Time: 817 PM Thu July 14, 2022 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- RAIN SHOWWERS CONTINUE POSSIBLE INTO THE EVENING, HEAVY RAINFALL THREAT INCREASING FRIDAY - Widely scattered rain showers with an occasional rumble of thunder have been persistent over NE areas of the District in Adams County and the DIA area and will continue at least another hour or two into the evening. Another area of shower activity to the west will move into the District and keep chances for light rain into the overnight period for remaining areas. - With temperatures cooling off precipitation will favor light rain showers but a weak thunderstorm cannot be ruled out. Heavy rainfall is not expected but a weak thunderstorm will be capable of producing brief moderate rain. Best chances for showers will be through midnight, then generally dry conditions are expected into Friday morning. - Thunderstorm chances will increase on Friday as a plume of monsoon moisture moves overhead. Strong, slow moving thunderstorms on Friday will be capable of producing heavy rainfall that may lead to excessive runoff and possibly flash flooding. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and possibly a weak thunderstorm will produce a trace to 0.3" in 10-30 minutes. WORST CASE SCENARIO: A moderate to strong thunderstorm is able to develop in a cooling air mass with the potential to produce 0.3-0.9" of heavy rain in 10-30 minutes. A LOOK AHEAD: NWS has issued a Flash Flood Watch for Boulder County above 6,000ft which will be effective from 11:00 AM to 9:00 PM Friday. The MHFD will issue a Message 2 for Boulder County matching the issue time from the NWS. Message 1's will likely be issued for the remainder of the District by 11:00 AM but may not become valid until Noon or 1:00 PM depending upon when storms are expected to fill in. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1159 PM THU Trace (90%) to 0.1" (60%) to 0.3" (15%) NONE Arapahoe Current TO 1159 PM THU Trace (80%) to 0.1" (60%) to 0.3" (10%) NONE Boulder Current TO 1159 PM THU Trace (80%) to 0.1" (60%) to 0.3" (10%) NONE Broomfield Current TO 1159 PM THU Trace (80%) to 0.1" (60%) to 0.3" (10%) NONE Denver Current TO 1159 PM THU Trace (80%) to 0.1" (60%) to 0.3" (15%) NONE Douglas Current TO 1159 PM THU Trace (80%) to 0.1" (60%) to 0.3" (10%) NONE Jefferson Current TO 1159 PM THU Trace (90%) to 0.1" (60%) to 0.3" (15%) NONE Foothills above 6500ft       Boulder Current TO 1159 PM THU Trace (90%) to 0.1" (60%) to 0.3" (15%) NONE Douglas Current TO 1159 PM THU Trace (90%) to 0.1" (60%) to 0.3" (15%) NONE Jefferson Current TO 1159 PM THU Trace (90%) to 0.1" (60%) to 0.3" (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]