Evans, Colorado 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

480
FXUS65 KBOU 290012
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
612 PM MDT Sat Jun 28 2025

.KEY MESSAGES...

- Hot today with a slight chance of afternoon showers and
  thunderstorms.

- Cooler Sunday and Monday with higher coverage of storms and a
  threat for some of these storms to be strong to severe.

- Scattered thunderstorms and normal temperatures are expected for
  the Fourth of July.

&&

.DISCUSSION /Through Saturday/...
Issued at 253 PM MDT Sat Jun 28 2025

Visible satellite shows two areas of storms in our forecast area
with one being in Lincoln County and another in Logan County.
These storms could produce strong wind gusts up to 55 mph given
the steep low level lapse rates and DCAPE values close to 1,800
j/kg on the SPC mesoanalysis page. The most likely location for
strong winds are in Phillips and Sedgwick Counties as storms will
have the best surface based CAPE there. Elsewhere, showers and
storms are struggling to form given the warm air aloft and
subsident flow. There will still likely be some virga that forms
which could produce dry microbursts with winds close to 45 mph
over the I-25 corridor.

There is currently a cold front in northeast Wyoming that will
help to generate an MCS this evening in Wyoming and eastward. The
combination of the cold front and outflow winds from the MCS will
move southward into northeast Colorado early Sunday morning.
Northeast winds will continue throughout the day across the plains
with healthy moisture arriving with dew points in the upper 50s.
Mixed-layer CAPE values will reach around 2,000 j/kg indicating
moderate instability. As for shear, upper level winds will be
lacking with speeds only around 25-30 knots at 500 and 250 mb. So
deep layer shear will only be about 30-35 knots. Given those
parameters, a few strong to severe storms are expected to form but
it will not be a widespread severe outbreak. Large hail and
damaging wind gusts will be the primary threats and an upgrade to
an SPC slight risk may be warranted.

Some high resolution models are indicating that strong storms
could form during the overnight hours Sunday night given the
moderate elevated instability and a weak shortwave moving through
aloft. This overnight convection will depend on how much
convection occurs during the day on Sunday. If there are very few
storms and the instability is untapped, there may be scattered
coverage of strong storms across the northeast plains. However,
if there are more numerous storms Sunday afternoon, the chance for
overnight convection will be much lower.

On Monday, temperatures will be well below normal across the I-25
corridor and eastern plains due to upslope winds and low level
clouds. Highs may not even reach 80 across the plains. This setup
of easterly winds with good moisture favors widespread storms over
the southern foothills and Park County. There are likely PoPs in
those areas and rainfall totals could exceed 1 inch. Elsewhere,
conditions look capped, especially near DIA and areas to the north
and east of the airport.

The center of a ridge aloft will be over Colorado on Tuesday and
Wednesday. Highs will warm up closer to normal and convection will
stay mostly over the higher terrain given the very weak steering
flow aloft and more stable conditions east of I-25.

A trough over the Las Vegas area and a ridge over the central US
will help to draw up moisture from the tropics on Thursday and
Friday. Precipitable water values may increase to over an inch in
Denver on Friday. Depending on the timing of a shortwave passage,
the Fourth of July has the potential to be a wet day with
scattered to numerous thunderstorms possible.

&&

.AVIATION /00Z TAFS through 00Z Monday/...
Issued at 543 PM MDT Sat Jun 28 2025

Multiple boundaries are moving across northeastern Colorado this
evening stemming from storms to the north, east, and south of the
TAF sites. We have been monitoring two more notable boundaries
to the NE and SW of KDEN that are looking to converge east of the
TAF site in the next 30 to 40 mins (~0030Z). Guidance holds on to
VRB wind potential through 3Z, so have extended the PROB30 until
then to account for the chance. Expecting winds to transition to
the east for a bit this evening from all the outflows off the
storms to the east before finally settling into diurnal winds
(S/SW at KDEN/KAPA SW/W at BJC) for the overnight hours.

Convection is still on track to impact all TAF sites Sunday
afternoon.


&&

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

&&

$$

DISCUSSION...Danielson
AVIATION...Bonner