Flash Flood Prediction Program

Time: 601 AM Sun June 4, 2023 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- ANOTHER COOL AND CLOUDY DAY WITH OFF AND ON MODERATE TO HEAVY RAINFALL Once again, there is very little change to the overall pattern as multiple rounds of rainfall are expected to move in from the east throughout most of the day today. Dew points are currently in the low to mid 50’s throughout the District and will likely hold in place through the rest of the day. These elevated surface dew points will suggest moderate to heavy rainfall possible from just general showers, similar to yesterday morning. Training of rain showers will also play a key component today as multiple rounds of showers could lead to rainfall in excess of 1” per hour today. The best chance for storms will be from now, picking up once again through the morning, with rainfall chances possible well into the evening. The best chance for widespread moderate to heavy rainfall will be now through this afternoon. Like yesterday, due to the lack of daytime heating, thunderstorm activity should remain minimal, however a few embedded thunderstorms cannot be completely ruled out today. Storm motions will once again be atypical, moving in from the east and pushing up against the foothills. This storm motion will result in a MODERTE chance of Message 1’s being issued today, mainly for the threat of 1” per hour rain, however, a quick 0.5” in 10-20 minutes cannot be completely ruled out today, especially if thunderstorms are able to develop. STORM RAINFALL POTENTIAL AND DURATION: Typical rain showers will produce 0.2-0.7” in 30-60 minutes. A moderate to heavy rain shower, or thunderstorm could produce 0.7-1.3” in 30-60 minutes. WORST CASE SCENARIO: An anchored thunderstorm, or training of moderate to heavy showers has the potential to produce up to 2.6” in 60 minutes. A LOOK AHEAD: This unusual pattern will finally start to break down tomorrow as upper-level flow shift back to a more typical west to east pattern. A chance will remain for showers and thunderstorms tomorrow, however drier air from the NW should help limit the available moisture, effectively decreasing the chances for heavy rainfall. Next week will resume a more seasonable pattern with high temperatures back into the 70’s along with afternoon/evening rain/isolated thunderstorm chances through the week. LOCATION PRIME TIME 60-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 1000 PM SUN 0.2" (80%) to 0.7" (50%) to 1.3" (30%) MOD Arapahoe Current TO 1000 PM SUN 0.2" (80%) to 0.7" (50%) to 1.3" (30%) MOD Boulder Current TO 1000 PM SUN 0.2" (80%) to 0.7" (50%) to 1.3" (30%) MOD Broomfield Current TO 1000 PM SUN 0.2" (80%) to 0.7" (50%) to 1.3" (30%) MOD Denver Current TO 1000 PM SUN 0.2" (80%) to 0.7" (50%) to 1.3" (30%) MOD Douglas Current TO 1000 PM SUN 0.2" (80%) to 0.7" (50%) to 1.3" (30%) MOD Jefferson Current TO 1000 PM SUN 0.2" (80%) to 0.7" (50%) to 1.3" (30%) MOD Foothills above 6500ft       Boulder Current TO 1000 PM SUN 0.2" (90%) to 0.7" (60%) to 1.3" (30%) MOD Douglas Current TO 1000 PM SUN 0.2" (90%) to 0.7" (60%) to 1.3" (30%) MOD Jefferson Current TO 1000 PM SUN 0.2" (90%) to 0.7" (60%) to 1.3" (30%) MOD MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]