539
FXUS63 KGID 021003
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
503 AM CDT Tue Sep 2 2025

.KEY MESSAGES...

- Although likely somewhat patchy in nature, at least localized
  dense fog remains likely this morning primarily within some
  counties along/north of I-80 (Dense Fog Advisory in effect
  until 10 AM).

- Although overall-unlikely to occur, a SMALL (20%) chance of
  thunderstorms has been introduced to mainly the western half
  of our Nebraska forecast area (CWA) for late this afternoon-
  evening.

- Although not yet in our official forecast, we`ll need to keep
  an eye on the potential for at least some degree of surface-
  level smoke (mainly from Canada wildfires) to infiltrate our
  area Wednesday afternoon-evening behind our next cold front.

- Temperature-wise "big picture": At least one more week of
  predominantly slightly-below-average temperatures is likely
  (highs mainly 70s on most days/lows mainly 50s on most
  nights...with a few nights more solidly into the 40s).

- Precipitation-wise "big picture": Compared to the last several
  days, these next several will average drier, with any
  shower/thunderstorm chances mainly of the isolated/scattered
  variety, and actually high confidence in outright-dry weather
  CWA-wide at times (especially Wed night-Thurs and Fri
  afternoon-Sat night).

&&

.DISCUSSION...
Issued at 500 AM CDT Tue Sep 2 2025

-- 7-DAY FORECAST BIG PICTURE COMMENTS, CHANGES, UNCERTAINTIES:

- This is this forecaster`s first "deep dive" into the next
  week, so not a lot of "personal history" with previous
  forecasts/trends. That being said, one thing that immediately
  stands out are the continued cooler-leaning temperatures
  (thanks largely to tandem cold fronts passing through mainly
  Wednesday daytime and again Thursday night).

- That being said (and especially if the latest ECMWF solution
  ends up verifying better than the GFS), we may be aiming a bit
  TOO COOL with our temperatures by around Sunday-Monday
  (something to watch).

- As for precip chances, they will mainly be very limited and of
  the "pesky/sneaky" variety these next couple of days.
  Fortunately, chances for severe storms appear overall-low (and
  we are not "outlooked" by SPC at this time)...however...a
  sneaky stronger storm cannot be ruled out not only Wednesday,
  but POSSIBLY even today (low probability). Confidence in our
  currently-low rain chances (PoPs) for Sunday-Monday admittedly
  leaves a lot to be desired...with the GFS suggesting
  considerably higher rain potential than the ECMWF.


-- 7-DAY FORECAST CHRONOLOGICAL DETAILS (heavily short-term
 focused):

- CURRENT/RECENT WEATHER SCENE AS OF 4 AM:
In the big picture aloft, water vapor satellite imagery and
short term model data clearly confirm that the Central Plains
remains under broad/large-scale north-northwsterly flow,
directed between a sprawling high/ridge anchored over the
Intermountain West, and a large-scale trough/upper low spinning
over the northeastern United States. On the smaller-scale closer
to home, a weak/remnant mid-level wave is still producing some
light shower activity over northeast KS/far southeast NE (not
far east-southeast of our CWA), but over our area there is
nothing more going on precip-wise than perhaps patchy/transient
light drizzle under widespread low cloud cover that blankets
most of our CWA. At the surface, winds are very light (mainly 5
MPH or less) and mainly out of the north-northeast). By far the
main issue is the potential for at least patchy/transient dense
fog especially north (see next paragraph).


- EARLY THIS MORNING THROUGH REST OF DAYTIME:
Starting with fog concerns, several hours ago coordinated with
neighboring WFOs OAX/LBF to issue a formal Dense Fog Advisory
for all counties north of I-80 along with Dawson/York along
I-80. However, at least thus far (and likely expected to
continue), fog has proven to be no worse than light/nuisance
over most of the Advisory area due to the presence of widespread
low clouds, although localized dense fog appears to have
developed (or yet still will try to develop) along the edge of
clearer skies flirting with mainly our far northeast counties
(such as Nance/Merrick/Polk) and far west-central (western
Dawson). Unless some greater-than-expected clearing takes place
over these next 3-5 hours, it`s looking more and more likely
that the going Advisory will be rather "weak" for most of the
area, but will let it ride for now given the potential for at
least patchy/localized dense fog impacting the AM commute.

Once any fog concerns diminish by around 10 AM or so, the next
big question of the day is just how efficiently low clouds
GRADUALLY scour out from west-northwest to east-southeast, as
low-level winds (albeit light) take on a more westerly
component. If anything, slowed the efficiency of this clearing
trend a bit versus previous forecast...BUT still expect the vast
majority of the CWA to average no worse than partly cloudy (if
not mostly sunny) by mid-late afternoon.

Temperature-wise, made very little change to highs today, with
most of the CWA aimed mid-70s, but warmer upper 70s/around 80
far west where sunshine should return first.

Going hand in hand with the expected, generally west-to-east
clearing, there appears to be a SMALL (but non-zero) chance for
a few isolated showers/thunderstorms to drift into or develop
over mainly the western half of our Nebraska CWA especially 5-9
PM. In the high-res model world, this possibility is admittedly
supported more by the often-overdone NAMNest than the HRRR, but
felt that there was JUST ENOUGH support for this possibility to
introduce a low-end slight/20% chance of storms to that area. IF
any do manage to break a weak cap and develop, the CAPE/shear
combo could be enough to promote a rogue stronger storm
(again...an overall-unlikely scenario).


- LATER THIS EVENING-OVERNIGHT:
Once any possible early evening convection dies off with sunset,
most of the CWA should have a dry night under mostly clear to
partly cloudy skies, as south-southwesterly breezes average
mainly 5-8 MPH (fog is NOT expected to be much of a concern).
However, by very late in the night/early Wed AM, spotty
showers/weak thunderstorms could develop into counties north of
I-80. Overnight low temps aimed mainly mid-upper 50s.


- WEDNESDAY DAYTIME-NIGHT:
A shortwave trough/upper low diving out of Canada into the Great
Lakes will drive a well-defined cold front southward across our
CWA during the day, its passage marked by sustained north winds
at least 15 MPH/gusts at least 20-25 MPH. Although a few spotty
showers and likely non-severe thunderstorms cannot totally be
ruled out during the daytime hours, fortunately this front is
expected to advance at least SLIGHTLY south of our CWA by late
afternoon, focusing the main chance for potentially severe
storms over central/southern KS. High temps will obviously
depend on the speed of this front, and we could see a decent
gradient from only low-mid 70s most Nebraska zones, to solidly
80s (even mid-upper 80s) in our KS zones. As winds drop off and
assuming no worse than partly cloudy skies Wed night, lows are
forecast to drop into the mid-upper 40s most places...except low
50s far south-southwest.

As touched on above, will need to closely monitor surface smoke
potential (mainly Canada wildfire source) behind this front Wed
afternoon-evening, but felt it was best to hold off at least
one more forecast cycle before potentially introducing to
official forecast.


- THURSDAY DAYTIME-FRIDAY NIGHT:
Thursday brings a quick warm up ahead of the next system diving
out of Canada into the Northern Plains/Great Lakes, with highs
rebounding into the mid 70s-mid 80s range (coolest east/warmest
west). Then the next cold front drives through Thursday night.
This should MOSTLY be a dry frontal passage, but spotty showers
could pass through and last into Friday morning. The remainder
of Friday looks dry and seasonably-cool with high temps mainly
mid 60s-low 70s. Friday night looks like another cool one with
widespread lows in the 40s.


-SATURDAY-SUNDAY:
Although some low-confidence rain chances return to mainly
southern zones for Sunday, overall it looks like a GREAT weekend
for those wanting to embrace seasonably-cool, but pleasant
early-fall weather, with highs Saturday mainly a few degrees
either side of 70 and Sunday currently aimed similar (although
there are signs this may need to trend up a bit per ECMWF).


- MONDAY:
By now, even the ECMWF suggest that least limited rain chances
could return, but the GFS remains more bullish on this
possibility. High temps currently aimed low 70s most areas, but
like Sunday, these could easily trend up if it ends up being
drier.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 110 AM CDT Tue Sep 2 2025

For KGRI/KEAR Airports:
- General overview (including winds and precipitation):
This period will feature two distinct aviation
regimes...starting with high confidence MVFR/IFR (and possibly
LIFR for a time?) in low clouds and some fog through these first
12 hours or so, followed by a high-confidence return to VFR
through at least the vast majority of the latter 12 hours.
Precipitation-wise, there is a low (only 10-20%) chance of a
spotty shower/thunderstorm late this afternoon/early evening,
but this chance is currently deemed too low for TAF inclusion.
Winds will not be much of an issue throughout the period, with
sustained speeds largely at-or-below 6KT and direction fairly
variable through much of the period before trending more
consistently southerly late in the period.

- Ceiling/visibility details:
Although confidence is very high in sub-VFR (mainly MVFR/IFR)
conditions through at least the first 12 hours, the main
uncertainties include whether things tend to favor more toward
the MVFR side of things, or perhaps deteriorate more solidly
toward low-end IFR or even LIFR (especially with regard to
ceiling. Right out of the gate, MVFR ceiling/VFR visibility
prevails at both KGRI/KEAR. However, latest guidance strongly
suggests at least IFR ceiling/MVFR visibility will prevail
especially 09-15Z, and have maintained a TEMPO group from
previous TAFs for LIFR ceiling potential focused 09-13Z. That
being said, confidence in LIFR is only considered "medium" at
this time. As for the return to VFR as low clouds gradually lift
and scatter out...this could potentially be as early as 17-18Z,
but have opted to lean a bit slower with 06Z TAFs and delay
outright-VFR until 20Z.

&&

.CLIMATE...
Issued at 500 AM CDT Tue Sep 2 2025

-- COOLEST FINISH TO AUGUST IN 33 YEARS AT GRAND ISLAND/HASTINGS

- Aug. 23rd-31st (the final 9 days of August) were the overall-
  coolest in 33 years (since 1992) at both Grand
  Island/Hastings airports.

- At Grand Island airport, the overall-average temperature
  (average of both daily highs/lows) Aug. 23-31 was 67.3
  degrees. This ranked as the 9th-coolest finish to August out
  of 129 years on record, and was the coolest since Aug. 23-31,
  1992 averaged 65.0 degrees.

- At Hastings airport, the overall-average temperature Aug.
  23-31 was 67.6 degrees. This tied for the 10th-coolest finish
  to August out of 119 years on record, and was the coolest
  since Aug. 23-31, 1992 averaged 65.8 degrees.

- At both Grand Island/Hastings, the cool finish to August was
  "driven" more by cool daytime high temperatures than cool
  nighttime lows...largely due to the fact that it was
  frequently cloudy (thus keeping daytime temps cooler and
  nighttime temps warmer compared to a weather pattern with
  clearer skies).

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Dense Fog Advisory until 10 AM CDT this morning for NEZ039>041-
     046>049-060-064.
KS...None.

&&

$$

DISCUSSION...Pfannkuch
AVIATION...Pfannkuch
CLIMATE...Pfannkuch