Flash Flood Prediction Program

Time: 830 AM Mon October 3, 2022 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- ANOTHER CHANCE FOR RAIN SHOWERS/ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING - The low-pressure system that has brought an active weather pattern over the region will finally start to progress eastward today which will effectively keep storm chances in for this afternoon and evening. Once again the strength of today's storms will depend on the amount of daytime heating with highs only expected in the low 70's this afternoon, which should help limit the storm potential. - Rain shower/isolated thunderstorm activity will initiate along the higher terrain by midday with the best chance for storm activity in the District between 2-8pm with a slight chance for rain showers to linger into the overnight. Storm motions will generally be from the W to E between 5-10mph, however, a few erratic moving storms cannot be completely ruled out, especially if a stronger storm is able to develop resulting in outflow boundaries that for additional slower moving storms. The largest threat today for heavy rainfall will likely be a quick 0.5" in 10-15 minutes, favoring areas along and east of the I-25 corridor at this time. - Storm intensity will diminish quickly after sunset with scattered rain showers possible through midnight, with off and on light rain showers possible through daybreak Tuesday. Overnight lows will dip into the upper 40's to low 50's on the plains with around 40 degrees along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers/isolated thunderstorms will produce a trace 0.2" in 10-30 minutes. A moderate to strong thunderstorm could produce 0.2-0.5" in 10-30 minutes. WORST CASE SCENARIO: A strong, slower moving thunderstorm has the potential to produce 0.5-1.5" in 45-75 Minutes. A LOOK AHEAD: This active pattern should hold for one more day as a slight chance remains for rain showers/isolated thunderstorms Tuesday. However, NW flow aloft should usher in slightly drier air which will decrease the chance for any moderate to heavy rainfall tomorrow. Conditions look to dry out completely both Wednesday and Thursday with no precipitation excepted in the District for both days. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.5" (15%) LOW Arapahoe 200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.5" (15%) LOW Boulder 200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.5" (15%) LOW Broomfield 200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.5" (15%) LOW Denver 200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.5" (15%) LOW Douglas 200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.5" (15%) LOW Jefferson 200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.5" (15%) LOW Foothills above 6500ft       Boulder 200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.5" (10%) LOW Douglas 200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.5" (10%) LOW Jefferson 200 PM TO 900 PM Trace (60%) to 0.2" (30%) to 0.5" (10%) LOW MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]