000
FXUS64 KOUN 240849
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
349 AM CDT Wed Apr 24 2024

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

.SHORT TERM...
(Today and tonight)
Issued at 348 AM CDT Wed Apr 24 2024

Scattered showers (and eventually thunderstorms) will continue to
develop this morning as isentropic ascent/warm advection
increases north of the stalled front (located near the Red River).
Any convection that develops should move to the east-southeast.
The most intense cores may produce hail. Abundant cloud cover and
light easterly winds will result in a cooler day for locations
north of the front (upper 60s to mid 70s deg F). South of the
front, western north Texas will see warmer conditions (upper 70s
to low 80s deg F).

By late afternoon into the early evening, isolated thunderstorms
may develop across the Texas panhandle (near Lubbock). If
thunderstorms develop, they may move into western north Texas this
evening with a threat for large hail and damaging wind gusts.

Late tonight, the front will begin to lift back to the north as a
warm front as winds veer back to the south. Increasing isentropic
ascent/warm air advection in tandem with a strengthening low-
level jet will result in the development of showers and
thunderstorms, especially across the northern half of Oklahoma.
Elevated instability will be sufficient for hail with the most
intense cores.

Mahale

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 348 AM CDT Wed Apr 24 2024

Thursday into Thursday Evening: Elevated thunderstorms may
persist across the north central Oklahoma throughout much of the
day with continued isentropic ascent/warm air advection. By
Thursday afternoon, a shortwave trough will lift into the Plains
with increasing synoptic-scale ascent. At the surface, a dryline
will sharpen across the Oklahoma and Texas panhandles as a low
deepens across eastern Colorado/western Kansas. Even given these
synoptic-scale features that would be favorable for convection,
there remains uncertainty on the amount of daytime/early evening
convection that will develop along the dryline. Forecast soundings
indicate a subtle capping inversion at ~800 mb, which may
partially explain why several parameterized and convective-
allowing models have no convective initiation during this period
(some of the CAMs may also be overmixing dewpoints east of the
dryline). Nevertheless, there remains the potential for at least
isolated supercell development given the synoptic-scale pattern
(e.g., a couple HREF members do have convective initiation). If
storms develop, they would move eastward into western Oklahoma
during the evening with an environment favorable for large hail,
damaging wind gusts, and tornadoes.

Thursday Night/Friday Morning: Overnight, thunderstorms become
more likely as the trough lifts across the area. Upscale growth
into line segments may occur given the large-scale ascent in
tandem with the eastward acceleration of the dryline/Pacific
front. Damaging wind gusts will be the primary hazard, including
with any mesovortices. In addition, given the large amount of low-
level shear due to a 50 knot low-level jet (e.g., ~35 to 40 knots
of 0 to 1 km shear), tornadoes are possible within any QLCS
structures or embedded supercells. These thunderstorms will sweep
across the area from west to east through Friday morning.

Friday Afternoon: As the trough lifts toward the Midwest, the
trailing dryline will stall, likely near or east of I-35. While
synoptic-scale ascent will be lacking (perhaps even synoptic-scale
subsidence in the wake of the exiting trough), the environment
ahead of the dryline will have little or no cap present by
afternoon. Therefore, isolated to widely scattered thunderstorms
are possible if there is enough low-level convergence for
convective initiation. These storms would likely be supercells
with the threat for large hail, damaging wind gusts, and
tornadoes.

To the west of the dryline, critical fire weather conditions will
likely develop across northwest into west central Oklahoma.
Southwest winds at 20 to 25 mph with wind gusts in excess of 30
mph are expected. This will be combined with relative humidity
values around 15%.

Saturday: Saturday still has the potential for a significant
severe weather event across the entire area as a negatively-tilted
trough lifts into the Southern Plains. At the surface, low-level
moisture will advect back to the northwest. The dryline will
sharpen near or just east of the Oklahoma/Texas state line as a
surface low deepens in response to the approaching trough.

The greatest uncertainties that will affect the magnitude of the
severe risk continue to be the timing of the shortwave trough and
any early convection. There is a signal among deterministic model
and ensemble members that early convection may occur, which would
likely temper the potential severity of the event (i.e., prevent
the worst case scenario). Both the 24/00Z GFS and ECMWF suggest
this might be due to warm air advection at around 700 mb. If the
morning convection does not occur and the trough is timed with
peak heating, a high-end severe weather event is likely Saturday
afternoon and evening. Even if this worst case scenario does not
occur, there will still be the risk of severe weather with the
risk for large hail, damaging wind gusts, and tornadoes in highly
sheared, moist environment (significant severe weather can occur
on cloudy days if the ingredients are present and the storm mode
is favorable). Flooding may also be a risk by Saturday with the
potential for multiple rounds of storms.

Sunday: Strong to severe thunderstorms may persist across
southeast Oklahoma on Sunday. A slightly less humid and cooler
air mass is expected elsewhere.

Monday and Tuesday: There will be a low chance of showers and
thunderstorms across southeast Oklahoma with the low- level
moisture/remnant front in close proximity.

Mahale

&&

.AVIATION...
(06Z TAFS)
Issued at 1010 PM CDT Tue Apr 23 2024

MVFR ceilings are expected to form tonight over most central and
southern Oklahoma TAF sites and at KSPS. Showers and scattered
thunderstorms are expected before sunrise and will persist through
the morning over these areas. Scattered showers and thunderstorms
may reform during the evening with IFR ceilings at times. A weak
front will shift winds from south to northeast as it moves slowly
toward the Red River tonight.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  70  61  76  64 /  50  70  60  90
Hobart OK         70  62  79  60 /  30  50  40  80
Wichita Falls TX  78  67  80  65 /  20  30  20  90
Gage OK           67  54  82  54 /  40  40  50  50
Ponca City OK     71  57  72  62 /  40  80  90  90
Durant OK         78  66  79  66 /  40  30  20  60

&&

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

$$

SHORT TERM...10
LONG TERM....10
AVIATION...09