660
FXUS63 KGLD 031722
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1122 AM MDT Fri May 3 2024

.KEY MESSAGES...

- Thunderstorms will develop along a cold front surging
  southeastward through the area late this afternoon and
  evening. Damaging winds and instances of large hail appear to
  be the primary hazards. Isolated supercells capable of
  producing all hazards may develop in advance of the front,
  south of Highway 40 in CO/KS, between 4-8 pm MDT.

- Fire weather concerns return Monday through Thursday for most
  of the Tri-State area, but favor along and south of I-70.

- Thunderstorms, a few of which may become strong to possibly
  severe, will be possible Monday afternoon/evening.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 345 AM MDT Fri May 3 2024

Overview: An upper level low centered invof the Saskatchewan-
Manitoba-North Dakota border this morning will slowly progress
northeastward across central Manitoba/Ontario (today-tonight)
and northward into Hudson Bay (Sat-Sat night).

Today-Tonight: Shortwave energy presently centered invof
southern Idaho will track eastward across southern Wyoming today
(rounding the base of the aforementioned upper low and broad
upper trough over the Northern Plains).. then lift northeastward
across South Dakota and Minnesota (tonight). A low-level
southerly return flow regime will be re-established in the lee
of the Colorado Front Range today.. as the MSLP-H85 height
gradient re-orients and tightens in response to the development
of a modest lee cyclone in Colorado (aided by the aforesaid
shortwave energy /DPVA/ approaching from the west).
Strengthening southerly flow will advect seasonably rich low-
level moisture (4-9C 850 mb dewpoints) beneath a pronounced
elevated mixed layer (8-9 C/km H7-H5 lapse rates) in place over
eastern Colorado and northwest Kansas.. yielding 500 J/kg
(Colorado) to 1500 J/kg (western Kansas) MLCAPE at peak
heating. Guidance indicates that an evaporatively-cooled
airmass /effective cold front/ emanating from fairly widespread
precipitation over portions of Wyoming and the Nebraska
Panhandle will surge southeastward through northeast Colorado
late this afternoon (~00Z) and northwest Kansas by ~03-04Z this
evening.

Simulated reflectivity forecasts via recent runs of the HRRR
and NAM NEST indicate that convection will [1] rapidly develop
along the effective cold front in northeast CO late this
afternoon and [2] increase in coverage along the front as it
progresses into an increasingly unstable airmass (with southern
and eastern extent) this evening.. where damaging winds and a
few instances of large hail are anticipated to be the primary
convective hazards.

However, guidance also suggests that isolated convection..
possibly discrete supercells.. will develop in advance of the
front along the Arkansas River Valley in southeast Colorado
(Bent-Prowers-Kiowa counties) ~22Z, progressing eastward into
western Kansas ~23-02Z. *If* discrete supercells develop, all
convective hazards are on the table.. mainly in the 23-02Z time
frame.. before said updrafts are consumed/cannibalized by the
southeastward advancing cold front.

Sat-Sat night: Benign weather and cooler temperatures will
follow, on Saturday.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 243 AM MDT Fri May 3 2024

For the long term period, active weather is possible Monday
with generally average temperatures and daily precipitation
chances through the week.

Sunday is forecast to have an upper low/trough push into the
Western CONUS and move towards the Four Corners region.
Meanwhile, moisture is forecast to stream in from the south near
the surface as a surface low develops along the Front Range
while additional moisture moves in over the mountains. This
could lead to a fairly cloudy day where temperatures will cap in
the 60`s, though any area with sun for a couple of hours should
reach the 70`s, especially near and west of the Colorado
border. Showers and a few storms could develop with all the
moisture in the area, but the severe threat should be near zero
with instability still forecast to be fairly low with MUCAPE
generally near or less than 500 J/KG.

Sunday night through Monday is when conditions are forecast to
get more interesting as the upper low moves near and over the
area along with the surface low. One the first things to watch
will be the winds. With the speed of the upper trough and how
deep it could get, the pressure gradient and height gradients
could get fairly strong and allow winds to exceed 30 mph and
gusts exceed 55 mph starting as soon as Sunday evening. However,
confidence is currently only around 40% as ensembles show a
fairly high spread in 500mb tracks and progression. This in turn
also affects the surface low and it`s progression. One of the
main things that could keep the winds on the lower side is that
some of the ensembles are pulling the trough north. This would
shift the stronger gradients more towards Nebraska and the
Dakotas. Our winds would still strengthen above 20 mph with
gusts above 35 mph, but high wind criteria warnings would become
unlikely. The chances for the high winds then increase the
further south the track of the main surface low goes (farthest
south looks to be around the Southern KS border). In either
scenario, low temperatures Sunday night will likely stay in the
50`s with the moisture, cloud cover, and increased winds over
the area.

For Monday, conditions are fairly variable given the surface
low has solutions with tracks that go through the area during
the day or hug the KS/CO border along with tracks that are north
of the area and south of the area (I am referring to the
deepest part of the surface low). In scenarios where the low
moves through the area and is to the east during the day,
moisture would lower across the area, increasing critical fire
weather chances and lowering storm and severe storm potential.
In solutions where the low and front stay over or near the area,
critical fire weather conditions become less likely while storm
and severe storm chances increase. Winds approaching high wind
warning criteria become more likely as well. Would could be of
particular concern is if the low is south of the area and the
warm front is draped across the area. We then begin to face
scenarios similar to recent events with a warm front and a
dryline/cold front acting as storm genesis points. High
temperatures are forecast to be in the 60`s behind the system
and in the 70`s and maybe low 80`s ahead of the system. Monday
night remains just as varied with conditions ranging from
calming and dry, to stormy with high winds. Currently, don`t
have a good inclination towards any one scenario so have gone
with a more neutral forecast and am waiting for better consensus
in guidance and maybe better sampling of the system (since it
is still offshore).

Tuesday and Wednesday look to be more "average day" with near
average temperatures in the 60`s and 70`s and some small chances
for precipitation as the upper pattern is forecast to turn more
to a broad trough with the initial disturbance pushing east
while the trough as a whole spins over the Northern Plains. Will
need to watch for critical conditions south of I-70 with the
drier air over the area dropping RH into the teens.

For the end of the work week, currently forecasting near
average conditions in a broad trough pattern. Guidance is split
on whether the upper trough just pushes off to the east or if a
small low splits off and retrogrades west. In either case, there
is the possibility of another front if the trough is strong
enough as it pushes off to the east, though there may not be
much moisture available for storms to work with.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1118 AM MDT Fri May 3 2024

VFR expected to prevail at both KGLD and KMCK through this
afternoon. Isolated storms may develop in northwest Kansas late
this afternoon, but probability of directly impacting the
terminal is low. Tonight, a strong cold front will move through
both terminals between 02-04z. The front will be accompanied by
thunderstorms and strong surface winds shifting to the north.
Some visibility restrictions due to blowing dust will be
possible along and immediately behind the front. Storms will
continue south during the late evening with surface winds
gradually diminishing through the overnight.

&&

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

&&

$$

SHORT TERM...BV
LONG TERM...KAK
AVIATION...024