Flash Flood Prediction Program

Time: 833 AM Wed June 16, 2021 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- ANOTHER RECORD BREAKING HOT DAY WITH A SLIGHT CHANCE FOR HIGH-BASED AFTERNOON RAIN/ISOALTED THUNDERSTORMS - The heat wave continues as high temperatures reach the upper 90's to low triple digits today. Overnight lows remained above 70 for most areas in the District with temperatures already closing in on 80 degrees this morning. - Mostly sunny skies currently with clouds increasing into the afternoon. A very slight chance today for a few high-based rain showers/isolated thunderstorms, however most rainfall will struggle to reach the surface today with the main threat likely being gusty winds and a few lightning strikes. Storm motions will be from the W to E between 5-10mph. If a stronger, slower moving storm is able to develop rainfall rates could reach the 0.1-0.3" range, although chances are unlikely at this time. Storms will initiate along the higher terrain around midday with the best storm chances for the District between 1-6pm this afternoon. Storms have a better chance of picking up in intensity as they move further eastward and away from the District. - Skies will gradually clear this evening with overnight lows dropping into the upper 60's to around 70 for the plains with low to mid 60's along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical high-based rain showers/isolated thunderstorms will produce between a trace-0.1" of rainfall in 10-30 minutes. A moderate rain shower/thunderstorm is capable of producing 0.1-0.3" in 10-30 minutes. WORST CASE SCENARIO: Anchored thunderstorms, or a thunderstorm that forms along an outflow boundary has the potential to produce 0.3-0.8" in 60-90 minutes. A LOOK AHEAD: Hot conditions persist at least through tomorrow as high temperatures are once again expected to hit the triple digit mark in the afternoon/early evening. Similar conditions weather wise as a few high-based rain showers/isolated thunderstorms will be possible. A cold front moves through the overnight and into Friday effectively bringing high temperatures into a cooler upper 80's to low 90's. A better chance for rain showers/isolated thunderstorms in the afternoon and evening. Hot temperatures remain through the weekend with rain showers/thunderstorm chances picking up both Saturday and Sunday. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 600 PM Trace (20%) to 0.1" (10%) to 0.3" (5%) NONE Arapahoe 200 PM TO 600 PM Trace (20%) to 0.1" (10%) to 0.3" (5%) NONE Boulder 200 PM TO 600 PM Trace (20%) to 0.1" (10%) to 0.3" (5%) NONE Broomfield 200 PM TO 600 PM Trace (20%) to 0.1" (10%) to 0.3" (5%) NONE Denver 200 PM TO 600 PM Trace (20%) to 0.1" (10%) to 0.3" (5%) NONE Douglas 200 PM TO 600 PM Trace (20%) to 0.1" (10%) to 0.3" (5%) NONE Jefferson 200 PM TO 600 PM Trace (20%) to 0.1" (10%) to 0.3" (5%) NONE Foothills above 6500ft       Boulder 100 PM TO 500 PM Trace (20%) to 0.1" (10%) to 0.3" (5%) NONE Douglas 100 PM TO 500 PM Trace (20%) to 0.1" (10%) to 0.3" (5%) NONE Jefferson 100 PM TO 500 PM Trace (20%) to 0.1" (10%) to 0.3" (5%) 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]