340
FXUS63 KGID 300601
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
101 AM CDT Thu May 30 2024

.KEY MESSAGES...

- Thunderstorms will move into the area during the late evening-overnight
  hours with gusty winds and small hail possible.

- Strong to marginally severe thunderstorms possible on Thursday
  the main concerns for large hail and damaging wind gusts.

- Precipitation chances (50-70%) throughout the day on Thursday
  and decreasing throughout the day on Friday (20-50%).

- Scattered precipitation chances this weekend (20-60%) and
  into next week, mainly during the late afternoon-overnight
  hours.

&&

.DISCUSSION...
Issued at 400 PM CDT Wed May 29 2024

This Evening and Overnight...

A line of thunderstorms over the western High Plains will move east
into the area late this evening-overnight, with precipitation
chances for most areas arriving after midnight. Weak instability and
shear will help to keep storms marginally severe at most as they
enter the forecast area. Areas west of Hwy 283 are in the SPC day 1
risk for severe thunderstorms, with wind gusts to 60 mph and small
hail possible. Storms are expected to weaken as they continue to
move east across the area overnight. There is some uncertainty in
how widespread this line of storms will be, with 12z HREF
ensemble members in agreement that the line will become split
as it propagates east.

Thursday and Friday...

Scattered showers and thunderstorms will be ongoing to start the day
on Thursday. How widespread cloud coverage is from these storms will
impact precipitation chances for the rest of the day. Areas that see
sustained clearing will likely be able to destabilize
sufficiently to break the "cap" and have scattered afternoon
thunderstorms. Western portions of the area appear to have the
best chances to see clearing, as the 12z HREF members indicate
showers/storms may continue across eastern portions of the area
late Thursday morning. A cold front will enter northwestern
portions of the area Thursday afternoon which will provide an
additional source of lift for thunderstorm development. Shear
values of 25-30Kts combined with instability of 1000-2000 J/Kg
will allow for a few strong to marginally severe thunderstorms
to develop. The main severe weather concerns would be for large
hail and damaging wind gusts. Severe weather concerns will
decrease overnight as stability increases. Scattered showers and
thunderstorms will continue overnight (25-70%). ECMWF and GFS
ensembles indicate PWAT values will be around 150% of normal
which could lead to locally heavy rainfall of 2-3 inches. Areas
that receive multiple rounds of storms will have the highest
chances to see localized flooding.

Scattered to isolated showers and thunderstorms will come to an end
during the day on Friday. Thunderstorms over the western high plains
may impact western portions of the area late Friday evening, though
there is uncertainty on how far east these storms make it. Highs on
Friday will be in the 70s.


This Weekend...

A series of shortwave troughs will move through the area this
weekend. While the GFS and ECMWF still differ some on the strength
and timing of the troughs, it appears that thunderstorms are
possible (30-60%) during the late afternoon-overnight hours
each day. Moderate instability will be in place on Saturday,
with storms developing off the lee of the Rockies. Storms that
enter the area would have the potential to be severe. Highs on
Saturday will be in the upper 70s to low 80s. Instability will
be higher on Sunday as temperatures climb into the mid to upper
80s, along with higher dewpoints. Warmer air aloft on Sunday may
inhibit thunderstorm development, however a cold front moving
through the area may provide enough forcing for thunderstorms to
develop. Thunderstorms that develop on Sunday would have the
potential to be severe. Details on the timing, evolution and
type of any severe weather chances this weekend will become
clearer as the event gets closer.

Next Week...

Precipitation chances (15-45%) linger into next week, with the
highest chances occurring during the late afternoon-overnight
hours each day. A more impactful shortwave will move through on
Tuesday, though there is still model disagreements on the timing
and strength of this trough. Behind this shortwave a ridge will
begin to build over the western United states. ECMWF and GFS
ensembles disagree on the strength and placement of this ridge,
however warmer and drier weather would move in towards the
middle-end of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1255 AM CDT Thu May 30 2024

Primarily VFR during the period, though non-zero chance for MVFR
CIGs afternoon into overnight.

Tricky forecast due to uncertainties regarding thunderstorm
timing, coverage, and intensity. First this morning, cluster of
weakening thunderstorms will push in from the W next few hrs.
This activity is forecast to weaken beyond 09Z, but isolated
pop-up thunderstorms will be possible to redevelop just about
anytime through the remainder of the overnight, and even through
much of the daytime hrs. Tried to back off the VCTS to VCSH
during periods where chances are lowest. Conceptually speaking,
would expect an increase in thunderstorm chances by late
afternoon and into the evening, but very low confidence in
details (timing/coverage) continue as forcing is nebulous. CIGs
will fluctuate lower in and near convection, but should remain
primarily VFR 4-8K ft. There are some indications for CU with
MVFR worthy bases to develop this aftn, but coverage is
uncertain. At least MVFR CIGs become increasingly probable
(50-60%) beyond 00Z Friday, but will tackle this in later TAFs.

Winds outside of convection should be primarily SErly 9-14kt
with gusts near 20kt. Convection this morning should give at
least a 2-3hr window for a wind shift to gusty W/SW winds, but
think a turn back to SErly will occur by sunrise. This evening
winds will gradually back to E then NE at 5-9kt.

&&

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

&&

$$

DISCUSSION...Davis
AVIATION...Thies