Time: 1216 PM Sun July 3, 2022 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- SURFACE MOISTURE INCREASING/THUNDERSTORMS BECOMING MORE LIKELY THIS AFTERNOON WITH BRIEF HEAVY RAINFALL POSSIBLE - Surface moisture is increasing as the day wears on instead of mixing out with dew points in the mid 40's to 50 currently over the District. The additional moisture to work with at the surface today will lead to better chances for thunderstorms this afternoon, some of which may contain heavy rainfall. - Thunderstorms are just now beginning to initiate over the higher terrain west of the District and will become more numerous as the afternoon progresses. Upper level steering winds from SW to NE at around 20mph will keep most of the storm activity moving along with widely scattered coverage. Surface wind convergence or outflow boundaries may generate slower moving thunderstorms or briefly anchored thunderstorms which may lead to extended periods of heavy rainfall and possibly excessive runoff. - Prime time for thunderstorm activity will be from roughly 1pm to 9pm. 1-3 rounds of thunderstorms are expected with S and W areas of the District looking favored at this time for higher storm coverage. In addition to the threat for heavy rainfall, thunderstorms may also contain gusty/erratic winds, frequent cloud-to-ground lightning and possibly hail. STORM RAINFALL POTENTIAL AND DURATION: Rain showers will produce a trace to 0.2" of rain. Weak to moderate thunderstorms will produce 0.2-0.6" in 10-30 minutes. Strong thunderstorms will have the potential to produce 0.4-1.2" in 10-30 minutes. WORST CASE SCENARIO: An anchored strong thunderstorm or a slower moving large thunderstorm may result in up to 2.0" of rain in 60-90 minutes. A LOOK AHEAD: Isolated to widely scattered afternoon thunderstorms will continue into the 4th of July with best chances from roughly 2-8pm along the I-25 corridor. As daytime heating is lost, storms will diminish and clouds will decrease leading to dry conditions for evening celebrations most areas in and around the District. Highs Monday afternoon will continue to run either side of 90 degrees over the plains. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 900 PM 0.1" (60%) to 0.5" (30%) to 1.0" (10%) MOD Arapahoe 200 PM TO 900 PM 0.1" (60%) to 0.5" (30%) to 1.0" (10%) MOD Boulder 200 PM TO 900 PM 0.1" (70%) to 0.5" (40%) to 1.0" (15%) MOD Broomfield 200 PM TO 900 PM 0.1" (70%) to 0.5" (30%) to 1.0" (10%) MOD Denver 200 PM TO 900 PM 0.1" (60%) to 0.5" (30%) to 1.0" (10%) MOD Douglas 100 PM TO 900 PM 0.1" (70%) to 0.5" (40%) to 1.0" (15%) MOD Jefferson 100 PM TO 900 PM 0.1" (70%) to 0.5" (40%) to 1.0" (15%) MOD Foothills above 6500ft       Boulder Current TO 900 PM SUN 0.1" (85%) to 0.5" (50%) to 1.0" (20%) MOD Douglas Current TO 900 PM SUN 0.1" (85%) to 0.5" (50%) to 1.0" (20%) MOD Jefferson Current TO 900 PM SUN 0.1" (85%) to 0.5" (50%) to 1.0" (20%) MOD MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]