831
FXUS64 KOUN 221806
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
106 PM CDT Wed May 22 2024

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

.UPDATE...
Issued at 1048 AM CDT Wed May 22 2024

This morning`s storms have generally pushed the outflow boundary
further south than CAMS indicated (not a shock, as this is a
persistent CAM bias). Around 10:30 am local time, the synoptic
cold front can be found on satellite in an arc from the storms
near Madill/Tishomingo back to the southwest to near Abilene. It`s
still trucking to the south, and a secondary outflow boundary
from today`s convection is currently running from Marietta to near
Seymour and moving south on its own. Current indication via
satellite analysis is that the area north of these boundaries is
currently quite stable. However, the HRRR indicates a remaining
reservoir of 2,000- 3,000 J/kg of MUCAPE north of the boundaries
this afternoon.

Convection initiation after this current round of storms is rather
uncertain. Members of the 12Z HREF that failed to depict the
magnitude of this morning`s storms generally showed early afternoon
redevelopment occurring in southeast Oklahoma, which seems rather
implausible in the face of the ongoing MCS. The latest few runs of
the HRRR, which did a somewhat better job of depicting this MCS,
shows redevelopment occurring early this afternoon along the
outflow boundary just south of our area. The margin of error (and
the suggestion of a continued reservoir of instability) are enough
for us to want to keep our guard up for the potential for
elevated strong to severe storms this afternoon, especially in the
Clay-to- Bryan County corridor where the outflow hasn`t blasted
as hard. However, the spatial and probabilistic window for severe
weather this afternoon appears to be shrinking.

Meister

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 104 PM CDT Wed May 22 2024

Northerly winds will begin to weaken this evening as the upper
trough ejects into the Great Lakes. Skies may be clear in the early
part of the period prior to an expected switch to southerly surface
winds as southwesterly flow builds back in aloft. The moist airmass
will begin to filter back in prior to daybreak, especially in
southern Oklahoma and western north Texas where 6-hour dewpoint
rises may be as much as 5-10 degrees. Given this regime, the
development of advection fog along and south of I-40 is possible
late tonight and lingering into tomorrow morning.

The surface low will deepen to 994 mb across the High Plains
tomorrow afternoon, allowing for an impressive surface response. By
all indications, even the overmixed models like the HRRR/FV3/ARW all
show a pool of 70-73 dewpoints within our area by 22Z with the
dryline hanging around the 100th meridian. Storm coverage is very
much in question; the primary forcing mechanism will be a trough
moving into the central/northern Plains, and secondary forcing from
the STJ will pass through central Texas. On numerous occasions this
year we have seen STJ "lead waves" throw a wrench in the forecast on
Day 1. However, given the extremely rich boundary-layer moisture, a
sufficient environment is in place along the dryline that only weak
forcing will be necessary to trigger convection. If storms do
develop, the environment is favorable for supercells with an initial
risk for large-to-very-large hail. In the evening, the tornado risk
with supercells will increase as the LLJ increases and hodographs
take on a more streamwise shape. Overall, the risk for severe
weather at any one place tomorrow is on the low-to-medium side due
to questions about storm coverage, but interests in the path of any
of those storms tomorrow evening will want to pay very close
attention.

As an aside: a flood watch remains in effect for southeast Oklahoma
until late tomorrow evening. It doesn`t look like we`re going to end
up verifying widespread flooding conditions, but given the potential
for early-day CI in southeast Oklahoma with the STJ and maybe
another round later on, will continue the watch for at least one
more cycle.

Meister

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 104 PM CDT Wed May 22 2024

As the upper-level wave translates eastward across the northern
Plains Thursday night into Friday morning, another cold front will
crash southward. Right now, no members of the HREF suggest a signal
for convection with this front at least through 12Z on Friday
morning. Based on the 12km NAM, the front may begin to slow down in
our southeast Oklahoma counties Friday afternoon and evening, so we
may see some anafrontal convection develop with a low-end
severe/flood risk in the region. Highs during the day look
stratified across our area, with northern Oklahoma staying in the
low 80s and western north Texas/southern Oklahoma approaching 90.

Potentially the highest-ceiling day for severe weather in the
current stretch will be on Saturday. More substantial (50+ knots at
500 mb) flow will be impinging on the dryline near the 100th
meridian during peak heating, with plenty of instability and deep-
layer shear forecasted. Supercells capable of all severe hazards
will be possible in the afternoon and evening as it currently
stands, although uncertainty remains high thanks to the multiple
rounds of storms between now and then.

The dryline looks like it will make an eastward push during the day
on Sunday, keeping the storm risk lower and allowing highs to soar
into the 90s across a large portion of our area. By Monday, a
transition to western ridging looks likely across the US, which will
increase the potential for northwest flow, cold fronts, and
potentially MCSs across the northern half of our area.

Meister

&&

.AVIATION...
(12Z TAFS)
Issued at 638 AM CDT Wed May 22 2024

Scattered TSRA will progress slowly east and southeast this
morning across central into southern Oklahoma. MVFR cigs will be
widespread across central and southern portions of Oklahoma, with
mainly VFR cigs farther north in drier low level air. Cigs should
rise through the day, although MVFR and additional TSRA possible
at KDUA this afternoon. Frontal boundary will lift north tonight
and allow moisture return and lowering cigs into MVFR and possibly
IFR by end of forecast.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  62  82  66  83 /  20  50  10   0
Hobart OK         60  89  64  85 /  10  30   0   0
Wichita Falls TX  66  88  69  89 /  40  40   0   0
Gage OK           55  91  57  81 /  10  20   0   0
Ponca City OK     58  81  65  81 /  10  40  30   0
Durant OK         66  84  68  91 /  70  50  30   0

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch through late Thursday night for OKZ032-041>043-
     046>048-050>052.

TX...None.
&&

$$

SHORT TERM...04
LONG TERM....04
AVIATION...11