National Weather Service Forecast Discussion

Thornton Weather Forecast   
Today's Forecast Story   
944
FXUS65 KBOU 012335
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
535 PM MDT Fri May 1 2026

.KEY MESSAGES...

- Warmer and drier conditions expected for the weekend.

- Unsettled weather returns Monday night through Wednesday with
  increasing chances for mountain snow and rain showers over the
  plains.

&&

.DISCUSSION /Through Friday/...
Issued at 126 PM MDT Fri May 1 2026

The remnants of the storm system that brought some rain and snow
to the region continues to weaken as the parent trough axis
continues to push well to the east of the forecast area. Satellite
shows mostly fair weather cumulus across the forecast area, and
any afternoon rain/snow showers across the higher elevations
should be quite weak. Temperatures across the plains have warmed
into the upper 50s to low 60s and are currently close to forecast
highs today. Clear skies overnight should allow temperatures to
fall back into the low to mid 30s once again overnight.

Weak ridging is expected to develop for the weekend, leading to a
period of above normal temperatures. Saturday will be sunny with
temperatures across the plains settling around 70F. While some
increase in cloud cover is likely for Sunday, highs should also
warm several degrees with mid-level temperatures warming a few
degC with a bit more of a downslope component as well.

As we enter next week, a return of cooler and unsettled weather
looks increasingly likely... beginning late Monday and continuing
through Wednesday. Guidance is reasonably consistent handling the
main synoptic scale features during this period, with a broad
upper low near west-central California Monday afternoon, with a
stronger upper trough centered near Manitoba/western Ontario. The
upper low is expected to drift eastward towards the desert
southwest by mid-week, while a lobe of the longwave trough pushes
down towards eastern Wyoming. Somewhere between these two
features, a quasi-stationary frontal boundary is likely to be the
focal point for an organized round of precipitation... eventually
transitioning to more of a traditional upslope flow regime here
by Tuesday or Wednesday as the front pushes further to the south.

A review of the last couple cycles of deterministic and ensemble
model data shows a variety of solutions for both temperatures and
QPF for our CWA, largely dictated by how the cutoff low is
absorbed by the northern trough, and where the initial
frontogenesis sets up. The ECMWF and its ensemble remain on the
bullish side, with 10th percentile QPF through Wednesday evening
over a half an inch... while the GEFS has several far drier
members. While these solutions are certainly a reason to have some
optimism, it`s hard to ignore how precarious the overall setup
appears... especially since we just went through a similar process
over the last several days. Our overall forecast thoughts have
not changed significantly (despite the far too bullish NBM PoP
grids for Tuesday), and we`ll continue to watch the period
closely.

Beyond that system, broad ridging is expected to redevelop across
the region, leading to a return of warmer and drier conditions to
end next week.

&&

.AVIATION /00Z TAFS through 00Z Sunday/...
Issued at 527 PM MDT Fri May 1 2026

VFR conditions are expected through this TAF package. Winds are a
bit breezy at DIA this evening, with winds around 10 to 12kts and
an occasional gusts around 18kts. The gusts should die down soon,
with winds weakening and turning more easterly over the next
couple of hours. Overnight winds should follow the typical diurnal
pattern with periods of light and variable winds in there. Winds
tomorrow will generally remain below 10kts, with winds shifting
from the SW to NE in the late morning to early afternoon.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Hiris
AVIATION...AP

NWS BOU Office Area Forecast Discussion