Flash Flood Prediction Program

Time: 825 AM Thu July 15, 2021 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- WARMER AND SUNNY WITH A SLIGHT CHANCE FOR AFTERNOON RAIN SHOWERS/ISOLATED THUNDERSTORMS - A bit warmer today as we have mostly sunny skies this morning as afternoon highs reach the mid to upper 80's on the plains with mid to upper 70's along the foothills. A slight chance this afternoon for a few scattered rain showers/isolated thunderstorms. Dew points currently in the upper 40's to low 50's and will slowly decrease into the afternoon into the mid to upper 40's as surface moisture retreats towards the east. - Storms today will initiate in the higher terrain around midday with the best chance for storms in the District between 2-8pm. Storm motions will be relatively brisk this afternoon from the NW to SE between 10-20mph helping limit point rainfall amounts. Generally storms will not produce heavy rainfall today, however a slower moving storm that forms along an outflow boundary cannot be completely ruled out this afternoon and early evening which could potentially lead to isolated brief heavy rainfall resulting in a low threat for heavy rainfall today. - By 8pm, most if not all storm activity should move eastward and further onto the plains and out of the District. Overnight lows will drop into the upper 50's to low 60's for the plains with low to mid 50's along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers/isolated thunderstorms will produce a trace-0.2" of rainfall in 10-30 minutes. A moderate to strong thunderstorms will produce 0.2-0.4" of rainfall in 10-30 minutes. WORST CASE SCENARIO: A moderate to strong stationary thunderstorms or training of thunderstorms cells has the potential to produce 1.2" in 45-60 minutes. A LOOK AHEAD: Similar conditions remain in place through the weekend with temperatures in the upper 80's to low 90's Friday along with another chance for afternoon rain showers/isolated thunderstorms. High temperatures increase into the low to mid 90's for the plains Saturday and Sunday along with a continued chance for rain showers/isolated thunderstorms, however the threat for heavy rainfall remain minimal at this time. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 800 PM 0.2" (30%) to 0.4" (15%) to 1.2" (5%) LOW Arapahoe 200 PM TO 800 PM 0.2" (30%) to 0.4" (15%) to 1.2" (5%) LOW Boulder 200 PM TO 800 PM 0.2" (30%) to 0.4" (15%) to 1.2" (5%) LOW Broomfield 200 PM TO 800 PM 0.2" (30%) to 0.4" (15%) to 1.2" (5%) LOW Denver 200 PM TO 800 PM 0.2" (30%) to 0.4" (15%) to 1.2" (5%) LOW Douglas 200 PM TO 800 PM 0.2" (30%) to 0.4" (15%) to 1.2" (5%) LOW Jefferson 200 PM TO 800 PM 0.2" (30%) to 0.4" (15%) to 1.2" (5%) LOW Foothills above 6500ft       Boulder 200 PM TO 800 PM 0.2" (30%) to 0.4" (15%) to 1.2" (5%) LOW Douglas 200 PM TO 800 PM 0.2" (30%) to 0.4" (15%) to 1.2" (5%) LOW Jefferson 200 PM TO 800 PM 0.2" (30%) to 0.4" (15%) to 1.2" (5%) 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]