Time: 955 AM Sun August 4, 2024 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- Hot, isolated late afternoon showers and thunderstorms Monsoonal moisture is beginning to make its way into Colorado, though most of it will stay contained west of the Continental Divide today. Precipitable water (PWAT) values across the District have returned to normal early August values (~0.75"), but near triple-digit temperatures and minimal atmospheric forcing will create isolated coverage of storms that are more likely to produce gusty outflow winds and lightning than significant rainfall. Storms will begin to fire in the high country west of the District in the early afternoon, and make their way into the foothills and urban corridor by mid afternoon. Storms today will likely favor the Palmer Divide south of the District and plains to the east, however with the relative proximity of these storms and the potential for outflow boundary-driven storm initiation, the chance for message issuance will be LOW today. Mainly for a quick 0.50" in 10-20 minutes from an anchored storm rather than any long-lasting rainfall. Overnight will start to clear out with mild and dry conditions expected through Monday morning. Temperatures will drop into the mid to upper 60s on the plains with low 60s along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers and thunderstorms will be capable of producing Trace-0.25" total in 10-30 minutes. Moderate to strong thunderstorms will be capable of producing 0.25-0.50" total in 10-30 minutes. WORST CASE SCENARIO: A strong/slow moving thunderstorm, or training of thunderstorms may produce 1.00" of rain in 30-60 minutes. A LOOK AHEAD: Monsoonal moisture will spill over the Continental Divide by tomorrow, and southwesterly flow aloft will continuously deliver available moisture to Colorado for the entirety of the work week. Rainfall chances will likely be >50% each day of the work week; Wednesday appears to have the lowest chances of the week as of now. A strong cold front will drop temperatures Thursday. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 300 PM TO 1100 PM Trace (30%) to 0.25" (20%) to 0.5" (10%) LOW Arapahoe 300 PM TO 1100 PM Trace (30%) to 0.25" (20%) to 0.5" (10%) LOW Boulder 300 PM TO 1100 PM Trace (30%) to 0.25" (20%) to 0.5" (10%) LOW Broomfield 300 PM TO 1100 PM Trace (30%) to 0.25" (20%) to 0.5" (10%) LOW Denver 300 PM TO 1100 PM Trace (30%) to 0.25" (20%) to 0.5" (10%) LOW Douglas 300 PM TO 1100 PM Trace (30%) to 0.25" (20%) to 0.5" (10%) LOW Jefferson 300 PM TO 1100 PM Trace (30%) to 0.25" (20%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder 300 PM TO 1100 PM Trace (40%) to 0.25" (25%) to 0.5" (15%) LOW Douglas 300 PM TO 1100 PM Trace (40%) to 0.25" (25%) to 0.5" (15%) LOW Jefferson 300 PM TO 1100 PM Trace (40%) to 0.25" (25%) to 0.5" (15%) LOW MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]