647
FXUS63 KOAX 211041
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
541 AM CDT Thu Aug 21 2025

.KEY MESSAGES...

- Near to slight above-normal temperatures are expected today
  and Friday, with highs in the 80s to low 90s.

- A cold front pushing into the area on Friday will bring
  chances (20- 40%) for showers and thunderstorms, with a few
  strong to severe storms possible.

- Cooler temperatures move in this weekend into early next week,
  with widespread highs generally in the 70s.

&&

.DISCUSSION...
Issued at 223 AM CDT Thu Aug 21 2025

Today and Tomorrow...

Water vapor imagery this morning displays a mid- to upper-level high
anchored over the Four Corners region, with broad ridging extending
across much of the western and central CONUS. At the surface, a wide
corridor a high pressure spans the central Plains into the Great
Lakes region, bringing calm winds and clear skies. This has allowed
for efficient radiational cooling overnight, setting the stage for
fog development again this morning, most likely in areas along and
east of the Missouri River, where model soundings depict a shallow
saturated layer near the surface. Fog is expected to remain less
dense than previous mornings, though patchy areas of reduced
visibility under two miles will be possible.

Fog should gradually dissipate after sunrise, giving way to another
warm and humid afternoon. Highs will reach the 80s to low 90s, while
dewpoints in the low 70s push heat indices into the 90s. Scattered
fair-weather cumulus is expected once again this afternoon, and CAM
guidance hints at enough deepening for a few brief, isolated
showers, especially in southeast NE and southwest IA where a weak
zone of surface convergence slides by. However, model soundings
exhibit some dry sub-could air, pointing towards virga being the
more likely scenario. Therefore, have opted to leave PoPs dry
for the time being.

Tonight into Friday, a potent shortwave trough will pivot across
Saskatchewan/Manitoba toward the Great Lakes region, dampening the
ridge and driving a cold front into the region. The boundary is
expected to reach northeast NE by Friday morning, bringing PoPs of
15-30%.

Friday`s highs will depend on frontal placement, with upper 80s to
low 90s expected ahead of the boundary and the low 80s behind it.
Additional showers and thunderstorms are expected Friday afternoon
and evening along the front (PoPs 20-40%). Steepening lapse rates
will yield a modestly unstable airmass (MLCAPE of 1500-2000
J/kg), and when combined with sufficient bulk shear (25-30 kts),
a few strong to severe storms will be possible. SPC maintains a
Marginal Risk (Level 1 of 5) for the entire area, with hail and
damaging wind gusts the primary hazards.

Saturday and Beyond...

The post-frontal airmass will be felt on Saturday, with highs
topping out in the mid 70s to low 80s. Persistent troughing over the
eastern CONUS will maintain northwesterly flow aloft, enhanced by an
unseasonably strong speed max feeding into the region. This will
reinforce CAA and keep temperatures cool. Highs in the 70s and lows
in the upper 40s to mid 50s are expected Sunday through at least
Wednesday, roughly 10 to 15 degrees below seasonal norms.

The dampened ridge will allow a few shortwave disturbances to track
across the region, bringing occasional precipitation chances
(10-20%), especially across southeast NE. However, the overall
trend continues to favor more dry periods than wet. Looking
further ahead, the CPC`s 6-10 day and 8-14 day outlooks continue
to highlight a signal for below-average temperatures.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 537 AM CDT Thu Aug 21 2025

Fog has developed this morning, with patchy areas of dense fog.
MVFR conditions are expected to move into KOMA and perhaps KOFK,
though confidence is too low to include in KOFK at this time
(30% chance). Amendments will be made if needed. Fog is
expected to improve by 14-15Z (9-10 am), with a return to VFR
conditions at all terminals. Winds will remain out of the
southeast and under 12 kts through the period. Scattered low
level cumulus clouds may develop around 5000 ft this afternoon.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.

&&

$$

DISCUSSION...Wood
AVIATION...Wood