Time: 1003 AM Fri July 19, 2024 Forecaster: Laura Smith ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- Scattered to widespread thunderstorms this afternoon and evening across the District A ridge of high pressure is parked over the Four-Corners region today, transporting monsoonal moisture into Colorado. Sunny morning skies will permit afternoon temperatures to climb into the upper 80s to low 90s with surface dewpoints around 50°F, sufficiently destabilizing the atmosphere. Precipitable water (PWAT) values will reach 0.85” by the early afternoon. However, upper-level support is less impressive, and will therefore limit overall thunderstorm development and duration across the District broadly. If storms manage to develop over the District, they will have the potential to produce moderate to brief heavy rainfall this afternoon and evening. Convection initiation will begin around noon across complex terrain, moving southeast towards the plains between 15-25 mph. Thunderstorm activity is expected to dissipate by the late evening, with skies gradually clearing overnight. STORM RAINFALL POTENTIAL AND DURATION: Thunderstorms today have the potential to produce up to 1.00” in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm, or training of storms, may be capable of producing up to 1.50” or more in 30 minutes or less. A LOOK AHEAD: A subtle cold front is expected to meander across the northern Plains early Saturday morning, supporting cooler temperatures and a more active pattern this weekend and early next week. Highs will be in the upper 70s to mid 80s Saturday and Sunday with chances for scattered to widespread showers and thunderstorms. This slower moving disturbance, coupled with elevated atmospheric moisture will support thunderstorm clusters producing efficient rainfall across the District throughout the weekend. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 100 PM TO 900 PM 0.25" (50%) to 0.5" (30%) to 1" (10%) MOD Arapahoe 100 PM TO 900 PM 0.25" (50%) to 0.5" (30%) to 1" (10%) MOD Boulder 100 PM TO 900 PM 0.25" (50%) to 0.5" (30%) to 1" (10%) MOD Broomfield 100 PM TO 900 PM 0.25" (50%) to 0.5" (30%) to 1" (10%) MOD Denver 100 PM TO 900 PM 0.25" (50%) to 0.5" (30%) to 1" (10%) MOD Douglas 100 PM TO 900 PM 0.25" (50%) to 0.5" (30%) to 1" (10%) MOD Jefferson 100 PM TO 900 PM 0.25" (50%) to 0.5" (30%) to 1" (10%) MOD Foothills above 6500ft       Boulder 1200 PM TO 800 PM 0.25" (60%) to 0.5" (30%) to 1" (10%) MOD Douglas 1200 PM TO 800 PM 0.25" (60%) to 0.5" (30%) to 1" (10%) MOD Jefferson 1200 PM TO 800 PM 0.25" (60%) to 0.5" (30%) to 1" (10%) 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]