252
FXUS63 KGLD 012002
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
202 PM MDT Wed May 1 2024

.KEY MESSAGES...

- A few thunderstorms may develop in northwest Kansas late this
  afternoon, south of Interstate 70 and east of Highway 25. An
  isolated supercell is possible, mainly between 4-8 PM MDT,
  capable of producing large hail, damaging winds and perhaps a
  tornado.

- More widespread thunderstorms will develop north of I-70 in
  northwest KS and southwest NE this evening. A few severe
  storms capable of producing large to very large hail are
  possible, mainly between 8pm-3am MDT. Storms will rapidly exit
  the region (into south-central and southeast NE), thereafter.

- Scattered thunderstorms are anticipated to develop over
  portions of northeast CO and northwest KS Friday afternoon.
  Severe storms capable of producing damaging winds are
  possible, mainly late Fri aft/eve, when storms may increase in
  coverage and track SE toward southwestern and south-central KS.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 200 PM MDT Wed May 1 2024

Most of the area remains cloudy and cool this afternoon, with
some clearing noted on satellite across southern and western
portions. A warm front was surging northward across southwest
Kansas, and at 19z was roughly along a Garden City to Jetmore
line. Meanwhile, a cold front was moving out of the Colorado
Front Range in response to an upper level shortwave trough.

Not much has changed from previous thinking. The warm front to
the south has a chance of reaching southern Logan and Gove
counties by later this afternoon, which would potentially put
them in the warm sector which is very unstable. Latest RAP
analysis shows up to 3000 j/kg in that area with bulk shear
values of up to 60 kts. In fact, latest runs of the HRRR and RAP
show initiation occurring by 21-23z around the Lake Scott area.
Any discrete supercell in that location would be capable of
producing large hail, damaging winds and perhaps a tornado.
Those storms seem to fade by 02-03z, and attention turns to the
northwest where more widespread convection will be getting
underway in response to the upper dynamics and surface cold
front. While storms may initially be surface based, expecting
mostly elevated storms this evening across much of northwest
Kansas and southwest Nebraska. MUCAPE values will be around
1500-2500 j/kg and shear values around 60 kts. So elevated
supercells will certainly be possible, capable of producing
large to very large hail and perhaps a few isolated damaging
wind gusts. This risk will move east through the late evening
hours and spill into the overnight hours in far eastern areas
like Norton and Graham counties, finally exiting to the east by
07-09z. There will also be a risk of excessive rainfall in the
northeast part of the area, particularly from McCook to Oberlin
and Norton, where mean rainfall amounts are around 1 inch and
90th-95th percentile rainfall amounts are in the 1 to 2 inch
range. Low temperatures will range from the upper 30s in
Colorado to the middle 40s in north central Kansas.

Thursday will be breezy in the morning, then diminishing winds,
mostly sunny and mild in the afternoon with highs in the 60s. A
weak shortwave trough comes out of Colorado in the afternoon and
evening hours bringing a chance for scattered showers and
perhaps an isolated thunderstorm through the evening and
overnight, with best chances in northeast Colorado. Low
temperatures will range from the upper 30s to lower 40s.

The pattern does not change much on Friday. Another shortwave
trough moves out of the Rockies in the afternoon, a bit stronger
than the one on Thursday, with increasing chances for showers
and thunderstorms with the associated surface cold front.
Showers and storms will be likely by Friday night as the front
moves through the area. Surface based instability will be rather
limited, generally under 1000 j/kg is forecast ahead of the
front, but deep layer shear values will be 40-50 kts. Those
parameters may be sufficient for a few severe storms capable of
producing hail up to quarter size and gust winds. Instability
rapidly decreases after about 03z as the front races southeast,
probably ending the severe threat. High temperatures will be in
the upper 60s to lower 70s and lows Friday night ranging from
the lower 30s in northeast Colorado to the middle 40s in north
central Kansas.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
Issued at 149 AM MDT Wed May 1 2024

The area is under southwesterly flow aloft at the start of the long
term period with low pressure centered over Saskatchewan/Manitoba on
into Ontario, upper level ridging building across the western CONUS,
and our next low pressure system coming into view off the coast of
the Pacific Northwest. At the surface, a front is forecast to push
through during the Friday afternoon-Friday evening timeframe. With
this, expecting gusty southerly winds shifting northerly and
shower/storm chances up to ~50-70% working in from the west with QPF
ranging generally from a quarter to three-quarters of an inch,
locally higher amounts possible.

Heading into the weekend, upper level ridging will build back in
with flow becoming briefly zonal before approach of the next system
has flow returning southwesterly. A disturbance skirts south of the
area, then east on Sunday, and with the low level southeasterly flow
allowing for increased moisture into the area, at least expect to
see some increased cloud cover but also some shower/thunderstorm
chances (up to around 20-30%).

Guidance is coming into somewhat better agreement with regards to
timing/placement of the early week system. Latest deterministic
guidance shows the upper low centered in vicinity of the Great Basin
Sunday evening before crossing the Rockies throughout the day Monday
within an upper level trough becoming negatively tilted. Still
monitoring potential for multiple hazards with this system,
including gusty southerly to southwesterly winds ahead of it and
associated increased fire weather concerns/possible blowing dust
concerns. Additionally will be looking at the potential for strong
to severe thunderstorms across eastern portions Monday afternoon-
evening where the dryline is forecast to set up with instability
reaching around 1000-2000 J/kg and 0-6 km shear values in the 50-70
knot range. A frontal passage will then sweep through the area, with
gusty post-frontal winds into Tuesday. Again will be looking at
potential for fire weather concerns.

For temperatures, highs are forecast generally in the low-mid 70s
Friday, mid 60s to lower 70s Saturday before warming into the 70 to
low 80s thereafter. For low temperatures, the forecast calls for low-
mid 30s to middle 40s Saturday morning, low-mid 40s Sunday morning,
middle 40s to middle 50s Monday morning, and 40s Tuesday, Wednesday
mornings.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1118 AM MDT Wed May 1 2024

MVFR ceilings likely to prevail at both KGLD and KMCK through
the afternoon, though a brief improvement to VFR possible at
KGLD in mid afternoon. Tonight, scattered to numerous showers
and thunderstorms will develop with an upper level disturbance.
Both terminals likely to be impacted by  lower ceilings and
rain. There is also a slight risk for hail with any stronger
thunderstorm. Convection expected to end around 06-07z, but low
ceilings persisting through the overnight. A return to VFR
expected at both terminals early Thursday morning.

&&

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

&&

$$

SHORT TERM...024
LONG TERM...CC
AVIATION...024