817
FXUS63 KGLD 272052
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
252 PM MDT Thu Jun 27 2024

.KEY MESSAGES...

- Not as hot but humid today with scattered severe storms this
  afternoon and evening with all hazards possible.

- Severe storm potential continues Friday with large to very
  large hail and wind threat.

- Daily potential for afternoon/evening storms this weekend into
  next week.

- Heat index values in the low triple digits Monday.

&&

.UPDATE...
Issued at 252 PM MDT Thu Jun 27 2024

Severe Thunderstorm Watch #475 has been issued for the entire
Tri State region until 900 PM MDT/1000 PM CDT. Looking for
threats to include large hail, damaging winds and even a few
tornadoes. Also could see locally heavy rainfall.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 224 AM MDT Thu Jun 27 2024

Showers and embedded storms are finally starting to become a bit
more established across the area. As mentioned in last nights
discussion that there was a chance we would have to overcome some
drier air which would cause rainfall to be a bit delayed. Looking at
current RAP soundings that was the case. With the continued decaying
of showers through the evening, that has allowed the area to
saturate just enough for precipitation to form. Overall severe
threat is low through the night, however will need to watch for
some wind and perhaps some heat bursts as mesoanalysis still
showers well over 1000 j/kg of DCAPE present.

Anticipating some stratus to develop in wake of these showers and
storms around sunrise, however guidance has been struggling handling
the coverage and duration of the ongoing rain so overall coverage
with the stratus is low. The stratus continues to appear to hang on
for the majority of the day so have continued the keep
temperatures across the east in the low to mid 80s. Elsewhere
highs in the 90s are currently forecasted, with the humidity in
place a fairly muggy day for High Plains standards will be on
tap.

As for convection potential for Thursday. If the stratus does manage
to hang on for the majority of the day then a mesoscale differential
heating boundary will be the main focus for afternoon convective
initiation ahead of a subtle shortwave. Should storms initiate
along this boundary which at this time appears to be from Graham
County back into Wichita/Greeley county vicinity the
environment would be favorable for supercell development with
all hazards in play. The NAM does also show a 700mb jet streak
situated across SW Kansas into eastern portions of the area
roughly where this differential heating boundary may be which
would help lift across the area. It is worth noting at this time
the NAM is the only guidance showing this feature.

The above mentioned shortwave will also bring some potential for
isolated to scattered storms off of the Palmer Divide. Some
potential for large hail is possible with this activity but warmer
temperatures aloft and meager lapse rates may keep this threat
lower. Perhaps the greater severe threat with this activity will be
wet microbursts as a very moist air mass will be in place. The RAP
and NAM soundings all have a microburst composite of 7-8 which
is on the higher end of "chance potential" according to SPC
Mesoanalysis page.

A potential 3rd area of concern for severe weather for Thursday will
be across northern and northeast portions of the area. Discrete
supercells that develop in the Sandhills and Nebraska panhandle may
merge into a cluster impacting portions of SW Nebraska and
adjacent northeast CWA counties in Kansas. CAMS overall are not
in very good consensus with this solution, however the HREF and
WRF NSSL both suggest this potential which typically handles
coverage fairly well. Damaging winds would be the primary hazard
with this area. As mentioned above a very moist air mass is in
place with PWATS of 1.7 to 2 inches which is around 90th
percentile to max for this area for this time of year according
to SPC sounding archives so will need to monitor for potential
localized flooding concerns with storms.

Friday will see a surface trough push through the area from the
northwest. Highs for the day will again be the upper 80s to mid 90s
across the area. Storms are forecast to develop off of the Front
Range and along the surface trough in the Nebraska Panhandle and
eventually become an area of cluster of storms with some embedded
supercell potential as it moves ESE across the area. Any supercell
that can materialize may pose a very large hail threat despite
relative lower MUCAPE along with lower PWAT values and dew points,
wind shear is very strong which would help keep hail aloft longer.
700 mb temperatures are also cooler than the previous days as
well which would support hail growth. Will also need to watch
for damaging wind threat especially if a cluster does form and
does bow out.

Saturday, will be a similar pattern to Friday but overall
mesoscale features at this time are a little uncertain along
with quality of moisture. NAM suggests that 60-low 70 dew points
return ahead of a potential MCS developing across northeast
Colorado; whereas the GFS is a bit delayed with the moisture
return keeping it across southern Kansas. If the NAM does pan
out then a severe risk would again be possible along with very
heavy rain. GFS would virtually have no precipitation except
for extreme western and southern portions of the area which may
be clipped by the MCS. A lot still needs to be worked out for
Saturday so stay up to date with the latest forecast.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 1223 PM MDT Thu Jun 27 2024

From the latest runs of the GFS and ECMWF, amplified 500mb ridge
will persist over the central Plains for Sunday and Monday, before
the ridge flattens to zonal flow and shifts slightly eastward from
Tuesday onward. There will be several shortwaves that traverse the
northern periphery of the ridge each day.

At the surface, the focus will be on a couple lows and their
associated fronts that move through the region. The first system
starts off a trough over the eastern slopes of the Rockies on
Sunday, with a very slow shift south and east into Monday, settling
south of the CWA for the Tue-Wed timeframe. A quicker system for the
end of the week will push through the area, aided by a digging ridge
from the north.

As a result, each day the passage of the aforementioned shortwaves
will interact the surface front/low, creating rw/trw. For Sun-Mon,
while some initiation is expected for the late afternoon hours each
day, the best chances(30-40%) will occur during the evening,
especially north of the Interstate. These areas will be closest to
the system as it slowly moves into the CWA. Better moisture feed and
instability is expected for Tue-Wed as the boundary sets up
along/south of the area, opening the area up to more of an easterly
fetch for better low level moisture/instability and thus better
storms chances(40-60%). High PW values around 1-2" are expected each
day, with high numbers in the east, combined with daytime heating,
will create as least the chances for storms producing heavy
rainfall. But strong to severe storms are possible as well.

For Thu-Fri, this will envelope the arrival of the second boundary
albeit a bit weak. There still be be chances for storms like
mentioned above, but lower chances of coverage area-wide(30-40%).

For temps, daytime highs each period will continue at above normal
levels. On Sunday, 80s area-wide. 90s will persist each day next
week except for Monday where a range from the mid 90s to lower 100s
are expected. Hottest areas will be along and east of Highway 25.
With a return to 100+ degree heat, heat indices will be around 100
in areas along/east of Highway 83. This will have to be watched for
a potential Heat Advisory. Overnight lows will range in the 60s. A
few spots east on Monday night could only drop to the 70F mark.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1026 AM MDT Thu Jun 27 2024

For KGLD, looking for VFR conditions through the forecast
period at this time. There is the chance for thunderstorms to
impact the area closer to the 00z Friday timeframe. For now due
to low confidence on timing, have only mentioned a 3-hr window
of VCTS and will adjust forecast as storms develop closer to
the terminal. Winds, south-southwest 10-20kts with gusts to
30kts through 21z. By 00z Friday, south around 10kts, shifting
southwest by 03z, then northwest by 12z.

For KMCK, mainly VFR through the forecast period. There is
current thinning MVFR ceilings that will dissipate as the
afternoon progresses. Also, there is the chance for
thunderstorms to impact the area closer to the 01z Friday
timeframe. For now due to low confidence on timing, have only
mentioned a 2-hr window of VCTS and will adjust forecast as
storms develop closer to the terminal. Winds, south-southeast
15-30kts through 03z Friday, then south-southwest 5-10kts. By
13z, shifting northwest. LLWS 03z-10z Friday 180@40kts and
again 10z-13z Friday 230@35kts.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.

&&

$$

UPDATE...JN
SHORT TERM...Trigg
LONG TERM...JN
AVIATION...JN