132
FXUS64 KOUN 031855
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
155 PM CDT Mon Jun 3 2024

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

.MESOSCALE UPDATE FOR SEVERE WEATHER... Issued at 1102 AM CDT Mon
Jun 3 2024

Ongoing convection continues along and just south of I-40 from
Hobart to Prague. This convection consists of weak cells loosely
organized into an MCS that is propagating south-southeastward along
the leading edge of the cold pool. No severe weather is anticipated
with this activity, but periods of heavy rain and frequent cloud-to-
ground lightning are expected with this cluster as it continues on
its merry way.

Concern is increasing for convective potential this afternoon and
evening to the west of the current storms. Satellite, radar, and
surface observations show an outflow boundary extending from the
western edge of convection back to the northwest toward a triple
point low near Borger. Closer to storms off to the east, this
outflow is still making steady southward progress toward the Red
River, and will probably clear into western north Texas by this
afternoon. However, with convection on the decrease in western
Oklahoma, there`s concern that this boundary will begin to slow and
stall this afternoon.

If and when this occurs, the environment along and immediately on
the cool side of the boundary will be highly concerning for
potential severe weather. Short-range guidance suggests MLCAPE may
reach 6,000 J/kg, and while deep-layer winds will be on the
modest side of things, easterly surface wind enhancement along
the boundary will lend itself to about 35-45 knots of effective
bulk shear, 30 knots of which can be found in the lowest 3 km. All
of this paints the picture of a conditional, highly localized,
but potentially significant threat for severe weather. Any
supercells that do develop along and just northeast of the outflow
boundary this evening will be capable of large to giant hail from
2 to 4 inches in diameter. A relatively focused threat for
tornadoes is also possible along the boundary this evening with
ambient environmental vorticity, modest enhancement from the LLJ,
and strong low-level instability. The threat from these storms
should begin to diminish not long after sunset as surface-based
capping returns.

Meister

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 154 PM CDT Mon Jun 3 2024

Storm potential this evening will transition from southwest
Oklahoma/western north Texas to the northeast, as several members of
the 12Z HREF depict thunderstorm development in central Oklahoma
between sunset and midnight. This appears to be triggered by an
elevated warm front along the leading edge of the LLJ, as MUCAPE
rises to near 4,000 J/kg late in the evening. Bulk shear will be
sufficient for the development of likely elevated supercells
initially, which will pose a threat for large to very large hail
near the OKC metro. Thereafter, the continued strengthening of the
low-level jet will likely induce further convection initiation
and the development of an MCS, which guidance shows moving south-
southeast into south central Oklahoma with more of a risk for
damaging wind gusts. All of this remains lower-confidence, but
sufficient signal and meteorological reasoning exists for us to
keep a close watch on this potential round of storms.

One thing you learn in this area and in this time of year is to
never say "Tomorrow will be dry". But... at least for now, there is
an indication of weakening of deep-layer flow and potentially no
obvious boundaries to initiate convection tomorrow afternoon. Most
guidance indicates a rather warm-to-hot day with highs in the low
90s to low 100s. There`s some reason to be doubtful given the
widespread rain today, but this would just turn the day more humid
rather than more pleasant.

A breath of northwest flow returns into our area tomorrow night, so
another MCS will likely occur sometime overnight mostly north of I-
40. We`ll get those details locked down as uncertainty gets reduced.

Meister

&&

.LONG TERM...
(Tuesday night through next Sunday)
Issued at 154 PM CDT Mon Jun 3 2024

This is an especially difficult long-term AFD to write, because,
well... it`s especially difficult to figure out what`s going to
happen beginning on Wednesday.

A powerful mid-latitude jet will eject into the northern Plains
during the day on Wednesday, which will be the primary driver of
this uncertainty. It will create a northeast-to-southwest dipole,
with an unseasonably strong (594 dam) ridge across the Staked Plains
and an unseasonably strong (549 dam) trough across the Upper Great
Lakes. Between that, we`ll find ourselves right on the northeastern
fringe of the ridge. This could play out in a couple of different
ways - either we could end up with just enough northwest flow to
keep nightly MCSs moving into our area, especially the northeast
portion, or we could end up hot and dry. We could end up both - June
2023 in Wichita Falls was hot and dry even while OKC and points
north were repeatedly receiving heavy rainfall and cooler
temperatures. Right now, I`d lean towards using the experience from
2023 and the last few weeks here in 2024 where chances for storms
have largely overperformed model guidance rather than vice versa.
This might signal a somewhat more active and cooler than normal end
to the week and weekend, especially further north and east in our
area.

Meister

&&

.AVIATION...
(18Z TAFS)
Issued at 1242 PM CDT Mon Jun 3 2024

Showers & thunderstorms across southcentral Oklahoma will be
moving into southeast Oklahoma and south of the Red River into
northern Texas, which will be affecting terminals KSPS & KDUA
through 22Z maintaining MVFR conditions there. Our terminals
across northern Oklahoma will remain under VFR conditions at least
through 01Z, while our remaining terminals will be trending toward
MVFR conditions after 21Z. Another MCS coming down from the High
Plains could impact terminals generally along and south of I-40
between 03-12Z. The MCS combined with lowering stratus could
reduce terminals from MVFR to periods of IFR conditions.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  69  90  69  90 /  40  10  40   0
Hobart OK         68  96  69  94 /  30   0  20   0
Wichita Falls TX  71  97  71  92 /  30  10  20   0
Gage OK           66  91  64  95 /  10  10  10   0
Ponca City OK     66  86  66  90 /  40  10  50   0
Durant OK         70  90  72  88 /  30  20  40  10

&&

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

$$

SHORT TERM...04
LONG TERM....04
AVIATION...68