Chalco, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

559
FXUS63 KOAX 242324
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
624 PM CDT Tue Jun 24 2025

.KEY MESSAGES...

- Wet weather continues with shower and storm chances continuing
  this afternoon and evening. Redevelopment is likely after
  midnight with PoPs peaking at 60 to 90% after 2 am. Heavy
  rainfall and severe weather remain possible.

- Storms redevelop Wednesday afternoon and evening over
  northeast Nebraska (60-80% chance). Once again, storms may be
  capable of producing heavy rainfall and some severe weather.

- Storms linger Thursday with dry weather expected for most on
  Friday. Temperatures warm Thursday through the weekend before
  cooling down late Sunday as a front and PoPs return.

&&

.DISCUSSION...
Issued at 331 PM CDT Tue Jun 24 2025

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

17z subjective sfc analysis shows the stalled frontal boundary
draped along a line from near Hastings, Nebraska northeastward
toward Columbus, Tekamah, and toward Denison, Iowa. Just to the
south of the boundary, weak warm air advection observed at 925 mb
seems to be driving much of the weak showery and storm activity
currently observed by 19z KOAX radar imagery mainly across the
Lincoln area and points south. Have cut back on highs a bit from NBM
guidance for today given the abundance of cloud cover, but should
reach the mid 70s north of the boundary to low 80s near the
Kansas/Nebraska border.

CAMs try to develop more showers and storms along the stalled
boundary this afternoon and into the evening hours, with subtle
differences observed regarding placement of the front. Synoptic
scale mid level forcing is still looking weak, and with weak shear
and poor lapse rates, the severe potential is looking rather
limited, but can`t completely rule out a strong wind gust or two
with convection. However, with abundant moisture and CAPE, we will
continue to see periods of heavy rainfall with any storm activity.

20z RAP mesoanalysis shows an impressive amount of precipitable
water available in the atmospheric column this afternoon across
southeast Nebraska into southwest Iowa, around 2 inches, while the
rest of eastern Nebraska and western Iowa have values anywhere from
1.6 to 1.8 inches. Warm cloud depths remain at 3,500 to 4,000 meters
across a good chunk of eastern Nebraska and western Iowa, and with
the healthy PWATs, expect the efficient rainfall processes to
continue for the short term. As of this afternoon, MRMS 24 hour QPE
ranges from 2 to 5 inches across portions of eastern Richardson,
eastern Fremont and Page counties. Any additional accumulations
experienced in this area may aggravate flooding concerns in an
already saturated ground.

Later tonight, will see a 500 mb shortwave eject from the southwest
toward the forecast area in tandem with an 850 mb low level jet. As
the jet overspreads a vast swath of eastern Nebraska, CAMs hint at a
secondary round of convection developing after 4z along the jet nose
where speed convergence is observed. This has resulted in a band of
PoPs peaking at 60 to 90% primarily along a line from near Boone and
Antelope counties southeastward toward Pottawattamie counties and
progressing northeastward during the early morning hours Wednesday.
24 hr MRMS rainfall amounts across northeast Nebraska remain in the
1 inch range with a few pockets of 2 inches, so current thinking is
that the ground should be able to hold additional rainfall here, but
will continue to monitor flood potential. However, can`t rule out a
few strong storms during initial onset of the LLJ, with
marginal shear and instability observed.

Will see another midlevel disturbance approach the forecast area on
Wednesday which will help generate more showers and thunderstorms
along the boundary as it nudges slightly northward toward northeast
Nebraska. PoPs peak here at 60 to 80% by Wednesday evening. A few
CAMs like the FV3 do hint at some areas of northeast Nebraska
receiving up to five inches of rain from tonight through late
Wednesday evening, while the majority of CAMs show slightly more
muted output of an inch to two inches with a few pockets of 3
inches. With additional heavy rain expected with this activity, will
need to closely pay attention as flooding concerns may be observed
across this area, but this will largely be dependent on how much
rainfall occurs tonight into early Wednesday morning. Have
considered the potential for a Flood Watch across northeast
Nebraska, but have held off for now and will let later shifts
address potential. Some severe potential exists for Wednesday
evening as modest shear and instability will be in the area
prompting the SPC issuance of a marginal risk.

In addition to the storm and heavy rain potential Wednesday, some
clearing will be observed across the southern half of the forecast
area. This will result in heat indices climbing to the upper 90s to
near 100F in the afternoon hours.

.LONG TERM.../Thursday through Monday/

Thursday will see another 500 mb shortwave eject from the
Colorado/Nebraska Panhandle region, leading to NBM mentions of 50-
70% PoPs Thursday afternoon. Storms will once again have the
potential to cause heavy rainfall, and some severe weather may be
seen despite rather poor bulk shear. Dry conditions are finally
expected on Friday for most of the forecast area (some low end 15-
20% chance lingers across far southeast Nebraska and southwest Iowa)
as the weak 500 mb wave moves off toward the WI/IA/IL area with
zonal flow aloft expected.

By the weekend, the aforementioned zonal flow pattern is expected to
break down, while at the sfc, a low is induced across the Dakotas
dragging along a frontal boundary. This boundary will result in PoPs
returning back to the forecast Saturday evening into Sunday. NBM
extended has 15-30% PoPs across the majority of the area those days,
then peaking to 50 to 70% chance Sunday evening into Monday morning
as the front finally pushes through eastern Nebraska and western
Iowa. Machine learning guidance shows at least a low end 5% chance
for a severe storm during this period.

A brief warm up is expected from Thursday through Sunday, with highs
reaching the low to mid 90s by Sunday before cooling to the mid to
low 80s by Monday behind the front.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 624 PM CDT Tue Jun 24 2025

Main concern for the period will be timing of scattered showers
and isolated storms. Currently only expect a brief shower at
most at any site before 06Z, but can`t completely rule out an
isolated rumble of thunder before then. Guidance suggests higher
TS chances arrive after 06Z and should last for a few hours at
each terminal with a likely transition to mainly showers for a
few hours after. Expect MVFR to IFR conditions with showers and
storms, though ceilings should scatter out at OMA and LNK late
in the period. At OFK, IFR ceilings will persist through much of
the period with improvement to MVFR late. Otherwise, winds will
largely remain southeasterly to southerly and light before
becoming southwesterly and gusting 18-20 kts by early afternoon.


&&

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

&&

$$

DISCUSSION...Castillo
AVIATION...CA