294
FXUS63 KGLD 200817
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
217 AM MDT Thu Jun 20 2024

.KEY MESSAGES...

- There is a marginal risk for a severe thunderstorm early this
  evening clipping Yuma County in Colorado and Dundy County in
  Nebraska. Brief wind gusts to 60 mph and hail up to quarter
  size will be possible in those areas.

- There is a marginal risk for a severe thunderstorm or two
  Friday afternoon and evening for northeast Colorado and into
  southwest Nebraska. Wind and hail will be the main hazards
  near any stronger storm that develops.

- Heat indices of 100 to 105 degrees along and east of Highway
  283 Monday and Tuesday as temperatures climb back into the
  upper 90s and lower 100s across the area.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 200 AM MDT Thu Jun 20 2024

Showers have been slow to develop overnight. However, there is
an area of light rain/isolated thunderstorms moving off the
Front Range between Pueblo and Denver that appears to be
associated with the main shortwave aloft. If it holds together,
and that is far from certain based on the best performing CAM
with the current situation the HRRR, it would move through
northeast Colorado and into southwest Nebraska later in the
overnight and into Thursday morning before exiting to the north.
Otherwise, some patchy fog may develop with the near-saturated
surface conditions, but cloud cover and precipitation is also
hindering radiational cooling, so confidence is low.

Expect skies to become mostly sunny across the area by this
afternoon with high temperatures in the upper 80s. Next
shortwave trough rotating around the strong ridge to the east
will skirt the far northwest forecast area early this evening.
It is possible the storms miss the area completely. There will
be a marginal risk for wind and hail associated with these
storms which should exit fairly quickly to the north by mid
evening. Low temperatures will be in the 60s.

Upper ridge weakens over the area on Friday as the next
shortwave trough moves out of Colorado in the afternoon and
evening hours. High temperatures will warm into the lower 90s.
Thunderstorm coverage is fairly isolated after 21z in western
areas Friday afternoon. MUCAPE is also weak in that area at
around 500 j/kg, with deep layer shear of 35-40 kts. Those
parameters suggest a marginal severe risk at best. The isolated
to widely scattered storms continue into Friday evening as the
shortwave moves through. A weak front/surface trough will shift
winds to the northwest overnight. Low temperatures will be in
the 60s and 70s.

Weak ridging will build over the area by Saturday afternoon as
the shortwave moves east. At the surface there will be light
north winds with the trough far to the south. Any forcing would
have to come from a weak perturbation working through the ridge,
and models just not showing much. As a result, will go with a
dry forecast. Temperatures continue to warm with highs in the
middle 90s. Low temperatures Saturday night will be in the 60s.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Issued at 1254 AM MDT Thu Jun 20 2024

Current runs of the GFS/ECMWF continue to amplified 500mb ridge
working northward from the southern to the central Rockies. This
will occur on Sunday into the beginning of next week, providing a
W/NW flow aloft. By the midweek timeframe, the ridge amplification
stretches northward through the Rockies, with a slight eastward trek
towards the Plains region. The amplification/movement, changes the
flow aloft to northwesterly. A few weak shortwaves will traverse the
eastern side of the ridge during the forecast period, mainly during
the afternoon/evening hours.

At the surface, guidance brings a couple troughs/boundaries off the
Front Range and through the central Plains by the afternoon/evening.
Weak instability will have a 15-20% chance for rw/trw. Going into
Tuesday, the second boundary does settle south of the cwa, with a
low extending of the western portion. This front/boundary will be
the focus for increased RH along/in the vicinity, aided by winds
shifting more E/SE. The instability will trigger higher pops (30-
40%) area-wide Tue-Thu. Timing/coverage of the rw/trw chances do
differ each day between the GFS/ECMWF. This will be do to a strong
ridge rolling south behind the front, and eventually pushing east.
The extent of the ridge axis nosing south into the Kansas area could
push high RH further south and limit instability, or focus it more
into southern and western portions of the cwa.

Overall, chances for rw/trw do increase as the week progresses, but
the other concerns will be the return to hot, above normal
temperatures area-wide.

For temps, the latter portion of the upcoming weekend into next week
will see hot conditions return area-wide. Daytime highs on Sunday
will range in the mid to upper 90s. Monday and Tuesday, upper 90s to
low 100s. Wednesday and Thursday, mid to upper 90s.

With these expected highs around the area, concerns for high heat
indices will crop up. Currently looking at the Monday and Tuesday
timeframe where indices along/east of Highway 83 could reach into
the low to mid 100s and possibly need a Heat Advisory as a result.
Will be monitoring for further westward expansion. The remainder of
the extended period will have indices at or below forecasted highs
aided by lower after RH readings.

Overnight lows will range mainly in the 60s for the entire period,
but locales along/east of Highway 83 could only see the 70F mark a
few nights.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1038 PM MDT Wed Jun 19 2024

Stratus and fog has been a bit slow to get going so far but am
seeing signs of development across SE portions of the area, so
forecast expectations remains on track. The slow development has
been from a slower progression of incoming shortwave across SE
CO. Ceilings are forecast to decrease over the next 6 hours with
at least IFR conditions at each terminal and perhaps some LIFR
at KGLD along with some fog potential. Shortwave looks to create
some showers which is favored to impact KMCK which should keep
the fog at bay. Breezy to gusty winds will ensue after the
fog/stratus breaks mid morning with gusts of 30-40 knots across
the area from the south.

&&

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

&&

$$

SHORT TERM...024
LONG TERM...JN
AVIATION...Trigg