347
FXUS63 KGLD 090107
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
707 PM MDT Fri Aug 8 2025

.KEY MESSAGES...

- Isolated to scattered thunderstorms are possible this
  afternoon and evening, a few of which could be strong to
  severe. Strong wind gusts are the main hazard, but large hail
  and a brief landspout tornado can`t be ruled out.

- Temperatures trend cooler over the weekend, and additional
  storm chances exist during the afternoon and evening of both
  Saturday and Sunday, with the highest chances being in eastern
  Colorado. Strong to severe storms are possible.

&&

.UPDATE...
Issued at 705 PM MDT Fri Aug 8 2025

We have allowed the Heat Advisory to expire as scheduled.
Temperatures are cooling across the area. Additionally, the
severe weather threat is waning for this evening, but there is
still some risk for severe storms until about 2 AM MT.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 1245 PM MDT Fri Aug 8 2025

A sfc trough is evident in 18z obs, roughly extending from near
Hill City, KS, northward to Cherry County, NE, and minor sfc
pressure falls (a millibar or two) have been noted over the last
several hours. Much of the short-term forecast hinges on the
dewpoints, and 18z obs show a gradient ranging from 40s east of
a St. Francis to Leoti line to 55+ east of a Colby to Scott City
line. Two areas of high clouds are present, one across southern
CO and the other across NW CO. Across the drier air and cloud
free parts of the CWA, temps have outpaced guidance, with
Goodland reaching 100 degF at 10 AM MT, and Goodland and St.
Francis at 105 and 102 degrees, respectively, as of 18z. With
the dry air across eastern CO, there is still concern about
periods of near-critical fire danger through this afternoon, but
wind gusts should stay below 30 mph, and to this point
observed wind gusts have been around 20 mph.

There is a weak boundary evident on radar, with winds shifting
from NW to NNW following it`s passage. Dewpoints are a bit
higher behind this feature, and as its interacting with the
considerably hotter air in place across Kit Carson, Cheyenne
(KS) and Sherman counties, there has been an uptick in the
vertical growth of the Cu field. This seems like the most likely
area for t-storm development in our area between 1-3 PM MT.
Elsewhere, there is agitated Cu beneath the high clouds across
SE CO, and convective development is eventually expected to
occur in this area and spread NE into the GLD CWA. Given the dry
air across the western portions of the CWA, the main hazard will
be gusty winds (with isolated gusts over 70 mph possible). If
storms manage to persist farther east into the higher dewpoint
air, the hail threat could increase. The landspout tornado
threat is low, but not zero, especially if storms develop and
remain in the vicinity of a boundary. The best window for severe
storms will be between 1 PM and 6 PM MT.

Several heat bursts were recorded in obs last night, including
Goodland which rose 12 degF in an hour to 97 degF at 10 PM MT.
While most of these did not register strong wind gusts at
observation sites, we did receive a few public reports that
locally strong winds were associated with some of the heat
bursts. There could be additional heat bursts this evening after
the sfc decouples and isolated/scattered convection persists
into the late evening ahead of the cold front, but with the
southward advance of the cold front overnight I do not
anticipate the heat bursts to continue overnight.

Models continue to show much higher moisture content behind the
cold front. There is some concern that despite modest sustained
winds behind the front, this increase in moisture could lead to
fog and/or stratus, which is not currently captured by model
guidance. Additionally, the northeast wind direction will result
in an upslope component to the low-level flow. Satellite imagery
and obs from across NE/SD this morning showed a stratus deck
with ceilings between 1-3km AGL, and would not be surprised if a
similar deck occurred in the post-frontal regime early Sat AM.
MAV/MET guidance have had a better handle on some of the other
recent fog/stratus events, and these guidance sources do have
much higher cloud cover early Sat AM than other models, so
trended the sky cover forecast higher (but still may not be high
enough).

&&

.LONG TERM /SATURDAY THROUGH FRIDAY/...
Issued at 1247 PM MDT Fri Aug 8 2025

The expectation remains that the cold front will push south of
the CWA for the daytime hours tomorrow, and the post-frontal
regime will feature cooler temps with highs in the upper
80s/near 90F. It is expected to be more humid, however, as most
models show a plume of higher dewpoints positioned across the
CWA, ranging from the low 60s in east CO to near 70F in the
eastern CWA. (Notably, some models have this swath of higher
moisture shunted completely south of the CWA). While most of
the area should stay dry through mid- afternoon, convection is
expected to develop along the Front Range and moderate 500mb
westerly winds (35-45 knots) within the base of the upper
trough should help advect this activity eastward. Thanks to the
expected higher dewpoints, these storms should move into an
environment with greater instability than what has been present
in recent days, with forecast MUCAPE values of 2000-3500 J/kg.
With decent upper level flow, deep layer shear values approach
40 knots, and this parameter space will be conditionally
supportive of severe storms.

There are still a number of questions complicating Saturday`s
severe storm forecast, including the potential influence of
anvil shading from the initial convection along the Front Range
and what impact it will have on the thermodynamics across our
area. Forecast hodographs are straight, with the mean wind
almost due east (tracking directly parallel to the anvil level
winds), and bunkers motions for right/left movers are not
sufficiently deviant to avoid their own anvil shading. NAM
forecast soundings show a subtle warm nose (cap), so the loss of
insolation could dramatically reduce the severe threat. For
now, a marginal risk feels appropriate given the uncertainties,
but if everything comes together favorably, the parameter space
could support significant severe hazards (wind gusts over 70 mph
and hail larger than 2"). CAMs do not agree on the storm
timing, but do suggest that storms and associated severe risk
could continue into late Sat night.

Another round of storm development is expected along the Front
Range Sunday, aided by a slow-moving upper wave. This will keep
precip chances in the forecast for Sun afternoon-evening,
increasing with westward extent. Once again, there is a
conditional threat for strong to severe storms, although the
latest guidance does suggest that instability values on Sun will
be lower relative to Sat.

Can`t rule out some lingering precip into the early parts of
next week as a weak upper level trough slowly shifts east of the
areal. Otherwise, next week is looking mostly dry with warming
temperatures as upper level ridging builds over the Plains. High
temps are forecast to rise from the low/mid 80s on Mon to
mid/upper 90s Wed-Fri.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 355 PM MDT Fri Aug 8 2025

Some showers and storms may impact each terminal this evening
but any threat currently appears to be done around 06-07Z. Winds
are forecast to remain from the northeast which is
climatologically favored for fog and stratus development with
MVFR ceilings currently looking to be the main concern at this
time. VFR conditions are then forecast to return around 14-15Z.
Another round of storm potential may impact the GLD terminal
just after the end of this TAF period as well with severe
potential on the table.

&&

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

&&

$$

UPDATE...CA
SHORT TERM...Erwin
LONG TERM...Erwin
AVIATION...Trigg