Time: 952 AM Sun May 1, 2022 Forecaster: Brad Simmons ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- MHFD 2022 SEASON BEGINS/RAIN SHOWERS AND THUNDERSTORMS TO IMPACT THE DISTRICT LATER TODAY AND TONIGHT - After the 3rd driest April on record for the Denver Metro area the month of May will usher in a more active weather pattern. Conditions will be dry and a little breezy during the day today ahead of a storm system that will move into NE CO late this afternoon and evening. Temperatures will climb into the 60's to around 70 for highs over the plains with 50's and 60's in the Front Range foothills. - The first rain showers and isolated thunderstorms associated with the incoming low pressure system will become possible over the foothills between noon-2pm. Showers and isolated thunderstorms are then expected to initiate over the plains between 2-4pm. 2-3 rounds of showers and weak to moderate thunderstorms are then expected to move through the District during the evening and overnight persisting into daybreak on Monday. The snow line will lower overnight and the higher foothills above 7,000ft and in particular above 8,000ft will likely experience some late season snowfall overnight into Monday morning. - The thunderstorm activity expected to develop this afternoon and evening will generally feature weak to moderate thunderstorms with stronger storms possible E of the I-25 corridor, most likely remaining just to the N and E of the District. If a stronger storm does develop further west of I-25 a brief period of heavy rainfall cannot be ruled out resulting in a LOW Message potential. Stronger storms will also feature gusty winds and hail. Prime time for thunderstorm activity is from 3pm to midnight with mainly rain showers after midnight but a weaker thunderstorm cannot be ruled out. Thunderstorms will be relatively fast moving from SW to NE at 20-25mph helping to lower point rainfall amounts. STORM RAINFALL POTENTIAL AND DURATION: Rain showers will produce a trace to 0.2" of rainfall in 10-30 minutes. Weak to moderate thunderstorms will have the potential to produce rainfall rates of 0.2-0.6" in 10-30 minutes. WORST CASE SCENARIO: Strong thunderstorms are able to develop further west than expected with the potential for moderate to brief heavy rainfall of 0.4-1.2" in 15-45 minutes. A LOOK AHEAD: Lingering rain showers Monday morning expected to exit the area before noon. Monday afternoon is looking generally dry but a stray rain shower or weak thunderstorm cannot be ruled out producing light to briefly moderate rainfall(no flood threat). Highs Monday only in the 40's to around 50 over the plains. Another system will move into the area on Tuesday with thunderstorms possible during the afternoon and rain showers overnight into the day on Wednesday. More snow can be expected for the higher terrain, mainly above 8,000ft. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 300 PM TO 1000 AM MON Trace (100%) to 0.2" (75%) to 0.6" (40%) LOW Arapahoe 300 PM TO 1000 AM MON Trace (100%) to 0.2" (75%) to 0.6" (40%) LOW Broomfield 300 PM TO 1000 AM MON Trace (100%) to 0.2" (60%) to 0.6" (20%) LOW Denver 300 PM TO 1000 AM MON Trace (100%) to 0.2" (70%) to 0.6" (35%) LOW Douglas 300 PM TO 1000 AM MON Trace (100%) to 0.2" (60%) to 0.6" (25%) LOW Boulder 200 PM TO 1000 AM MON Trace (100%) to 0.2" (65%) to 0.6" (25%) LOW Jefferson 200 PM TO 1000 AM MON Trace (100%) to 0.2" (65%) to 0.6" (20%) LOW Foothills above 6500ft       Douglas 100 PM TO 1000 AM MON Trace (100%) to 0.2" (75%) to 0.6" (15%) LOW Boulder 1200 PM TO 1000 AM MON Trace (100%) to 0.2" (75%) to 0.6" (15%) LOW Jefferson 1200 PM TO 1000 AM MON Trace (100%) to 0.2" (75%) to 0.6" (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]