Council Bluffs, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

180
FXUS63 KOAX 142329
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
629 PM CDT Mon Apr 14 2025

.KEY MESSAGES...

- A Red Flag Warning is in effect until 9 PM due to the
  combination of strong winds and low relative humidity.

- Widely scattered showers and thunderstorms will affect
  portions of northeast Nebraska and western Iowa this afternoon
  and evening. Localized wind gusts of 55-65 mph are possible.

- Higher shower and storm chances (30-50%) Wednesday into
  Thursday. A few storms could be severe on Thursday (10-15%
  chance).

- Another chance for rain and a few storms Sunday.

&&

.DISCUSSION...
Issued at 258 PM CDT Mon Apr 14 2025

     Late this afternoon through tonight...

Current water vapor imagery shows an intense vorticity maximum
over the Dakotas, which will progress southeast through the mid
MO Valley late this afternoon into tonight. Strong forcing for
ascent and associated steepening lapse rates have contributed to
an area of showers and thunderstorms over central and eastern
SD, a few of which have produced wind gusts of 55-60 mph. Latest
CAM output indicates that activity will overspread portions of
northeast NE and western IA later this afternoon into tonight.

The presence of the steep lapse rates and a deep, inverted-v
type boundary layer will be supportive of locally strong
downburst winds (potentially up to 55-65 mph) with the more
robust convective elements into mid evening. Outside of the
anticipated convection, the strong gradient winds being observed
across the area today are forecast to gradually diminish
tonight as high pressure builds into the area from the northwest.
Clouds are also expected to diminish, allowing for a little
better radiational cooling potential late tonight with
temperatures falling to near or slightly below the freezing mark
across our western counties. Current guidance suggests that
locations generally south of I-80 now have vegetation
susceptible to freezing conditions. While the current forecast
has near-freezing conditions for an hour or so south of I-80 and
west of U.S. 77, we will hold off on any freeze headlines and
let the evening shift re-evaluate the situation.


     Tuesday and Wednesday...

Surface high pressure will quickly build through the area on
Tuesday, giving the region a reprieve from the strong winds
observed over the past few days. That being said, the presence
of a dry air mass with minimum relative humidities of 15-20%
will result in high to very high fire danger. If winds end up
being stronger than currently forecast, areas of extreme fire
danger could materialize, necessitating the issuance of another
Red Flag warning. Highs on Tuesday will be warmer than those
today with readings in the 60s.

On Wednesday, a deepening lee trough over the High Plains will
lead to gusty south winds. And while low-level moisture will
increase, afternoon relative humidity is forecast to fall into
the 20-30% range, with very high fire danger forecast across
much of the area. Warmer conditions are predicted by Wednesday
with highs in the 70s to around 80.


     Wednesday night through Friday...

The primary focus during this timeframe is a mid-level trough,
which is expected to amplify along and west of the Rockies.
Several weak disturbances are forecast to eject from the trough
into the northern Plains from Wednesday night into Thursday
night, with potentially a more prominent vorticity maximum
moving through the mid MO Valley on Friday. In the low levels, a
surface cold front will settle south through the northern
Plains, eventually reaching our area on Thursday. The boundary
may temporarily stall owing to the progression of a frontal wave
along it, before resuming its southward advance Thursday night
into Friday.

Strengthening warm thermal and moisture advection occurring
along a southwesterly low-level jet and ahead of the frontal
wave may support a complex of elevated showers and thunderstorms
Wednesday night across portions of KS and MO. A subset of that
convection could spread into parts of eastern NE and western IA
Thursday morning. In the wake of the morning convection, the
combination of daytime heating, increasing boundary-layer
moisture, and steepening low/mid-level lapse rates are expected
to yield a moderately unstable air mass ahead of the front.

Model soundings indicate the presence of a capping inversion
across the warm sector, with some uncertainty in whether
surface-based storms can develop in the absence of any
appreciable large-scale forcing mechanisms. However,
convergence along the front, especially in the event of a
migratory surface wave, may be sufficient to initiate storms
during the afternoon and evening hours, a few of which could be
strong to severe.

It appears that Thursday will be the warmest day of the week
with highs in the 80s to potentially low 90s expected ahead of
the cold front.

As mentioned above, a more significant shortwave trough is
forecast to move through the region on Friday. However, the
surface cold front is forecast to be located to the south of
our area by then with the best shower and thunderstorm chances
across KS and MO. Highs on Friday will be cooler than previous
days with readings in the 60s.


     This Weekend...

The western U.S. trough is projected to advance into the Great
Plains with the 12z global ensemble means depicting a notably
less amplified 500-mb pattern compared to their deterministic
counterparts. This is likely due to member spread in the
location of the closed mid-level system. That notion is
confirmed by the significant spread in the associated ensemble
member low positions. All that is to say that predictability in
the track and intensity of that storm system remains in
question, which has implications on precipitation and severe-
weather potential.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 617 PM CDT Mon Apr 14 2025

Main concerns for this TAF cycle continue to be the strong
northwest winds gusts. Gusts may briefly reach 40 kts at times
through about 0200 to 0300z before largely subsiding by 0500 to
0600z. 23z radar imagery is showing areas of widely scattered
showers and a few thunderstorms, primarily north of KOFK and
another area just north northwest of KOMA. Have not included
any -RA or TSRA mentions for this issuance given confidence is
low on whether the terminals will see direct impacts, but will
continue to monitor and make amendments as needed. Otherwise,
expect VFR conditions for this TAF cycle with the SCT to BKN
cumulus deck dissipating late tonight. Winds tomorrow will be
from the northwest and at 12 kts or less.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Wind Advisory until 9 PM CDT this evening for NEZ011-012-
     015>018-030>034-042>045.
     Red Flag Warning until 9 PM CDT this evening for NEZ011-012-
     015>018-030>034-042>045-050>053-065>068-078-088>093.
IA...Wind Advisory until 9 PM CDT this evening for IAZ043.
     Red Flag Warning until 9 PM CDT this evening for IAZ043-055-
     056-069-079-080-090-091.

&&

$$

DISCUSSION...Mead
AVIATION...Castillo/Nicolaisen