Flash Flood Prediction Program

-	A cold front is currently entering the District from the NE and will significantly increase low level moisture as well as the threat for thunderstorms with the potential for heavy rainfall.
-	Strong storms have already developed behind the front in Weld County and additional storms are likely to develop behind the front as it moves through the District late this afternoon and early evening. Storms that develop will be very slow moving(10mph or less) due to weak steering winds aloft. Large hail and strong winds may also accompany strong thunderstorm cells.
-	Due to slow storm motions moderate and heavy rainfall may persist over a single location which may result in excessive runoff and possibly flash flooding. Best chances for thunderstorm activity will be from 7pm-midnight tonight resulting in Message 1's likely being issued sometime over the next hour.

STORM RAINFALL POTENTIAL AND DURATION: Moderate to strong thunderstorms will have the potential to produce 0.5-1.5" in 10-30 minutes.

WORST CASE SCENARIO: A large, slow moving thunderstorm complex may produce up to 2.75" in 60-90 minutes.

A LOOK AHEAD: Much cooler Wednesday with highs in the 80's over the plains and the threat for afternoon and early evening thunderstorms with the potential for heavy rainfall.

Location	Prime Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	600 PM TO 1159 PM	0.1" (90%) to 0.5" (45%) to 1.5" (20%)	HIGH
Arapahoe	600 PM TO 1159 PM	0.1" (90%) to 0.5" (45%) to 1.5" (20%)	HIGH
Boulder	600 PM TO 1159 PM	0.1" (90%) to 0.5" (45%) to 1.5" (20%)	HIGH
Broomfield	600 PM TO 1159 PM	0.1" (90%) to 0.5" (45%) to 1.5" (20%)	HIGH
Denver	600 PM TO 1159 PM	0.1" (90%) to 0.5" (45%) to 1.5" (20%)	HIGH
Douglas	600 PM TO 1159 PM	0.1" (90%) to 0.5" (45%) to 1.5" (20%)	HIGH
Jefferson	600 PM TO 1159 PM	0.1" (90%) to 0.5" (45%) to 1.5" (20%)	HIGH
Foothills above 6500ft
Boulder	600 PM TO 1159 PM	0.1" (80%) to 0.5" (30%) to 1.5" (10%)	MOD
Douglas	600 PM TO 1159 PM	0.1" (80%) to 0.5" (30%) to 1.5" (10%)	MOD
Jefferson	600 PM TO 1159 PM	0.1" (80%) to 0.5" (30%) to 1.5" (10%)	MOD

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.