets this threat is much lower than just a couple hours ago. As time passes this evening the threat for heavy rainfall also diminishes likely allowing Messages to expire at 10pm. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.2" of rain. Moderate to strong thunderstorms will have the potential to produce 0.2-0.6" of heavy rain in 10-30 minutes. WORST CASE SCENARIO: A stationary strong thunderstorm will have the potential to produce up to 1.2" in 30-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Adams County 1 Current TO 1000 PM Current TO 900 PM Broomfield County 1 Current TO 1000 PM Current TO 900 PM Jefferson County 1 Current TO 1000 PM Current TO 900 PM Boulder County 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 1000 PM THU Trace (50%) to 0.2" (20%) to 0.6" (10%) ISSUED Arapahoe Current TO 1000 PM THU Trace (25%) to 0.2" (10%) to 0.6" (5%) LOW Boulder Current TO 1000 PM THU Trace (60%) to 0.2" (30%) to 0.6" (10%) ISSUED Broomfield Current TO 1000 PM THU Trace (50%) to 0.2" (20%) to 0.6" (10%) ISSUED Denver Current TO 1000 PM THU Trace (25%) to 0.2" (10%) to 0.6" (5%) LOW Douglas Current TO 1000 PM THU Trace (25%) to 0.2" (10%) to 0.6" (5%) LOW Jefferson Current TO 1000 PM THU Trace (50%) to 0.2" (20%) to 0.6" (10%) ISSUED Foothills above 6500ft       Boulder Current TO 1000 PM THU Trace (90%) to 0.2" (60%) to 0.6" (15%) ISSUED Douglas Current TO 1000 PM THU Trace (25%) to 0.2" (10%) to 0.6" (5%) LOW Jefferson Current TO 1000 PM THU Trace (50%) to 0.2" (20%) to 0.6" (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]