textproduct: Denver/Boulder

KEY MESSAGES

- Gusty winds up to 50 mph from high based-showers and thunderstorms late this afternoon and evening.

- Warming trend with above normal temperatures through Friday. Even warmer weather possible this weekend.

- Chance of afternoon showers and thunderstorms mainly over the higher terrain most days. Best chance of rain comes Wednesday and Thursday.

DISCUSSION /Through Tuesday/

Issued at 216 PM MDT Tue Jun 10 2025

A warm dry airmass is in place across the area. Noon temperatures were already well into the 80s with dew points in the 30s. The latest hi-res models seem to agree we will see some high-based convection later today, mainly in the form of showers, though a few thunderstorms will be possible over the mountains. Any rainfall, is expected light, but gusty outflow winds will be likely due to the large temperature/dew point spreads. This activity quickly dissipates this evening as the air stabilizes.

For Wednesday and Thursday, the upper level pattern is messy with a trough over the Southern Plains and a second one passing north of Colorado. Shortwave riding forms over Colorado in response to the deepening trough to our southeast. Moisture does increase a little for Wednesday and Thursday. This is expected to lead to an increase in showers and thunderstorms. Limited moisture, instability, and weak shear is expected to keep storms sub-severe. The far eastern plains could see a couple severe storms if the better instability and shear shifts westward a little. As far as temperatures go, they are expected to stay above normal with highs in the mid 80s to lower 90s across northeast Colorado.

On Friday, the shortwave ridging slides off to the east and flow aloft increases. Large scale ridging begins, but is more pronounced this weekend. Surface high pressure over the Northern Plains will lead to east to southeast winds across the eastern Colorado plains, increasing the moisture and shear. A dry line sets up where the southeast winds intersect the drier west winds. If we are to see severe thunderstorms this upcoming week, Friday looks like the day as instability will be enough for strong/severe storms. The storms could still run into issues forming, such as too warm air aloft from the developing ridge and also we may not see as much moisture return to the area as the models show. Upper level ridge will be centered over the Central and Southern Rockies this weekend. Not surprising, this will lead to warmer temperatures with highs reaching the upper 80s to mid 90s across northeast Colorado. Sunday is looking like the slightly warmer and drier day. The 12Z GFS shows a decent batch of late afternoon and evening showers/storms, but nearly all (more than 90%) of the ensemble members of the GFS and ECMWF indicate dry conditions. Given the ridging overhead along with the limited moisture and instability, dry conditions would be expected.

For early next week (Monday and Tuesday), the ridging over the region eventually is flattened or pushed off to the east by an upper level trough moving in from the Pacific. Models still greatly vary when and how this will happen. Will keep the cool down gradual for Monday and Tuesday and PoPs generally on the low side (20-30%) during the afternoon and evening hours.

AVIATION /06Z TAFS through 06Z Thursday/

Issued at 131 AM MDT Wed Jun 11 2025

Drainage winds will give way to light and variable winds during the mid morning today. The main concern will be afternoon showers and thunderstorms. High resolution model data has been pretty consistent in showing convection moving across the terminals between 21-00Z this afternoon. The primary concern will be wind gusts up to 40 knots. There was some consideration to increase the PROB30 to a TEMPO but will wait until more model guidance to make that change.

BOU WATCHES/WARNINGS/ADVISORIES

None.