Flash Flood Prediction Program

High pressure ridging continues over the Intermountain West today supporting warm temperatures and chances for isolated to scattered showers and thunderstorms across the District. Afternoon highs in the upper 70s to low 80s, dewpoints in the mid to upper 30s, and PWAT values up to 0.6”. Chances for showers and thunderstorms improve this afternoon and evening ahead of an advancing cold front. Storm velocity will be from west to east around 20-30 mph. Quick storm motions will help limit point rainfall amounts.

Another surge late this evening could bring another chance for showers and possibly an isolated thunderstorm or two. This late round will be between 9pm-midnight and will also move quickly from west to east between 20-30 mph. Chances for isolated showers diminish overnight as temperatures drop into the upper 40s to low 50s on the plains with mid 40s along the foothills.

STORM RAINFALL POTENTIAL AND DURATION: Typical showers will produce light rainfall of up to 0.15” total in 15-30 minutes. A stronger shower or isoalted thunderstorm will produce 0.15"-0.25” total rainfall 15-30 minutes.

WORST CASE SCENARIO: A moderate to strong thunderstorm will have the potential to produce up to 0.50” total rainfall total in 15-30 minutes.

A LOOK AHEAD: Ridging will break down overnight as the cold front sweeps across the Plains. Afternoon highs will be in the mid 60s, dew points in the low 40s, and PWAT values between 0.65” and 0.75”. This pattern will support chances for scattered to widespread showers and thunderstorms capable of producing more meaningful rainfall across portions of the District likley leading to LOW Message potential. Storms are possible through Wednesday evening followed by clearing skies overnight.

Location	Prime Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	200 PM TO 800 PM	0.05" (60%) to 0.15" (30%) to 0.25" (15%)	NONE
Arapahoe	200 PM TO 800 PM	0.05" (60%) to 0.15" (30%) to 0.25" (15%)	NONE
Boulder	200 PM TO 800 PM	0.05" (60%) to 0.15" (30%) to 0.25" (15%)	NONE
Broomfield	200 PM TO 800 PM	0.05" (60%) to 0.15" (30%) to 0.25" (15%)	NONE
Denver	200 PM TO 800 PM	0.05" (60%) to 0.15" (30%) to 0.25" (15%)	NONE
Douglas	200 PM TO 900 PM	0.05" (60%) to 0.15" (30%) to 0.25" (15%)	NONE
Jefferson	200 PM TO 800 PM	0.05" (60%) to 0.15" (30%) to 0.25" (15%)	NONE
Foothills above 6500ft
Boulder	100 PM TO 800 PM	0.05" (80%) to 0.15" (40%) to 0.25" (20%)	NONE
Douglas	100 PM TO 900 PM	0.05" (80%) to 0.15" (40%) to 0.25" (20%)	NONE
Jefferson	100 PM TO 900 PM	0.05" (80%) to 0.15" (40%) to 0.25" (20%)	NONE

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.