160
FXUS63 KGLD 031136
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
536 AM MDT Wed Jul 3 2024

.KEY MESSAGES...

- Severe storms are possible this afternoon/evening. However, if
  storms/cloud cover are present through the morning and early
  afternoon hours, storm and severe chances will be very low.
  Otherwise, the storms later today will be capable of producing
  hail up to 3 inches, wind gusts to 80 mph, and a tornado or
  two. Be sure to look for updates this afternoon.

- Breezy to gusty 4th of July; normal to below normal
  temperatures into early next week.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 227 AM MDT Wed Jul 3 2024

Another night, another round of storms moving/developing in the
area. Radar continues to show storms trying to develop and move into
the area generally south of I-70. Given the moisture advecting into
the area and the general east/northeast movement, am expecting these
storms to move through the area in a few clusters through the
morning. The storms and additional cloud cover should help mitigate
fog chances, though prior nights suggest that some patchy fog may
still be able to form in this moist low level air mass.

Today will largely be dictated by whether cloud/storms are present
through the day or not. Areas that remain cloud cover or see storms
through the morning will be more likely to only warm to around 80,
while the rest of the area would warm into the mid to upper 80s.
Currently, Northwest Kansas is favored to be cloud covered with
counties near the Colorado border more likely to clear. Should
storms be present through the morning, severe weather looks to be
unlikely with CAPE generally less than 1000 J/KG and cloud cover
inhibiting the development of more instability. Maybe could see a
severe wind gust with a stronger storm, but the lack of DCAPE and
winds remaining generally below 50 kts will keep the chance very
low.

For this afternoon, still looking at a shortwave trough moving
through the Western Rockies and Northern Plains with a deepening low
pressure near the Front Range. This will provide more than adequate
forcing for storms to develop, especially along the Palmer Divide.
The complicating factor is how long cloud cover and storms will
linger through the morning and early afternoon. If storms and cloud
cover linger through much of the day, this afternoons storms could
be limited in coverage and intensity, if they even form at all.

If the storms and cloud cover break during the early afternoon
hours, then the area will have a decent chance for a few cluster of
storms to develop and move through parts of the area. In this
scenario, higher instability (CAPE 2000 J/KG, Mid Lapse Rates 8C+)
and high effective shear (45-60 kts) could allow for some initial
supercell development. This would favor Eastern Colorado and give
the highest chance for large hail today, potentially up to 3 inches
in size. A tornado may also be possible, though low level shear and
SRH continues to be forecast to be low. As storms progressed east,
clusters and lines would become more likely and increase the wind
threat. With DCAPE greater than 1000 J/KG, downshear vectors around
50-65 kts, and mid to high cloud winds around 50-70 kts, damaging
wind gusts to 80 mph are possible, especially in a linear mode.
Large hail and maybe a QLCS tornado would also be possible, but wind
would be the main threat at that point.

In summary, there is a chance for strong severe storms this
afternoon and evening (likely between 3-9pm MT). All hazards are
possible, though wind is the main threat, followed by hail. If this
morning`s storms and/or cloud cover persist, the risk for storms and
severe storms will lower considerably.

Tonight, skies are forecast to initially clear from any
afternoon/evening storms. However, another round of storms is
possible as the trough swings through and the surface low/front push
through the area. Storms would likely be sub-severe, but there could
be enough instability and DCAPE for an instance or two of large hail
or wind gusts to 65 mph. Lows are forecast to drop to 50`s for the
western half of the area, but 60`s for the eastern half of the area
where the second round of storms is possible.

For the 4th of July, a relatively mild day is forecast with highs in
the 80`s and skies becoming mostly sunny as drier air works into the
area behind the front. The main inconvenience will be the presence of
stronger winds from the north with speeds around 20 mph and gusts up
to 40 mph. For the evening hours, winds are forecast to begin
tapering off as the sun sets. Skies should remain clear short of a
low potential for some storms to develop over the higher terrain in
Eastern Colorado. Chances are only 15% and even then would likely be
limited to an isolated storm or two that dissipates fairly quickly.
The overnight hours would see temperatures drop into the 50`s with
lighter winds and mostly clear skies.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 100 AM MDT Wed Jul 3 2024

Friday...the forecast area is forecast to be under northwest flow
aloft, in between low pressure to our north and east and a
strengthening ridge to our west. GFS/NAM 700-500mb relative humidity
forecasts advertise a weather system moving through the
western/southwestern 1/3-1/4 of the forecast area during the
afternoon with potentially another moving through the entire area or
much of the area overnight if the NAM/ECMWF models are correct.
Presently, we`ll cap the pops at 20% for the time being. High
temperatures are forecast to remain below normal in the lower to
upper 80s with low temperatures in the 55 to 60 degree range.

Saturday...not much change in the general 500mb pattern when
compared to Friday. There is some agreement from the GFS/ECMWF/GEM
models that another weather system will move into the eastern part
of the forecast area during the afternoon hours from the southwest,
supporting NBM 20%-30% pops for thunderstorms generally east of
Highway 27. Overnight, there may be some type of weather system
moving through from the northwest, supporting 20%-40% chances for
thunderstorms. Timing of when this system arrives in somewhat in
question. GFS/ECMWF/GEM 850mb temperatures are showing a little more
spread compared to 24 hours ago with the GFS the warmest. If it were
to verify using typical mixing at 850mb, high temperatures would be
a few degrees lower than currently forecast. Presently, highs are
forecast to be in the upper 80s to lower 90s. Low temperatures are
forecast to be in the middle 50s to lower 60s.

Sunday...500mb pattern is showing an upper level trough axis moving
through within the broader pattern featuring troughing over the area
and ridging to our west. With surface high pressure moving in, high
temperatures look to be cooler than Saturday. Just how much cooler
is the question as ECMWF/GEM 850mb temperatures are in the 13C to
18C range with the GFS in the 19C to 21C range. Given the spread, no
chance of improving the current temperature forecast of highs in the
upper 70s to middle 80s. Low temperatures are forecast to be in the
50s. Regarding rainfall chances, there appears to be at least a 20%-
30% chance as there is some moisture in the 850-500mb layer moving
through which with the trough axis moving through should support at
least isolated to scattered chances for thunderstorms.

Monday and Tuesday...we remain under northwest flow aloft with slim
(20%) chances for thunderstorms to move off the Colorado front range
and into the area during the late afternoon through overnight hours.
High temperatures Monday are forecast to be in the 85 to 90 degree
range with 90 to 95 Tuesday. Low temperatures are forecast to be
in the middle 50s to lower 60s.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 527 AM MDT Wed Jul 3 2024

For KGLD... Varied conditions are forecast for the morning as
some showers/storms move through the area. The first few hours
will likely be characterized by ceilings varying between 1000ft
and 3000ft+ and intermittent rain showers. Once the showers
clear and clouds begin to break, skies will clear and VFR
conditions are forecast. The next hazard to watch for will be
strong to severe storms moving through around the 00Z hour.
There is some uncertainty if the storms will move over the
terminal or form. Severe storms are unlikely if cloud cover or
showers linger through much of the day. After about 03Z, storm
chances decrease and a front will begin to move through. The
front should bring drier air and a shift in winds to out of the
north. Clear skies are forecast for the remainder of the period.

For KMCK... Lower ceilings and visibility are possible for the
first few hours of the period. Higher level sky cover is trying
to help keep fog from forming, though low level moisture seems
to be developing intermittent fog. Later in the morning, cloud
cover is forecast to break, though there is a round a 30% chance
it will persist through the day. The next hazard will be the
potential for strong to severe storms around or shortly after
00Z. There is some uncertainty if those storms will reach the
terminal (especially if cloud cover lingers), but currently have
a cluster forecast to move through around 01Z. Once this passes,
there should be a brief period of clearing before another chance
for storms as the front moves through after 06Z. Didn`t have as
much confidence in that round, so left it out for now. If that
wasn`t enough, if the front doesn`t remove enough moisture, fog
and low stratus will be possible near the end of the period.

&&

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

&&

$$

SHORT TERM...KAK
LONG TERM...99
AVIATION...KAK