Time: 755 AM Wed August 19, 2020 Forecaster: Justin Brooks

Heavy Precipitation Outlook
Flash Flood Prediction Program

ANOTHER HOT AND HAZY DAY WITH A SLIGHT CHANCE FOR AN ISOLATED HIGH-BASED THUNDERSTORM THIS AFTERNOON AND EARLY EVENING
-Not much has changed to the overall weather pattern as NW upper-level flow will continue to dominate over the region today leading to high temperatures in the low to upper 90's across the plains with low to upper 80's along the foothills
-A weak disturbance will move in this afternoon bringing a chance for a few scattered high-based rain showers/thunderstorms, although it is likely that any precipitation will struggle to reach the ground today resulting in a good chance for gusty winds and dry lightning under cells that do produce rain that evaporates before making it to the ground. Storm movement will be from the NW to SE at 10-20mph which will also help limit any point rainfall amounts under cells that are capable of producing light to moderate rainfall. Best chance to see any storm development will be from 3-8pm with skies clearing out after sunset.
-Overnight lows will drop into the low to upper 60's across the plains with mid to upper 50's along the foothills.
STORM RAINFALL POTENTIAL AND DURATION: High-based Rain showers and/or a weak thunderstorms will produce a trace to 0.1". An isolated moderate thunderstorms will have the potential to produce 0.1-0.3" in 10-30 mintues. Supplemental QPF is available at https://qpf.udfcd.org

WORST CASE SCENARIO: A large, slower moving thunderstorm formed off an outflow boundary may produce rainfall amounts of up to 0.8" in 45-60 minutes.

A LOOK AHEAD: Hot temperatures will continue through the weekend with highs expected to remain in the 90's. Another chance for rain/isolated thunderstorms Thursday afternoon and early evening, although the threat for any heavy rainfall will be minimal at best. Precipitation chances dwindle heading into the weekend, although a 10-20% chance for afternoon/early evening rain/isolated thunderstorms well persist through Sunday.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 300 PM TO 800 PM
Trace (40%) to 0.1" (20%) to 0.3" (5%) NONE
Arapahoe 300 PM TO 800 PM
Trace (40%) to 0.1" (20%) to 0.3" (5%) NONE
Boulder 300 PM TO 800 PM
Trace (40%) to 0.1" (20%) to 0.3" (5%) NONE
Broomfield 300 PM TO 800 PM
Trace (40%) to 0.1" (20%) to 0.3" (5%) NONE
Denver 300 PM TO 800 PM
Trace (40%) to 0.1" (20%) to 0.3" (5%) NONE
Douglas 300 PM TO 800 PM
Trace (40%) to 0.1" (20%) to 0.3" (5%) NONE
Jefferson 300 PM TO 800 PM
Trace (40%) to 0.1" (20%) to 0.3" (5%) NONE
Foothills above 6500ft      
Boulder 300 PM TO 800 PM
Trace (40%) to 0.1" (20%) to 0.3" (5%) NONE
Douglas 300 PM TO 800 PM
Trace (40%) to 0.1" (20%) to 0.3" (5%) NONE
Jefferson 300 PM TO 800 PM
Trace (40%) to 0.1" (20%) to 0.3" (5%) NONE
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.