721
FXUS65 KBOU 042120
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
320 PM MDT Fri Jul 4 2025

.KEY MESSAGES...

- Scattered showers and thunderstorms this afternoon, diminishing
  from west to east early this evening. Some storms could produce
  wind gusts up to 50 mph across the eastern plains with small
  hail. It is expected that almost all storms come to an end
  before 9pm across the I-25 corridor.

- A chance of afternoon and evening thunderstorms and above normal
  temperatures are expected for the weekend into early next week.
  Some strong to severe storms are possible with large hail and
  damaging wind gusts across the eastern plains.

- Hot temperatures expected Wednesday with the upper 90s expected
  across the plains.

&&

.DISCUSSION /Through Friday/...
Issued at 225 PM MDT Fri Jul 4 2025

SPC mesoanalysis shows 1,000 j/kg of surface based CAPE across the
plains this afternoon with higher values exceeding 2,000 across
the northeast corner by Nebraska. With 500 mb winds around 20
knots, deep layer shear is lacking today so the severe weather
threat is rather low. However, the easterly winds and healthy dew
points in the upper 50s will help to create storms that will
merge into a line during the late afternoon. This line may have
wind gusts up to 50 mph associated with it and there could be one
or two severe wind gusts above 60 mph especially in the far
northeast corner of the state since there is better instability
there. Across the I-25 corridor, some weak showers and storms may
linger into the early evening hours. But with subsidence aloft due
to the departing shortwave trough, the only thing keeping the
storms going is the daytime warming. Therefore, showers and
storms are expected to end at sunset with minimal threat to
evening firework shows.

Saturday and Sunday will have similar setups. There will be weak
zonal flow aloft on the northern edge of a ridge. There will be
weak lee cyclogenesis over northeast Colorado which will keep
surface winds light out of the east. The easterly winds will keep
in decent moisture and moderate instability especially east of
DIA each day. High resolution models indicate isolated to
scattered storms will form over the eastern plains and they may
become strong to severe with large hail and damaging wind gusts.
The shear will be the limiting factor so storms are not expected
to be particularly long-lived. This will keep the severe threat in
the marginal or slight SPC categories.

Monday may be the day with the best severe setup since similar
instability and moisture will be in place. However, there will
likely be a shortwave aloft that will increase deep layer shear
and forcing so better coverage of strong to severe storms is
expected. This threat may require a slight or enhanced SPC risk if
the timing of the shortwave is roughly in the afternoon or evening
Monday.

A ridge will strengthen and move north over Colorado on Tuesday
and Wednesday. This will result in dry conditions and much warmer
temperatures. Wednesday appears to the be warmest day with highs
reaching the upper 90s across the plains with some locations like
Greeley having a chance to hit 100.

&&

.AVIATION /18Z TAFS through 18Z Saturday/...
Issued at 1152 AM MDT Fri Jul 4 2025

VFR conditions expected throughout the TAF period. The main impact
today will be wind gusts from isolated thunderstorms. If a storm
were to go over a terminal, gusts could reach 35 knots. The most
likely time for a storm to impact the terminals is 19-22Z.
Drainage will return for the latter part of the evening but a weak
boundary will move across the terminals shifting winds to the
north or northwest overnight. Isolated storms are again possible
Saturday afternoon with winds being the primary impacts.

&&

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

&&

$$

DISCUSSION...Danielson
AVIATION...Danielson