Flash Flood Prediction Program

Time: 950 AM Sat September 18, 2021 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- HOT AND GENERALLY DRY WITH A VERY SLIGHT CHANCE FOR LATE EVE/OVERNIGHT RAIN SHOWERS - Another unseasonably hot day today as high temperatures reach the mid 80's to low 90's on the plains with mid to upper 80's along the foothills. - Mostly sunny skies with clouds increasing into the evening. A few mountain rain showers/isolated thunderstorms are expected this afternoon, with a very slight chance for scattered rain showers late this evening and through the overnight and into Sunday morning. Most areas are expected to stay dry, however a few sprinkles to light rain showers cannot be completely ruled out at this time. Best chance for any sprinkles to light rain will be from 9pm until daybreak Sunday. - Overnight lows are expected to drop into the 50's along the plains with low to mid 40's along the foothills. A few areas of fog may be possible in the early morning hours Sunday before conditions quickly warm with highs in the 80's to around 90 once again. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers will produce a TR-0.10" of rainfall in 10-30 minutes. A moderate rain showers could produce 0.1-0.2" of rainfall in 10-30 minutes. WORST CASE SCENARIO: A thunderstorm or brief moderate to heavy rain shower has the potential to produce 0.2-0.5" in 60 minutes. A LOOK AHEAD: Sunday will be hot, mild and dry with temperatures reaching the 80's to around 90. A cold front moves in Monday effectively dropping high temperatures to around 70 degrees. This cold front will also bring a decent chance for rain showers across the district, however the threat for heavy rain will be minimal at best. Temperatures remain in the 70's Tuesday with dry conditions expected throughout the day. Wednesday begins to warm as high temperatures return to the 80's with mostly sunny skies. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 900 PM TO 600 AM SUN Trace (20%) to 0.1" (10%) to 0.2" (5%) NONE Arapahoe 900 PM TO 600 AM SUN Trace (20%) to 0.1" (10%) to 0.2" (5%) NONE Boulder 900 PM TO 600 AM SUN Trace (20%) to 0.1" (10%) to 0.2" (5%) NONE Broomfield 900 PM TO 600 AM SUN Trace (20%) to 0.1" (10%) to 0.2" (5%) NONE Denver 900 PM TO 600 AM SUN Trace (20%) to 0.1" (10%) to 0.2" (5%) NONE Douglas 900 PM TO 600 AM SUN Trace (20%) to 0.1" (10%) to 0.2" (5%) NONE Jefferson 900 PM TO 600 AM SUN Trace (20%) to 0.1" (10%) to 0.2" (5%) NONE Foothills above 6500ft       Boulder 900 PM TO 600 AM SUN Trace (30%) to 0.1" (15%) to 0.2" (5%) NONE Douglas 900 PM TO 600 AM SUN Trace (30%) to 0.1" (15%) to 0.2" (5%) NONE Jefferson 900 PM TO 600 AM SUN Trace (30%) to 0.1" (15%) to 0.2" (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]