Flash Flood Prediction Program

Time: 900 AM Wed July 13, 2022 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- HOT TODAY WITH A CHANCE FOR HIGH-BASED AFTERNOON RAIN SHOWERS/ISOLATED THUNDERSTORMS - Northwesterly flow aloft will continue today leading to another chance for afternoon and evening rain showers/isolated thunderstorms. A good chance showers stay minimal, however with upper 40's to low 50's dew points currently, a low chance for moderate to brief heavy rainfall will remain, with increased chances if low-level moisture does not mix out into the upper 30's to low 40's through the morning hours as anticipated. - Initial storm development along the higher terrain will likely begin between noon and 2pm with the best chance for rain showers/isolated thunderstorms in the District between 2-7pm this evening. Typical thunderstorms today will produce light to brief moderate rain and breezy winds. Storm motions will be fairly brisk, between 10-20mph from the WNW to ESE, however a gust front, or outflow boundary has the potential to produce storms that anchor in place for an extended period of time. Storms are expected to strengthen E of the I-25 corridor possibly becoming strong over the plains, although the better chances for strong storms today should be well east of the District boundaries. - Skies will gradually clear this evening with mild and dry conditions expected through the overnight and into Thursday. Overnight lows will dip into the low to mid 60's on the plains with low to mid 50's along the foothills. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce a trace to 0.2" of moisture. Moderate thunderstorms will have the potential to produce rainfall rates of 0.2-0.5" in 10-30 minutes. WORST CASE SCENARIO: Strong thunderstorms are able to develop with the potential to produce heavy rainfall of 0.4-1.0" in 10-30 minutes and up to 1.5" in 45-60 minutes. A LOOK AHEAD: An uptick in mid to upper-level moisture tomorrow will increase chances of widespread rain showers/thunderstorms in the afternoon and early evening. A slight chance for storms to become severe, mainly from gusty winds and possibly large hail. Afternoon and evening storm chances continue Friday, again with a slight chance for severe weather, mainly towards the eastern plains at this time. Mid to upper-level moisture decreases into the weekend, however a chance will remain for afternoon rain showers/isolated thunderstorms both Saturday and Sunday. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 200 PM TO 700 PM Trace (50%) to 0.2" (30%) to 0.5" (15%) LOW Arapahoe 200 PM TO 700 PM Trace (50%) to 0.2" (30%) to 0.5" (15%) LOW Boulder 200 PM TO 700 PM Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Broomfield 200 PM TO 700 PM Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Denver 200 PM TO 700 PM Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Douglas 200 PM TO 700 PM Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Jefferson 200 PM TO 700 PM Trace (50%) to 0.2" (20%) to 0.5" (10%) LOW Foothills above 6500ft       Boulder 200 PM TO 700 PM Trace (60%) to 0.2" (30%) to 0.5" (10%) LOW Douglas 200 PM TO 700 PM Trace (60%) to 0.2" (30%) to 0.5" (10%) LOW Jefferson 200 PM TO 700 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]