707
FXUS63 KGID 251759
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
1259 PM CDT Wed Jun 25 2025

...AVIATION UPDATE...

.KEY MESSAGES...

- Ongoing showers/storms that have produced locally heavy rain
  will end from south to north over the next few hours, leaving
  warm and steamy conditions for the rest of the day.

- Yet another round of thunderstorms is expected to redevelop by
  mid to late afternoon, and continue into tonight. Some of this
  activity could be severe and produce large hail and damaging
  wind gusts - particularly near and N of I-80.

- Perhaps the greater threat will be training thunderstorms and
  another bout of locally heavy rainfall of 2-3 inches, or more.
  This could lead to flash flooding. Sherman County area will
  be of particular concern due to recent heavy rain last night.

- Forecast generally dries out and heats up for Friday and
  Saturday before periodic storm chances and more seasonable
  temperatures return Saturday night into early next week.

&&

.UPDATE...
Issued at 1057 AM CDT Wed Jun 25 2025

Due to the potential for heavy rainfall on top of already
saturated soils this afternoon and tonight, a flood watch was
issued for parts of the area starting at 3 PM and continuing
until 7 AM Thursday morning. Minor flooding is already occurring
in spots across the watch area, and this flooding will likely
worsen later today with the potential for an additional 2 to 4
inches of rainfall in spots.

&&

.DISCUSSION...
Issued at 440 AM CDT Wed Jun 25 2025

Have had quite a bit of convection for much of the night, with
only a few counties missing out on at least a half inch of new
rain. Some areas have received quite a bit more than that,
however, particularly within a SW to NE swath from around
Arapahoe to North Loup. 1-2.5" will likely be fairly common
within this swath, and much of Sherman Co. could easily average
2.5-3.5" before all is said and done by around dawn. This
activity is being fed by a decent 30-40kt LLJ per regional VADs
amidst an environment with very high PWATs. The LLJ is forecast
lift and veer next few hours, which should take the main band
of rain N and E of the area by ~12Z. Increasingly breezy S winds
and decreasing clouds should allow for warm and steamy
conditions to develop for the aftn hours. Expect highs to top
out in the mid 80s to mid 90s from N to S, which combined with
dew points around 70F and the recent overnight rain, it`ll feel
a couple/few deg warmer than that.

Attention then turns to the next round of thunderstorms that is
forecast to develop between 3pm-6pm along a lingering boundary
that looks to setup SW to NE just W through N of the Tri-Cities.
Expect moderate instability (MLCAPE 1500-2000 J/kg) and modest,
but sufficient, deep layer shear (25-35kt) to develop prior to
convective initiation. Greatest combination of instability and
shear looks to favor the N half of the CWA, which is where SPC
has raised into the Slight Risk (level 2 of 5) with the latest
Day 1 outlook. Main severe threats look to be large hail
(quarter to half dollar) and damaging wind (60-65 MPH) in the
late afternoon through evening time frame. Weak mid level lapse
rates and high PWATs suggest a transition to mainly hydro
concerns for the overnight. These concerns are discussed in
greater detail below.

Models have come into decent agreement that Wed night`s
convection should push the aforementioned boundary through most
of the area by mid to late Thu AM. This should all but eliminate
convection concerns for most of the CWA by mid to late AM. Will
have to still monitor far SE zones where the boundary could
hang up and be the focus for renewed development during the mid
to late aftn. Even so, shear and lapse rates are weak, so
probably only looking at an iso, "pulsey" severe threat, if any,
from Beloit to Hebron. Subsidence and light Nrly flow should
lead to nice summer day in the 80s for the rest of the area.

Shortwave ridging and rising heights will favor mainly dry
conditions and a warm-up to widespread 90s for the daytime hours
Friday into Saturday. Saturday looks to be the hotter of the
two days (though not quite as hot as last Saturday!), with SW
zones possibly rising into the low 100s. Elsewhere could still
feel like 100F thanks to dew points in the mid 60s to around
70F. There are non-zero chances for convection to move in from
the W each night, but confidence on this is low.

Models bring next shortwave trough and associated cold front
into the region Sunday eve/night. PoPs have increased into the
40-60% range Sun night, which seems more than reasonable given
potential for convection that develops over the High Plains
during the afternoon to roll E/SE with the front overnight.
Temperatures fall back to seasonable levels behind this front
for early next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1251 PM CDT Wed Jun 25 2025

For KGRI/KEAR Airports:

A weak frontal boundary will cross the terminals this evening
bringing with it an increasing chance for MVFR CIGS/VSBYs
associated with SHRAs and TSRAs...beginning during the late
afternoon hours (KEAR) and continuing into the evening and
overnight hours (both KEAR AND KGRI). This front will also bring
a wind shift at both sites, with a switch to northerly winds
overtaking KEAR around 26/00Z and reaching KGRI by around
26/02-03Z. Coverage of precipitation should diminish by daybreak
Thursday, and despite the chance for some SHRAs/TSRAs during
the day, decided not to include this mention in either TAF for
the time being.

&&

.HYDROLOGY...
Issued at 445 AM CDT Wed Jun 25 2025

Recent swaths of heavy rain and model trends are leading to
increasing hydro concerns for later today and into tonight. As
mentioned above, will likely have some swaths of 1.5-3" of
observed rain from last night, the heaviest and most widespread
of which will be over the NW third, or so, of the CWA.
Unfortunately, these areas also look to be under the gun for
another round of moderate to locally heavy rain this afternoon
into tonight. Of concern is that the orientation of the primary
initiation zone looks to be roughly parallel to the 850-300mb
mean flow...and a nocturnally 30-40kt low level jet could allow
for some backbuilding. These factors suggest that training cells
could be a real possibility. Throw on top of that the fact that
PWATs will continue to run abnormally high in the 1.75-1.9"
range - which is 2-2.5 standard deviations above normal - and we
could be looking some training convection that is also very
efficient at producing high rain rates. This general scenario is
supported by 03Z SREF max 24hr QPF values of 1.5-3.0", and
similar values from the 06Z HRRR. Strongly considered a Flash
Flood Watch on this shift, but will ultimately pass along
concerns to day shift and allow for additional HRRR/RAP/HREF
runs and possible coordination with neighbors. Areas along and N
of a line from Gosper to Nance appear to be most at risk.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Flood Watch through Thursday morning for NEZ039>041-046>048-
     060>062-072-073-082.
KS...None.

&&

$$

UPDATE...Rossi
DISCUSSION...Thies
AVIATION...Rossi
HYDROLOGY...Thies