349
FXUS63 KGID 171124
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
624 AM CDT Sat May 17 2025

.KEY MESSAGES...

- Severe thunderstorms expected for parts of the area Sunday
  evening into Sunday night, although there is still some
  question on how much of the area is impacted. With any storms
  that develop, very large hail will be the primary concern,
  although localized damaging wind and isolated tornadoes are
  also possible. The primary timeframe of concern is 6pm Sunday
  to 3am Monday.

- Thunderstorms are expected to redevelop on Monday, and some of
  these may be severe. The most favored area will be near and
  east of Highway 281 in the 3pm to 10pm timeframe.

- Cooler with lingering showers and perhaps a few rumbles of
  thunder on Tuesday...then drying out for Wed-Thu.

&&

.DISCUSSION...
Issued at 412 AM CDT Sat May 17 2025

The weather today remains quiet. Northwest winds increase
briefly this morning, but turn more easterly and decrease this
afternoon as the surface ridge of high pressure moves eastward
through the area. Skies remain mostly clear, with just some
mid-high clouds over northern parts of the area. High
temperatures are expected to be near climatology, ranging from
the low 70s to near 80 degrees in parts of northern KS. Tonight
into Sunday morning, clouds will increase from the southwest to
northeast with returning moisture ahead of our next system.

On Sunday, an approaching upper trough and deepening surface low
over eastern Colorado will set the stage for severe weather
across the region. A warm front is expected to extend eastward
from the low, lifting northward into the forecast area by mid to
late Sunday afternoon. CAMs suggest two primary areas for
convective initiation. The first is central/eastern Kansas,
gradually lifting northeastward through the evening hours, and
this would primarily affect southeastern parts of the forecast
area. Secondly, isolated to widely scattered thunderstorms may
initiate near the surface low over SW Nebraska and NW Kansas.
These storms would then potentially track through the
northwestern half to 2/3rds of the forecast area through the
late evening and into the overnight. This means that some of the
forecast area could end up "stuck in-between" and miss out
entirely. In both cases, deep layer shear and MUCAPE will be
more than sufficient for supercells capable of producing very
large hail, and there will be at least a brief window favorable
for tornado development in the evening. The severe threat will
then extend well into the overnight hours, fueled by a
strengthening LLJ (50kt+ at 850 hPa).

Storms eventually decrease in intensity and depart the area to
the northeast early Monday morning. Attention then shifts to
potential redevelopment Monday afternoon into the evening. This
will be heavily dependent on how storms play out Monday night,
along with remaining convective debris/cloud cover into Monday
morning. Therefore, exact location of storm redevelopment
remains uncertain. Storms COULD end up entirely east of the
area, or could develop right overhead as the upper trough pushes
eastward into the area. The highest instability will remain in
our east and southeast, so those areas are most favored to see
severe hail/wind or an isolated tornado in any storms that do
develop.

Rain and non-severe thunderstorm chances persist Monday night
through Tuesday as the upper system slowly progresses eastward.
Tuesday will remain quite cool with temperatures struggling to
reach 60 degrees in some spots. Completely dry conditions are
expected to return by Wednesday. Total rain amounts are quite
uncertain given the nature of warm- season convection, but
northeastern areas appear to be most favored to see beneficial
rainfall totals. The 01Z NBM shows a 90% chance for 0.50"+ over
our northeastern areas...decreasing to just a 50% chance in our
southwestern zones.

After another cooler-than-normal day on Wednesday, seasonably
warm temperatures return for Thursday/Friday. Low chances for
thunderstorms return late next week into the Memorial Day
weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 622 AM CDT Sat May 17 2025

For KGRI/KEAR Airports:

VFR conditions are expected through the TAF period. Some lower
ceilings may start moving in from the south Sunday morning, but
should remain to the south of GRI/EAR through at least 12Z
Sunday.

Winds turn from the northwest to east through the day today.

&&

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

&&

$$

DISCUSSION...Mangels
AVIATION...Mangels