Time: 902 AM Sat May 18, 2024 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- Cooler today with a chance for high-based afternoon showers/isolated thunderstorms The high-pressure ridge shifts slightly south today leading to westerly upper-level flow aloft across the region which will bring mostly sunny and mild conditions throughout the morning. Today’s high temperatures will reach around 80 degrees this afternoon. Clouds will increase this afternoon and early evening as high-based showers and a few isolated thunderstorms initiate along the higher terrain foothills. Most thunderstorm activity should remain anchored to the foothills this afternoon, however a slight chance will remain a few thunderstorms will make their way onto the plains and into the District. Dew points will drop into the low to mid 30s, which should help limit storm strengths today. Storm motions will also be brisk, between 15-25mph from west to east which should also help limit any point rainfall amounts. The best chance for storms will be between 1pm-7pm with skies gradually clearing overnight. Overnight lows will drop into the low 50s on the plains with mid to upper 40s along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers will produce a trace to 0.10” total in 10-30 minutes. A weak to moderate shower/thunderstorm will produce a trace to 0.20” total in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm will have the potential to produce 0.20” to 0.40” total in 10-30 minutes. A LOOK AHEAD: High pressure builds tomorrow bringing high temperatures back into the 80s across the District. Sunny, breezy, and dry conditions are expected throughout most of the day tomorrow with mild and dry conditions heading into Monday. Cooler Monday with highs reaching the upper 70s. A good chance for afternoon showers and thunderstorms, picking up into the evening with a slight chance for some brief isolated moderate to heavy rainfall if stronger storms can develop. A continued chance for showers overnight and into Tuesday. Tuesday will remain cool with highs in the low 60s will likely limit rainfall potential with off and on showers likely throughout most of the day. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 700 PM Trace (40%) to 0.1" (20%) to 0.2" (10%) NONE Arapahoe 200 PM TO 700 PM Trace (40%) to 0.1" (20%) to 0.2" (10%) NONE Boulder 200 PM TO 700 PM Trace (40%) to 0.1" (20%) to 0.2" (10%) NONE Broomfield 200 PM TO 700 PM Trace (40%) to 0.1" (20%) to 0.2" (10%) NONE Denver 200 PM TO 700 PM Trace (40%) to 0.1" (20%) to 0.2" (10%) NONE Douglas 200 PM TO 700 PM Trace (40%) to 0.1" (20%) to 0.2" (10%) NONE Jefferson 200 PM TO 700 PM Trace (40%) to 0.1" (20%) to 0.2" (10%) NONE Foothills above 6500ft       Boulder 100 PM TO 600 PM Trace (50%) to 0.1" (30%) to 0.2" (15%) NONE Douglas 100 PM TO 600 PM Trace (50%) to 0.1" (30%) to 0.2" (15%) NONE Jefferson 100 PM TO 600 PM Trace (50%) to 0.1" (30%) to 0.2" (15%) NONE MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]