786
FXUS63 KGID 201156
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
Issued by National Weather Service Omaha/Valley NE
655 AM CDT Fri Sep 20 2024

.KEY MESSAGES...

- Today will likely be the warmest day well see for at least the
  next 2 week, with well-above-normal highs a few degrees
  either side of 90.

- Though coverage will likely be rather spotty, at least a few
  thunderstorms are expected this evening-overnight particularly
  from around the Tri Cities and farther south/east. Marginal
  Risk for a marginally-severe storm (quarter size hail and/or
  50-60 MPH winds).

- The much-advertised weekend rain event is still generally on
  track, with by far the highest chances/coverage expected Sat
  evening-Sunday daytime (if anything, Saturday daytime has
  trended a bit drier for most of our coverage area/CWA.

- Although beneficial rain is still likely area-wide, cumulative
  2-day rain amounts have continued to trend down (only our
  southern/southeast counties most favored to receive widespread
  1+ now). Will this downward trend continue?)

- At least for now, Monday-Thursday now features a dry forecast
  area-wide.

- Temperature-wise today: We see a definite-cool down with highs
  70s-80s Sat, only 50s-60s Sunday, but then rebounding to mainly
  60s Mon and 70s Tues-Thurs. Overnight lows Saturday night onward
  mainly in the 40s...so feeling more like fall for sure.


&&

.DISCUSSION...
Issued at 510 AM CDT Fri Sep 20 2024

-- PRIMARY CHANGES WITH THIS 7-DAY FORECAST PACKAGE VERSUS THE
 PREVIOUS ONE ISSUED THURS AFTERNOON:

- Small (mainly 20%) thunderstorm chances have been added to most
  of our CWA (but especially southeast half) for the pre-
  midnight hours this evening (previous forecast held off any
  chances until post-midnight). The Marginal Risk of severe from
  SPC (level 1 of 5) in especially our southeast 1/3 is also
  new.

- Unfortunately for those really wanting significant/soaking rains
  this weekend, Sat-Sun cumulative rainfall totals are on a
  downward trend, with generally our northwest 1/2 now expected
  to top out mainly in the 0.50-1.00 range, and our southeast
  half more so 1-2, but with dwindling potential for anything
  over 2 except for maybe in our extreme southern KS zones.

- Looking well into next week, high temps for the Tues-Thurs period
  have trended up a good 2-4 degrees from previous forecast
  (still mainly 70s, but more so mid 70s versus lower
  70s...especially Wed-Thurs). All things considered, from an
  early fall weather enthusiast/comfort standpoint, Mon-Thurs
  are really looking quite pleasant!

-- 7-DAY FORECAST OVERVIEW/DETAILS:

- UP FRONT ADMIN NOTE:
First 7-day forecast shift in a while for this forecaster, so
between familiarizing with the latest trends and some ongoing
behind-the-scenes communication outage challenges (thanks for
the assist OAX!) will be keeping these paragraphs a bit more
generic than usual...

- CURRENT/RECENT WEATHER SCENE AS OF 430 AM:
Its been a dry and tranquil night/early morning, as the combo
of a mix of clear skies/thin high cirrus aloft and high pressure
at the surface (promoting extremely light/near-calm winds) has
overnight low temps on track to bottom out mainly low-mid 50s
north to upper 50s-low 60s southeast (although its quite likely
typical cooler spots such as Ord could easily slip into the
upper 40s). In the big picture aloft, a big/closed low pressure
system is still way off to our southwest, centered just off the
southern CA coast.

- TODAY DAYTIME:
Maintained a dry forecast CWA-wide through at least 00Z/7PM,
with a mix of mostly sunny/partly cloudy skies under variable
coverage of high cirrus drifting over. The big story will be ONE
LAST day of truly well-above average warmth, with all areas
aimed a few degrees either side of 90. As surface high pressure
departs east, especially this afternoon will feature breezy
south-southeast winds generally sustained 10-15+ MPH/gusts 15-25
MPH.

- THIS EVENING-OVERNIGHT:
Although MOST places will likely remain dry as the main/large-
scale upper level low pressure system remains well to our
southwest over AZ, the combo of weak disturbances lifting out
ahead of the main low, along with convergence along the nose of
a south-southwesterly low level jet will likely promote at least
isolated to perhaps scattered showers/thunderstorms this
evening-overnight, particularly after 10 PM. While most of our
CWA stands at least a small chance, the overall highest chances
should focus within our southeast 1/2, much of which has now
been assigned a Marginal Risk of severe from SPC. Despite the
expected spotty coverage, hard to totally dismiss the Marginal
Risk given what should be at least 1000-1500 J/kg of elevated
CAPE and 30-40KT of deep layer shear (a few storms capable of
producing hail to around quarter size/winds to around 60 MPH).
Low temps ranging from upper 50s-mid 60s northwest half to mid-
upper 60s southeast half.

- SATURDAY DAYTIME:
By late in the afternoon, the big upper low should reach
southwestern CO area. However, here at home, and leaning closely
on latest HRRR/NAMNest higher-res models, especially most areas
north of the KS border will probably stay dry much of the day,
and rain chances/PoPs have trended down somewhat. Of any storms
that do form, probably cannot totally rule out severe, but the
main threat for marginal severe should focus slightly east of
our CWA (per SPC Day 2 Marginal). High temps will be fairly
tricky as a well-defined cold front drops down from the north,
but for now have highs aimed from mid-upper 70s northwest to
mid-upper 80s southeast.

- SATURDAY NIGHT-SUNDAY NIGHT:
Although cumulative rain amounts have trended downward (see
above), these 36 hours are still expected to feature fairly
widespread rain/showers with embedded, mainly weak
thunderstorms, as the aforementioned strong upper low over the
Rockies slowly/gradually approaches and passes directly overhead
our local area. Rain amounts of at least 0.50-1.00 should be
fairly widespread, but anything over 2 is now looking to be more
of a localized exception and favoring far southern counties.
Temp-wise, while Sunday will CERTAINLY be the overall-coolest
day of the next 7, just how cool will depend on how widespread
clouds/rain actually are. For now though have most areas aimed
56-60, with lows Sunday night ranging low 40s west to upper 40s
east.

- MONDAY-TUESDAY:
Although probably cannot totally rule out some spotty rain, our
official forecast is dry CWA-wide as we remain in between
systems (especially per ECMWF). High temps start to rebound,
aimed mainly mid-upper 60s Mon and low 70s Tues.

- WEDNESDAY-THURSDAY:
The dry forecast continues as both ECMWF/GFS suggest at least
weak ridging aloft to be the dominant influence. Although not a
major change by any means, high temps have bumped upward (more
so mid 70s than lower 70s), with overnight lows creeping back up
more into the low 50s than 40s.


&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 655 AM CDT Fri Sep 20 2024

For KGRI/KEAR Airports:

- Ceiling/visibility/precipitation/thunderstorm potential:

High confidence in VFR ceiling/visibility through the period, with
the majority of it featuring only varying degrees of high level
cirrus. There is also high confidence that at least the vast
majority of the period will remain rain/thunderstorm-free
(especially the first 15 hours). However, there are hints later this
evening overnight (mainly after 03Z and probably more so after 06Z)
that isolated thunderstorm activity could develop over the general
area. IF this were to occur, a quick bout of hail/gusty winds cannot
be ruled out. That being said, the probability of any storms
impacting KGRI/KEAR is currently deemed no higher than 20%, and thus
will refrain from any thunderstorm TAF inclusion at this time.

- Winds:

Very light/variable direction breezes remain in place for a
few hours right away this morning. Then, mid-late morning will start
to see a gradual uptick out of the south-southeast, peaking 18-23Z
during which time sustained speeds 13-15KT/gusts around 20KT will be
common. Finally, speeds will again ease down this evening-overnight
to mainly under 10KT as direction remains out of the south-southeast.

&&

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

&&

$$

DISCUSSION...Pfannkuch
AVIATION...Pfannkuch