013
FXUS63 KGLD 211726
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1126 AM MDT Fri Jun 21 2024

.KEY MESSAGES...

- Continued very windy today with 20%-30% chances for afternoon
  and evening thunderstorms, mainly along/north of I-70, some
  of which could become severe(Yuma/Dundy/Hitchcock counties).

- Weekend looks to remain hot with highs in the 90s. Could be a
  few thunderstorms Sunday afternoon/evening.

- Hottest temperatures of the period Monday/Tuesday. Heat index
  values of 100-105 degrees east of Highway 25.

- Not as hot (highs in the 90s) Wednesday/Thursday with better
  chances (20%-40%) for thunderstorms moving through the area
  from the west during the late afternoon to overnight hours.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 312 AM MDT Fri Jun 21 2024

Across the region this morning, skies are mainly clear, except for
lingering clouds north from exiting precip, and some mid/high clouds
over southern portions of the area. As of 100 AM MDT, temperatures
are ranging in the 60s and 70s. With a surface low sitting off to
the southwest of the CWA, and a front sitting over the extreme
northern portion of the area, persistent southerly flow is occurring
for most. Areas along/north of Highway 34 are seeing an easterly
fetch in the vicinity of the boundary.

Weather concerns for the short term period will focus on the hot
conditions each day with above normal temperatures, strong southerly
flow over the area today/tonight and the threat for showers and some
thunderstorms(some may be strong to severe for portions of the area
later today/this evening).

Currently for today/tonight, the latest RAP40 500mb analysis and mid
level water vapor imagery are showing a broad elongated ridge over a
good portion of the eastern U.S. and with the western extent of this
ridge extending into central/southern Plains, the Tri State area is
seeing SW flow aloft. The aforementioned surface low sitting over
eastern Colorado will shift eastward through the afternoon/evening
hours, combining with a shortwave that works over the
western/northern periphery of the upper ridge, and will trigger
chances for convection with about 15-20% chance near I-70 and
increasing to about 30-40% from Highway 36 and points north
especially NW zones.

The remnant front to the north will also aid in focusing convection
as the entire complex lifts E/NE later this afternoon into the
evening hours. SPC is carrying a Marginal Risk for severe storms for
Yuma county in Colorado extending east into Dundy and Hitchcock
counties in Nebraska. Best instability will be located closest to
the front/low combo, but with daytime heating drying out lower
levels ahead of expected activity later today, guidance is having
inverted-v soundings around the 21z-03z timeframe, giving DCape
values 1000-1400j/kg on top of PW values that increase form an inch
in the west to around 1.5" in the east. While hail can`t be ruled
out with any storms that do develop, wind could be the main threat
along with locally heavy rainfall. Bulk of activity will clear the
CWA by 06z Saturday per latest CAMs, with some scattered showers
thereafter through 12z Saturday.

Before seeing an increase in convection, the southerly gradient
ahead of the low passage will afford the area gust potential into
the 40-50 mph range by midday into the evening hours, tapering off
from west to east as the flow shifts to the northwest.

Guidance continues to shift the upper ridge westward into the
upcoming weekend, allowing for SW flow aloft to become zonal both
days. Dry conditions are expected to persist over the area Saturday,
with a weak shortwave passage on Sunday. This system will track east
over the northern extent of the ridge. 15-20% pops for isolated
rw/trw over western areas during the day, tapering off over NW
Kansas during the evening hours. Other than these storms chances,
hot weather will persist area-wide.

For temps, highs today will range in the lower to mid 90s. On
Saturday, upper 80s to mid 90s are expected, and for Sunday, a range
mainly in the upper 90s with a few spots around the 100F mark.

Heat indices for the most part will range at or below forecasted
highs, however, on Sunday a few spots east of Highway 25 will start
to see readings approach the low 100s.

Overnight lows tonight will range mainly in the 60s west of Highway
83. East of there, upper 60s through the mid 70s. Lower to mid 60s
Saturday night will give way to mainly mid to upper 60s on Sunday
night. Some locales across Graham and Norton counties will only drop
to around 70F.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Issued at 250 AM MDT Fri Jun 21 2024

Mon-Tue: Long range guidance indicates that the Tri-State area
will be situated on the northern periphery of a broad, west-
east elongated ridge (centered over the Desert Southwest,
Southern Plains and Lower MS River Valley).. at the southern
fringe of the mid-latitude westerlies. Above average
temperatures are likely. In such a regime, precipitation chances
will largely be tied to the development (and downstream
propagation) of diurnal convection emanating from the Colorado
Front Range and Palmer Divide.. augmented (perhaps) by small
amplitude waves on the southern fringe of the westerlies.

Wed-Fri: Long range guidance indicates that the aforementioned
upper ridge will consolidate/amplify over the Desert Southwest
and extend northward to the 4-Corners and central Rockies (Wed-
Thu).. then flatten and regress southward to the Desert
Southwest/Southern Plains (Fri).. as an upper level trough
progresses eastward ashore the Pacific Coast and cyclonic flow
aloft envelopes the Intermountain West. Above average
temperatures are apt to persist. In such a regime, precipitation
chances /convective development/ will highly depend upon the
evolution of the ridge. -- At present -- guidance suggests that
the magnitude, position and orientation of the ridge will be
such that (1) synoptic subsidence may largely suppress diurnal
convective development along the Colorado Front Range/Palmer
Divide and (2) that low-level forcing/moisture may be
insufficient for in-situ convective development on adjacent
portions of the High Plains (i.e. northwest KS). In this
pattern, at this range.. convective forecast confidence is below
average.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1117 AM MDT Fri Jun 21 2024

Generally VFR conditions will be observed at both KGLD and KMCK,
but strong winds, made worse with storms this afternoon and
evening, will make for some tricky conditions. Models are
having a difficult time figuring out exactly what is going to
happen over the next 8 hours, but we are currently expecting two
waves of storms. The first will form around 21Z and move away
from the TAF sites by 0Z. The second wave, the wave with higher
confidence, will impact KGLD around 1Z and should stay south of
KMCK. This second wave is expected to produce strong winds as it
progresses eastward. If any of the stronger cells moves overhead
of either TAF site, heavy rainfall will reduce visibility
significantly. The heavy rain is the only concern for IMC
throughout the period. Later in the period, winds will weaken
and become northwesterly.

&&

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

&&

$$

SHORT TERM...JN
LONG TERM...BV
AVIATION...CA