004
FXUS63 KGLD 182053
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
253 PM MDT Sat May 18 2024

.KEY MESSAGES...

- Thunderstorms will progress eastward from CO into western KS
  late this evening and overnight. A few severe storms are
  possible, mainly between ~7 PM and ~3 AM MDT.

- Severe storms capable of producing very large hail and
  damaging winds are possible in northwest KS and southwest NE
  Sunday afternoon, mainly between 3-9 pm MDT / 4-10 pm CDT.
  Latest guidance suggests that the severe weather threat in the
  Goodland CWA will be isolated in nature (i.e. not widespread).
  Thunderstorm coverage and severe weather potential increases
  with eastern extent into central KS. In other words, locations
  along/east of Highway 283 appear to be most at-risk.

- Cooler with frost concerns mid week.

- Active weather may return next weekend (Memorial Day Weekend)

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 245 PM MDT Sat May 18 2024

Through Noon on Sunday: Southern stream shortwave energy
presently located invof the southern CA/AZ border will track ENE
across the 4-Corners and central Rockies (tonight) and adjacent
portions of the High Plains (Sunday morning). Current and
recent runs of the HRRR and NAM NEST suggest that scattered
diurnal convection developing along the Palmer Divide this
afternoon will progress eastward to the CO/KS border this
evening.. continuing eastward across northwest KS overnight.
Guidance suggests that convection will increase in both coverage
and intensity this evening and overnight.. aided and assisted
(presumably) by DPVA attendant the aforementioned shortwave
energy (approaching from the SW-WSW) and strengthening low-level
(SFC-H85) warm advection over western KS.. when modest (albeit
increasing) airmass destabilization and strengthening deep layer
shear appear supportive of severe weather.. especially if
forcing is favorably/further augmented by convection itself
(e.g. an MCV).. mainly in the 03-09 UTC time frame. Wind gusts
up to 65 mph, quarter size hail and torrential rainfall appear
to be the primary hazards.

Sun PM-Sun night: Challenging forecast. Early morning
convection may significantly alter environmental conditions over
the Tri-State area during the day on Sunday, esp. in a pattern
characterized by a rather weak/broad/ill-consolidated lee
cyclone in southeast CO. Latest available guidance indicates a
scenario characterized by little/low convective coverage over
northwest KS and southwest NE Sunday afternoon, suggesting that
severe weather in the Goodland CWA may be isolated in nature
(i.e. not widespread).. and largely confined to the 21-03 UTC
time frame. Very large hail and damaging winds appear to be the
primary hazard(s). Broadly speaking, guidance continues to
indicate that convective coverage and severe weather potential
increases with eastern extent into central KS. In other words,
locations along/east of Highway 283 appear to be most at-risk.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 140 PM MDT Sat May 18 2024

The latest from the GFS/ECMWF continues to show potential for
rainfall/storms to impact mainly the northern portion of the CWA
from late Monday on into the end of next week.

With a blocking upper ridge over the eastern portion of the
country through the midweek timeframe, a strong trough will
swing east out of the north central Rockies late Monday, making
a slow trek eastward due to the blocking effects of the eastern
ridge. This system will eventually lift northeast along the
western periphery of the block. This will be followed by a
second shortwave taking a similar track although a bit more
easterly as guidance breaks down the ridge for the latter
portion of the week. Another amplified ridge build into the
Plains region for Thursday, shifting east to end the week. This
will be ahead of an elongated trough stretching through the
northern/central Rockies.

At the surface, low pressure sets up across southern Kansas
late Monday into Tuesday, lifting northeast with an associated
front. The position/track of this low will allow for a moist,
easterly upslope flow from the surface to 850mb and eventually
going northerly by Tuesday as the low lifts east. A similar
setup will occur late Tuesday into Wednesday for the second
system, although a bit further south based on both the
GFS/ECMWF. High pressure traverses the CWA Thursday/Thursday
night, with southerly flow setting up increased warmth/moisture
ahead of the end-of-week upper system. A surface low does work
off the Front Range in tandem with the upper system.

As a result, the main wx concerns are going to focus on the
potential for showers and storms. QPF/track through midweek puts
the best chances for rain north of the Interstate, especially
along/north of Highway 36. For Fri/Sat, the coverage is ahead of
the low/front that moves off the Front Range, but for areas
closest to the surface low.

The chances for storms will be focus mainly for the Mon-Tue
timeframe with the passage of the aforementioned shortwaves. The
end of week system does differ with timing/placement of
storms/QPF, but these could be problematic.

Decent instability along with increasing PW values from west to
east on Mon-Tue, will afford the potential for strong to severe
storms, especially Monday. SPC currently has a Marginal risk
for most locales east of the Colorado border. The surface low
passages to the south will bring in PW values of an inch plus,
especially east of Highway 83 which is closest to the surface
trough/front that extends into central Kansas. So, besides a
hail/wind threat, heavy rainfall/flooding potential will also be
high. Monday looks to be the main focus, with WPC having a
Marginal risk area out for locales north of highway 36 Mon
night-Tue. Please refer to the Hydro section below for more
details.

The passage of the second system Tuesday night into Wednesday
will bring about some cooler/colder air into western locales.
Areas in Colorado could see some frost potential, but will be
highly dependent on the extent of clearing from the exiting
system. Right now, western portions of Kit Carson/Cheyenne
counties are most prone.

For temps, with a cold front settling through the region during
the first portion of next week, looking for a downtrend in
daytime highs before rebounding for the latter portion of the
week. On Monday, mid 70s north through the mid 80s south are
expected. A wide range for Tuesday with mainly 60s north of the
Interstate and 70s south will give way to lower and mid 70s
area-wide for Wednesday. 80s Thursday drops to the mid 70s
through the lower 80s to end off the week.

Lows during this time will mainly range from the mid 40s west
through the lower and mid 50s east. Tuesday night will be the
coldest, with lower to mid 40s east of the Colorado border, with
upper 30s to around 40F for northeast Colorado.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1200 PM MDT Sat May 18 2024

VFR conditions will prevail through the afternoon. Sub-VFR
conditions associated with thunderstorms are possible at both
terminals this evening and overnight (~03-07 UTC at GLD, ~05-09
UTC at MCK). IFR (GLD) to MVFR (MCK) stratus is expected to
develop by or shortly after sunrise Sunday morning. Ceilings
are anticipated to lift to MVFR-VFR by late morning and early
afternoon. Thunderstorms are possible at both terminals late
Sunday afternoon and evening.. mainly in the 21-03 UTC time
frame, though.. confidence in thunderstorm location, coverage
and distribution is below average. Light northeasterly winds
will veer to the east this evening.. further veering to the
south late tonight and Sunday morning. Breezy SW winds will
follow, on Sunday afternoon.

&&

.HYDROLOGY...
Issued at 226 AM MDT Sat May 18 2024

Some potential does exist for torrential rainfall and isolated
flash flooding starting Saturday night/Sunday morning into early
portions of the new work week. The majority of the area,
especially western and southern portions have seen a lack of
rainfall in recent weeks and worsening drought conditions.
Overall main concern for any hydro issues lies to the east of
Highway 83 in Kansas where portions of Gove county for example
received 1-3 inches of rainfall earlier in the week. PWATS will
rapidly increase tonight around 1.25 inches and remain above 1
inch for the duration of the weekend. Overall widespread
flooding potential is relatively low as overall systems should
be fairly quick moving with fast Corfidi Vectors. The overall
main concern for any hydro related issues lies in multiple
rounds of heavy rainfall and any potential training locales.

&&

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

&&

$$

SHORT TERM...Vincent
LONG TERM...JN
AVIATION...Vincent
HYDROLOGY...Trigg