954
FXUS63 KGLD 202028
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
228 PM MDT Fri Sep 20 2024

.KEY MESSAGES...

- Showers and thunderstorms will develop over majority of the
  Tri-State area this weekend. Both severe weather and flooding
  chances are very low (<5%).

- Low temperatures in the mid to upper 30s are forecast for
  eastern Colorado by Monday morning.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 218 PM MDT Fri Sep 20 2024

Current observations continue to show some streaks of mid-level
moisture streaming from the southwest with storms developing in
Southwestern Kansas. The Tri-State area is more in a dry streak
which is keeping cloud cover and precip chances low. There should be
some sprinkles and showers for Greeley, Wichita, Logan, and Gove
counties, but not anything that should be impactful. This evening
and tonight, skies should clear out with the moisture stream
shifting more east/south. Winds should lower to around 10 mph. Even
with the clearing skies and lowering winds, lows are forecast to
remain fairly warm in the 50`s and 60`s as the southeasterly flow
across a majority of the area has brough dewpoints in the 50`s and
60`s to the area.

Tomorrow, the upper low currently near the CA/NV border is forecast
to shift east to near the Four Corners region during the day. This
will help push a surface cold front through the area during the
morning. With the frontal passage, winds will strengthen to 20-25
mph with gusts up to 35 mph and bring in some cooler and drier air
to the area. Meanwhile, additional mid-level moisture is forecast to
stream in from the northwest and help saturate the air column. The
issue is that by the time the air saturates, the front is forecast
to be in the southern part of the area. This will limit the better
rainfall to the far southern portions of the area. So for most of
the area, temperatures would likely peak around the noon hour, and
then remain steady or cool as cloud cover increase and colder air
advects in from the north. Rain looks to be limited through the
afternoon except for far southern portions of the area.

For the evening and overnight hours, the upper low is forecast to
begin swinging through the region. This will provide some upper
level support for showers and storms to develop along the higher
terrain in Eastern Colorado. Showers and storms should then move
through across the area with the saturated air unless the higher
pressure can move in quickly and undercut storms. Once this line
moves through the area, precipitation chances and amounts are
forecast to drop off as subsidence begins to take over and drier air
is forecast to move in the mid-levels.

Sunday, a dreary day is forecast as the lower levels remain
saturated and allow for fog and mist to develop. With the cooler air
and persistent cloud cover, highs are forecast to only be a few
degrees warmer than the lows in the 50`s. Temperatures may end up
being dictated by how low/high the dewpoints are. Winds are forecast
to slowly lower through the day as the higher pressure moves over
the area. The evening and overnight hours are forecast to see skies
slowly clear as the upper low pushes east of the area and drier air
moves in. This could cause a potential issues where parts of Eastern
Colorado could hit 36 degree or less for the first time this season.
Looks to be dependent on how low the dewpoints will get with clear
skies and light winds.


&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 1255 PM MDT Fri Sep 20 2024

The latest extended guidance from the GFS/ECMWF do start off the
period on Monday consistent showing a 500mb shortwave trough sliding
southeast through the central Rockies. The models then do break off
as to the evolution of the system as it slides to our S/SW. The GFS
carries the system through the Kansas area as an open wave Monday
night into Tuesday morning, followed by amplified ridging coming
eastward through the Rockies. This will provide the CWA with mainly
dry conditions for most of Tuesday onward. The current ECMWF however
allows the shortwave to move slower into Tuesday, forming a cutoff
low over northern Texas then lifting northeast towards the southern
Kansas border late in the week.

The latest NBM guidance does take into account both models initially
as the trough approaches the CO/KS border Monday night with a 15-30%
chance for precip. Highest pops closest to the Colorado tapering off
into the central CWA. It does look like the consensus is for the
cutoff system to occur then slide south of the CWA Tue-Tue night,
keeping a 15-20% chance over S/SW zones into Tuesday night. This
does follow previous runs yesterday at this time, so will stick with
this consistency for now. The bulk of the QPF will stay south of the
area closest to the formed cutoff low. Late Thursday into Friday as
the system lifts northeast, the northern periphery of the system
could bring enough moisture into eastern zones that could trigger a
few rw/trw(15-20%).

For temps, upper 60s to lower 70s expected for highs Monday and
Tuesday due to expected clouds/rain, will give way to mid 70s
Wednesday, trending warmer to the upper 70s and lower 80s for most
for next Thursday and Friday as the aforementioned upper ridge works
east off the Rockies and southerly surface flow persists area-wide
these days. Lows in the 40s Monday night will trend warmer as well
with upper 40s west into the mid 50s east for the end of next
week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1104 AM MDT Fri Sep 20 2024

For KGLD & KMCK... VFR conditions are forecast through the
period. There is a less than 10% chance of storms this afternoon
and evening with the forecast keeping storms well southeast of
the airports. The low level jet is forecast to develop tonight
across the area around 03Z and persist until around 12-15Z when
a front passes through the area. Winds will then shift from out
of the south, to out of the north and strengthen to 20-25 kts
with gusts to 35 kts. A few sprinkles may occur at the very end
of the period.

&&

.HYDROLOGY...
Issued at 323 AM MDT Fri Sep 20 2024

The forecast continues to call for precipitation this weekend
with the low levels becoming saturated through low level
moisture advection from the southeast and mid-level advection
from the southwest.

However, forecast amounts continue to trend down as the best
forcing does not appear to line up with when the air is most
saturated. The front is forecast to move through early Saturday
before the air can saturate. The best chance for rain during the
day Saturday is for southern parts of the area as the front
passes. Rainfall amounts and chances will be better if the front
stalls in the southern portion of the area. The next good chance
for rain is overnight Saturday into Sunday as the upper low
swings through and brings a chance for showers and storms off
the higher terrain in Eastern Colorado. However, a mid-level
dryslot may interfere with this round and weaken chances.

Amounts around a quarter of an inch or less are suggested with
this kind of a setup for the whole event. If the forcing and
moisture align better, than amounts of one to two inches become
more likely, especially if the front stays over southern parts
of the area. Flooding looks to be possible in scenarios where
the front over performs and produces a couple of inches early,
mainly from Wallace, KS to Norton, KS and south. Overall chance
is around 5 to 10%.

&&

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

&&

$$

SHORT TERM...KAK
LONG TERM...JN
AVIATION...KAK
HYDROLOGY...KAK