| - | Message 1's have been issued for the entire District and will be valid until 10:00 PM for all Counties except Boulder and Douglas as they transition to Message 2's. The NWS in Boulder has issued a Flash Flood Watch for the higher terrain of Boulder County above 6,000ft from 3:00 PM until Midnight. The NWS has also issued a Flood Watch for the E 2/3's of Douglas County above 6,000ft from 3:00 PM until Midnight and implies flash flooding, thus Message 2's will supersede the Message 1's for Boulder and Douglas Counties and will go into effect at 3:00 PM. The Message 2's from the MHFD will be valid until 10:00 PM to match the Message 1's end time as the Watches are expected to be cancelled early as the stronger storms are likely well east of the I-25 corridor by that time. Message 1's and 2's may be extended until midnight if a flooding threat remains. Although NWS Flood/Flash Flood Watches are not in effect for the remainder of the District the flood threat is elevated area wide. |
| - | Thunderstorms will begin to initiate over the next 1-2 hours over the higher terrain to the W and S of the District. Upper level steering winds from W to E or WSW to ENE at 15-20mph will push the storms onto the plains into the early afternoon. Prime time for moderate to strong thunderstorms will be from 2:00 PM to 9:00 PM. 1-3 rounds of storms are expected through the afternoon into the early evening. Large thunderstorms or briefly anchored thunderstorms will pose the greatest threat for extended periods of heavy rainfall. The first or second round of storms will likely be the strongest of the day. |
| - | Moderate to strong thunderstorms that develop today will be efficient rainfall producers as moisture levels are very high for Colorado standards. Even moderate thunderstorms will have the potential to produce heavy rainfall and strong thunderstorms will be very capable of producing heavy downpours that may lead to excessive runoff and possibly flash flooding. |
WORST CASE SCENARIO: A large thunderstorm complex or a slower moving large thunderstorm may result in rainfall rates of 1.0-2.5" in 10-30 minutes and up to 3.5" of heavy rain in 45-75 minutes.
| County-specific Quantitative Precipitation Outlook |
Precipitation Time | 30-Minute Rainfall and % Probability |
Message Potential |
|---|---|---|---|
| Plains | |||
| Adams |
100 PM TO
1000 PM |
0.2" (95%) to 0.8" (70%) to 2.0" (20%) | |
| Arapahoe |
100 PM TO
1000 PM |
0.2" (95%) to 0.8" (75%) to 2.0" (30%) | |
| Boulder |
100 PM TO
1000 PM |
0.2" (95%) to 0.8" (70%) to 2.0" (20%) | |
| Broomfield |
100 PM TO
1000 PM |
0.2" (95%) to 0.8" (70%) to 2.0" (25%) | |
| Denver |
100 PM TO
1000 PM |
0.2" (95%) to 0.8" (70%) to 2.0" (20%) | |
| Douglas |
100 PM TO
1000 PM |
0.2" (95%) to 0.8" (75%) to 2.0" (30%) | |
| Jefferson |
100 PM TO
1000 PM |
0.2" (95%) to 0.8" (70%) to 2.0" (20%) | |
| Foothills above 6500ft | |||
| Boulder |
Current TO
1000 PM SUN |
0.2" (100%) to 0.8" (75%) to 2.0" (25%) | |
| Douglas |
Current TO
1000 PM SUN |
0.2" (100%) to 0.8" (75%) to 2.0" (30%) | |
| Jefferson |
Current TO
1000 PM SUN |
0.2" (100%) to 0.8" (75%) to 2.0" (25%) |
MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.