Chalco, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

892
FXUS63 KOAX 260459
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1159 PM CDT Fri Jul 25 2025

.KEY MESSAGES...

- Thunderstorms developing along a slow-moving boundary may
  produce heavy rainfall, potentially leading to localized
  flooding in southeast NE through tonight. A Flood Watch
  remains in effect.

- A renewed stretch of dangerous heat is likely Sunday and
  Monday, potentially stretching into Tuesday. Afternoon heat
  index values may reach 105 to 115 degrees.

- Drier conditions are expected through at least Monday, with rainfall
  potential returning late Tuesday into Wednesday.

&&

.DISCUSSION...
Issued at 235 PM CDT Fri Jul 25 2025

Today and Tonight...

This afternoon`s synoptic scale pattern features a mid- to upper-
level ridge centered over the southeastern CONUS and an approaching
trough over the Pacific Northwest. In between these features, our
area sits within zonal to southwesterly flow aloft. As of 2 PM, a
slow moving MCV positioned over north-central KS is bringing a few
showers to southeast NE and southwest IA. Although some sunshine may
break through the cloud cover in place, highs will remain generally
in the low 80s. Dewpoints in the low 70s will bring a moist and
somewhat comfortable airmass.

At the surface, a stationary front remains draped from extreme
northeast KS into northwest MO and south-central IA. The
precise position of this boundary will significantly influence
the risk for excessive rainfall and flooding this evening. As of
2 PM, a vorticity maximum centered over north-central KS is
expected to lift northeastward through the evening, potentially
brushing extreme southeast NE. This feature may help to nudge
the stationary front slightly northward, although guidance has
trended away from previous solutions that lifted the boundary
closer to the I-80 corridor. Now, it appears the front will
struggle to move much beyond the NE-KS border. In the wake of
this vorticity maxima, a band of training thunderstorms is
expected to develop along the front, capable of producing heavy
to excessive rainfall and localized flooding concerns.

Atmospheric conditions remain favorable for very efficient rainfall
production, with PWAT values of 2.00-2.25" (above the 95th
percentile of late July OAX sounding climatology) and warm cloud
depths of 4 to 4.5 km. The key uncertainty remains whether this band
of thunderstorms will reach into southeast NE and southwest IA or
remain confined to northeast KS/northwest MO.

All factors considered, have opted to leave the Flood Watch in place
through the evening for extreme southeast NE. This is a conditional
threat, hinging on whether the axis of heavy rainfall shifts far
enough north. The most likely scenario brings storms into far
southeast NE, primarily affecting the Richardson and Pawnee county
vicinity. Rainfall rates may reach 2 inches per hour, and with 1-
hour Flash Flood Guidance in the area ranging from 1.25 to 1.50
inches, on top of the 3 to 5 inches of rain over the past 48 hours,
localized flooding will be a concern if these storms materialize.
WPC includes extreme southeast NE in a moderate risk (Level 3 of 4)
for excessive rainfall. PoPs peak around 75% this evening in far
southeast NE, tapering off sharply to the north. A few stray showers
and thunderstorms will be possible across the remainder of the
forecast area, though PoPs generally peak at 20-30% elsewhere.

Severe weather potential remains limited, as deep-layer shear is
weak (around 20 kts of 0-6 km shear). Still, a few stronger wind
gusts or even a brief tornado can`t be ruled out near the boundary
and vorticity maximum, though the risk should stay mainly south of
the NE-KS border. Given the proximity to the vorticity maximum
and sufficient 0-3 km MLCAPE, we could also see a few brief,
weak funnel clouds in any storms that do form.

Saturday...

Lingering precipitation is expected to taper off early Saturday. In
its wake, a moist air mass combined with calm winds and residual
cloud cover will support another round of fog development overnight
into the morning. Areas of dense fog will once again be possible,
particularly in low-lying and sheltered areas. Fog should gradually
dissipate after sunrise as skies begin to clear, allowing afternoon
temperatures to climb into the upper 80s to low 90s. With dewpoints
holding in the low 70s, heat index values will likely reach 95 to
103 degrees.

Sunday and Beyond...

Toward the end of the weekend, the ridge centered over the
southeastern CONUS will expand into the region, ushering in a
stretch of dangerous heat. Sunday and Monday are expected to be the
hottest days of the week, with highs climbing into the upper 90s and
heat index values ranging from 105 to 115 degrees. Heat headlines
will be needed for entire CWA, with an Extreme Heat Warning probable
for most.

Heat will persist into Tuesday for some areas, though a shortwave
disturbance moving across the northern Plains will help amplify a
trough over Ontario and Quebec, which in turn will flatten the ridge
locally. An associated cold front is expected to push through the
region on Tuesday, with high temperatures depending on the timing
and extent of the frontal progression. High temperatures could range
from the mid 80s behind the front to the mid 90s ahead of it.
Additional heat headlines may be needed for portions of the area,
with heat index values of 105 possible for the southern portion of
the CWA. The front is expected to bring a round of precipitation
Tuesday evening into Wednesday, with PoPs currently ranging from 30-
60%. Some severe weather potential exists with this system, as
machine learning guidance indicates a 5-15% probability of severe
weather; however, confidence in timing and details remains low in
this extended time frame.

Forecast confidence decreases further beyond Tuesday, as long-range
guidance suggests the front may stall somewhere nearby, potentially
supporting additional rounds of precipitation during the latter half
of the work week. With northwesterly flow aloft, lingering showers,
and increased cloud cover, high are expected to cool into the upper
70s to low 80s Wednesday through Friday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1159 PM CDT Fri Jul 25 2025

Ceilings are beginning to deteriorate earlier than guidance
suggested with the 00z issuance, primarily at KOMA and KLNK
were drops to MVFR are observed. Have adjusted times accordingly
for 06z issuance. Still expecting gradual expansion northward
of IFR ceilings and visibilities after 8z, with potential for
LIFR at KOMA and KLNK through at least 13z. Ceilings and
visibilities will improve by mid to late morning.

May see a pop up shower or storm at KLNK or KOMA, but model
guidance has trended this activity southward so have kept
mentions out given probability of occurrence is at 30% or less.

Winds remain under 12kts for this TAF cycle but will gradually
switch from southeast to southwest.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Flood Watch until 1 AM CDT Saturday for NEZ090>093.
IA...None.

&&

$$

DISCUSSION...Wood
AVIATION...Castillo