Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0751 AM CDT Tue Sep 29 2026
Valid 291300Z - 301200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN
ARIZONA/NEW MEXICO TO WEST TEXAS...
...SUMMARY...
Isolated severe thunderstorm wind gusts and possibly a tornado or
two could occur this afternoon into tonight from southern and
eastern New Mexico into west Texas, and across southeast Arizona.
...Synopsis...
A mid/upper-level low and attendant trough will move across the
Desert Southwest through the period. In response to the approaching
deep trough, Hurricane Polo is forecast to move from the Gulf of
California into Sonora this morning. While the tropical cyclone is
forecast to weaken over the mountainous terrain of northern Mexico
later today, a phasing of the mid-level remnants of Polo with the
approaching deep mid/upper-level trough will result in a
consolidating surface low that is forecast to deepen and move across
eastern New Mexico and west Texas tonight.
...Southern/eastern New Mexico to west Texas...
Widespread convection is ongoing and expected to generally continue
into this afternoon and tonight from southern/eastern New Mexico to
west Texas, as increasing large-scale ascent overspreads a very
moist environment. The influence of the remnant tropical system will
result in poor mid-level lapse rates, but increasing deep-layer
flow/shear and enlarging low-level hodographs will favor some storm
organization, especially later this afternoon and evening. The
widespread storm coverage will result in a tendency toward complex
or linear storm modes with time, though a few/episodic supercells
will also be possible. The weak lapse rates and modest buoyancy are
expected to limit the overall magnitude of severe potential, but a
localized tornado and severe-gust threat could accompany any
organized storm structures, particularly this afternoon and evening,
influenced by a nocturnally strengthening low-level jet.
...Southern Arizona...
A moist environment resides in close proximity to the Southwest
Deserts mid/upper-level low, with a belt of very strong deep-layer
winds sampled in available 12z upper-air data and regional WSR-88D
VWPs. Scattered thunderstorms are common this morning, and while
this convection/related cloud cover will generally hinder overall
destabilization, modest diurnal heating will probably lead to some
convective intensification during the day. The strong nature of the
wind profiles could support a few at least weak/transient
supercells, and potentially more organized convective bands later
today, with at least some potential for strong thunderstorm winds
and mostly sub-severe hail.
..Guyer/Bentley.. 09/29/2026
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