Flash Flood Prediction Program

Time: 1040 AM Fri July 8, 2022 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- MOISTURE DECREASING BUT CHANCES FOR THUNDERSTORMS LINGER - Moisture is on the decrease which will lower the chances for thunderstorm activity today but not eliminate it. Temperatures will continue their upward climb with highs this afternoon warming well into the 90's over the plains. - There will be a few isolated/weak thunderstorms that develop over the higher terrain but stronger storms will form N and NE of the District this afternoon. These storms are expected to develop over the Cheyenne ridge and move to the SE, avoiding the District but outflow from these storms may push back to the west and increase our surface moisture while also supplying a triggering mechanism for storms. If this scenario were to play out there will be a slight chance for stronger thunderstorms later this afternoon on the plains between 3-9pm. - Typical storms today will produce light to brief moderate rain and gusty winds. If outflow boundary storms develop later this afternoon brief heavy rainfall may occur, favoring areas along and E of I-25. Individual storms will move from NW to SE at 15-20mph but storms that form on surface wind convergence may move more erratically. STORM RAINFALL POTENTIAL AND DURATION: Rain showers will produce a trace to 0.1" of rainfall. Weak to moderate thunderstorms will produce rainfall rates of 0.1-0.4" in 10-30 minutes. WORST CASE SCENARIO: Outflow boundary induced thunderstorms may become strong with the potential to produce rainfall rates of 0.3-0.8" in 10-30 minutes and up to 1.2" in an hour. A LOOK AHEAD: Moisture continues to decrease on Saturday with dry conditions expected and temperatures warming into the upper 90's to around 100 degrees over the plains. Isolated thunderstorm chances return to the area on Sunday with better chances on Monday and Tuesday. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 300 PM TO 900 PM Trace (75%) to 0.1" (50%) to 0.4" (20%) LOW Arapahoe 300 PM TO 900 PM Trace (75%) to 0.1" (50%) to 0.4" (20%) LOW Boulder 300 PM TO 900 PM Trace (65%) to 0.1" (40%) to 0.4" (15%) LOW Broomfield 300 PM TO 900 PM Trace (50%) to 0.1" (30%) to 0.4" (10%) LOW Denver 300 PM TO 900 PM Trace (65%) to 0.1" (40%) to 0.4" (15%) LOW Douglas 300 PM TO 900 PM Trace (65%) to 0.1" (40%) to 0.4" (15%) LOW Jefferson 300 PM TO 900 PM Trace (65%) to 0.1" (40%) to 0.4" (15%) LOW Foothills above 6500ft       Boulder 100 PM TO 900 PM Trace (75%) to 0.1" (40%) to 0.4" (10%) NONE Douglas 100 PM TO 900 PM Trace (75%) to 0.1" (40%) to 0.4" (10%) NONE Jefferson 100 PM TO 900 PM Trace (75%) to 0.1" (40%) to 0.4" (10%) 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]