699
FXUS64 KOUN 221550
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
1050 AM CDT Wed May 22 2024

...New UPDATE...

.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...
(Today and tonight)
Issued at 237 AM CDT Wed May 22 2024

At least intermittent severe risk is expected, perhaps by as
early as ~3-4 AM this morning, focusing primarily along/south of
the Interstate 40 corridor. A weak frontal boundary has `washed
out`/stalled across portions of west-central into southeast
Oklahoma early this morning. As a second (stronger) surface front
impinges on this feature, scattered to potentially widespread
precipitation/storm development is expected to ensue.

Current objective analysis and short-term guidance highlights a
mesoscale environment favorable for severe weather. With sufficient
to locally extreme (2000-4000 J/kg MUCAPE) instability and very
strong deep/cloud-layer wind shear, large hail will be possible
with robust storm cores. Evolution of individual/clusters of
storms will determine whether surface-based hazards (damaging
wind/very low tornado risk) can be realized this morning. Storms
developing south of or having sustained motion (more
southeasterly) along the front and consolidating cold pool will
have the greatest opportunity to carry aforementioned risks. The
most likely scenario is for dominant/quick transition towards
elevated convection this morning, especially as convective
reinforcement allows the boundary to surge quicker to the
south/southeast.

A second round of severe weather is expected by early this afternoon
into this evening, focusing near the Red River Valley/southeast
Oklahoma. Latest guidance is more bearish on potential/coverage for
this round, likely the result of greater southward push (into north-
central Texas) of the aforementioned boundary. Should this occur,
`elevated` convection would be favored, posing a continued risk
for large to potentially very large hail owing to favorable
instability/organizing wind shear persisting north of the front.
In a more unlikely scenario, should portions of the front remain
draped across far southern zones into the afternoon, then a brief
period of damaging wind and low tornado (along with hail) risk
would develop with robust storms.

In addition, concern for at least localized flash flooding will
likely develop across southeastern Oklahoma today, perhaps by
midday/early afternoon. This will be especially true if a heavy
round of morning storms "primes" soil conditions for additional
heavy bouts of precipitation later in the day. A Flash Flood Watch
has been maintained, and continues into early Friday morning
owing to potential for additional rounds of storms on Thursday.

Ungar

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 237 AM CDT Wed May 22 2024

Thursday: Potential exists for a notable severe weather episode from
the afternoon into late evening, with at least limited potential for
much/all of the forecast area. Broad southwesterly upper flow looks
to be maintained into the late week, with both jet stream branches
(i.e. polar/subtropical) in close proximity across the
western/central CONUS. Low amplitude/compact upper features remain
advertised to move out into the Plains on Thursday within each
branch. As this occurs rather impressive mass response is forecast
across our area. A combination of storm development originating
along a dryline near the 100th meridian, and associated with warm
air advection processes, is possible. Uncertainties in
coverage/exact corridors of highest potential/hazards remains,
owing to subtle synoptic/mesoscale forcing expected. However, at
this point, all areas of the forecast area will harbor some risk
for severe weather from the afternoon into evening on Thursday.
All storm hazards (hail/winds/tornadoes) appear possible. Stay up
to date on trends for Thursday, as signals concerning
aforementioned factors will hopefully converge towards a most
likely outcome.

Friday-Holiday Weekend: Additional chances for storms/severe weather
will exist, especially on Saturday afternoon into evening. Friday
will likely feature the nadir of storm and severe weather
potential through Sunday. Still with a front expected across
central into eastern Oklahoma, limited diurnally-driven convection
is possible across mentioned areas.

By Saturday, attention will once again turn towards the possibility
of another impactful severe weather episode. A majority of global
model/grand ensemble guidance depicts a slightly stronger (when
compared to Thursday) subtropical-based wave sliding out across the
Southern Plains through the day. Once again, impressive mass
response is expected ahead of an evolving dryline feature across
western Oklahoma. At this point, development of a few organized
storms would be favored, posing risks for large hail, damaging winds
and tornadoes. This will be another period to monitor closely over
coming forecast cycles.

Sunday-Next Week: General consensus is for a transition towards
drier weather. Expectation is for main upper support to shift
towards the Mississippi Valley by Sunday. Should this occur, then
a dry and warm (many areas seeing highs of 90+ degrees) Sunday
can be expected. Into the next work week, grand ensemble guidance
shows transition towards upper ridge development across the
western US. This will favor mostly dry days. Frontal intrusion
early in the week may help keep maximum daily temperatures near to
slightly below average heading into the midweek period.

Ungar

&&

.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  77  63  81  67 /  40  20  50  20
Hobart OK         79  61  87  64 /  10  10  30  20
Wichita Falls TX  80  66  86  69 /  40  30  40  20
Gage OK           80  55  88  58 /   0  10  20  10
Ponca City OK     78  59  81  65 /  20  10  50  30
Durant OK         84  66  82  69 /  90  60  60  30

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch until 5 PM CDT this afternoon for OKZ032-041>043-
     046>048-050>052.

TX...None.
&&

$$

SHORT TERM...34
LONG TERM....34
AVIATION...11