356
FXUS63 KGID 161041
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
541 AM CDT Mon Jun 16 2025

.KEY MESSAGES...

- Although the daytime hours should mainly be "quiet"/dry
  today- Tuesday, these next TWO evenings-overnights are looking
  fairly active in terms of severe storm threats, with the
  overall- biggest concern being damaging winds at least 60-70
  MPH, and overall-lesser (but certainly not zero) concerns for
  large hail and perhaps a mainly brief tornado or two.

- While the overall?/"big picture" severe storm threats are very
  evident (and seem to be pretty-well captured by SPC threat
  categories for Day 1-2), the FINER DETAILS of "exact"
  timing/location/magnitude of storm evolution are not yet "set
  in stone", as evidenced by some still-fairly-striking
  differences between high-res models (CAMs) even at this fairly
  close range.

- By far the biggest story beyond these next few days will be
  later-week/weekend heat, as our first, at least semi-
  widespread round of 100+ heat index looks to arrive primarily
  Friday-Saturday (albeit accompanied by breezy south winds).

&&

.DISCUSSION...
Issued at 540 AM CDT Mon Jun 16 2025

-- PRIMARY 7-DAY FORECAST BIG PICTURE THOUGHTS, CHANGES,
UNCERTAINTIES:

- As already touched on above, while there is almost zero doubt
  that PARTS of our forecast area (CWA) will surely deal with
  severe storms each of these next few evening-overnights,
  cannot over-emphasize the uncertainty in the "finer details"
  of this pattern, as it will a delicate balance between healthy
  instability/decent shear versus at least weak capping
  (especially to early-evening activity) and somewhat-subtle
  forcing both aloft (low amplitude disturbances) and at the
  surface (fairly weak boundaries). As evidence of this, note
  the at-times minor and at-times fairly significant differences
  in timing/placement of storms between recent runs of higher-
  res models such as HRRR/NAMNest through these next 48 hours
  (and even within subsequent runs of the same model).

- Going hand in hand with the above, this is also a pattern
  where one would be advised not to get too caught up in the
  "exact cutoff" of severe risk category boundaries from SPC
  (always good advice, but more so in these regimes more forced
  by smaller-scale features). Overall agree with SPC that MOST
  of our CWA is probably well-deserving of at least a Slight
  Risk (Level 2 of 5) these next few evenings- overnights, but
  arguments could be made based on a few of the latest higher-
  res models that this evening`s Enhanced (Level 3 of 5)
  currently focused along/north of I-80 MIGHT need nudged a bit
  farther south, while looking ahead to Tuesday (Day 2)
  arguments could probably be made that a Level 3 Enhanced could
  be shifted a bit farther north to include more of especially
  our KS zones (officially right now the Enhanced BARELY clips
  EXTREME southern Osborne/Mitchell counties.

- Turning to the late-week/weekend heat:
It`s looking rather fitting that the official start to
astronomical summer (Friday the 20th) corresponds exactly to
what appears to to be the overall-hottest 2-3 day stretch that
we will have had so far this year, with widespread high temps
mid-90s to low-100s and peak heat index readings mainly 96-104
especially Friday-Saturday. While we are not currently
forecasting heat index to TECHNICALLY reach our long-standing
Advisory criteria of 105+ at this time, the fact that this will
be our first round of 100+ heat index this year is already
pegging the "Major" (3 out of 4) category for most of our CWA
Fri-Sat on the NWS HeatRisk maps, so as long as forecast trends
hold it`s quite possible that formal Advisories will be at least
strongly considered.


-- 7-DAY FORECAST CHRONOLOGICAL BREAKDOWN:
- CURRENT/RECENT WEATHER SCENE AS OF 430 AM:
As was relatively-well anticipated, a line/fairly small complex
of what ended up being sub-severe thunderstorms slipped into
our far western Nebraska counties late Sunday evening,
fortunately losing their "wind punch" before getting in, but
still producing some sporadic gusts of 40+ MPH along with some
very LOCALIZED pockets of decent rainfall at least 0.25-0.50",
as confirmed by personal weather stations/radar estimation in
various small pockets of mainly Dawson/Furnas/Buffalo counties.
However, the vast majority of our CWA saw little-to-no rain, as
the vast majority of this activity faded away before reaching
Hwy 281.

In the big picture of the mid-upper levels, water vapor
satellite imagery and short-term model data reveals mainly
northwesterly flow overhead (especially from 600 millibars
upward), as we reside along the interface between broad
troughing over hte Midwest/OH Valley, and a large-scale high
pressure ridge currently centered over the AZ/NM/Mexico border
area.

At the surface, there are no significant features of note early
this morning, with breezes mainly 5-12 MPH from some variation
of southerly. Cannot completely rule out some patchy fog these
next few hours especially where it rained earlier tonight
(Cambridge airport currently reporting 4SM visibility), but do
not currently anticipate fog being enough of an issue to
formally include in our forecast. Morning low temps are on track
to bottom out mainly mid-upper 60s but some spots perhaps not
slipping out of the low 70s.


- TODAY DAYTIME (through around 7 PM):
Barring a fairly big surprise (and admittedly leaning more
toward recent HRRR runs than anything), the vast majority of our
CWA should get through at least 7 PM dry/storm-free. That being
said, some very isolated/spotty sprinkles cannot be ruled out
almost anytime this morning (mainly northeast half of our CWA),
so this has been added to the forecast. Getting later into the
afternoon, cut back official rain/thunderstorm chances between
4-7 PM to only some of our far northern/western Nebraska
counties, and only 20% chances/PoPs at that...JUST in case
something would happen to develop along a weak frontal boundary
in that area as suggested by NAM/NAMnest. However, again leaning
more toward the latest HRRR solutions, expect the aforementioned
boundary to remain far enough north and enough warm air aloft
(forecast soundings indicate a warm nose centered around 750
millibars) to most likely keep our entire CWA thunderstorm-free
until beyond 7 PM.

As a result, today looks like another seasonably-warm and
somewhat-humid day under partly cloudy to mostly sunny skies. If
anything, high temps were nudged up very slightly from previous
most areas (also very slightly warmer than yesterday), with most
of the CWA aimed 92-97. Some very spotty 100-degree heat index
readings could materialize over primarily parts of
Furnas/Harlan/Phillips/Rooks in our far southwest, but short of
Advisory criteria. Winds today will be a little breezy out of
the south...mainly peaking sustained around 15 MPH/gusting 20-25
MPH.


- THIS EVENING-OVERNIGHT (after 7 PM):
In the big picture, an evident (albeit low-amplitude) shortwave
trough will track eastward into our area out of the Central High
Plains, which combined with modest low-level convergence along a
few boundaries and the development of a respectable 30-40+ KT
low level jet whose nose will be aimed into our CWA...will all
combine to give us very high rain/thunderstorm chances and
severe storm potential.

Again leaning fairly heavily on the usually-reasonably-reliable
recent HRRR runs, there could be fairly explosive/initially
supercellular storm development this evening at least slightly
north of our CWA along a weak surface front (within north
central NE), while other activity again develops to our west
over the higher terrain and starts tracking east. EXACTLY how
this convection unfolds is yet to be seen, but GENERAL
expectation is for southward and/or eastward moving areas of
storms to merge over/near our northern/western CWA and track
east-southeastward through much of our area, especially between
9PM-4AM. The combination of fairly strong (albeit mainly
slightly elevated) instability/CAPE of at least 2000-3000 J/kg
along with sufficient (but not overly-strong) deep-layer shear
of 30-40KT should yield halfway-decent severe potential, with
the biggest threats being 60-70 MPH winds, hail up to around
ping pong ball size (potentially larger if a semi-discrete
supercellular structure develops within our CWA mainly early-on.
A brief, mainly QLCS-induced tornado probably cannot be ruled
out, but should not be the main threat. Rainfall-wise, could
easily see at least limited areas pick up a quick 1-2", but am
not currently too concerned about more problematic totals of
3-4+" given what should be a fairly progressive nature of
convection. While the primary severe threat should in theory end
by around 4 AM, at least weak, trailing convection could easily
continue right through/beyond sunrise especially within our
southern half.

Overnight low temps changed very little...mainly mid 60s.


- TUESDAY-TUESDAY NIGHT:
In some ways, it`s "rinse and repeat" from these first 24 hours,
but with probably two main differences:
1) a bit higher potential for at least spotty showers/mainly
non-severe thunderstorms especially during the early and later
stages of the the 7AM-7PM (daytime) time frame.

2) Perhaps a slightly earlier onset of a severe threat (perhaps
as early as 5-7 PM), but also maybe not lasting quite as late as
tonight (severe threat waning closer to 1 AM versus 4 AM).

In the big picture aloft, we`ll be looking at overall-stronger
forcing/lift from a stronger shortwave trough passing through in
quasi-zonal (west-east) flow aloft, while in the lower-mid
levels, temps won`t be quite as warm, implying weaker capping
and more potential for robust late afternoon-early evening
thunderstorm development. While yet to be resolved "mesoscale
details" will surely change expectations at least slightly
between now and then, latest RAP/HRRR suggests a somewhat
volatile early-evening environment especially near/south of the
KS border with 3000-4000 J/KG CAPE and stronger deep-layer shear
of 40-50KT. Thus in theory, especially our KS zones could be
under the gun for some early-on, semi-discrete supercell
development with a large hail and at least brief tornado threat,
while another larger-scale complex rolls in from the west-
northwest off the High Plains, perhaps sparking a corridor of
damaging winds. Again though, this severe potential looks to end
a bit earlier as we get behind the main upper wave and
instability decreases later into the night.

In other departments, Tuesday will be cooler owing to likely a
more easterly wind direction with highs mainly low-mid 80s.
Tuesday night lows will also be a bit cooler than tonight,
mainly upper 50s-low 60s.


- WEDNESDAY-THURSDAY:
Although Wednesday daytime will likely feature some lingering
showers and most likely non-severe storms on the backside of the
departing system, confidence is fairly high that most of Wed
night- Thursday will be dry (unless some storms try clipping our
far north Thurs evening-night). However, there will be no
appreciable disturbances aloft. Temps will start to increase as
upper ridging/rising heights aloft nudge in from the southwest,
with highs climbing from mainly low 80s Wed to mainly low-90s
Thurs (except mid 90s southwest).


- FRIDAY-SUNDAY:
In brief: seasonably-hot and most likely dry (at least through
Sunday late afternoon), as upper ridging to our south becomes
our most prominent influence. As already covered above,
especially Fri- at look to bring the first semi-widespread 100+
heat index readings of 2025 into the picture, with actual high
temps mainly mid 90s to low-100s. Although it will probably give
it somewhat of a "blast furnace" feel, southerly winds do look
to be fairly breezy with gusts 30-35 MPH each day at least
providing some relief. At least for now, Sunday is aimed very
slightly "cooler" than Fri-Sat, but still with high temps
solidly mid 90s most places.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 113 AM CDT Mon Jun 16 2025

For KGRI/KEAR Airports:
- General overview (including winds):
High confidence in VFR ceiling/visibility and rain/thunderstorm-
free weather at least the vast majority of the period. That
being said, an area of weak convection will pass through at
least the general area right away early this morning (especially
KEAR), with potential for a more widespread area of
thunderstorms (possibly severe?) toward the end of the period
Monday evening-night. Outside of any thunderstorm-related
outflow influences, winds should not be a significant issue,
although especially Monday afternoon will be a bit breezy with
southerly gusts into the 20-25KT range.

- Shower/thunderstorm potential (and chances of sub-VFR
  conditions):
Starting off right away early this morning, an area of
isolated/scattered showers/weak thunderstorms are making their
way through the area (currently very near KEAR). Although this
activity should not be very significant, it could at least
briefly produce some mainly westerly gusts up to around 20KT.
Have included this potential in PROB30 group 06-08Z KEAR/07-09Z
KGRI, with less potential for thunder at KGRI assuming weakening
and/or dissipation occurs.

Following what should be mainly dry/storm-free conditions
through most of the daytime and early-evening hours, things
could turn considerably more active at SOME POINT late in the
period mainly 02-06Z, as there is greater potential for one or
more clusters of strong to severe storms to move in from the
north and/or west...possibly in the form of an organized
line/complex. Should this occur, at least brief torrential rain,
gusts at least 40-50KT and perhaps hail up to around quarter
size certainly cannot be ruled out. Given this potential is well
out toward the end of this valid period, have opted to only
introduce a PROB30 group for now, and will defer to later TAFs
to introduce TEMPO and/or prevailing groups as needed.

&&

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

&&

$$

DISCUSSION...Pfannkuch
AVIATION...Pfannkuch