495
FXUS63 KGID 301153
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
653 AM CDT Wed Sep 30 2026

.KEY MESSAGES...

- Periodic bouts of moderate to locally heavy rain and localized
  flooding remains the primary forecast concern. Rain
  intensity/coverage should peak this afternoon/evening, then
  taper off from north to south late tonight into Thursday.

- Flash Flood Watch remains in effect for the potential of 2-4",
  localized 5", of total rainfall...though the northern side has
  been trimmed to reflect a southward shift in model trends.

- A Dense Fog Advisory is also in effect this morning for
  visibilities less than 1/2 mile along and W/NW of a line from
  Smith Center to York.

- Much drier, and seasonably cool, conditions settle in for the
  weekend. Next week looks to be mild and continued dry.

&&

.UPDATE...
Issued at 415 AM CDT Wed Sep 30 2026

Won`t belabor the "meteorology" of this system, as it has
already be laid out in previous AFDs. In some ways the system is
playing out near expectations, but it other ways its not. The
overall coverage and intensity of rain across the area on
Tuesday/Tuesday evening was less than anticipated. This will
likely lead to lower total rain amounts for this system in areas
N of I-80 as a result. Also factoring into a downward trend in
amounts for northern areas is a general southward shift to the
system as a whole. This trend began on some of the model
guidance yesterday, and really solidified as a bonafide trend
with most of the 00Z guidance. Given the above factors, have
opted to trim some of our northern counties out of the Flood
Watch. Some model guidance argues this wasn`t enough - esp.
Gosper, Dawson, Buffalo, Hall, Merrick, and Polk Counties - but
with the heaviest part of the system still to go, and some
lingering uncertainty in fine scale details - felt this was a
good compromise and still makes the forecast "better". Am still
MOST concerned about the area along and SE of a line from
Stockton to Superior and Geneva for the greatest risk of 3-4"
amounts, locally as high as 5". These are also the areas that
are most "primed" from late last week`s rain, and also some
moderate rain already this morning.

One thing that hasn`t been talked about much is the potential
for a few rogue severe storms this afternoon. Obviously,
widespread rain/cloud cover casts considerable uncertainty in
our ability to destabilize this afternoon...and we won`t exactly
be helped along by steep mid level lapse rates considering the
sub-tropical feel to this system. Nonetheless, there are non-
zero chances that *just enough* surface based instability could
develop along an effective warm front near roughly I-70 to
support some robust convection this afternoon. Should that
happen, backed SErly sfc winds ahead of the primary surface low,
amidst very low LCLs and elongated hodographs, COULD support
some supercells and tornadoes. SPC has expanded the Marginal
Risk (level 1 of 5) to include all areas S of I-80...though
would be most concerned about areas along and S of the state
line. Roughly 3PM to 8PM looks to be the main window for this
conditional threat.

The general idea that the rain coverage and intensity peaks
today/tonight has NOT changed. In fact, several pieces of
guidance (deterministic and ensemble) suggest the noon to
midnight time frame especially will be the window of greatest
potential. I`d say the greatest uncertainty that still remains
with this system is when and the manner in which rain
dissipates and/or shifts SE. Some models indicates another
uptick for at least our KS zones during the day Thursday,
whereas other guidance is mostly isolated to scattered light
showers, kind of similar to Tuesday. This is probably an
uncertainty that`s most meaningful to our KS counties, as
guidance is in better agreement that rain/coverage will be much
more limited in Nebraska by the Thursday daytime hours. Thus, I
anticipate we`ll be able to drop the Flood Watch sooner than the
currently scheduled expiration time of 7PM Thursday for these
areas.

As for the fog...the current advisory area should cover the
overall greatest threat pretty well...and similar to recent
mornings, would expect gradual improvement through out the mid
to late AM hours. Currently am NOT expecting fog to be an issue
again tonight.

Once this system departs, still looks high and dry for the most
part this weekend and into next week. Going to feel more like
fall with cooler temperatures over the weekend - highs 60s to
lower 70s and lows in the 40s to lower 50s. Ensemble trends are
for slightly warmer temperatures next week.

&&

.DISCUSSION...
Issued at 415 PM CDT Tue Sep 29 2026

Currently...

The first of several rounds of precipitation to impact the
forecast area made its way through the area last night into
early this morning, dropping a swath of roughly 0.25-0.75in
across the NWrn quarter of the forecast area. The next round is
currently working its way northeast across the Central
Plains...and will continue to do so through the rest of the day.
Upper air and satellite data showing these shortwave
disturbances being ejected north east out ahead of the main
western CONUS troughing and low pressure spinning over the
CA/NV/AZ border area...while remnants of Hurricane Polo are
working their way northeast into northern Mexico, providing an
increased moisture source into the overall pattern. At the
surface, it`s an overall weak pattern across the forecast area,
sitting between broad high pressure over the eastern CONUS and
frontal boundary extending southwest from northern MN into the
Desert SW. This is keeping winds generally southerly, and light
around 5-10 MPH.

Tonight through Thursday...

The main story for this 7-day forecast period remains squarely
focused on this short term period through mid-week, with the
entire forecast area getting additional (but not necessarily
welcomed) rainfall...with the potential for quite a gradient
across the area. There hasn`t been any significant changes in
the general evolution of the next couple of days...with models
remaining in good agreement showing the remnants of Polo
becoming increasingly phased into the main upper trough axis/low
sitting over the Desert SW. Through this evening/tonight, while
the main upper low looks to only slide east into the AZ/NM
border region by around 12Z Wed, that shortwave energy left over
from Polo is expected to continue on a northeastward trek out
ahead of the main low...driving the next round of precipitation
chances across our forecast area.

Once the current batch of activity pushes further east...hi-res
models showing a continued lull into tonight, especially across
the northern half of the forecast area. Increased low-mid
level forcing (closer to 850-700mb) will keep better chances
tonight focused across areas near the NE-KS state line...with
some lingering, but important, uncertainties between models with
exactly where that axis sets up...important as that looks to be
the be first heavier band of rain to develop. Closer to, mainly
after 12Z Wednesday, models show that more widespread swath of
precipitation to push north through the forecast area...with the
potential for a more distinct drop off on both the north and
south sides than currently shown in the broader scale forecast.
That could make the afternoon hours a bit more interesting on
the southern side, with models showing a push of better
instability also working its way north with time. Still some
uncertainty with just how far north that lull in precip/better
instability push and sfc frontal boundary gets, but it`s not out
of the question that some additional convective
enhancement/redevelopment occurs...and the southern half of the
forecast area remains in the SPC Day 2 Marginal Risk area. Not
looking at widespread severe weather...but gusty winds/hail
possible, and with a sfc frontal boundary lingering in the area
and more easterly winds, an isolated tornado is a concern as
well. The overall main threat remains with heavy rain...and with
such a good fetch of moisture for this pattern to tap into, any
activity will be efficient rain-makers, even moreso for
anything with any strength...and rates of 1-2 inches per hour is
certaintly not out of the question.

Further into the evening/overnight hours Wednesday and Thursday,
the main push of the upper level system looks to pass through
the Central Plains...again there is still some lingering overall
minor uncertainties with its exact track. Models aren`t in too
bad of agreement showing the upper low filling/weakening as it
passes through during the day on Thursday...with precipitation
chances dropping off fairly quickly during the second half of
the day. Again some lingering uncertainties with exact
timing...but current forecast as all but the far SSE dry by
evening.

By the time its all said and done...still looking at a fairly
widespread area of 2-3 inches, with localized swaths of higher
amounts (potentially much higher depending on the model). One of
the main changes in the models today is with increasing
agreement focusing on the area with the better potential for
those higher amounts (totals closer to 4-5 not out of the
question)...running that axis mainly across the SSErn half of
the forecast area. Some models have a more marked southward
shift in the axis, clipping an even smaller portion of our SSErn
forecast area (showing more of an eastern KS and points NW
issue). A result of both trends...a notably tighter rainfall
gradient from north to south. Especially the further north one
goes from I-80, chances of even getting an additional one inch
drops off quickly...a few models show it may even be a struggle
to get another half-inch through the rest of the event. Areas
roughly I-80 to HWY 6, lot of uncertainty still remains here due
to lingering questions about where the banding sets up as then
main low moves out. Where more of the support for the location
of the heaviest axis currently sits (for the entire event) isn`t
too displaced from the area that picked up 2-5 inches last
week...and with crops not soaking up the moisture anymore, lack
of sun/wind and time...still a lot of saturated area out there
for problems to develop. Made no changes to the Flood Watch that
runs through 7PM Thursday...though depending on how models
trend, if they stick with that more southern focus, possible
that northern portions of the watch could be dropped early.

Friday on into early next week...

Don`t be alarmed by the bright light at the end of the
tunnel...it`s the sun, which will finally make a more widespread
return for the end of the week, along with drier conditions.
With main focus being tonight-Thursday, not a ton of time spent
on Friday through Monday...but the main story is the forecast
for this period is DRY, and currently there continues to be good
agreement between models with that. Overall it`ll feel more
like fall...highs through the weekend are forecast to mainly in
the 60s (some low 70s in KS this weekend), along with some
cooler lows...Fri night-Sat AM currently has widespread mid-
upper 40s. Winds through the weekend remain on the lighter
side...overall looking to be a pleasant stretch of weather.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 650 AM CDT Wed Sep 30 2026

For KGRI/KEAR Airports:

Today: Tricky VSBY forecast next couple of hours. We`ve have
some dense fog around the terminals early this morning, but it
seems to be more the exception than the norm. Have eased up on
the VSBYs with this update, and may still be a bit too
pessimistic. Later this morning, expect steady rain to move in
from the SW and continue through the rest of the daytime hours.
There could be a few rumbles of thunder, but instability is
weak, so kept this as PROB30s for now. CIGs should be mostly
LIFR to IFR today, and winds will go from light and variable
this morning, to NErly 5-10kt by this afternoon. VSBYs should be
mostly MVFR to IFR today, with the lowest IFR levels most likely
in the heavier rain this afternoon. Confidence: CIGs - High,
VSBYs - low to medium.

Tonight: Expect decreasing rain chances throughout the evening
and into the overnight. In fact, latest guidance is mainly dry
after 06Z. Confidence is quite low on how CIGs respond after the
rain ends. Some guidance clears the low clouds out entirely, but
could envision a scenario where IFR stratus is stubborn and
hangs on. Compromised at MVFR for now. Doubt fog will become an
issue overnight as winds will be a bit more elevated around
10-12kt out of the NE.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Flood Watch through Thursday evening for NEZ048-049-060>064-
     072>077-082>087.
     Dense Fog Advisory until 11 AM CDT this morning for NEZ039>041-
     046>049-060>064-072>076-082>085.
KS...Flood Watch through Thursday evening for KSZ005>007-017>019.
     Dense Fog Advisory until 11 AM CDT this morning for KSZ005-006.

&&

$$

UPDATE...Thies
DISCUSSION...ADP
AVIATION...Thies