423
FXUS63 KGID 281149
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
649 AM CDT Mon Sep 28 2026

.KEY MESSAGES...

- Wet weather pattern will begin tonight into Tuesday and
  continue through Thursday. Widespread total rainfall amounts
  of 1.5-3" are expected over the three days, aided by
  unseasonably high atmospheric moisture associated with the
  remnants of Hurricane Polo.

- Prospects for appreciable dry breaks in the rain are limited,
  effectively leading to "washout" type days Wednesday-Thursday.

- Ensemble 90th percentile QPF forecast maxes out between 4-5",
  which, if comes to fruition, could lead to areas of flooding
  given already wet soils from last week`s rain event. There is
  a Slight Risk (level 2 of 4) for excessive rainfall/flooding.

- Much quieter weather arrives in time for the weekend. Slightly
  below normal temperatures are favored - highs 60s/70s, and
  lows in the 40s/50s.

&&

.UPDATE...
Issued at 645 AM CDT Mon Sep 28 2026

Issued a Dense Fog Advisory for a good chunk of south central
Nebraska where airport obs and webcams suggest visbilities
mostly in the 1/4 to 1/2 mile range. Ran it through 11AM, though
may improve by around 10AM.

&&

.UPDATE...
Issued at 415 AM CDT Mon Sep 28 2026

Here we are with yet another early morning of expanding
stratus/fog. Latest thinking is that fog shouldn`t be quite as
dense as it was 24 hours ago, or if it does become dense, it
won`t be quite as widespread. Have little confidence in short
term models to accurately handle the cloud cover once we get
past midday. Guidance suggests we remain socked in low cloud
cover most of the day (which, conceptually, seems plausible
given weak mixing and light E/SE low level flow). However,
this is no different than the past couple of days, and each
afternoon we were able to scatter out the clouds quite a bit
more than expected. Forecast highs may once again be too cool,
but figure surprises to the warm side aren`t too impactful, or
complaint-worthy, this time of year.

Obviously, focus shifts to the incoming rain chances as early as
Monday night in our W/NW...with gradually expanding chances
expected throughout the daytime hours Tuesday. Appears the
initial surge of moisture will generally favor areas from around
the Tri-Cities, but especially W and N, through the AM hours
Tuesday. As such, S/SE zones may remain dry through at least the
first half of the day Tuesday. However, models are in decent
agreement rain chances will expand to encompass the entire
forecast area Tuesday afternoon/evening.

The duo combination of a large scale upper low (currently
digging S/SE along the CA Coast) and the remnants of Hurricane
Polo will emerge onto the Central Plains on Wednesday, and only
slowly fill/shift SE on Thursday. Exactly where one or two
primary SW to NE bands set-up, and when they truly peak in
intensity, still remains uncertain...owing to the complex mid-
upper level interactions and mesoscale nuances. Will probably be
facing some training and/or nearly stationary, very efficient
rain producing bands wherever they do setup - similar to last
week. PWATs look to be extremely anomalous for this time of year
at +3 to +4 standard deviations (or 250%+ of normal), and given
already damp soils from last week`s rainfall...am concerned we
could see some hydro issues. WPC has placed us in a "Slight
Risk" for excessive rainfall. Would place the overall-greatest
threat for flooding in our area roughly along and south of the
NE/KS state line. As noted below, this system will probably
have a fairly sharp gradient in amounts on it`s northern
side...which COULD come into play for our far W/NW zones. At
this point, however, am hesitant to say anyone is going to truly
"miss out" on this system as relatively coarse ensemble guidance
often "washes out" (bad pun) these signals 3-4 days out.

&&

.DISCUSSION...
Issued at 124 PM CDT Sun Sep 27 2026


Tonight and Monday...

Gentle ridging aloft today will keep conditions fairly quiet tonight
and for the first half of the day Monday. Given the partly cloudy
skies, highs (outside of a few north central Kansas locations) have
struggled to break out of the 70s. Similar to the previous night,
low temperatures overnight should return back to the upper 50s to
low 60s. Though model prognostics tend to be less excited about the
fog potential tonight (only 50% of the HREF members as opposed to 80%
the previous night), it is hard to overlook the similar returning
conditions (light easterly winds and low 60s dewpoints). The main
uncertainty regarding the fog potential for tonight would be from
the presence of a thick layer of low-level stratus. This deck of
clouds could act like a blanket, insulating temperatures by a few
degrees (possibly keeping lows from reaching their dewpoints). If
this plays out, the fog potential could be limited or less intense
than from this past morning. The RRFS guidance also hints that the
pockets of dense fog may overall be more isolated than widespread.

Beyond the potential for fog Monday morning, cloudy skies retaining
across much of the day will once again keep temperatures from
escaping out of the 70s for Monday, despite the presence of steady
southeasterly warm air advecting winds. Aloft, a shortwave trough
ejecting out of the Rockies overnight Monday could bring the area
its next precipitation chances. The bigger forecast shift over the
last 24-hours has been to delay the onset of precipitation chances
from overnight Monday to Tuesday. This lag in the guidance comes as
higher resolution model guidance (HREF members) have been slower to
move in precipitation compared to the global models (GFS/ECMWF). Now
that this event is within range of the higher-res short-term
guidance, a greater contribution to or weight of the forecast is
shifting from the GFS/ECMWF timing more towards the HREF/RRFS
guidance. This trend, though slower to present itself, is also
starting to be observed with the National Blend of Models (NBM) as
well.


Tuesday and Beyond...

The main story for the middle of the week will be the potential for
extended periods of steady and occasionally heavy rainfall,
especially across the Tuesday-Thursday time period. Hurricane Polo
in the Pacific is soon expected to be steered northeast and into the
Southern Plains by an approaching southwest U.S. trough. The outer
plume of moisture by this hurricane is likely to stretch north and
into the local area by Wednesday. This increase in moisture content
across the area will enhance precipitation efficiency across the
middle to end of the week (PWAT values as high as 1.75-2"...over 2
times greater than the average end of september values around
0.75").

The earliest arrival for precipitation this week now looks to come
Tuesday. Between Tuesday and Thursday, multiple rounds of widespread
rain showers will be expected to lift north and up across all of
central Kansas/Nebraska. Though steady precipitation chances
generally hold across all three days, the highest confidence window
and peak rainfall amounts will look to come across the Wednesday and
Wednesday night period when the surface low is closest to the area
(crossing through southern Kansas). This low will continue to push
east and away across the day Thursday, leaving the most uncertainty
within the first arrival window of showers on Tuesday and the last
lingering bands of precipitation on Thursday.

The latest NBM QPF guidance project between 2-4" of precipitation to
fall across the area over this three day period with the locally
heavier amounts generally concentrated towards the south and east
(locations closer to the system center). It is important to know that
some guidance has suggested a slightly further northward track of this
system that could shift our forecast amounts northward. If this
northward trend continues, areas north of I-80 could overachieve
current expectations with the far south and southeast portions of
the area underachieving expectations.

For far northern portions of the area (locations north of I-80),
through the mean/most likely value is around 2-2.5" of
precipitation, a large gap separates the high end (75th percentile)
and the low end (25th percentile) model guidance (spread of the NBM
ensemble). In fact the low end values (25% percentile where 75% of
the guidance exceeds) is around 1.25-1.75" with the upper limit
(75th percentile where only 25% of the guidance exceeds) is between
2-4". This high range comes from the fact where central Nebraska is
likely to find itself within the outer bounds of the system.
Precipitation amounts for these locations are the most susceptible
to the system track (sharp precipitation gradient). A north or south
shift of the system track can vastly effect precipitation amounts
across the "fringes" compared to locations across central Kansas
that lie closer to the system center track. In comparison, the
portions of the forecast area with the higher end forecast
precipitation amounts (3-4" for north central Kansas and Nebraska
areas southeast of the Tri-Cities), have the lower end guidance
(25th percentile) around 2-2.75" with the upper end guidance (75th
percentile) around 3.5-4". Within the last 24-hours, the confidence
in the higher-end amounts have seemed to diminish some. If this
trend continues, it is possible for forecast amounts to also
decrease in the upper bounds.

Given the anomalously high moisture concentration with the large
window of steady rain showers, the WPC has included the entire area
underneath a Slight Risk of Excessive Rainfall (15-40% chance of
rainfall exceeding flash flood guidance within 25 miles of a point)
for Tuesday and Wednesday.

Besides the precipitation potential this week, temperatures look to
be on track to steadily decrease a few degrees. Given the
continuation of mostly cloudy skies across much of the week
(primarily through Thursday) and the passage of a cold front Tuesday
night, temperatures are forecast to peak between the upper 50s and
70s each day this week. Highs could reach their coolest point for
the week around Friday (upper 50s to mid 60s). Overnight lows in the
mid 40s to low 50s appear possible to achieve both Thursday and
Friday nights.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 645 AM CDT Mon Sep 28 2026

For KGRI/KEAR Airports:

Today: LIFR conditions (CIGs and VSBYs) have overspread both
terminals this morning and don`t expect any improvement until at
least 15Z. In fact, both sites will likely be at or below their
minimums for at least a couple more hours. Fog will gradually
lift and scatter late AM/midday, with hopefully a return to VFR
conditions in the 19-21Z time frame. Winds will be out of the
ESE/SE and gradually increase to 8-12kt.

Tonight: May finally have a night without substantial flight
category reductions. Most guidance keeps conditions VFR through
the night, though don`t want to completely discount potential
for patchy, minor fog. Rain chances increase at or just beyond
of this valid period, so kept it dry this go around.

Confidence: Medium to high.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Dense Fog Advisory until 11 AM CDT this morning for NEZ046>048-
     060>064-072>077-082>087.
KS...None.

&&

$$

UPDATE...Thies
DISCUSSION...Stump
AVIATION...Thies