547 FXUS65 KBOU 151119 AFDBOUArea Forecast Discussion National Weather Service Denver/Boulder CO 519 AM MDT Mon Sep 15 2025
.KEY MESSAGES...
- Warmer and drier today, with only a slight chance of a weak afternoon shower or thunderstorm.
- More unsettled and cooler Tuesday and Wednesday, with scattered to widespread showers and thunderstorms expected.
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.DISCUSSION /Through Sunday/... Issued at 154 PM MDT Sun Sep 14 2025
Satellite imagery showing the upper level low over Nebraska. The low will continue to lift northward, taking the showers and storms over northeast Colorado with it. By early evening, the showers and thunderstorms will be northeast of Colorado.
Weak ridging moves across the region Monday leading to warmer and drier conditions. High temperatures are expected to reach the lower to mid 80s across northeast Colorado. Scattered showers and thunderstorms are expected to form over Wyoming ahead of an upper level low approaching Colorado from the north. There is a slight chance for a few of these to graze far northern Colorado. A cold front pushes south through the area Monday night as the upper level low slowly moves south into Wyoming Monday night. Scattered showers and thunderstorms are expected to track across the area Tuesday. The upper level continues to slowly advance southeastward and will be over or near eastern Colorado on Wednesday. This will continue the cool and unsettled pattern over Colorado. The low is then expected to be east of Colorado late Wednesday.
The weather pattern is still somewhat unclear for Thursday through next weekend. Upper level ridge builds west of Colorado, over the Great Basin. Meanwhile the upper level low remains just east of Colorado. Latest runs show this ridging a little farther west with more of a north-northwest flow aloft over Colorado. It`s beginning to look more likely that Thursday will be another cool and unsettled day. Friday`s weather will depend on far east the ridging builds and advances, but latest trends has slowed the eastward advancement of the ridge, slowing the warming trend. For next weekend, there`s a slight preference for ridging for Saturday, but there are plenty of other solutions, though none point to any large systems just weak waves embedded in the flow aloft.
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.AVIATION /12Z TAFS through 12Z Tuesday/... Issued at 515 AM MDT Mon Sep 15 2025
VFR conditions will prevail for all terminals through the TAF period. Southerly drainage winds of 9-15 kts will persist through ~16Z for KDEN/KAPA, then give way to lighter winds steadily turning to the SE through 18Z. Expect return to drainage in the evening. Potential for any -SHRA is low (~15%) and thus not included in TAFs. If a weak cell does develop, it would occur between 21-01Z.
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.BOU WATCHES/WARNINGS/ADVISORIES... None.
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DISCUSSION...Meier AVIATION...Rodriguez
NWS BOU Office Area Forecast Discussion