289
FXUS63 KGLD 092242
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
442 PM MDT Sun Aug 9 2026

.KEY MESSAGES...

- Air temperatures nearing 100-105 are forecast through Tuesday.
  Heat indices may approach 105 along and east of Highway 83 in
  Kansas.

- Isolated storms with dry lightning and possibly wind gusts up
  to 60 mph are forecast to develop south of Interstate 70 this
  afternoon. Additional fire starts due to lightning is
  possible as humidity is forecast to be in the low to mid
  teens.

- Another round of strong to severe storms is forecast during
  the evening hours and may linger past midnight. Wind gusts up
  to 70 mph and hail around half dollar size are possible.

- Patchy fog in Red Willow County area overnight into Monday
  morning.

- Storm chances continue daily the next few days.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 1141 AM MDT Sun Aug 9 2026

Upper air analysis continues to show the ridge of high pressure
centered over the Four Corners Region.  The ridge is expanding
slightly to the east, and should continue to do so through the day.
Satellite imagery shows clouds and smoke moving around the ridge;
area of fog was shrinking over Central/Eastern Nebraska.  At the
surface a cold front was slowly moving south through the middle
forecast area.  Further north another boundary was moving south
through Southern Nebraska.

Unclear at this time how far south the weak cold front will move and
how the other boundary moving south in Nebraska will affect the
weather. Dew points are increasing behind it, so it may reinforce
the higher dew points behind the cold front this afternoon.  If it
continues moving south through the morning it may push the cold
front further south, which may also expand how far the better
environment for hail would be.

This afternoon some models show a potential for isolated storms over
the southeast part of the forecast area as a weak upper level trough
axis moves through.  The weak cold front is already in the southwest
part of the forecast area, and clouds are increasing in coverage
nearby the front.  Confidence is 20% for storms to form along the
stalled front due to almost no instability and very weak lift at
best.  There may also be some aid from the LLJ nose along the
southeast border of the forecast area.  Dry lightning and wind gusts
up to 60 MPH will be the main risk for any storms that form there.

Regarding the heat potential, concur with prior shift that the
heat index will be low enough to negate a heat advisory. In
addition, the heat has been mentioned for a couple days in
weather graphics and hazardous weather outlook so this is not a
surprise heat wave.

The main round of storm activity will move in from the west around 6
PM MT ahead of the upper level short wave trough.  Model guidance
indicates the majority of the storm activity should remain north of
I-70.  Worst case for wind gusts would be 70 MPH.  Most of the model
data is in the 40-50 MPH range for wind gusts.  The best time for
any severe wind gusts will be 7-10 PM MT, with the window for wind
gusts from thunderstorms ending around midnight.

Confidence is low (20%) for blowing dust to be much of an impact. As
prior shift observed, mixing heights are quite high allowing dust to
mix out, plus the most likely wind speeds will be under 60 MPH (dust
storm conditions typically occur with wind gusts above 60 MPH).

There continues to be a potential for large hail up to half dollar
size this evening.  This threat will mainly be north of Highway 36
where the deep layer shear will be around 30 kts and the instability
will be higher due to the higher dew points.  The window for large
hail will be 7 PM to midnight MT.

Given the same air mass as last night, heat busts may also occur
with any storms that move through.

There will be moisture advection over the northeast part of the
forecast area overnight through sunrise Monday. As such fog may
form so included a mention of patchy fog.

Continue to be skeptical regarding receiving much rainfall with
these storms.  The cloud bases will be quite high, allowing
evaporation to limit rainfall reaching the ground.  However,
wouldn`t be surprised if the storm coverage ends up being higher
than what the current forecast is suggesting.  This is due to the
role of the outflow boundaries potentially generating storms.  If
this happens storm coverage may be greater than forecast, but the
storms will likely be moving rather quickly and not last long if the
outflow boundaries are the main source for storm formation.

The upper level short wave trough will move east of the forecast
area during the overnight hours bringing storm chances to an end.


Monday a similar weather pattern will continue.  Highs will be
similar to today.  An upper level short wave trough will move into
the forecast area from the west during the early evening.  However
the short wave trough looks to fill as it moves into the forecast
area; this may be due to the ridge over the Southeast CONUS joining
with the ridge over the Four Corners Region.  Precipitation
potential is much less than this evening, confined to East Central
CO.  Wind gusts should be of less magnitude than this evening.  The
storm/wind threat should end around 9 PM MT.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 239 PM MDT Sun Aug 9 2026

***Tuesday***

A flattened ridge at 500-mb is favored to be in place overhead
Tuesday morning. A shortwave trough embedded in the ridge favors a
low developing at the surface across the forecast area. Surface
winds are expected to be light as the low only undergoes weak to
modest deepening and centers itself over the County Warning Area
(CWA). Hot conditions look to continue under this setup, with highs
currently forecast in the upper 90s to mid 100s. Confidence in a
Heat Advisory being needed Tuesday continues to rise, currently
around 40%. Additionally, dry conditions are forecast as light
westerly to southwesterly surface flow continues to bring in dry
air, and temperatures rise through the afternoon. Relative
humidities are forecast as low as the upper teens across Eastern
Colorado Tuesday afternoon. However, the risk for critical fire
weather conditions is low due to the weaker surface winds.
Confidence in a Red Flag Warning being needed is less than 5%.
However, it should be noted that there is a small chance (20%
chance or less) for showers during the evening hours Tuesday,
particularly in West-Central Kansas and East-Central Colorado.
NAMNST model soundings for 00z Tuesday show inverted-V profiles
up to around 3 km, which may suggest the potential for dry
lightning with these storms. This could serve as an additional
form of fire starts.


***Wednesday/Thursday***

GEFS and EC ensemble guidance are in support of upper-level ridging
remaining overhead through Thursday, as troughing builds in across
the Western United States. The surface low from Tuesday looks to
remain approximately stationary over the area Wednesday and
Thursday. Easterly/northeasterly surface flow in Southern Nebraska
ahead of southerly flow from the Gulf of America would support
moisture returning to the area, in addition to temperatures
beginning to cool. Highs are forecast in the 90s on Wednesday, and
the upper 70s to upper 80s on Thursday. Additionally, LREF guidance
shows a 75% chance or higher both Wednesday and Thursday for
dewpoints greater than 60 F, most particularly across portions of
Red Willow County in Southwest Nebraska, and Decatur and Graham
Counties in Northwest Kansas. Thunderstorm activity appears more
probable across the area as well. NBM 24 hr precipitation guidance
shows probabilities in the 60-80% range across Southwest Nebraska
and Northern Yuma County in Colorado for greater than 0.1 inches of
rain Wednesday. These probabilities extend into Northwest Kansas and
East-Central Colorado on Thursday. LREF guidance also shows
that this activity will be in association with a 30-50% chance
for surface CAPE (a measure of atmospheric instability) greater
than 1000 J/kg. Thunderstorms are in the forecast both days, but
the risk of them becoming severe is low at this time, as GFS
and EC model soundings show less than 30 kts of sfc-500mb
vertical shear both days. However, it is important to note that
hotter conditions on Wednesday may promote microburst conditions
with thunderstorms, which could be associated with 60-70 mph
winds. Even so, confidence in severe weather occurring is about
5% each Wednesday and Thursday.


***Friday-Sunday***

Deterministic guidance diverges a bit by Friday, though ensembles
continue to show troughing off to the west alongside ridging
overhead. As such, conditions similar to that of Wednesday and
Thursday are forecast, though there is some uncertainty regarding
whether storms will be severe or not. Still, NBM 24 hr precipitation
guidance shows the highest probabilities for greater than 0.1 inches
of rain across Eastern Colorado (60-75% through Saturday). As for
temperatures, highs in the 70s and 80s are forecast to continue
through the weekend.

&&

.AVIATION /0Z TAFS THROUGH 0Z WEDNESDAY/...
Issued at 436 PM MDT Sun Aug 9 2026

VFR conditions forecast for the TAFs. Main focus is the
thunderstorm timing for this evening. The primary threat with
these storms will be wind gusts. There is a potential for wind
gusts to be 50 kts+, however confidence for this happening at
either site is around 10%. The more likely speed is 30-40 kts.
As such placed a mention in the TAF. KMCK may end up being north
of the wind gusts, so decided to not include a mention for that
site. Fog may occur at KMCK from 9-14z. However confidence is
not high enough for fog to form to place a mention in the TAF
for KMCK.

&&

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

&&

$$

SHORT TERM...JTL
LONG TERM...Davis
AVIATION...JTL