Time: 919 AM Mon August 26, 2024 Forecaster: Tim Tonge ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- Seasonal temps, isolated late afternoon showers/t-storms if clouds break A mid-level cyclone is currently over Yellowstone National Park in northwestern Wyoming, and is taking a strong hold on Colorado's weather. Upper-level cloud cover stretches from North Dakota to Arizona as a result, blanketing most of Colorado and allowing varying degrees of cloud cover to come in and out of the District this morning. Eventually, some of this cloud cover will break, but it will be a major limiting factor for storm formation today despite synoptic-scale lift provided by the aforementioned storm system to the northwest. In regions of the District where clouds do break for extended periods throughout the morning and early afternoon, storms will form in isolated fashion in the late afternoon. Indications are that any storms today will come and go in one wave late afternoon/early evening, and be capable of producing brief heavy rainfall, small hail, and gusty outflows to 45mph. Moisture is in slightly better shape than the past few days, and with afternoon dews set to be in the mid 40s and precipitable water values between 0.75"-0.85", enough moisture is available for LOW message issuance potential despite indications of very isolated storm coverage. STORM RAINFALL POTENTIAL AND DURATION: Typical showers and thunderstorms will produce 0.05"-0.25" of rainfall in 10-30 minutes. Stronger thunderstorms will produce 0.25"-0.50" in 10-30 minutes. WORST CASE SCENARIO: A strong/stationary thunderstorm, or training of thunderstorms, could be capable of producing 1.25" of rainfall total in 60 minutes or less. A LOOK AHEAD: The eastward trajectory of the cyclone mentioned above will alter the flow direction over Colorado, finally cutting off the monsoonal moisture supply. Storm coverage tomorrow will be contained far south of the District, and all signs are pointing to a dry Wednesday and Thursday as well. A late evening cold front Wednesday will drop temps a few degrees Thursday. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 300 PM TO 700 PM 0.05" (30%) to 0.25" (20%) to 0.5" (10%) LOW Arapahoe 300 PM TO 700 PM 0.05" (30%) to 0.25" (20%) to 0.5" (10%) LOW Boulder 300 PM TO 700 PM 0.05" (30%) to 0.25" (20%) to 0.5" (10%) LOW Broomfield 300 PM TO 700 PM 0.05" (30%) to 0.25" (20%) to 0.5" (10%) LOW Denver 300 PM TO 700 PM 0.05" (30%) to 0.25" (20%) to 0.5" (10%) LOW Douglas 300 PM TO 700 PM 0.05" (30%) to 0.25" (20%) to 0.5" (10%) LOW Jefferson 300 PM TO 700 PM 0.05" (30%) to 0.25" (20%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder 200 PM TO 600 PM 0.05" (30%) to 0.25" (20%) to 0.5" (10%) LOW Douglas 200 PM TO 600 PM 0.05" (30%) to 0.25" (20%) to 0.5" (10%) LOW Jefferson 200 PM TO 600 PM 0.05" (30%) to 0.25" (20%) to 0.5" (10%) 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]