483
FXUS63 KGLD 290606
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1206 AM MDT Tue Sep 29 2026

.KEY MESSAGES...

- Scattered showers this morning will gradually increase in
  coverage and intensity through the day, becoming widespread
  tonight.

- A Flood Watch is in effect for the entire area starting
  tonight and continuing through the day on Thursday. While
  rainfall totals are forecast to generally be around 1-2"
  during that time, there is the possibility for some parts of
  the area to see 3-5" of rain.

- There is a marginal risk for severe thunderstorms Wednesday
  afternoon and early evening. Wind and hail will be the main
  hazards, but a brief tornado will also be possible.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 1200 PM MDT Tue Sep 29 2026

Upper low over southern California today will move into the
Four Corners region tonight, northern New Mexico and eastern
Colorado Wednesday and into the Tri State area Wednesday night.
Scattered showers this morning will gradually increase in
coverage from the south through the afternoon and evening,
followed by widespread rain after midnight through Wednesday
morning, with embedded areas of moderate to heavy rain during
that time. Models show 12-hour QPF (06z to 18z) of 1-2" across
much of the area but as much as 2-4" where training occurs. CAMs
do differ with how far north to bring the heavier rain totals,
with highest confidence south of Interstate 70. There will be
some risk of flash flooding during that time, if rain can fall
in a short enough period of time. A dry slot will overspread the
area from the south by mid to late Wednesday morning which may
temporarily result in a break in the rain, primarily south of
Interstate 70. However, scattered showers and thunderstorms will
quickly redevelop Wednesday afternoon with the upper low
directly overhead. REFS shows instability in southern and
eastern areas of 500-1000 j/kg and around 40 kts of deep layer
shear. If there is any clearing at all with the dry slot
instability could be higher. There is currently a marginal risk
for severe thunderstorms in those areas for wind and hail, and a
brief tornado may also be possible given the favorable set-up
of a closed upper low directly over the area enhancing 0-3 km
helicity values. Additional storms may be possible even into
Colorado, though instability will be limited further west. Any
severe threat will likely end early Wednesday evening with the
loss of instability, transitioning to scattered to numerous
showers and isolated thunderstorms through the rest of the night
as the upper low will be slow to move out. The heavy rain and
flooding threat will continue, with eastern areas somewhat
favored by the latest model runs Wednesday night (east of
Highway 83).

Temperatures through the period will be below normal due to
clouds and precipitation. Highs will be in the 60s to lower 70s
and lows mainly in the 50s.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 231 PM MDT Mon Sep 28 2026

Thursday through Friday:

Synoptically, the upper level trough will begin moving into the Tri-
State area Thursday morning. The majority of guidance indicates that
the center of the trough will track to the southeast of the County
Warning Area (CWA). By Friday, the system is expected to move out of
the CWA, leaving our upper level flow mainly from the northwest to
north.

At the surface, guidance indicates a boundary will move through from
the northwest, as well as a potential surface low to the southeast.
Expect breezy winds Thursday morning. Gusts of 30-45 mph are
currently forecast, with higher gusts expected across the Colorado
counties as well as areas south of I-70. Highs on Thursday and
Friday are forecast to be in the 60s to lower 70s.

The main hazard associated with this system will be heavy rainfall.
Storm total precipitation guidance shows 1-4 inches across the area
by Friday night into Saturday morning, with the majority of guidance
agreeing the higher amounts staying south of the Nebraska border.
However, some models, such as the ICON and GDPS, show a heavy
precipitation band of 4-5 inches right along the eastern border of
the CWA. The LREF shows a 10-25% probability of exceeding 3 inches
by Friday night. Ultimately, these totals will depend heavily on the
track of the upper level trough and potential surface low set up. A
farther north track would shift the the higher precipitation amounts
northward. A flood watch remains in effect for the CWA through
Thursday afternoon.


Saturday through Monday:

Synoptically, for the weekend into the early next week, upper level
flow returns predominantly for the northwest as the jet stream
remains near the US/Can border. Certain long range models, such as
the GFS, depict an upper level shortwave detaching from the main jet
and moving through the area Saturday afternoon. The ECMWF and
Canadian-NH models show a weaker, more subtle shortwave feature. The
Probabilities of Precipitation (PoPs) for the weekend remain under
10%. If this feature becomes strong then, it could increase our
precipitation chances.

High temperatures though the weekend are forecast to remain below 80
degrees. Saturday and Monday highs will be in the low to mid 70s
across the Tri-State area, with a brief "cooldown" into the 60s on
Sunday. Winds throughout the latter half of the long term period
look fairly breezy, with Saturday having the highest forecast gusts
in the 20-30 mph range as yet another boundary passes through.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1114 PM MDT Mon Sep 28 2026

Widely scattered showers overnight will gradually increase in
coverage through the day on Tuesday, eventually becoming
widespread Tuesday night. Flight categories will gradually
worsen, mainly at KGLD, where ceilings will reach MVFR by
Tuesday afternoon and IFR by Tuesday night. Confidence is lower
at KMCK, where ceilings may remain VFR until Tuesday night as
the main bulk of the showers stays south, but still could see
occasional MVFR ceilings there with any passing shower.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Flood Watch from Tuesday evening through Thursday afternoon
     for KSZ001>004-013>016-027>029-041-042.
CO...Flood Watch from Tuesday evening through Thursday afternoon
     for COZ090>092.
NE...Flood Watch from Tuesday evening through Thursday afternoon
     for NEZ079>081.

&&

$$

SHORT TERM...024
LONG TERM...Holdren
AVIATION...024