141
ACUS02 KWNS 170603
SWODY2
SPC AC 170602

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0102 AM CDT Sat May 17 2025

Valid 181200Z - 191200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
OKLAHOMA AND MUCH OF CENTRAL AND EASTERN KANSAS...

...SUMMARY...
Severe thunderstorms capable of all severe hazards are expected on
Sunday across portions of the central and southern Plains.

...Synopsis...
A mid-level shortwave trough will move from the Southwest into the
Central Plains on Sunday as the broader trough develops across the
Intermountain West. By 00Z Monday, a ~992mb lee cyclone will develop
along the KS/CO border. A warm front will extend from this surface
low into northern Kansas/southern Nebraska by Sunday evening and
will remain mostly stationary across the Southeast. A dryline will
extend from central Kansas to the southern Plains.

...Kansas and northern Oklahoma...
A very moist airmass will be in place east of the dryline on Sunday
with low 70s dewpoints forecast across much of Texas, Oklahoma, and
southern Kansas ahead of the surface boundary. As temperatures warm,
strong to very strong instability is forecast to develop. As the
mid-level shortwave trough emerges across the Plains, synoptic-scale
ascent will combine with the increasing instability to decrease
inhibition across much of the dryline. Forecast guidance shows
limited convergence along the dryline in Oklahoma and Texas during
the day Sunday with the better convergence focused across Kansas.
Therefore, confidence is higher for storms across central and
southern Kansas and perhaps into northern Oklahoma.

Any storms which develop will be supercellular with a threat for
very large hail and tornadoes, particularly by later in the evening
as the low-level jet strengthens. While confidence is higher in
storms across the Enhanced risk area, storm evolution remains
unclear. 00Z CAM guidance has wide variations in the northeastward
progression of the surface warm front which will significantly
impact storm development on Sunday. A more discrete storm mode would
likely pose a greater very large hail and tornado threat, while more
widespread storm development would likely favor development into a
MCS which could pose a greater severe wind threat across eastern
Kansas and into Missouri.

Despite the uncertainties, the Enhanced (Level 3 of 5) risk seems
appropriately placed where severe storms are most likely. The 10%
tornado probabilities do not extend to the northern extent of the
Enhanced due to the aforementioned uncertainties in the warm frontal
position. However, elevated hail will remain a threat north of the
warm front.

...Oklahoma/Texas...
A dryline will be in place across western Oklahoma and north Texas
for much of the day Sunday. Convergence will be mostly weak along
the Oklahoma dryline for much of the day with better convergence
farther south in Texas, farther from the better upper-level forcing.
However, by the evening, convergence will increase somewhat which
could result in isolated supercell development as the low-level jet
intensifies during the evening. The environment across Oklahoma and
North Texas will be very volatile with a conditional threat for
intense supercells capable of very large hail and strong tornadoes.

...Northeast CO/Southwest Nebraska Vicinity...
By Sunday afternoon, low to mid 60s dewpoints will advect westward
around the surface low into northwest Kansas, northeast Colorado,
and southwest Nebraska. Moderate to strong instability is forecast
ahead of the dryline which will aid in supercell development by the
afternoon. A narrow corridor of instability will be the primary
limiting factor to the tornado threat in an otherwise very favorable
STP environment. It appears supercells will likely be north of the
boundary before maturing which will support a primary threat for
large hail. However, if a storm can rapidly mature as it develops
off the dryline, it could pose a tornado threat given the favorable
low-level shear across the region.

...Mid Mississippi Valley to the Southeast...
Isolated thunderstorms are possible along a stalled frontal zone
that will extend from the Mid-Mississippi Valley to the Southeast.
Moderate to strong instability will be in place within a moderately
sheared environment. Forcing will be weak along the front with
neutral to perhaps slightly rising heights aloft. However, forecast
soundings show minimal inhibition and therefore, isolated
development is possible. A greater severe threat could materialize
from a remnant MCV/MCS which will likely evolve from Day 1/Saturday
convection across north Texas. If this maintains along the frontal
zone into the late morning on Sunday, it could provide a focused
region of greater severe weather threat Sunday afternoon across
AL/GA.

..Bentley.. 05/17/2025

$$