ACUS02 KWNS 180541
SWODY2
SPC AC 180540

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1240 AM CDT Fri Oct 18 2024

Valid 191200Z - 201200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHERN HIGH PLAINS...

...SUMMARY...
Strong to severe thunderstorms are possible across the southern High
Plains Saturday into Saturday night. Large hail will be the primary
threat, though isolated severe winds and a tornado may also occur
with the strongest storms.

...Synopsis...
The upper-level trough within the lower Colorado River Valley will
become a closed low in the Southwest and become nearly stationary
just south of the Four Corners on Saturday. Mid-level winds
associated with this feature are expected to weaken some as compared
to Friday, though some intensification may occur as the trough
becomes more progressive by early Sunday morning. At the surface,
modest return flow of generally poor-quality low-level moisture will
continue into the southern High Plains as a surface trough is
maintained from eastern Colorado into eastern New Mexico. Nebulous
ascent from the upper-level low as well as low-level warm advection
should promote some showers/thunderstorms early in the period,
especially in New Mexico.

...Central/eastern New Mexico into western Texas...
Southeasterly return flow around the surface high in the Ohio Valley
will maintain mid to upper 50s F dewpoints in the southern High
Plains. Forcing from the upper low and a Pacific cold front will
promote late-afternoon thunderstorm development from central to
eastern New Mexico. Ongoing precipitation early in the period gives
some uncertainty as to how much surface-based destabilization will
occur. MLCAPE of around 1000 J/kg appears possible where greater
heating occurs with closer to 500 J/kg elsewhere. However, there
appears a slightly more favorable zone for heating from the Davis
Mountains into east-central New Mexico. Deep-layer shear will be
favorable for supercells, and mid-level lapse rates will remain
steep enough to support some threat for large hail even if some
storms remain slightly elevated. Isolated strong to severe gusts
could occur with the most organized supercells. Low-level shear will
increase after 00Z, but a simultaneous increase in low-level
stability is also expected. Even so, a narrow window exists for a
tornado or two should a mature supercell persist into the early
evening. Given a slightly slower eastward progression of the upper
low in recent guidance, a small westward shift in severe
probabilities was made.

Some guidance shows convection developing within the Davis
Mountains. Given the weak synoptic lift and potential for low-level
clouds and stable conditions to the east, it is not clear if storms
will develop or for how long they can persist eastward into
marginally greater moisture. A conditional threat for severe hail
would exist if a storm or two can develop and mature in the
Trans-Pecos region.

..Wendt.. 10/18/2024

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