767
FXUS65 KBOU 072341
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
541 PM MDT Mon Jul 7 2025

.KEY MESSAGES...

- Severe threat shifting east of our forecast area through the
  rest of the evening. A few strong storms still possible in the
  far northeast corner through about 7PM.

- Very hot temperatures expected Wednesday with the upper 90s to
  low 100s expected across the I-25 corridor and plains. It is
  possible the hot temperatures extend into Thursday.

- Cooler Friday into the weekend with a chance of storms.

&&

.DISCUSSION /Through Monday/...
Issued at 244 PM MDT Mon Jul 7 2025

The strength of today`s storms was known right away as a
microburst produced 70 mph winds a couple miles west of
Centennial Airport and 66 mph winds at the ASOS sensor at
Centennial Airport. Very steep lapse rates and DCAPE values around
1,700 j/kg indicate that these type of winds (60-70mph) will be
possible across the I-25 corridor and eastern plains this
afternoon and early evening. In addition, storms to the east of a
line from Fort Morgan to Limon will be able to tap into better
instability (surface based CAPE values 2,000-3,000 j/kg) to
produce large hail greater than an inch in diameter. The only
limiting factor to severe storms is the weak, but sufficient, deep
layer shear with values are around 30-35 knots in the northeast
corner of Colorado. A Severe Thunderstorm Watch was issued for all
areas east of I-25 until 9pm this evening.

On Tuesday, warmer and drier air aloft will move into Colorado
along with rising 500 mb heights. Across the Cheyenne Ridge and
Palmer Divide, some lingering moisture and slight convergent flow
may be enough for a few storms to develop. Overall coverage of
showers and storms should be about 20 percent so PoPs are around
that threshold. High temperatures across the plains will warm up
to the mid 90s.

The axis of an upper level ridge will be over Colorado on
Wednesday. 500 mb heights will be flirting with 597 dm in our
forecast area. There will be an upper level jet streak over
northern Utah and Wyoming that will position our forecast area
under the right exit region with subsident flow. All factors look
to great compressional warming and near record highs are forecast
as a result. There was an office discussion about whether to issue
a Heat Advisory. A few factors were considered with a main factor
being the HeatRisk is forecast to be 3 for Denver, Boulder, and
Fort Collins. Given the heat may break records (record highs in
Denver, Boulder, and Fort Collins are 100, 99, and 99 respectively
with the forecast highs of 99, 99, and 100 respectively) and
there will be minimal cloud cover along with light winds, the
decision was made to issue a Heat Advisory for zones 38, 39, 40
(Fort Collins, Boulder, and Denver). The decision was made to hold
off on an advisory for Greeley and other areas farther east since
temperatures will be a few degrees below records. For example,
the record high in Greeley is 105 with a forecast of 101.

A quick moving shortwave trough will push through our forecast
area midday Thursday. With warm air aloft, temperatures will
still be quite warm with highs in the mid to upper 90s across the
plains. With this trough, winds will likely increase and it may
lead to elevated fire weather conditions with relative humidity
dropping to as low as 10 percent and gusts around 25 mph.

Cooler conditions and a chance of scattered storms will return on
Friday as a cold front moves through.

&&

.AVIATION /00Z TAFS through 00Z Wednesday/...
Issued at 530 PM MDT Mon Jul 7 2025

VFR conditions are anticipated through the TAF period. Main
concern in the TAF is once again in the first few hours beyond
00z. Well defined shear zone/outflow boundary working towards the
terminals, with at least a brief wind shift anticipated at DEN
prior to 01z. Should see a northeast shift there followed by a
gradual turn back to the east/southeast through 03z. Less
confidence in this boundary making it to BJC/APA. Drainage should
prevail later on.

A decrease in convective coverage is expected for Tuesday, with
a few scattered high based showers capable of producing gusty
outflow winds during most of the afternoon hours. Winds outside of
any weak convection are expected to be light.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 10 AM to 9 PM MDT Wednesday for COZ038>040.

&&

$$

DISCUSSION...Danielson
AVIATION...Hiris

NWS BOU Office Area Forecast Discussion