375
FXUS63 KOAX 081951
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
251 PM CDT Tue Jul 8 2025

.KEY MESSAGES...

- Quiet conditions expected for today with highs in the mid to
  upper 80s with light and variable winds.

- Showers and storms (15-30% chance) develop early Wednesday
  morning primarily across our west. May see redevelopment again
  Wednesday evening into Thursday morning (20-40% chance) and
  some of these storms may be strong to severe.

- Higher chances (50-70%) for showers and storms exist Thursday
  evening into early Friday morning. Some storms may be strong
  to severe.

&&

.DISCUSSION...
Issued at 251 PM CDT Tue Jul 8 2025

.SHORT TERM.../Today through Wednesday Night/

Lingering clouds from the MCS overnight have cleared the forecast
area with the H5 shortwave pushing off to the southeast. 19z H5 RAP
objective analysis shows the trof and vort max along eastern Iowa
into northern Missouri, while a stronger trof across Ontario into
Minnesota keeps pushing east resulting in northwest flow aloft. At
the sfc, a channel of high pressure extends from southern Manitoba
into the Dakotas, eastern Nebraska, and much of western Iowa.

Conditions should remain quiet for today with the sfc high pressure
dominating much of the Northern Plains. A few CAMs try to generate
weak scattered showers this afternoon, but current thinking is that
we should remain dry. Highs today will be in the mid to upper 80s
with light and variable winds. With continued dew points in the
upper 60s to low 70s this afternoon, will still feel uncomfortable
outside.

H5 mid level high based across the southwest US will result in a few
shortwave trof disturbances moving within the northwesterly flow for
Nebraska and western Iowa. The first will sneak through later
tonight into the early morning hours Wednesday, primarily affecting
eastern Nebraska. Forcing in the midlevels remains rather weak, but
low level forcing aided by H8 warm air advection may help trigger a
few scattered showers and storms. CAMs show convection developing by
10z across far northwestern portions of the CWA, eventually
spreading along our western border with the Hastings WFO through
about the noon hour Wednesday. Have introduce 15 to 30% PoPs along
our western border to account for this. BUFKIT soundings show around
1,000 J/kg of MUCAPE with the instability profile looking skinny. 0-
6 km bulk shear also remains marginal at around 20-25 kts, so not
really expecting much regarding severe potential with this activity.
Lows tonight will be in the mid 60s with light and variable winds.

Another shortwave disturbance will advance from the western Dakotas
and Nebraska Panhandle region to the east throughout the day
Wednesday. Low and mid level forcing looks a little bit stronger
with this wave, but the best instability (around 3,000 J/kg of
MLCAPE) and stronger bulk shear are located along our western border
into central Nebraska. CAMs show convection firing off across
central Nebraska Wednesday afternoon and evening, although
differences exist with how the convection tracks east in the evening
and overnight hours toward OAX. Some CAMs like the HRRR and HiRes
ARW show convection spilling into western portions of the forecast
area Wednesday evening where some severe threat may exist as shear
is a bit better here. However, forecast soundings show much of the
instability across eastern Nebraska remaining capped, so any
development will most likely be rooted aloft if convection can
spread farther east. Questions also remain regarding how truly
unstable the airmass will be given morning convection may hinder
atmospheric recovery. The SPC has highlighted primarily western
portions of our forecast area in a marginal risk of severe
weather, with the main threats being large hail and strong wind
gusts. Have kept latest NBM solution where PoPs peak at 20 to
40% across much of the forecast area late Wednesday into early
Thursday. Otherwise, highs Wednesday will be in the upper 80s to
low 90s with southerly winds around 10-15 mph. Lows Wednesday
night will be in the mid 60s to low 70s.

.LONG TERM.../Thursday through Monday/

By Thursday, the H5 high across the southwest US will weaken as two
shortwave trofs begin developing across the Rockies. These waves
will eject to the east into the Dakotas and Nebraska towards midday,
eventually fusing together into one main shortwave. Ahead of the
approaching wave, will see strong 1000-850 mb moisture transport
resulting in low 70s dew points making for a rather unpleasant
airmass. This may result in a few spots having heat indices reach
the upper 90s to near 100F briefly in the afternoon. With ample
instability pooling ahead of the wave, 0-6 km bulk shear of 30 to 40
kts, and large scale forcing for ascent overspreading the area in
the afternoon and evening hours, could certainly see strong to
severe storms. The SPC has highlighted the entirety of our
service area in a slight risk of severe weather for Thursday,
with all modes of severe weather possible at initial onset
before upscale growth.

Will also need to keep an eye on the potential for heavy rainfall.
Given the ample low level moisture, PWAT values range from 1.75 to 2
inches, and coupled with warm cloud depths of 4,000 meters, expect
to see efficient warm rain processes. Some portions of northeast
Nebraska and west central Iowa could see up to an inch and a half of
rain by early Friday morning. This has prompted the WPC to issue a
slight risk for excessive rainfall across much of eastern Nebraska
and western Iowa for Thursday. PoPs currently peak Thursday evening
into early Friday morning at 50 to 70%, gradually moving east
overnight.

PoPs linger on Friday as the shortwave will stick around for one
more day before pushing out Friday evening (30-60%, with highest
chances in western Iowa). A low end chance (15%) for a shower or
storm exists south of I-80 on Saturday as a weak shortwave sneaks
through northwesterly flow aloft, but best chances remain well south
into Kansas. Sunday through Monday will see low end chances (15-20%)
for scattered showers and storms as northwesterly to nearly zonal
flow at H5 allows a few shortwaves to move through the forecast area.

Aside from Friday and Saturday where temperatures cool to the upper
70s and low 80s, highs in the extended will remain in the mid 80s to
low 90s.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1219 PM CDT Tue Jul 8 2025

VFR conditions expected for this TAF cycle. May see a SCT
cumulus field around 5,000 ft at KOFK this afternoon. Winds
will remain light under 12 kts and turn more easterly as sfc
high pressure moves to the east.

May see some scattered showers and storms affect KOFK after 11z
and KLNK after 14z, but given confidence remains less than 50%
at terminals seeing impacts, have left mentions out at this
time. Expect further refinements and adjustments with future
issuances.

&&

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

&&

$$

DISCUSSION...Castillo
AVIATION...Castillo