521
FXUS63 KGLD 091750
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1150 AM 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/...
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 /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 145 PM MDT Sat Aug 8 2026

***Monday/Tuesday***

A 500-mb high looks to be overhead Monday morning, with the main jet
stream flow to the north of the forecast area. GEFS and EC ensembles
suggest that this feature will remain in place through Tuesday. Weak
surface flow underneath the high would allow for higher temperatures
to continue Monday and Tuesday, with highs forecast in the upper 90s
to mid 100s both days. Heat index values in the 100s are possible as
well, which may indicate the potential for Heat Advisories being
needed. However, a couple things that lower confidence for a
Heat Advisory include thunderstorms driven by an 850-mb low
across the Rockies, and a cold front that may come through the
area as early as Tuesday afternoon according to forecast
guidance. That being said, thunderstorm potential appears to be
relatively scattered, and begin during the evening hours both
days. Additionally, northerly winds on Tuesday don`t look to be
strong enough to produce significant cooling. As such confidence
in a Heat Advisory being needed is around 30% each for Monday
and Tuesday.

Regarding thunderstorms on Monday and Tuesday, GFS, EC, and NAMNST
soundings show inverted-V profiles up to around 500-mb. So, while
sfc-500mb wind shear is favored to remain 30 kts or less, there is
potential for microbursts with thunderstorms. Locally high winds
around 60-70 mph would be possible under this scenario. Even so,
confidence in severe weather occurring is about 5-10% for each
Monday and Tuesday. It is also important to note that relative
humidities (RH) may drop below 20% both days, particularly across
portions of East-Central Colorado, and West-Central Kansas. This is
nearing criteria for critical fire weather conditions (15% or less),
though wind gusts above 20 mph seem unlikely at this time. Thus,
confidence in critical fire weather conditions being in place is
less than 5%. However, lightning from thunderstorms may serve as an
additional source for fire starts Monday and Tuesday.


***Wednesday-Saturday***

Model guidance begins to diverge by Wednesday. There are indications
that a stronger cold front may come through the area associated with
a strengthening trough in Southeast Canada. Forecast guidance
suggests that this will place highs in the low to mid 90s Wednesday,
and 70s and 80s Thursday through the end of the week. Even so,
ensemble guidance appears to be in favor of a ridge axis remaining
in place over the forecast area, with troughing across the Western
United States. This may suggest the potential for the warmer end of
these ranges being experienced for highs. Persistence of the 850-mb
low across the Rockies along with troughing to the west at 500-mb
may allow thunderstorms to develop during this period as well.
Confidence in severe weather occurring during this period is
relatively low, as sfc-500mb wind shear is primarily less than 30
kts according to GFS and EC model soundings. Additionally, LREF
guidance suggests that most days in this range have less than a 50%
chance of experiencing vertical wind shear greater than 30 kts. The
exception is Thursday, where there is up to a 60% chance for greater
than 30 kt shear in Southwest Nebraska. Even so, confidence in
severe weather occurring during this period is around 5% or
less.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1141 AM MDT Sun Aug 9 2026

VFR conditions forecast for the TAFs. Winds will be light and
somewhat variable for both sites. However thunderstorm
development will impact winds at both sites. Current model data
indicates wind gusts of 30-40 kts with thunderstorms; worst case gusts
would be 60 kts. At this time do not have enough confidence to
place a mention in the TAFs aside from the VCTS. Best time for
KGLD to be impacted by wind gusts would be 3-5z. KMCK may be far
enough north to not be impacted by thunderstorm winds.

Otherwise there may be fog near KMCK overnight through 14z.

&&

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

&&

$$

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