SPC Oct 20, 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
1125 AM CDT Tue Oct 20 2026

Valid 201630Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Organized severe thunderstorms are not expected through tonight.

...Southwest...
Beneath a belt of 30-40-kt southwesterly flow aloft, isolated to
widely scattered thunderstorm development is expected along the
higher terrain across parts of southeastern AZ into western NM this
afternoon. Diurnal heating amid middle/upper 50s dewpoints will
yield weak surface-based buoyancy, which combined with around 35 kt
of effective shear, may promote transient storm organization. While
an isolated instance of marginally severe hail (around 1 inch in
diameter) and/or locally strong gusts cannot be ruled out, the
overall severe threat is expected to remain isolated/limited today.

An increase in thunderstorm coverage is expected late in the period
across central/northern AZ as forcing for ascent strengthens within
the exit region of a robust midlevel jet. While deep-layer shear
will be increasing, most of this activity should remain elevated
amid weak buoyancy -- limiting the overall severe risk.

..Weinman.. 10/20/2026


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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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