169
ACUS01 KWNS 201242
SWODY1
SPC AC 201240

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0640 AM CST Thu Nov 20 2025

Valid 201300Z - 211200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS INTO ARKANSAS...

...SUMMARY...
Isolated strong to severe thunderstorms may occur today into this
evening across the southern Plains into Arkansas. Large hail,
damaging winds, and a tornado or two all appear possible.

...Southern Plains into Arkansas...
A mid/upper-level trough extending from the Southwest into northern
Mexico this morning will eject northeastward across parts of the
southern Plains today. In response, a surface low will gradually
deepen across the south-central High Plains and develop eastward
through the period. A front extending across parts of OK/AR this
morning will lift slowly northward as a warm front ahead of the
surface low. Thunderstorms ongoing across parts of the southern
Plains/ArkLaTex this morning are being aided by a modest low-level
jet and ascent attendant to the approaching upper trough. Weak to
locally moderate instability and effective shear of 40-50 kt may
support a few strong to severe thunderstorms this morning from parts
of eastern NM into west/central TX and OK, with a threat for mainly
isolated hail and locally gusty winds.

Convection and widespread cloud cover will likely persist through
the day, resulting in generally modest diurnal heating and weakening
mid-level lapse rates with time. While enhanced deep-layer shear
will remain across the warm sector owing to persistent strong
southwesterly mid-level flow, the potential for organized
thunderstorms downstream or in the wake of ongoing morning
convection remains uncertain. Still, depending on the extent of
heating and related destabilization, most guidance continues to show
some potential for isolated supercells and/or organized multicell
clusters this afternoon/evening across portions of TX, with a threat
of isolated severe hail and damaging winds. Modest enlargement of
low-level hodographs with time could also support a tornado threat
from parts of central/east TX into eastern OK/western AR along and
south of the warm front, assuming surface-based supercells can be
sustained. An isolated severe risk may persist into east TX and the
ArkLaTex tonight. However, confidence in a corridor of greater
severe risk remains too low to include higher severe probabilities
at this time.

Farther west, some high-resolution guidance continues to show the
development of a modestly organized convective line across far
eastern NM into west TX during the afternoon/evening, in closer
proximity to the ejecting upper trough. This convection could pose a
threat of strong gusts and perhaps some hail, but it remains
uncertain as to whether sufficient instability will develop to
support a severe threat. Have therefore maintained the Marginal Risk
across this region with only minor changes.

..Gleason/Broyles.. 11/20/2025

$$