Flash Flood Prediction Program

Time: 916 AM Thu August 17, 2023 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- ANOTHER HOT DAY WITH A SLIGHT CHANCE FOR A FEW HIGH-BASED AFTERNOON SHOWERS/ISOLATED THUNDERSTORMS High-pressure continues to build over the region resulting in high temperatures reaching the low to mid 90s this afternoon. Another slight chance for a few high-based showers/isolated thunderstorms this afternoon and early evening. Once again storms should stay mainly along the foothills as most precipitation struggles to reach the surface on the plains. This is in part due to the continued wide temperature/dew point spread with high temperatures in the 90s and dew points expected to mix out into the low to mid 40s throughout the day today. Initial storm development will be along the Continental Divide around midday and move onto the foothills between 12-1pm. The best chance for storm activity within the District will be between 1-7pm with skies gradually clearing through the evening. Overnight will be breezy and dry with lows dropping into the 60s on the plains with upper 50s to around 60 degrees in the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical showers/weak thunderstorms will produce a trace to 0.10” total, in 10-30 minutes. A moderate to strong shower/thunderstorm will produce 0.10-0.25” total in 10-30 minutes. WORST CASE SCENARIO: A strong thunderstorm will have the potential to produce 0.25-0.75” total in 10-30 minutes. A LOOK AHEAD: An overall increase in moisture in the area tomorrow will likely bring a better chance for more widespread showers and thunderstorms across the District as high temperatures remain in the 90s. Upper-level flow will shift southwesterly bringing a slight chance for stronger storm development tomorrow, especially for areas east of the I-25 corridor, which will likely result in a LOW chance for Message 1s to be issued. Conditions dry out Saturday, however a slight chance for a few high-based showers/isolated thunderstorms will remain with minimal precipitation expected at this time. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 700 PM Trace (20%) to 0.1" (10%) to 0.25" (5%) NONE Arapahoe 200 PM TO 700 PM Trace (20%) to 0.1" (10%) to 0.25" (5%) NONE Boulder 200 PM TO 700 PM Trace (20%) to 0.1" (10%) to 0.25" (5%) NONE Broomfield 200 PM TO 700 PM Trace (20%) to 0.1" (10%) to 0.25" (5%) NONE Denver 200 PM TO 700 PM Trace (20%) to 0.1" (10%) to 0.25" (5%) NONE Douglas 200 PM TO 700 PM Trace (20%) to 0.1" (10%) to 0.25" (5%) NONE Jefferson 200 PM TO 700 PM Trace (20%) to 0.1" (10%) to 0.25" (5%) NONE Foothills above 6500ft       Boulder 100 PM TO 600 PM Trace (40%) to 0.1" (20%) to 0.25" (10%) NONE Douglas 100 PM TO 600 PM Trace (40%) to 0.1" (20%) to 0.25" (10%) NONE Jefferson 100 PM TO 600 PM Trace (40%) to 0.1" (20%) to 0.25" (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]