245
FXUS64 KOUN 150723
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
223 AM CDT Wed May 15 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Today and tonight)
Issued at 221 AM CDT Wed May 15 2024

An area of convection is noted across south central Kansas this
morning, slowly trundling east-southeastward. There`s a chance that
far north central Oklahoma sees some lightning and heavy rain from
this complex around daybreak, but no further impacts are expected.

More impactful convection is expected to develop later this
afternoon and evening across our area. A surface trough will extend
from northwest Oklahoma off to the southwest with at least some
eastward push of the dryline from the panhandle during the
afternoon. Boundary layer moisture will be modest, particularly in
the vicinity of the surface trough where convection initiation is
likely to occur. Still, strong surface heating to near 90 degrees
and MLCAPE rising to around 1,500 J/kg will contribute to the
development of scattered thunderstorms by midafternoon.

Initial convection seems likeliest across western Oklahoma and
adjacent western north Texas and may be somewhat outflow-dominant
given dewpoint depressions nearing 30 and weak low-level shear. With
time, mid-level shear will increase as a shortwave trough moves
overhead. This will increase updraft organization and potentially
foster transient supercell structures with one or two storms. The
majority of the convective hazard is likely to stem from upscale
growth of the initial convection, particularly as 0-3 km shear
increases to 30 knots from the west-southwest in the face of cold
pool amalgamation. With at least some 30-50 knot winds within the
convection-bearing layer and DCAPE values approaching 1,200-1,500
J/kg, damaging wind gusts will be the primary hazard from this
cluster. HREF members such as the HRRR and NAM 3km explicitly show a
swath of 50-65 mph winds from western Oklahoma to north central
Oklahoma over the course of the evening as the cluster moves
northeastward. Large hail will also be a concern with transient
supercells, and modest tornado potential is possible across north
central Oklahoma in the evening in the vicinity of backed surface
winds east of the surface trough.

The LLJ will strengthen to about 40 knots out of the south near
sunset, which will promote continued development and maintenance of
convective clusters. While the severe threat may decrease (but
probably not diminish altogether) overnight as the surface layer
becomes capped, there is some potential for flooding as outflow from
the storms slowly drives the zone for development of new convection
southward overnight. By daybreak, the greatest storm chances are
likely to have migrated southward toward I-40.

Meister

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 221 AM CDT Wed May 15 2024

Another risk for severe weather will exist on Thursday, though this
one will be heavily modulated by the extent and nature of the storms
today and tonight. As mentioned at the end of the short-term
section, outflow from overnight storms will sink southward toward
the Red River by morning. This will be driven by continued
redevelopment of convection atop the cold pool north of the
boundary. By early afternoon, the boundary should be mostly cleared
from our area, with a potential exception being far southern
Oklahoma and especially western north Texas. Given the nature of the
setup, early afternoon initiation of severe storms along and south
of the boundary is expected as it potentially keeps trucking toward
I-20. The severe risk will be maximized in western north Texas,
where some surface-based risk will exist for large hail with
supercells. To the north, a reservoir of 1,000 MUCAPE is likely to
develop in the afternoon across most of our area atop a stable
boundary layer. This should lead to another widespread round of
showers and thunderstorms.

The party continues on Friday, which looks a lot like Thursday.
There should be some risk for strong to severe thunderstorms as
moisture return/evapotranspiration reload instability, but overall
buoyancy and shear are likely to be rather weak (500 mb flow will be
10-20 knots). Therefore, the severe risk will remain on the low end.

Finally on Saturday, the STJ stream/cutoff low that is responsible
for the active weather will depart to the east, with the subtropical
ridge quickly taking over. A quiet Saturday and Sunday look to be on
track. Some guidance (notably the GFS) tries to return the mid-
latitude jet over us by early next week, so the near-zero-PoP
forecast NBM is outputting seems overly optimistic. This will be
watched as a potential target of opportunity as guidance becomes
less dispersive.

Meister

&&

.AVIATION...
(06Z TAFS)
Issued at 1042 PM CDT Tue May 14 2024

Light winds expected overnight. Some increase in mainly high
clouds possible across the north. South winds increase Wednesday
morning with an increase in mid/high clouds. Afternoon storms
expected to develop across west/northwest Oklahoma and then spread
east during the evening hours tomorrow. Some MVFR conditions
expected with this activity.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  87  63  78  60 /  30  70  60  60
Hobart OK         90  61  77  57 /  50  70  70  60
Wichita Falls TX  90  63  77  61 /  10  60  70  60
Gage OK           89  56  76  54 /  60  70  50  40
Ponca City OK     86  61  77  59 /  40  80  70  50
Durant OK         87  66  80  63 /   0  20  40  60

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&

$$

SHORT TERM...04
LONG TERM....04
AVIATION...30