120
FXUS63 KGID 261749
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
1249 PM CDT Thu Jun 26 2025

...AVIATION UPDATE...

.KEY MESSAGES...

- Rain and thunderstorms dissipate from SW to NE this morning,
  but flooding impacts will continue for at least another 24-48
  hours for areas from around Wood River to Columbus, including
  the city of Grand Island. These locations have received at
  least 4-7 inches of rain over the past 24-36 hours.

- Flooding impacts will continue for at least another 24-48
  hours (likely several days in areas around/NE of Grand Island)
  due to an axis of at least 4-7 inches of rain that has fallen
  over the past 24-36 hours from Wood River to Columbus.

- Mainly dry and becoming hot for Friday into Saturday.

- Periodic thunderstorm chances return Saturday night and
  continue into early next week. It is too soon to determine
  specifics (timing, coverage, intensity), but locally heavy
  rainfall may be possible Sunday night into Monday morning.

&&

.UPDATE...
Issued at 648 AM CDT Thu Jun 26 2025

Have cancelled the Flood Watch as the threat for additional
heavy rain (and any new flood products not already covering
affected areas) is low.

&&

.DISCUSSION...
Issued at 430 AM CDT Thu Jun 26 2025

Ongoing rain event is finally starting to come to an end from SW
to NE as of 4AM CDT. Several MCVs are apparent in regional
radar loops, which will continue to track NE in the 30-35 kt
850-300mb mean flow. These will provide increasing subsidence,
coincident with a weakening/veering low level jet, to bring an
end to the (locally extreme) heavy rain event. Latest
HRRR/RAP trends suggest any additional activity along a weak
cold front should stay mostly SE of the local forecast area, so
have trimmed PoPs considerably for the late AM to early eve time
frame. Clear skies and light winds will prevail overnight, which
could allow for some areas of fog to develop after midnight -
particularly in areas that have experienced recent heavy rain.
Will need to monitor trends as the pattern suggests a non-zero
chance the fog may become dense, in spots.

Main story Friday into Saturday will be the increasing
temperatures. Saturday continues to look the hottest with
widespread highs in the 90s, and even near 100F SW zones.
Factoring the typical late-June humidity and it will likely feel
as warm as low 100s where dew points are the highest (E half).
Models suggest convection will develop each afternoon over the
high plains, then shift E/SE during the evening into overnight
hours. Have slight chance (20%) in far NW-W zones Fri night,
but chances seem to be increasing for Sat night (now up to
30-40%) as the initial development likely occurs a bit further E
compared to Fri night - over central Neb vs Neb Panhandle.
New SPC Day 3 Outlook has spread the Marginal Risk into most of
south central Nebraska, and portions of the Slight Risk into the
Ord area. Damaging wind gusts would likely be the primary risk.
GFS isn`t quite as robust as the EC, so still some differences
to iron out.

Deterministic and ensemble solutions have been highlighting Sun
eve/night for a few days now as the next "best" chance for
organized convection. We`re getting out into "questionable
predictability" time frame, but first guess is that strong
instability and fairly week deep layer shear would promote
semi-organized clusters with some gusty winds. PWATs briefly
spike to around +2 std devs, but this could be convectively
contaminated in the model. Regardless, it doesn`t appear as
though we`ll have high-end deep layer moisture present and
connections to both the Gulf and sub-tropical Pacific.
Confidence drops off thereafter, but synoptic generalities would
support a drop in temps back to around normal and mainly dry
conditions, for at least a day, or two.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1237 PM CDT Thu Jun 26 2025

For KGRI/KEAR Airports:

Temporary MVFR CIGS will continue at KGRI for about one more
hour, before VFR conditions become dominant at both terminals
for the rest of the afternoon. Winds today will be mainly
northwesterly at less than 15 KTS...rapidly diminishing by
early evening as an area of surface high pressure slides into
the Missouri River Valley. Return flow around this area of high
pressure system will induce light southeasterly winds late in
the night, which combined with clear skies, saturated soils and
elevated dewpoints, will likely result in fog...potentially
dense towards daybreak. Due to some uncertainty, kept worst
conditions in a tempo group for the time being, but prevailing
LIFR VSBYS/CIGS may eventually be needed. This fog should not
stick around long into the daytime hours Friday, with VFR
CIGS/VSBYS again becoming predominant by 27/16Z at the latest.

&&

.HYDROLOGY...
Issued at 430 AM CDT Thu Jun 26 2025

Wow, what a night! Anticipated there could be some areas of
heavy rain, but the extreme 4-7" amounts over a 6-9 hour period
was obviously above the high-end of expectations. Also just so
happened to evolve over our most populated city. Nonetheless,
the combination of PWATs in the 95th-99th percentile, weak
surface boundary, and deep layer flow largely parallel to this
front, provided the necessary ingredients for a highly
anomalous event. See Climate section below for details on the
broken records. Radar estimates and automated weather stations
suggest a broad swath of at least 2-4" from Phelps and Kearney
Counties, northeast into Nance and Merrick Counties. Within this
swath, an even heavier corridor of 4-7" is evident roughly along
the Platte River corridor from Wood River to Genoa. MRMS peak
bullseye is near 8" in Merrick County, will still a little bit
more to go next 1-2 hours. Will obviously work to confirm this
with ground truth reports as the morning moves along.

Going forward...expect widespread aerial flooding to persist for
at least a day or two. Fortunately, a lot of this rain occurred
over the Platte River which can take quite a bit of volume. The
bad part, however, is that terrain is flat and it can take a
long time to get there. As such, would expect the Prairie Creek
and Silver Creek basins to be dealing with flooding for at least
several days - pending any potential additional rainfall Sat/Sun
eves/nights. The Wood River, Loup River downstream of St. Paul,
and other creeks and streams in Hall, Merrick and Nance Counties
will be dealing with some level of flooding over the coming
days. Expect updated river forecasts as new rainfall reports
gradually roll in through the morning hours.

&&

.CLIMATE...
Issued at 415 AM CDT Thu Jun 26 2025

Reposting information already released in the RERGRI products
given their significance:

     New Daily Rainfall Record For June 25th And Also The Month Of
June At Grand Island...

The Grand Island Central Nebraska Regional Airport recorded 6.41
inches of rain on June 25th. This set a new daily rainfall
record for June 25th, shattering the previous record of 1.55
inches, set in 1990. More notably, this set a new rainfall
record for ANY day in the month of June, breaking the previous
record of 4.18 inches, set on June 15, 1990. Finally, this was
the 2nd highest daily rainfall on record for ANY day of the year
for Grand Island, trailing only 6.50 inches, which fell on May
11, 2005.

With the additional rainfall since midnight, the two-day
rainfall record of 7.21", which also occurred with the heavy
rain event from May of 2005, has been broken. As of 4AM CDT,
7.32" (and counting) has fallen between yesterday and this
morning. More information (and official RERGRI) to come once
the rain (finally!) stops.

Precipitation records at Grand Island date back to 1895.

&&

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

&&

$$

UPDATE...Thies
DISCUSSION...Rossi
AVIATION...Thies
HYDROLOGY...Thies
CLIMATE...Pfannkuch/Thies