539
FXUS63 KGID 151156
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
656 AM CDT Sat Jun 15 2024

...Aviation Update...

.KEY MESSAGES...

- Mainly between 5 PM-Midnight this afternoon-evening, primarily
  the southeast half of our coverage area (CWA) stands a
  small/somewhat conditional threat of popping off a few strong
  to perhaps severe thunderstorms. This threat would likely be
  fairly localized in our CWA, with better chances for potential
  severe focusing slightly to our east (eastern NE into western
  IA).

- Although mainly northern parts of our CWA have small/"iffy"
  chances for storms Sunday evening into Monday, the MAIN STORY
  Sunday-Monday turns to heat, as both days look to feature
  highs well into the 90s, with mainly Sunday also featuring
  heat index readings as high as 100-105 especially in
  southern/eastern areas (flirting with Advisory criteria).

- In addition to being hot, Monday will be rather windy by mid-
  June standards, with southerly gusts up around 40 MPH likely.

- Record-warm LOW TEMPERATURES possible for Monday (June 17) at
  Grand Island/Hastings airports (see separate CLIMATE section
  below).

- Sunday evening onward, each and every day/night forecast
  period features at least small rain/thunderstorm chances, with
  the overall-most widespread activity currently anticipated
  Tues-Wed when the next weak cold front sags southward into our
  area (which also could give us at least one somewhat-cool day
  for Wednesday).

&&

.DISCUSSION...
Issued at 545 AM CDT Sat Jun 15 2024

-- PRIMARY CHANGES TO THIS 7-DAY FORECAST VERSUS THE PREVIOUS
 ONE (issued Fri afternoon):

- Honestly, nothing particularly noteworthy, as overall the
  basic expectations/highlights remain intact (as covered in
  KEY MESSAGES above). That being said, it is worth nothing that
  high temps for Wed continue to trend downward (down a solid
  5-10 degrees versus 2 days ago), as confidence grows that this
  will be the coolest day of the next week.


-- 7-DAY FORECAST OVERVIEW/HIGHLIGHTS:

- CURRENT/RECENT WEATHER SCENE AS OF 5 AM:
Although there is always a chance that daylight could bring a
"surprise" report or two, our initial overall impression of our
later evening-overnight thunderstorm complex (MCS) was that it
turned out about as ideal as could be hoped:
1) it was an overall "dud" in terms of truly severe weather (the
vast majority of known wind gusts were only 45-55 MPH tops) and
there was no sizable hail...tough to pin down a specific reason
why it was a weaker event, but lack of strong deep-layer shear
probably contributed.

2) Although there were limited drier/wetter exceptions, a good
majority of our CWA picked up at least 0.50-1.50" of rain
overnight...much needed from the perspective that the preceding
6 days had been very dry and that we have a few hot/windy days
ahead of us.

As of this writing, the main linear complex has pushed well off
to our east into the NE/KS/MO/IA border region, leaving our CWA
mainly dry, but interspersed with spotty/isolated showers and
perhaps an occasional weak thunderstorm.

In the big picture of the mid-upper levels, water vapor imagery
and short term model data confirm that a shortwave trough is
centered over western NE/KS early this morning (slowly trudging
east). At the surface, breezes in most areas are mainly out of
the southeast at 5-15 MPH, having "recovered" in the wake of
convective outflow. Overnight temps are on track to bottom out
between 64-69 most areas.


--TODAY INTO THIS EVENING (through midnight):
In the big picture aloft, the aforementioned shortwave trough
will continue tracking due eastward and directly overhead, with
its axis crossing over our CWA this afternoon-early evening
before it reaches a line from IA to eastern KS by midnight.
Meanwhile, at the surface, deepening low pressure mainly over
the Dakotas will allow our winds to become breezy out of the
south and southwest...effectively allowing a warm front to surge
off to our north and east this afternoon. Prior to this warm
front making its surge, the day will likely start with
considerable cloud cover (including low stratus many areas).
However, this should steadily burn off/vacate from south-to-
north with time, aided by southerly winds sustained at least
15-20 MPH/gusts at least 25-30 MPH this afternoon. High temps
will be a bit tricky depending on how quickly skies become at
least partly cloudy/mostly sunny, but most areas should be near-
to-slightly warmer than yesterday, with highs aimed a few
degrees either side of 90 most places.

The million dollar question is: will we see at least spotty
strong to severe thunderstorm development later this afternoon-
evening? Backing up this morning-early afternoon, expect MOST
places to be dry with only spotty showers/sprinkles mixed with a
FEW weaker thunderstorms here or there. By mid-late afternoon,
the aforementioned upper wave will be passing overhead, BUT the
main lift out ahead of it, along with the primary surface warm
front convergence, should be at least slightly off to our east
by then, focusing a better chance for severe storms into far
eastern NE/western IA. That being said, there is at least a
small chance for a few strong to severe storms to develop mainly
within our KS and southeastern Nebraska counties (south and
east of the Tri Cities), which could go severe in a moderately-
unstable environment featuring mixed-layer CAPE up around 2000
J/kg. However, deep-layer shear appears seasonably-weak through
this time frame (mainly only 20-30KT), which in theory should
limit the threat. So in summary, we have a conditional threat
for a few severe storms mainly between 5 PM-midnight, and mainly
within SPC`s current Slight Risk area focused within our
eastern zones.


- LATE EVENING-OVERNIGHT:
Once any possible storms vacate our far southeast zones this
evening (and assuming that no additional weak activity drifting
eastward off the High Plains is able to infiltrate our CWA
before it dies off), we are expecting a dry overnight with
steady southerly breezes holding low temps from dropping any
lower than 66-72 most areas.


- SUNDAY-SUNDAY NIGHT:
A return to legitimate HEAT is the number one story here, as at
least for now our daytime forecast remains void of any
thunderstorm chances as lack of forcing and warmer air aloft
should effectively cap us off. Although southerly breezes will
average 10-20 MPH in most areas (except lighter in our north-
northwest near a weak/stalling front), providing some relief
from the heat, we are looking at widespread highs in the mid-
upper 90s most areas, which combined with dewpoints in the 60s
(perhaps near 70 mainly northeast) will drive heat index
readings well into the 98-103 range most areas. This is
technically just short of our 105+ Advisory criteria, but
obviously plenty close.

Sunday evening-overnight, it will remain very warm, with
overnight lows mainly up in the 70-75 range providing only
limited relief. Rain/thunderstorm-wise, the vast majority of
regional thunderstorm activity should remain at least slightly
off to our west-through-north Sunday evening, overnight, but our
forecast does carry some small PoPs especially north of I-80,
just in case.


- MONDAY-MONDAY NIGHT:
Like the previous 24 hours, the vast majority of rain/storm
potential should focus to our north, but mainly our northern
zones do carry some small PoPs for now. Overall though, we are
looking at another hot and actually rather windy day by mid-June
standards. In fact, much of the day should feature sustained
winds at least 25-30 MPH, gusts to around (possibly slightly
more than ) 40 MPH. While these winds will provide a bit of
relief from the heat and likely allow dewpoints to mix down a
bit and not be quite as high as Sunday, actual high temps should
still reach well into the 90s most places.


- TUESDAY-WEDNESDAY NIGHT:
An upper trough passing well to our north will drive a decent
cold front southward into our region, sparking what will likely
be our most widespread rainfall/thunderstorm chances of the
week. Although details are still plenty uncertain, at least
limited severe storms and localized heavy rainfall are quite
possible. This front should keep Tuesday at least slightly
cooler than Monday, but the REAL cooler air takes center stage
Wednesday, which currently has highs ranging near-70 far
northwest to near-80 far southeast.


- THURSDAY-FRIDAY:
Obviously plenty of uncertainty out at this range, but early
model suggestions call for the front to start lifting back
north, allowing temps to climb back into the 80s area-wide Thurs
and mid 80s to low 90s Friday. Various, mainly low/uncertain
thunderstorm chances also continue.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 654 AM CDT Sat Jun 15 2024

For KGRI/KEAR Airports:
- General overview:
Very high confidence that the vast majority of the period
features VFR ceiling/visibility and rain/thunderstorm-free
weather, with the overall-main feature of the period being
moderately-breezy south winds (and a round of low level wind
shear late tonight). That being said, mainly these first 2-3
hours right away this morning will feature MVFR/IFR ceiling and
perhaps a few more showers/weak thunderstorms.

- Ceiling/visibility/rain and thunderstorm details:
Right out of the gate early this morning, both KGRI/KEAR could
see around 2-3 hours of continued MVFR/IFR ceiling, along with a
few passing showers/weak thunderstorms (with coverage spotty
have assigned a generic "vicinity thunderstorm"/VCTS for this).
By around 15Z, ceiling should scatter out/and/or lift to VFR
territory, with nothing more than a "fair weather" low-VFR
cumulus field expected this afternoon. Any late afternoon-
evening thunderstorm activity is expected to focus mainly 75+
miles to the east-southeast, so have left out of TAFs.

- Winds:
-Surface winds:
While winds are starting off southeasterly right away this
morning, they will soon turn more southerly today into tonight as
a warm front lifts north, with the majority of the period
featuring sustained speeds 15-20KT/gusts 20-30KT (overall-
strongest this afternoon).

- Low level wind shear (LLWS):
As a strong southwesterly low level jet kicks in late tonight, a
period of moderately-strong low level wind shear will commence
around 05Z. More specifically, winds within roughly the lowest
1,500 ft. AGL will accelerate to around 45KT out of the south-
southwest, setting up a solid 30-35KT of shear magnitude
between the surface and this level.

&&

.CLIMATE...
Issued at 545 AM CDT Sat Jun 15 2024

-- Regarding possible RECORD WARM LOW TEMPS on Monday
(June 17th):

Both Sunday night-Monday morning and Monday night-Tues morning
are expected to remain very warm, with most of our CWA not
dropping below the low-mid 70s. As a result, calendar day
(midnight-to-midnight) records for warmest low temperature could
be threatened at Grand Island/Hastings airports (the 2 sites
for which we issue formal Record Event Reports/RERs).

Any such records are most likely to be threatened on Monday the
17th, because a cold front arriving Tuesday the 18th is currently
expected to drop temps safely below record territory by midnight
that night.

- GRAND ISLAND
                   Record Warm Low      Latest Forecast
Monday June 17th     74 (1906)               73


- HASTINGS
                   Record Warm Low      Latest Forecast
Monday June 17th  72 (2020/2014/1946)        73


NOTE/REMINDER: in order for a new record warm low/minimum
temperature to become official it has to "survive" the entire
24-hour calendar day (in other words, it is not always based
solely on the early-AM low temp).

&&

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

&&

$$

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