889
FXUS63 KDDC 072116
AFDDDC

Area Forecast Discussion
National Weather Service Dodge City KS
416 PM CDT Fri Jun 7 2024

.KEY MESSAGES...

- Slight Risk (Level 2 of 5) Severe thunderstorms this evening
  with damaging straight line winds 60-70 mph the greatest risk.

- Slight Risk (Level 2 of 5) also for Saturday evening, as a
  larger thunderstorm complex likely to develop with severe wind
  gusts and a greater probability of 1"+ rainfall across much of
  southwest Kansas (30 to 50% chance).

- Shower and Thunderstorm chances continue, albeit lower, Sunday
  and Monday, but core of highest rainfall likely just south of
  southwest Kansas.

&&

.UPDATE...
Issued at 414 PM CDT Fri Jun 7 2024

** MESOSCALE DISCUSSION **

Surface-based thunderstorms were developing along a leeside
trough axis where boundary layer convergence was greatest within
region of 0-3km AGL lapse rates greater than 9 degC/km. Kansas
State mesonet observations of dewpoints out west were higher
than HRRR, which has a bias of over-mixing dewpoints after a wet
period. For instance, 21Z dewpoints were in the 62-64F range as
far west as a Lakin to Sublette line. Initial thunderstorms were
forming in the drier airmass, but once storms tap in to the
lower to mid 60s dewpoints, we expect the severe weather risk to
increase, especially as individual cells begin to interact and a
cold pool becomes established with damaging straight line winds
being the most likely risk, particularly in the 23Z to 02Z time
frame...which is the most likely 3-hour window for severe across
our forecast area. The new Severe Thunderstorm Watch #396
includes all 27 counties of the NWS DDC forecast area, which
runs through 03Z (10 PM CDT).

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 237 PM CDT Fri Jun 7 2024

The main forecast challenge will be severity and timing of severe
storms along with precipitation amounts for the first mesoscale
convective system (MCS) event this evening.

Early morning showers and weak thunderstorms moved into central
Kansas early in the afternoon with temperatures recovering into the
mid 80s as far east as Hays to Dodge City. West toward the Colorado
line, afternoon temperatures were warming well into the lower to mid
90s. Dewpoint temperatures were holding on nicely with afternoon
boundary layer mixing not having much impact on lowering
dewpoints...at least through 1830Z. Surface wind convergence along
the leeside trough will continue to strengthen through the afternoon
across far southeast Colorado, which is where initial thunderstorm
development is expected to occur. Most of the convection-allowing
models (CAMs) have the first storms developing in the 20-21Z time
frame (3-4PM CDT) with further development into far southwest and
west central Kansas not long after.

If the surface dewpoints do not mix out as much as the HRRR model
indicates, we will likely see scattered severe storms not long after
convective initiation from Elkhart northeast to Garden City up to
Scott City. Forecast hodographs do support at least some modest
storm organization, including a marginal supercell or two, however
temperature-dewpoint spreads of 35+ degrees (F) will strongly favor
outflow dominant storms and a transition to quasilinear structure(s)
as cold pools become more prevalent. A few wind gusts in the 65 to
70 mph range will be possible, and while a large hail threat will
exist with more discrete storms, the high wet-bulb zero heights and
large evaporative cooling potential early in the event will likely
limit very large hail. If we see storms later in the evening tap
upper 60s dewpoints along/east of Highway 283, the probability of
severe events will ramp up...at least until boundary layer cools off
too much after sunset.

Going in to Saturday, cool northeasterly winds will likely prevail
across much of western Kansas in the wake of tonight/early Saturday
morning`s MCSs, therefore the degree of warmup in the afternoon is
at least a little bit in question. The latest NBM 50th percentile
temperatures for Saturday afternoon are in the mid to upper 80s
along and north of the Arkansas River (89 to 93F south), which is a
good forecast for now, because if clouds do clear out, the early
June insolation should help temperatures rebound quickly, despite
the easterly winds. This will set the stage for what looks to be a
fairly impressive MCS later Saturday Night (more on that in the Long
Term section).

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 237 PM CDT Fri Jun 7 2024

At the onset of this Long Term Period, Saturday evening,
strong/severe thunderstorms will likely be underway across eastern
Colorado about to move into western Kansas. Nearly every model, both
CAM and non-CAM, shows a substantial MCS signal moving across west
central/southwest Kansas, and for that reason, POPs have been
increased to 70-80% for the Saturday Night period. The Storm
Prediction Center has upgraded the severe outlook to a Slight Risk
(Level 2 of 5), but there is some support for an even higher risk
outlook if models continue to show such strong support, backing up
traditional conceptual models of early-mid June western Kansas MCS
patterns. Low level moisture will not be a problem, along with low
level winds from the east-southeast providing long moisture
transport vectors into MCS(s). Much of the DDC CWA is within the
latest WPC QPF of 1"+, including Dodge City and Garden City. The
west-northwest to east-southeast axis of highest QPF is still likely
to shift slightly to the south or north, however any shift will not
likely be by much.

After Saturday Night`s system, cooler, more stable air will will
follow on Sunday which will likely push much of Sunday evening`s MCS
to the south of our southwest Kansas region. For that reason, POPs
Sunday Night will be highest in the far southwest portion of our
area (Morton County). On Monday/Monday Night, global models are
showing a mid level disturbance in vicinity of southwest Kansas down
into West Texas, which will likely aid in another MCS or two, so
POPs will remain in the forecast (mainly 30-40%). This mid level
weakness will likely then move east/southeast of our forecast area
Tuesday which will result in a drier forecast. Toward the end of
this forecast period, temperatures should warm back up as an upper
level ridge axis expands across New Mexico into southern Colorado
and adjacent West Texas/southwest Kansas

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1149 AM CDT Fri Jun 7 2024

Small clusters of showers and weak thunderstorms were pushing
east away from DDC and HYS terminals at the onset of this TAF
period. Winds will increase out of the south to southwest during
the afternoon, topping out 20 to 25 knots sustained for a few
hours late in the afternoon prior to surface-based thunderstorms
developing across far southwest Kansas. This new TAF will refine
the thunderstorm forecast, going with a 3-hr period of VCTS in
the early to mid evening hours. Winds are expected to be quite
gusty near thunderstorms. By late evening, thunderstorm risk
will move east of southwest and west central Kansas with fairly
light winds expected the remainder of the night.

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...Umscheid
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Umscheid