Time: 905 PM Fri May 26, 2023 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- ADDITIONAL STORMS DEVELOPING ALONG FOOTHILLS CURRENTLY RESULTING IN LOW CHANCE FOR MESSAGE 1'S THIS EVENING Additional storms have developed along the foothills at this time and will likely move into the District in the next hour or so. These storms are much weaker than this afternoon. However, persistent easterly surface flow, combined with dew points still around 50 degrees, will bring a LOW chance that Message 1’s will have to be issued this evening. The best chance for additional storms will be from now until midnight with skies gradually clearing through the overnight and into Saturday. The main threat for these storms will likely be a quick 0.5” in 10-30 minutes as storm motions remain fairly quick, between 10-15mph which will help limit point rainfall amounts. The biggest area of concern will be along the foothills, where storms are more likely to anchor in place, resulting in the best chance for brief heavy rain. Storm chances will taper off after 10pm with a few lingering showers through midnight. Overnight will be mild and dry, with lows dropping into the upper 40’s to around 50 on the plains, with low to mid 40’s along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Rain showers will produce rainfall amounts of TR-0.2” in 10-30 minutes. Weak to moderate thunderstorms will have the potential to produce rainfall rates of 0.2- 0.5” in 10-30 minutes. WORST CASE SCENARIO: A moderate to strong thunderstorm, or an anchored thunderstorm has the potential to produce heavy rainfall of up to 0.8” in 45-60 minutes. A LOOK AHEAD: Not much change in the overall pattern as tomorrow will bring another threat of severe weather for portions of northeastern Colorado, which could include areas east and up to the I-25 corridor. The best chance for storms will once again be during peak daytime heating in the afternoon and early evening. Expect at least a moderate if not high chance for Messages to be issued tomorrow as well. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1159 PM FRI Trace (60%) to 0.2" (20%) to 0.5" (10%) LOW Arapahoe Current TO 1159 PM FRI Trace (60%) to 0.2" (20%) to 0.5" (10%) LOW Boulder Current TO 1159 PM FRI Trace (60%) to 0.2" (20%) to 0.5" (10%) LOW Broomfield Current TO 1159 PM FRI Trace (60%) to 0.2" (20%) to 0.5" (10%) LOW Denver Current TO 1159 PM FRI Trace (60%) to 0.2" (20%) to 0.5" (10%) LOW Douglas Current TO 1159 PM FRI Trace (60%) to 0.2" (20%) to 0.5" (10%) LOW Jefferson Current TO 1159 PM FRI Trace (60%) to 0.2" (20%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder Current TO 1159 PM FRI Trace (80%) to 0.2" (40%) to 0.5" (20%) LOW Douglas Current TO 1159 PM FRI Trace (80%) to 0.2" (40%) to 0.5" (20%) LOW Jefferson Current TO 1159 PM FRI Trace (80%) to 0.2" (40%) to 0.5" (20%) 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]