Flash Flood Prediction Program

Time: 841 AM Sat July 2, 2022 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- WARMER TODAY WITH A CHANCE FOR SCATTERED AFTERNOON/EVE RAIN/ISOLATED THUNDERSTORMS - Not much change in the overall weather pattern today with another chance for afternoon and evening rain showers/isolated thunderstorms. Currently temperatures are in the low to mid 60's across the plains with highs in the upper 80's to around 90°F this afternoon. Currently dew points remain elevated with low to mid 50's, however, these dew points should mix out through the morning into the low to mid 40's. Once again, with the excess surface moisture in place this morning, a low chance will remain for message potential this afternoon and evening. - Similar to yesterday, rain showers/isolated thunderstorms are expected to develop along the higher terrain between 12-2pm today with rain showers/isolated thunderstorms possible in the District between 2-10pm. Storm motions will generally be west to east, between 10-15mph with peak storm chances between 2-8pm. A round or two of storms are possible today, with the first round bringing the best chance for moderate to heavy rainfall at this time, with additional storm development possible from outflow boundaries, especially if stronger storms are able to develop along the Wyoming Ridge and the Palmer Divide. Additional rain showers and possibly a weak thunderstorm will continue until midnight then skies will clear with dry conditions expected after midnight and into Sunday morning. - Slightly increased surface moisture and better daytime heating will be in place for a chance of moderate to brief heavy rainfall today resulting in a continued low risk for Message issuance, however if low-level moisture mixes out before adequate heating takes place it will help keep the moderate to heavy rainfall at bay. Overnight lows excepted to drop into the upper 50's to low 60's with mild conditions expected into daybreak Sunday. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers and weak thunderstorms will produce TR-0.2" of rain in 10-30 minutes. Moderate to briefly strong thunderstorms will have the potential to produce rainfall rates of 0.2-0.5" in 10-30 minutes. WORST CASE SCENARIO: Strong, slower moving thunderstorms if able to develop will have the potential to produce heavy rainfall rates of 0.5-1.0" in 10-30 minutes and up to 2.0" in 45-75 minutes. A LOOK AHEAD: An uptick in mid to upper-level moisture tomorrow, combined with a weak upper-level disturbance will bring a better chance for widespread rain showers and isolated thunderstorms in the afternoon and early evening. There will likely be a continued low to moderate chance for heavy rainfall Sunday afternoon and early evening with rain showers tapering off well before midnight. Conditions dry out slightly for the 4th of July, however a chance will remain for scattered rain showers/isolated thunderstorms in the afternoon and evening. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 1000 PM Trace (50%) to 0.2" (25%) to 0.5" (10%) LOW Arapahoe 200 PM TO 1000 PM Trace (50%) to 0.2" (25%) to 0.5" (10%) LOW Boulder 200 PM TO 1000 PM Trace (50%) to 0.2" (25%) to 0.5" (10%) LOW Broomfield 200 PM TO 1000 PM Trace (50%) to 0.2" (25%) to 0.5" (10%) LOW Denver 200 PM TO 1000 PM Trace (50%) to 0.2" (25%) to 0.5" (10%) LOW Douglas 200 PM TO 1000 PM Trace (50%) to 0.2" (25%) to 0.5" (10%) LOW Jefferson 200 PM TO 1000 PM Trace (50%) to 0.2" (25%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder 100 PM TO 900 PM Trace (75%) to 0.2" (50%) to 0.5" (15%) LOW Douglas 100 PM TO 900 PM Trace (75%) to 0.2" (50%) to 0.5" (15%) LOW Jefferson 100 PM TO 900 PM Trace (75%) to 0.2" (50%) to 0.5" (15%) 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]