SPC Oct 20, 2026 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0730 AM CDT Tue Oct 20 2026

Valid 201300Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Organized severe thunderstorms appear unlikely through tonight.

...Great Basin into the Southwest and Southern/Central Plains...
Isolated showers and thunderstorms ongoing this morning across parts
of southern/central NM may develop downstream today over portions of
the southern/central Plains as modest southwesterly mid-level flow
persists. As a closed mid/upper-level low digs southward off the
West Coast, convection capable of producing occasional lightning is
also forecast to develop this afternoon through tonight across parts
of the Great Basin and Southwest. Low-level moisture is forecast to
further increase through the period over the lower CO River Valley
and southern/central AZ.

While a stronger thunderstorm or two may develop across southeast AZ
this afternoon with daytime heating aided by orographic effects,
better large-scale ascent associated with a strong southwesterly
mid/upper-level jet will likely be delayed until late tonight/early
Wednesday morning. Greater coverage of thunderstorms may be realized
towards the end of the period across central/northern AZ, but in a
weak thermodynamic environment. The overall severe hail/wind threat
across the Southwest currently appears lower and even more isolated
than yesterday, so have not introduced any severe probabilities with
this update.

..Gleason/Kerr.. 10/20/2026


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SPC Oct 20, 2026 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1248 AM CDT Tue Oct 20 2026

Valid 201200Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
No severe thunderstorms are forecast across the U.S. today and
tonight.

...DISCUSSION...
A mid-level anticyclonic flow pattern will be in place across the
south-central U.S. today, as divergent flow aloft remains over the
Southwest. At the surface, a large area of high pressure will be
entrenched over the eastern half of the nation. An axis of low-level
moisture will be in place over the Desert Southwest, where scattered
thunderstorms will be possible today as instability increases. The
chance for storms in the Desert Southwest will continue into the
evening and overnight period. No severe threat is expected across
the continental U.S. through daybreak Wednesday.

..Broyles/Leitman.. 10/20/2026


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SPC Oct 20, 2026 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 PM CDT Mon Oct 19 2026

Valid 200100Z - 201200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHEAST ARIZONA AND SOUTHWEST NEW MEXICO...

...SUMMARY...
Thunderstorms with isolated severe gusts and hail will be possible
this evening across parts of southeast Arizona and southwest New
Mexico.

...Southeast Arizona/Southwest New Mexico...
Latest water vapor imagery shows a minor shortwave trough moving
through the Desert Southwest. An associated mid-level jet is
analyzed by the RAP over northwestern Mexico and southeastern
Arizona. Lift associated with the jet is providing support for
scattered thunderstorm development this evening. Near the exit of
the jet, a small cluster of storms is ongoing from far southeast
Arizona into southwest New Mexico along the eastern edge of a
corridor of instability. Within this corridor, the RAP has SBCAPE
from 1000 to 1500 J/kg. The RAP also has about 40 knots of 0-6 km
shear. This may be enough for an isolated threat for severe wind
gusts and hail for another hour or two this evening.

..Broyles.. 10/20/2026


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SPC Oct 19, 2026 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Mon Oct 19 2026

Valid 191630Z - 201200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST
ARIZONA/SOUTHWEST NEW MEXICO...

...SUMMARY...
Thunderstorms may produce isolated marginally severe hail and gusty
winds this afternoon and early evening across parts of southeast
Arizona and southwest New Mexico.

...Southeast Arizona/southwest New Mexico...
Generally cloud-free skies are noted late this morning as heating
has steadily occurred in the presence of a relatively moist airmass
with prevalent 50s F surface dewpoints in lower elevations.
Satellite imagery/derived-winds continue to portray a 35-45 kt
southwesterly mid-level jet associated with a weak shortwave trough
will continue northeastward today. Modest large-scale ascent related
to this feature coupled with terrain-driven influences should aid
thunderstorm initiation across southeast Arizona this afternoon as
convective temperatures are reached.

The boundary layer will not become overly well mixed across this
region through the afternoon, which should allow for around 500-1000
J/kg of MLCAPE to develop. This instability coupled with cool
mid-level temperatures and 30-40 kt of deep-layer shear appear
sufficient for some updraft organization with the scattered to
numerous thunderstorms that form. Isolated, marginally severe hail
and gusty outflow winds may occur with the stronger cells that
develop and spread east-northeastward across southeast Arizona into
southwest New Mexico through the afternoon and early evening. This
activity is expected to quickly weaken by mid-evening with the loss
of daytime heating.

..Guyer/Mosier.. 10/19/2026


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