Time: 701 AM Thu August 20, 2020 Forecaster: Justin Brooks

Heavy Precipitation Outlook
Flash Flood Prediction Program

CONTINUED HOT AND HAZY WITH A CHANCE FOR HIGH-BASED AFTERNOON/EARLY EVE THUNDERSTORMS
-Not much has changed to the overall weather pattern as N/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 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 N/NW to E/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 2-8pm with skies clearing out after sunset.
-Overnight lows will drop into the mid 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 0.6" in 45-60 minutes.

A LOOK AHEAD: High-pressure will slowly creep closer to western Colorado Friday and Saturday resulting in dry conditions as any available moisture gets pinched off from moving into the region. High temperatures will remain in the 90's through the weekend with the next chance for rain showers/isolated thunderstorms Sunday afternoon and early evening.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 200 PM TO 800 PM
Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE
Arapahoe 200 PM TO 800 PM
Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE
Boulder 200 PM TO 800 PM
Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE
Broomfield 200 PM TO 800 PM
Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE
Denver 200 PM TO 800 PM
Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE
Douglas 200 PM TO 800 PM
Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE
Jefferson 200 PM TO 800 PM
Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE
Foothills above 6500ft      
Boulder 200 PM TO 800 PM
Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE
Douglas 200 PM TO 800 PM
Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE
Jefferson 200 PM TO 800 PM
Trace (30%) to 0.1" (15%) to 0.3" (5%) NONE
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.