634
FXUS63 KGID 152044
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
344 PM CDT Tue Jul 15 2025

.KEY MESSAGES...

- A line of strong to severe storms is expected to power through a
good portion of the area from northwest to southeast between 8PM and
2AM tonight.

- Strong to damaging winds up to 60-70 MPH will be the primary
concern tonight with large hail or an isolated tornado possible.
Areas of greatest impacts will likely fall earlier in the
evening/night and for areas concentrated towards the northwest.

- Storms, potentially severe, will be possible again Wednesday
evening/night with the greatest potential towards the south. Storm
initiation will be highly depended of placement of cold front.

- A cool down Wednesday and Thursday should cap highs in the
  70s, quickly warming up for the weekend and for likely most of
  next week in the mid 80s and 90s.

&&

.DISCUSSION...
Issued at 343 PM CDT Tue Jul 15 2025


...Tonight...


Deepening low pressure over the eastern rockies has driven steady
southerly winds near 15-20 MPH, gusting as high as 25-30 MPH this
afternoon across the area. These winds have helped pump in some
warm, moist air, helping lift highs into the 90s with a few of our
southwestern areas approaching 100 degrees. The transport of moist
air up from the south today has allowed dewpoints to top out in the
upper 60s to low 70s. This hot and humid air mass has additionally
helped inflate afternoon instability with CAPE values up to near
2,000-3,000J/kg. Though deep layer shear does not look too overly
impressive (less than 30kts of bulk shear), the presence of an upper
level shortwave disturbance moving in overhead paired with a surface
cold front dropping southeast off the Nebraska sandhills late this
evening and tonight, should provide ample forcing to support
convective initiation.

A MCS (line or cluster of storms) is expected to erupt across
northern to northwestern Nebraska this afternoon (3-6PM), racing
east to southeast and into much of central Nebraska and likely a few
parts of north central Kansas. This system should reach our area
between mainly 8PM and 2AM (a time range generally agreed upon by
most CAMs), starting northwest and passing to the southeast. Given
the favorable thermal/moisture environment this afternoon, an
enhanced risk of severe weather (level 3 of 5) is in place across
our northwestern tier of counties (Areas northwest of a line from
northern Gosper to western Nance counties) with a slight risk (level
2 of 5) stretching across the rest of our nebraska and a few of our
northern Kansas areas.

The primary threat from these storms will be the presence of strong
to damaging wind gusts up to 60-70 MPH along the initial arrival of
storms. Large hail, though not the primary concern, up to the size
of golf balls may still be possible in a few spots. An isolated
tornado can`t be ruled out either, though this is by no means our
main concern for tonight. The strongest punch from this system will
likely occur earlier on in the evening/night with grater probability
and impacts likely concentrated in areas toward the northwest,
closer to where the storms initialize. The presence of a modest LLJ
(25-40kts) could enhance convergence along the leading edge,
allowing storms to keep their composure and potentially extending
their lifetime. The question remains on how far south these storm
will progress? The latest HRRR/RAP/NAMNEST guidance suggest this
boundary`s edge to fall close to the state line.

Models remain in fair agreement with the timing and location of
these storms, though there is still some mesoscale uncertainty in
identifying where the exact location of any narrower and potentially
more intense swath of wind gusts in association with the storm`s
leading edge, will end up. Light showers may linger behind the
initial line of storms up to a few hours, spreading rainfall amounts
up to between mainly 0.5-1" with greater amounts concentrated
generally towards the north.


...Wednesday & Thursday...


A few lingering early AM showers may be observed Wednesday morning
for a few of our eastern areas, though the fast moving nature of the
overnight system does not suggest for showers to stick around all
that long into the morning. The placement of the cold front in the
afternoon will greatly determine how far north storms will be able to
develop Wednesday afternoon to night. Generally the best chances
will be concentrated towards the south, the direction where storms
will be heading. Higher than normal model uncertainty makes it
challenging to narrow down PoPs across our northern and central
areas. The HRRR and the RAP models keep this boundary further north,
signaling developing storms over the I-80 corridor, though the
NAMNEST and global models (GFS/ECMWF) place this boundary further
south, closer to northern Kansas. If this secondary scenario plays
out, in theory, the northern half of our area should stay fairly
dry, with storms limited to our Kansas and far southern Nebraska
areas.

A few of these storms will have the ability to become severe. A
marginal risk (level 1 of 5) remains in place for the full area
besides a the northern half of Valley/Greeley counties. Though
impacts will likely not be as widespread as tonight`s event. Damaging
winds up to 60 MPH with large hail will still be a concern. Overall,
the better severe potential should lie towards the south where
longer prefrontal residence time as well as warmer temperatures and
greater dewpoint should lie, leading to increased instability.

Following the frontal passage late Tonight and Wednesday, cooler air
for July standards (15-20 degrees below normal) will fill in from
the north, reaching our far northwest portions of the area Wednesday
and the entire area on Thursday. Highs Wednesday will range the low
70s in the northwest, down to the 80s to low 90s for our Kansas and
far eastern Nebraska areas. Temperatures Thursday will feel fantastic
as highs drop down to the low to mid 70s areawide. Thursday will
likely become the coolest day in the next week, so be sure to take
advantage. A few nighttime pop-up storms (20-30%) could bud into
parts of north central Kansas and far southeast Nebraska late
Thursday night.


...Friday and Beyond...


Temperatures will raise sharply once again starting Friday as a
southern warm air advection pattern returns to the area, shoveling
up a more hot and humid airmass. Highs for the weekend will range
the mid 80s to mid 90s. Afternoon to nighttime storm chances between
20-50% return each night through next Tuesday with the greatest
potential falling Friday (35-50%) and Saturday (30-40%) nights.

A broad ridging pattern down south next week with the jet mainly
staying across the Northern Plains increases the likeliness for
increasing and lingering heat (highs often in the 90s most days).
Storm chances each day will become fairly dependent on how amplified
the fairly zonal upper-level flow may become.


&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1227 PM CDT Tue Jul 15 2025

For KGRI/KEAR Airports:

A complex situation is expected to unfold tonight as strong to
severe storms look likely to power though the terminals between
3z and 6z with lingering lighter showers possible following the
initially punch through 8z. Impacts may first be felt at KEAR
around 30-60 minutes prior to KGRI. The gustiest winds and
lowest visibility from the heaviest rainfall will likely fall
within the first hour of when the storms initially arrive.
Gusts up to 50-60kts may be briefly possible, though not a
guarantee.

Winds this afternoon begin from the south between 15-20kts and
gust as high as 25-30kts. A cold front passage associated with
the line of storms will abruptly swap the southerly winds to to
north, lightening up to near 10-15kt following the storms
passage. Clouds will increase in coverage a few hours before the
storms arrive, gradually lowering cloud bases and ceilings
between the range 6-12kft. There is about 70% confidence that
MVFR conditions will hold out through a vast portion of the
morning hours after the storms pass.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.

&&

$$

DISCUSSION...Stump
AVIATION...Stump