Time: 1004 AM Tue May 21, 2024 Forecaster: Laura Smith

Heavy Precipitation Outlook
Flash Flood Prediction Program

Another cool day with a chance for afternoon showers and isolated thunderstorms
The springtime pattern continues across the Front Range Urban Corridor as another upper-level trough sweeps across the state today. Afternoon highs will reach the upper 50s to low 60s, dew points in the upper 30s to low 40s, and precipitable water (PWAT) values around 0.5”-0.6”.

Chances for isolated showers and thunderstorms will gradually improve throughout the day, becoming scattered to widespread by the late afternoon. Storm motions will be from west to east around 20-25 mph. Storms will begin clearing after sunset, with precipitation fully concluding by the mid to late evening.
STORM RAINFALL POTENTIAL AND DURATION: Typical showers will produce a trace to 0.25” total in 10-30 minutes. A moderate shower/thunderstorm will produce 0.25”-0.50” total in 10-30 minutes.

WORST CASE SCENARIO: A strong thunderstorm, or training of thunderstorm cells, will have the potential to produce 0.50” to 0.80” total in up to 60 minutes.

A LOOK AHEAD: Warmer temperatures are expected Wednesday as sunny morning skies allow afternoon highs to reach the upper 60s to low 70s. Dewpoints will be in the upper 20s to low 30s, supporting slight chances for afternoon to evening showers and thunderstorms.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 200 PM TO 800 PM
Trace (90%) to 0.25" (60%) to 0.5" (30%) LOW
Arapahoe 200 PM TO 800 PM
Trace (90%) to 0.25" (60%) to 0.5" (30%) LOW
Boulder 200 PM TO 800 PM
Trace (80%) to 0.25" (40%) to 0.5" (20%) LOW
Broomfield 200 PM TO 800 PM
Trace (80%) to 0.25" (40%) to 0.5" (20%) LOW
Denver 200 PM TO 800 PM
Trace (90%) to 0.25" (60%) to 0.5" (30%) LOW
Douglas 200 PM TO 800 PM
Trace (80%) to 0.25" (40%) to 0.5" (20%) LOW
Jefferson 200 PM TO 800 PM
Trace (80%) to 0.25" (40%) to 0.5" (20%) LOW
Foothills above 6500ft      
Boulder 100 PM TO 800 PM
Trace (80%) to 0.25" (40%) to 0.5" (20%) LOW
Douglas 100 PM TO 800 PM
Trace (80%) to 0.25" (40%) to 0.5" (20%) LOW
Jefferson 100 PM TO 800 PM
Trace (80%) to 0.25" (40%) to 0.5" (20%) LOW
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.
https://f2p2.udfcd.org/generator/