Time: 934 AM Thu June 25, 2020 Forecaster: Brad Simmons

Heavy Precipitation Outlook
Flash Flood Prediction Program

CONTINUED UNSEASONABLY WARM WITH ISOLATED AFTERNOON THUNDERSTORMS
-Temperatures will continue to run above normal today with highs topping out in the lower 90's over the plains. Normal high for Denver today is 86 degrees.
-Much like the past couple days conditions will be dry through the morning with isolated thunderstorms developing over the foothills between 11am and 1pm. Storms will then move onto the plains in the 1-3pm time frame with chances for thunderstorms through about sunset. Typical storms today will be high-based producing light rainfall and gusty winds. A moderate to possibly strong thunderstorm will have the potential to produce brief moderate rain and damaging winds in excess of 60mph.
-Late tonight a cold front will move through and increase cloud cover into Friday morning. A few rain showers may develop along and behind the front continuing possible into daybreak Friday.
STORM RAINFALL POTENTIAL AND DURATION: Typical showers and weak thunderstorms will produce a trace to 0.1". A moderate to briefly strong thunderstorm will have the potential to produce 0.1-0.3" of rain in 10-30 minutes.

WORST CASE SCENARIO: A rain moistened gust front initiates a slow moving strong thunderstorm with the potential to produce 0.3-0.8" of rain in 10-30 minutes.

A LOOK AHEAD: Behind the cold front that moves through tonight temperatures on Friday will only warm into the upper 70's to lower 80's over the plains. Moisture will increase behind the front setting the stage for an active thunderstorm day. Strong to severe thunderstorms will become possible Friday afternoon with the potential to produce heavy rainfall which may lead to excessive runoff and possibly flash flooding.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 200 PM TO 800 PM
Trace (60%) to 0.1" (30%) to 0.3" (15%) NONE
Arapahoe 200 PM TO 800 PM
Trace (60%) to 0.1" (30%) to 0.3" (15%) NONE
Broomfield 200 PM TO 800 PM
Trace (60%) to 0.1" (30%) to 0.3" (15%) NONE
Denver 200 PM TO 800 PM
Trace (60%) to 0.1" (30%) to 0.3" (15%) NONE
Boulder 100 PM TO 800 PM
Trace (70%) to 0.1" (40%) to 0.3" (15%) NONE
Douglas 100 PM TO 800 PM
Trace (70%) to 0.1" (40%) to 0.3" (15%) NONE
Jefferson 100 PM TO 800 PM
Trace (70%) to 0.1" (40%) to 0.3" (15%) NONE
Foothills above 6500ft      
Boulder 1200 PM TO 800 PM
Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE
Douglas 1200 PM TO 800 PM
Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE
Jefferson 1200 PM TO 800 PM
Trace (80%) to 0.1" (60%) to 0.3" (30%) NONE
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.