Time: 1023 AM Sun June 2, 2019 Forecaster: Alan Smith

Heavy Precipitation Outlook
Flash Flood Prediction Program

WARMER WITH SCATTERED STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON
-A trough of low pressure remains centered west of Colorado, while southerly low level flow continues to transport moisture into Eastern Colorado. Temperatures will be warmer today with highs reaching the low 80s on the plains.
-Good surface heating along with increasing low level moisture will allow the atmosphere to destabilize with thunderstorms quickly developing over the foothills by early afternoon and tracking E/NE across the plains at 12-17mph. Storms today will have the potential to become strong or severe and produce heavy rainfall with dewpoints ranging from the upper 40s to low 50s. Large hail and gusty winds will also be possible with severe thunderstorms, and a tornado can't be ruled out across eastern portions of the District.
-The most widespread threat for strong/severe thunderstorms and heavy rainfall across the District will be from about 1-5pm. Additional isolated thunderstorms will remain possible through early evening, before tapering off after sunset with the loss of daytime heating.
STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce rainfall amounts of 0.1-0.4" in 10-30 minutes. Strong/severe thunderstorms will be capable of producing heavy rainfall of 0.4-1.0" in 10-30 minutes.

WORST CASE SCENARIO: A strong, slow-moving thunderstorm produces heavy rainfall of up to 2.25" in 60-90 minutes.

A LOOK AHEAD: The trough of low pressure southwest of Colorado will be very slow to shift eastward over the next several days, with daily chances of thunderstorms persisting through Wednesday. The threat for severe thunderstorms will gradually subside in the coming days, but the potential for heavy rainfall producing storms will likely remain. Temperatures will reach the low 80s for highs on the plains Monday and Tuesday, before cooling into the mid 70s on Wednesday.

Location Prime Time 30-Minute Rainfall
and % Probability
Message
Potential
Plains      
Adams 100 PM TO 800 PM
0.1" (95%) to 0.4" (60%) to 1.0" (30%) HIGH
Arapahoe 100 PM TO 800 PM
0.1" (95%) to 0.4" (60%) to 1.0" (30%) HIGH
Boulder 100 PM TO 800 PM
0.1" (85%) to 0.4" (45%) to 1.0" (20%) HIGH
Broomfield 100 PM TO 800 PM
0.1" (85%) to 0.4" (45%) to 1.0" (20%) HIGH
Denver 100 PM TO 800 PM
0.1" (90%) to 0.4" (50%) to 1.0" (25%) HIGH
Douglas 100 PM TO 800 PM
0.1" (95%) to 0.4" (60%) to 1.0" (30%) HIGH
Jefferson 100 PM TO 800 PM
0.1" (90%) to 0.4" (50%) to 1.0" (25%) HIGH
Foothills above 6500ft      
Boulder 1200 PM TO 800 PM
0.1" (85%) to 0.4" (45%) to 1.0" (20%) HIGH
Douglas 1200 PM TO 800 PM
0.1" (95%) to 0.4" (60%) to 1.0" (30%) HIGH
Jefferson 1200 PM TO 800 PM
0.1" (95%) to 0.4" (50%) to 1.0" (25%) HIGH
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.