National Weather Service Forecast Discussion

Thornton Weather Forecast   
Today's Forecast Story   
772
FXUS65 KBOU 140616
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1216 AM MDT Sun Jun 14 2026

.KEY MESSAGES...

- Cool and cloudy today.

- The best chances for showers/thunderstorms will be Sunday mainly
  along and south of I-70.

- Temperatures heat back up next week.

- Increasing fire weather concerns on Tuesday and Wednesday.

&&

.DISCUSSION /Through Saturday/...
Issued at 145 PM MDT Sat Jun 13 2026

A cold front moved through eastern Colorado last night with cool,
northeast winds behind it. With dry air aloft helping to keep
conditions mostly sunny, it is a pleasant day for June across most
of the northern half of Colorado. Low level convergence over the
Palmer Divide, southern foothills, and South Park may help to
create a few showers in those locations late this afternoon and
evening.

The next round of even cooler air will arrive tonight in our
forecast area. Low clouds currently in Wyoming are associated
with a nearby shortwave trough. Temperatures in Wyoming under
these clouds are mostly in the 40s and low 50s. This will move
into Colorado late this evening. Highs on Sunday are expected to
stay in the 60s across the plains tomorrow with mostly clouds
skies. The upslope flow will likely create some drizzle in the
foothills and adjacent plains. By the afternoon, there will be
enough instability in the central mountains that showers and a few
thunderstorms will form. The best chance for accumulating
rainfall will be along and south of I-70. These storms are not
expected to be severe due to lack of instability.

Ridging aloft will move over Colorado on Monday providing
subsidence. Temperatures will moderate from Sunday`s cool
conditions but will remain below normal.

West-northwesterly flow aloft will increase on Tuesday and
Wednesday as 700 mb temperatures will warm rapidly. 700 mb
temperatures will likely be around 17-18 C over Denver on Tuesday
and near 20 C on Wednesday. This will lead to hot temperatures
around 90 across the plains on Tuesday and the mid 90s on
Wednesday. There will be very dry conditions and moderate
downslope winds. Fire weather concerns will increase Tuesday and
Wednesday with Wednesday potentially reaching critical levels.

A sharp surface cold front will move through Colorado Wednesday
night. This will drop temperatures to more seasonal levels on
Thursday. The CPC and ensembles show a wetter pattern for Colorado
by next weekend and into early the following week. There is some
skepticism that there will be wetter than normal conditions at
this point.

&&

.AVIATION /06Z TAFS through 06Z Monday/...
Issued at 1139 PM MDT Sat Jun 13 2026

Northeasterly winds persist across the TAFs sites late tonight
with current nighttime microphysics showing stratus clouds filling
in from north to south along the Front Range. Looks like KDEN and
KBJC will be the last to fill in, but expecting CIG to drop to
5,000` AGL at all sites in the next hour. Winds are expected to
keep an upslope component through the overnight hours which will
keep stratus socked in, with MVFR conditions expected by 12Z-14Z.
We should see CIG lift out of MVFR between 17-18Z, with some
brief scattering out between 20-22Z, but expecting lower CIGs to
return along with some shower potential (best chances for KAPA)
for the late afternoon/early evening.

A cyclone is still on track to form early Sunday morning. This
is expected to bring northerly winds to KBJC and KAPA by the
afternoon, with a shear zone potentially setting up over KAPA
between 16-18Z that would have south-southeasterly winds on its
southerly flank and some sort of northerly component on its
northern flank. This makes for plenty of uncertainty on what winds
will do, and largely depends on where the cyclone forms. For now,
there is fairly decent agreement in guidance that winds at KDEN
will turn in a counterclockwise pattern starting from the
southeast by early morning, and move to northeasterly by 21Z.


&&

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

&&

$$

DISCUSSION...Danielson
AVIATION...9

NWS BOU Office Area Forecast Discussion