Time: 854 AM Sat July 25, 2020 Forecaster: Brad Simmons

Heavy Precipitation Outlook
Flash Flood Prediction Program

MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WITH HEAVY RAINFALL LIKELY
-Monsoon moisture continues to stream into Colorado from the SSW resulting in multiple rounds of showers and thunderstorms today with the potential for heavy rainfall.
-Moisture is abundant at both the surface and aloft resulting in efficient rainfall producing storms. Showers and thunderstorms will develop over the higher terrain to the W of the District before noon, spreading out onto the I-25 corridor between 1-2pm. 2-3 rounds of showers and thunderstorms are expected into the evening with additional lighter rain showers likely overnight.
-Relatively fast storm motions from SSW to NNE at around 25mph will help to reduce point rainfall amounts from a single storm with training of thunderstorm cells potentially producing extended periods of heavy rainfall that may lead to excessive runoff and possibly flash flooding. Message 1's will likely be issued by around Noon.
STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers and weak thunderstorms will produce 0.1-0.5" in 10-30 minutes. Moderate to strong thunderstorms will have the potential to produce 0.5-1.5" in 10-30 minutes. Supplemental QPF is available at https://qpf.udfcd.org

WORST CASE SCENARIO: Training of thunderstorm cells may produce up to 2.6" of rain in 45-60 minutes.

A LOOK AHEAD: Afternoon and evening thunderstorms with the potential for heavy rainfall will continue on a daily basis through Tuesday of next week with drier air moving into the District on Wednesday.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 100 PM TO 1000 PM
0.1" (100%) to 0.5" (65%) to 1.5" (20%) HIGH
Arapahoe 100 PM TO 1000 PM
0.1" (100%) to 0.5" (65%) to 1.5" (20%) HIGH
Boulder 100 PM TO 1000 PM
0.1" (100%) to 0.5" (65%) to 1.5" (20%) HIGH
Broomfield 100 PM TO 1000 PM
0.1" (100%) to 0.5" (65%) to 1.5" (20%) HIGH
Denver 100 PM TO 1000 PM
0.1" (100%) to 0.5" (65%) to 1.5" (20%) HIGH
Douglas 100 PM TO 1000 PM
0.1" (100%) to 0.5" (65%) to 1.5" (20%) HIGH
Jefferson 100 PM TO 1000 PM
0.1" (100%) to 0.5" (65%) to 1.5" (20%) HIGH
Foothills above 6500ft      
Boulder 1200 PM TO 1000 PM
0.1" (100%) to 0.5" (65%) to 1.5" (20%) HIGH
Douglas 1200 PM TO 1000 PM
0.1" (100%) to 0.5" (65%) to 1.5" (20%) HIGH
Jefferson 1200 PM TO 1000 PM
0.1" (100%) to 0.5" (65%) to 1.5" (20%) HIGH
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.