National Weather Service Raw Text Product

467 
FXUS64 KOUN 251736
AFDOUN

Area Forecast Discussion
National Weather Service Norman OK
1236 PM CDT Thu Apr 25 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 352 AM CDT Thu Apr 25 2024

Isentropic ascent/warm air advection is resulting in a few showers
and thunderstorms across north central Oklahoma this morning as
the warm front lifts to the north. This convection will likely 
persist through the morning hours before experiencing a downward 
trend late morning into the afternoon. Elsewhere, an isolated 
shower or storm may occur due to the warm air advection; however, 
coverage will be much more sparse (i.e., most locations should 
remain dry today).

By this late afternoon, a shortwave trough will lift into the 
Plains with increasing synoptic-scale ascent. At the surface, a 
dryline will sharpen from Kansas, southward through the Texas 
panhandle, as a low deepens across eastern Colorado into western 
Kansas. While the synoptic-scale pattern is favorable for severe 
convection, a capping inversion at around 800 mb will likely limit
the southern extent of daytime convection. Forecast soundings and
HREF members indicate the southern extent of convective 
initiation might be as far south as the first two rows of counties
in the Texas panhandle. If isolated supercells do develop this 
far south, they would move to the northeast and could affect 
northwest Oklahoma this evening before dissipating with the loss 
of daytime heating. Large hail, damaging wind gusts, and tornadoes
are possible with any supercells that can sustain themselves into
northwest Oklahoma. Note that the probability of this scenario 
occurring has been on a downward trend given the strength of the 
cap.

Overnight, the trough will lift across the area with the 
dryline/Pacific front accelerating to the east. Thunderstorms will
develop from the large-scale forcing--likely near Lubbock--and 
quickly move to the northeast and likely grow upscale into a 
quasi-linear convective system (QLCS)/squall line. Areas along 
and south of I-40 west of I-35 and along and southeast of I-44 to 
the east I- 35 have the highest probability of being affected by 
the line of thunderstorms. Damaging wind gusts will be the primary
hazard with any bowing segments and QLCS mesovortices. Given ~30 
to 35 knots of 0 to 1 km shear, tornadoes are possible with any 
QLCS mesovortices--especially on the left side of any bowing 
segments. 

Mahale

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 352 AM CDT Thu Apr 25 2024

Friday: Thunderstorms will exit southeast Oklahoma during the
morning hours. As the trough lifts toward the Midwest, the 
trailing dryline will stall near I-35. While synoptic-scale ascent
will be lacking with the departing trough, the environment ahead 
of the dryline across south central and southeast Oklahoma will 
have little or no cap present during the afternoon and early 
evening. Therefore, while the probability is rather low, the 
chance for redevelopment is not zero. If storms develop in this 
environment, they 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 far northwest into west central Oklahoma. 
Southwest winds at 20 to 25 mph with wind gusts in around 30 mph 
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 another trough lifts into
the Southern Plains with the dryline near or just east of the 
Oklahoma/Texas state line. 

While the synoptic-scale pattern is a classic significant severe 
weather event for the Southern Plains, there remains forecast 
uncertainty that could impact the magnitude of the risk. Several 
deterministic models and ensemble members indicate the potential 
for morning convection associated with a 700 mb wave and attendant
isentropic ascent/warm advection. If morning convection occurs, 
there is uncertainty on the magnitude of convective-overturning 
and recovery that will happen in its wake. At this time, most 
guidance indicates enough of a recovery for some severe weather 
with a moist, unstable, and highly-sheared environment east of the
dryline during the late afternoon and evening. There is even the 
potential the morning convection may intensify and become the 
start of the severe weather event itself (with more than one round
of severe weather). 

These sub-synoptic/mesoscale details on the morning convection will 
not be resolved until we are closer to the event. However, given the 
synoptic-scale pattern, the ceiling for the worst case scenario 
(e.g. How bad could it be?) is quite high on Saturday. Significant 
severe weather with large hail (2" or larger), damaging wind gusts 
(74 mph or higher), and tornadoes (EF2 or stronger) are all possible 
if the atmosphere sufficiently recovers (or remains undisturbed) and 
the storm mode is discrete supercells. In addition, with the 
rainfall Thursday night/Friday morning and the possibility of 
multiple rounds of thunderstorms on Saturday, flooding will also be 
possible. Bottom Line: It is important to stay weather aware on 
Saturday!

In addition, if the dryline is east of the Oklahoma/Texas state 
line, near critical to perhaps critical fire weather conditions 
are likely near the 100th meridian across northwest into west 
central Oklahoma Saturday afternoon. 

By late Saturday night, a strengthening low-level jet will likely
result in upscale growth into a complex of thunderstorms across 
southeast Oklahoma. This would increase the flooding threat across
this area. 

Sunday: The chance for strong to severe thunderstorms along with a
flooding risk may continue across southeast Oklahoma on Sunday. 
Elsewhere, a slightly less humid and cooler air mass is forecast.

Monday through Wednesday: There will be a low chance of showers 
and thunderstorms, primarily across the southeast on Monday and
Tuesday. More widespread chances of rain return on Wednesday with
a trough potentially impacting the area.
 
Mahale

&&

.AVIATION...
(18Z TAFS)
Issued at 1225 PM CDT Thu Apr 25 2024

MVFR to VFR conditions are expected through early evening. Then,
severe thunderstorms expected to develop off a dryline and congeal 
into a squall line tonight. Most likely timing for KCSM, KLAW,
KSPS would be 11PM to 3AM, KOKC/KOUN/KSWO/KPNC 2AM to 5AM, and 
KDUA 4 AM to 8 AM. There is a chance storms could impact KWWR,
also, however this is less certain as storms could grow upscale
after passing east of there. All hazards will be possible
initially before transitioning to mainly a wind and tornado threat
as it forms a squall line overnight.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  78  63  83  65 /  20  90  30   0 
Hobart OK         78  60  85  60 /  20  70   0   0 
Wichita Falls TX  79  64  85  65 /  20  80  10   0 
Gage OK           81  55  86  55 /  20  20   0   0 
Ponca City OK     75  63  83  64 /  60  90  30   0 
Durant OK         80  66  80  68 /  10  90  80  20 

&&

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

$$

SHORT TERM...10
LONG TERM....10
AVIATION...01