893
FXUS63 KGLD 300930
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
330 AM MDT Thu May 30 2024

.KEY MESSAGES...

- Strong/severe thunderstorms possible the next few days with
  all modes of severe weather possible along with excessive
  rainfall that could produce flooding/flash flooding.

- A bit drier with less shower/thunderstorm coverage Sunday
  through Wednesday with afternoon temperatures well into the
  80s. Lower to middle 90s are forecast Sunday and Tuesday.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 330 AM MDT Thu May 30 2024

For the end of the work week, active weather and daily chances for
severe storms remain in the forecast. The area is forecast to remain
under the influence of a broad trough across the Northern CONUS,
with shortwaves moving through the zonal flow over the area.

The showers and storms from the overnight hours continue to move off
to the east and should be clearing the area by 5-6am CT. There could
be some patches of fog, mainly near the Colorado border where skies
are forecast to clear and relative humidity in the lowest 1km
remains around 80-100%. Through the morning, skies should clear
across a majority of the area with the warming temperatures and the
current MCSs moving off to the east. As long as skies are sunny or
partly cloudy, highs should reach the low 80`s across the majority
of the area.

From the mid-afternoon on into the early overnight hours, the entire
area will have another chance for thunderstorms and severe weather.
The storms are forecast to have two initiation points. The first is
over Eastern Colorado, where the surface low and slightly higher
terrain should help spark storm development. This batch is forecast
to provide the main chance for severe weather as Eastern Colorado is
forecast to have the most sunshine during the day, allowing for more
instability to develop. The second batch (that has a lower chance of
occurring) is that there could be a convergence zone in the area
depending on how much of the area shifts to out of the north as the
surface low nears. If the winds for part of the area remain from the
south while the rest of the area shifts to out of the north, a
convergence zone will develop and serve as a focus for storms
development. These storms would then slowly move off to the south
and east.

For today`s hazards, the main severe hazards would be large hail up
to two inches and wind gusts up to 70 mph. However, most of the
severe weather would probably feature a lot of hail that is below
1.5 inches with effective shear forecast to be around 30-35 kts and
generally slow storm motions around or less than 30 kts. Wind gusts
would also likely stay below 60 mph except in the strongest storms
later in the evening. A concern that has increased is the potential
for flooding. With the area receiving another 1 to 4 inches this
past night, locales along and south of I-70 are starting to see an
increase in soil moisture. With the potential for slow moving
clusters later today, another couple of inches of rainfall could
fall and lead to some flooding. Will be monitoring closely. The
storms should pass by 3am local time with skies remain mostly cloud
and lows in the 50`s and low 60`s.

For Friday and Saturday, the overall patter remains the same with
the nearly zonal flow aloft, low pressure to the west and high
pressure to the east. The main difference between the two is that
higher pressure is forecast for Friday, with temperatures a little
lower in the 70`s instead of in the 80`s. Otherwise, in regard to
storms, both days are forecast to have storms develop along the
higher terrain in Eastern Colorado and move east into the rest of
the area. The difference between the two is that the environment is
a little less favorable Friday which should limit the coverage and
overall chances. In both cases hail to around 1.5 to 2 inches and
wind gusts up to 70 mph would be the main threat, but a tornado or
two and additional flooding concerns will also be in play.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Issued at 320 AM MDT Thu May 30 2024

The long-term pattern looks to remain zonal with an upper-level low
pressure system moving along the U.S./Canada border, maybe in the
northern row of states. This would lead to diurnal pop-up showers
and storms, but nothing very organized. The CMC-NH is showing the
low pressure system moving over the Tri-State area and becoming
cutoff Wednesday and lasting into the weekend. This seems highly
unlikely (<5% chance of occurrence), but if this does occur we could
see persistent storms and showers until it moves out.

RH values look to lower into the teens in southwest on Sunday and
Tuesday afternoon. This does increase fire weather concerns, but
winds do not support critical fire weather.

Temperatures will be fairly warm with highs in the mid 80s to mid
90s. Low temperatures will remain in the mid 50s to low 60s.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1003 PM MDT Wed May 29 2024

Showers and storms continue to move across each terminal
bringing with MVFR visibilities. This is forecasted to continue
through the first few hours of the new TAF period. Continue to
have concern for patchy dense fog across the area around sunrise
similar to this morning, so confidence isn`t overly high in
exact locations but do feel it is worth including as tempo.
stratus may linger across eastern portions of the area
especially KMCK; appearing more likely that status should be
clear of the KGLD terminal. Another round of potentially severe
storms is again forecast for tomorrow.

&&

.HYDROLOGY...
Issued at 358 AM MDT Wed May 29 2024

Highly efficient moisture return has already began and will continue
into the end of the workweek with aid from the 850 mb LLJ. This
moist conveyor belt will cause PWATS to increase above 1 inch
starting Wednesday and potentially remain that way until Sunday. The
highest values will be in the eastern CWA, but the majority of the
Tri-State area will have a good chance (70%+) at seeing PWATS above
1 inch. Throughout this active pattern, a high melting layer is also
expected, generally 11,000-15,000 feet agl.

Tuesday evening saw 2-3+ inches of rain in Cheyenne county Colorado,
and a few other locations in eastern Colorado. This rain did not
cause any flooding, but it will make it easier for flooding to occur
over the next few days. Locations that received heavy rainfall are
not fully primed for flooding (SAC-SMA soil saturation is around 30-
45% in these area), but will become susceptible to flooding sooner
than normal.

Based on what the CAMs are showing, the southern cluster of storms
would be a slower mover and larger in size, meaning based on its
projected path (south of I-70 across the CWA) and potential for
heavy rainfall, it will need to be watched closely for flash
flooding.

Thursday is currently the best day for training storms to create
heavy rainfall that could lead to rate-driven flash flooding and
duration-driven areal flooding. Friday and Saturday are also at risk
for flooding potential due to a combination of efficient rain
producing storms and potentially multiple days of heavy rain
saturating the soil.

Current confidence in localized flooding occurring through Saturday
is around 25-45%. Confidence in widespread flooding is about
20%.

&&

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

&&

$$

SHORT TERM...KAK
LONG TERM...CA
AVIATION...Trigg
HYDROLOGY...CA