764
FXUS65 KBOU 021142
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
542 AM MDT Sat Aug 2 2025

.KEY MESSAGES...

- A few severe thunderstorms are possible this afternoon/early
  evening over the eastern half of the plains.

- Chance of thunderstorms gradually decreases this weekend.

- Dry and hot early to mid portion of next week, with increasing
  fire danger Jackson and Grand Counties.

&&

.UPDATE...
Issued at 352 AM MDT Sat Aug 2 2025

Although the humidities are 90-100% over most of the plains at
this time, there is no fog or Stratus around. There are weak
drainage wind patterns in place in most places. Models are showing
a bit of drying, both in the surface dew point and precipitable
water fields from yesterday 00Z to late this afternoon at 00Z.
Overall the going pops in this afternoon`s grids look reasonable,
and with it being a bit drier, perhaps the threat of heavy
rainfall will be lessened somewhat.

&&

.DISCUSSION /Through Friday/...
Issued at 256 PM MDT Fri Aug 1 2025

The 18Z HRRR and NAMNest models continue the 12Z model trend of
showing strong/severe thunderstorms late this afternoon and
evening across the northeast Colorado plains. Satellite imagery
showing decreasing stratocumulus clouds over the northeast plains.
As of 2PM temperatures have reached the mid 70s to lower 80s over
the northeast plains. SPC Mesoscale Analysis page shows MLCAPE of
2000- 2500 J/kg already and may reach 3000 J/kg later this
afternoon. Dew points are higher than forecasted with readings
mainly in the 60s. Shear is better today than the past few days
with 0-6km bulk shear peaking at 30-40 knots. Given decent
moisture, instability, and shear, some of the storms should become
severe with large hail (slightly larger than golf balls), and
strong damaging winds to 70 mph. Can`t also rule a few tornadoes
with decent low level shear and low LCLs (Lifted Condensation
Level).

Farther west, it is drier with less shear and instability.
Scattered showers and thunderstorms will spread eastward through
the rest of the afternoon and early evening. Brief heavy rain,
small hail, and wind gusts to 50 mph will be possible with the
stronger storms along the Front Range.

On Saturday, a lee-side trough/dry line shifts east across the
area during the afternoon. Across the higher terrain, urban
corridor, and nearby plains, westerly winds will bring slightly
drier air. However, there still looks to be enough moisture and a
weak wave to produce scattered thunderstorms. The storms are
expected to begin late morning over the mountains and then spread
eastward through the afternoon. Brief heavy rain, small hail, and
gusty outflow winds to 50 mph will be possible with the storms.
Better moisture and instability hangs on over far eastern Colorado
where a couple severe storms will be possible before they push
eastward into Nebraska and Kansas.

A weak cold (cool) front pushes south through the area early
Sunday. This will bring slightly cooler air and drier into the
area. The air will be drier as well with precipitable water values
falling to 50- 75 percent of normal. The eastern plains may again
hold onto some moisture where scattered thunderstorms will be
late in the day.

For next week, the upper level high will intensify over the Central
and Southern Rockies with Colorado feeling the full effects of
the high by Tuesday. Mostly dry and hot conditions are expected
for Tuesday through Thursday with highs reaching the mid to upper
90s across northeast Colorado. Precipitable water values fall
below normal and will be well below normal Tuesday through
Thursday. So we are looking at a week of very little rainfall
across the area. We may begin to see some relief from the heat
next Friday as a longwave trough moves into the northwest part of
the country and may start to push the ridge off to the south.

&&

.AVIATION /12Z TAFS through 12Z Sunday/...
Issued at 538 AM MDT Sat Aug 2 2025

Although areas of low Stratus (OVC005) have recently developed
over areas of northeast Colorado, DIA remains under the influence
weak drainage winds. So perhaps the low ceilings will stay away.
If the wind shifts to a weak west/northwesterly direction, the
Stratus will likely move right on in. The latest hi-res models
keep the low ceilings out of the big airport for this morning.
Will leave the PROB30 in for late day convection along with
VRB20G38KT from the outflows.

&&

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

&&

$$

UPDATE.......rjk
DISCUSSION...Meier
AVIATION.....rjk