238
FXUS63 KGID 010248
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
948 PM CDT Sun Jun 30 2024

...Short Term Update...

.KEY MESSAGES...

- A Heat Advisory is in effect for Monday for north central
  Kansas and Gosper, Furnas, and Harlan Counties in south
  central Nebraska.

- There is a slight risk (level 2 out of 5) for Monday afternoon
  and evening. Large hail, damaging winds, and a few tornadoes
  will be possible.

- Heat index values of 100 to 105 degrees will be possible (with
  some uncertainty) for portions of north central Kansas on
  Tuesday.

- Strong to severe storms are possible (20% to 30% chance) on
  Tuesday generally along the cold front.

&&

.UPDATE...
Issued at 945 PM CDT Sun Jun 30 2024

- Various notes regarding our forecast through the rest of
  tonight into Monday (also see recently-updated Hazardous
  Weather Outlook/HWOGID for some added detail regarding
  thunderstorm/heat concerns for Monday-Tuesday):

- Overnight-Monday AM Thunderstorm potential:
The vast majority of our coverage area (CWA) will likely remain
dry/thunderstorm-free until at least 2 AM. However, anytime
thereafter, a potentially expansive area of elevated
showers/thunderstorms will likely blossom over western/central
counties, and then gradually shift east-northeast with time.
While most storms should be fairly weak, there WILL BE enough
elevated instability rooted mainly in the 800-700 millibar layer
(anywhere from 500-1500 J/kg) to support at least sporadic
instances of hail up to perhaps quarter size. A limiting factor
to a more concerning hail threat will be fairly modest deep-
layer/effective wind shear mainly only 20-30KT. Some places
could easily pick up some decent rain amounts of 1-2" late
tonight as well, but amounts this high will likely be the
exception across our CWA as a whole. Overall, confidence has
increased in overnight convection, and rain chances (PoPs) have
been boosted to 80-90% most areas.

- Monday AM drizzle potential in the wake of departing storms:
As the main area of convection gradually departs our eastern
zones between sunrise and mid-late morning Monday, a widespread
area of very low clouds/stratus is expected to linger well into
the late-morning to early afternoon while GRADUALLY eroding from
south to north. This appears to be a fairly decent setup for at
least patchy light drizzle under these low clouds, so have
added this mention to all areas for at least a portion of the
Monday morning forecast block.

- Monday afternoon-evening severe storm potential:
Will defer to overnight forecaster to really discuss/dive into
the somewhat complex looking severe storm potential for Monday
late afternoon-evening. But in short, still looks like plenty of
"pros" vs. "cons" in play, as it will be a "battle" between warm
air aloft/capping (possibly enhanced by stubborn erosion of low
clouds?), versus healthy instability/shear and seasonably strong
forcing/upper support by early-July standards.

&&

.DISCUSSION...
Issued at 344 PM CDT Sun Jun 30 2024

Today and tonight...

An upper ridge is centered over the southern Plains. A shortwave is
moving along the north edge of this ridge over Kansas and southern
Nebraska. This feature has increased upper lift which has resulted
in some areas of rain. The increased cloud cover and precipitation
has resulted in cooler temperatures. High temperatures today are
expected to be in the 60s and 70s. Precipitation will continue to
decrease this afternoon but is expected to increase in coverage
again later tonight as a shortwave and low-level jet move over the
area. Winds will be out of the southeast with lows in the 50s and
60s tonight.

Monday and Monday night...

An upper trough from the west will begin moving over the northern
and central Plains on Monday. The rain and storms from the morning
hours will be pushed northward and eastward by a warm front moving
into north central Kansas and south central Nebraska. This warm
front will result in high temperatures Monday climbing into the
upper 90s to triple digits across most of north central Kansas and
portions of southern Nebraska. Heat index values of 100 to around
107 degrees are expected across the above mentioned areas. A Heat
Advisory has been issued for Monday for north central Kansas and
Furnas, Gosper, and Harlan Counties in south central Nebraska.
Fairly high CAPE, wind shear, and mid-level lapse rates are expected
across much of the area late Monday afternoon into Monday evening.
These factors along with increased lift from the approaching upper
trough will lead to potential severe weather development late
Monday afternoon into Monday evening. South central and central
Nebraska remain in a slight risk on SPC`s Day 2 outlook. Large
hail, damaging winds, and a few tornadoes will be possible.
Storms are expected to develop across western portions of the
forecast area (west of the Tri-Cities) during the late
afternoon/early evening and move eastward. Storms will diminish
in coverage and intensity during the overnight hours with a cold
front beginning to move into the area. Low temperatures Monday
night are expected to range from the low 60s to upper 70s.

Tuesday through Wednesday night...

The cold front will continue moving through the area on Tuesday.
Showers and storms may develop along the leading edge of this front.
Some of these storms may become strong to severe. The high
temperatures on Tuesday across south central and central Nebraska
are expected to range from the low 80s to low 90s. There is more
uncertainty in regards to temperatures across north central Kansas
but generally expect highs to range from the lower to upper 90s.
Heat index values across mainly Mitchell, Osborne, and Jewell
Counties are expected to range from 100 to around 105 degrees. Low
temperatures Tuesday night will range from the upper 50s to upper
60s. Winds will return to the southeast on Wednesday with high
temperatures mostly in the 80s. Rain and storm chances (up to around
30%) will be present on Wednesday then increase (up to around 55%)
Wednesday night as a shortwave moves over the area. Low temperatures
Wednesday night will be in the 60s.

Thursday through Saturday night...

An upper trough will move over the northern and central Plains on
Thursday bringing a cold front through south central and central
Nebraska and north central Kansas. Rain and storm chances of up to
around 40% will continue across portions of the area on Thursday.
Low temperatures Thursday night will range from the mid 50s to mid
60s. A surface high will be across the area on Friday with high
temperatures in the upper 70s to upper 80s. Slight rain and storm
chances (up to 25%) will continue on Friday. Temperatures Friday
night will decrease slightly from the previous night with lows in
the mid 50s to lower 60s. Winds will become southerly on Saturday
with temperatures warming up into the low 80s to mid 90s. Low
temperatures Saturday night will mainly be in the lower to mid 60s.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 743 PM CDT Sun Jun 30 2024

For KGRI/KEAR Airports:
- General overview:
The majority of the period will likely feature sub-VFR ceiling
(possibly as low as LIFR at times) which could be accompanied by
at least minor visibility reductions in light drizzle, and there
will be at least a 4-hour "window of opportunity" for passing
showers/thunderstorms late tonight/early Monday AM, and possibly
again toward the VERY end of the period Monday afternoon (not
reflected in current TAFs). Wind-wise, a fairly consistent
southeasterly direction will prevail throughout, with speeds
especially late tonight into Monday daytime sustained around
15KT/gusts 20-25KT.

- Ceiling/visibility/rain/thunderstorm details:
Right out of the gate, this evening, mainly no worse than a
lower-VFR ceiling should prevail, but there is some higher-end
MVFR around the general area so this cannot be ruled out.
However, there is much-higher confidence in ceiling lowering to
MVFR/IFR (and possibly even LIFR) starting around 08-09Z and
lasting well into Monday daytime. These low ceilings could be
accompanied by light drizzle, which could easily result in
slight visibility reductions. For now have kept visibility low-
end VFR, but certainly MVFR cannot be ruled out. There is
definitely some uncertainty on the "exact" timing of a return to
VFR ceiling, but for now have taken a "best stab" with 21Z
KEAR/22Z KGRI.

As for shower/thunderstorm potential, particularly the 08-13Z
time frame carries a decent chance for perhaps a fairly broad
shield of rain with embedded thunderstorms to pass through, but
with these chances beyond the first 6 hours have opted for only
a basic "vicinity thunderstorm" (VCTS) group for now. Should any
heavier rain materialize, some sub-VFR visibility could also
develop. This convection should not be severe, but small hail
cannot be ruled out.

Jumping ahead to very late in the period (mainly 22-00Z), there
is a slim chance for rapid and potentially severe thunderstorm
development, but with better chances for this likely holding off
until JUST beyond this valid period will defer to later TAFs to
introduce.

- Wind details:
Outside of any possible thunderstorm-outflow influences, things
appear fairly straightforward here. Direction will remain quite
consistent out of hte southeast. The overall-lightest sustained
speeds (around 10KT) will occur these first several hours, but a
modest uptick will prevail especially during the latter half of
the period Monday daytime (sustained around 15KT/gusts 20-25KT).

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Heat Advisory from 1 PM to 8 PM CDT Monday for NEZ072-082-083.
KS...Heat Advisory from 1 PM to 8 PM CDT Monday for KSZ005>007-
     017>019.

&&

$$

UPDATE...Pfannkuch
DISCUSSION...Schuldt
AVIATION...Pfannkuch