SPC Oct 18, 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
0754 PM CDT Sat Oct 17 2026

Valid 180100Z - 181200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not expected across the U.S. through
tonight.

...DISCUSSION...
At upper-levels, a trough and associated low will move eastward into
the western Atlantic tonight as a ridge dominates over the central
U.S. At the surface, dry and cool air associated with a large area
of high pressure will be in place over much of the nation. Moisture
and instability will be confined to south Florida, where isolated
thunderstorms will be possible this evening. Isolated storms may
also form over parts of southern Arizona this evening. No severe
threat is expected over the continental U.S. through daybreak on
Sunday.

..Broyles.. 10/18/2026


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SPC Oct 17, 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
1114 AM CDT Sat Oct 17 2026

Valid 171630Z - 181200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

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

...Synopsis...
Water-vapor imagery late this morning shows a positive-tilt upper
trough over the East and a closed low near the California/Baja
California border. An extensive area of tranquil conditions
influenced by surface high pressure will prevail across much of the
contiguous U.S. Widely scattered diurnal thunderstorms are possible
across the southern half of the FL Peninsula primarily through
sunset before much of the convective activity is relegated to the FL
Straits and offshore waters tonight. Weak thunderstorms are
possible tonight in association with the upper low over southern AZ.

..Smith/Supinie.. 10/17/2026


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SPC Oct 17, 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
0658 AM CDT Sat Oct 17 2026

Valid 171300Z - 181200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

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

...Synopsis and Discussion...
Highly amplified upper troughing over the eastern CONUS this morning
will move eastward off the Atlantic Coast today, while a closed
mid/upper-level low eventually develops over the NC Outer Banks and
adjacent western Atlantic. An expansive area of surface high
pressure and related dry and/or stable conditions across much of the
central/eastern states will greatly limit thunderstorm potential
today, with two exceptions. One area will be across parts of the FL
Peninsula along/south of a cold front, where sufficient instability
may support isolated to scattered thunderstorms this afternoon in a
weak deep-layer shear environment. While gusty winds could occur
with the strongest cores that develop, overall severe potential is
expected to remain low. A second area of isolated thunderstorm
potential will exist across parts of southern AZ, on the northeast
periphery of a weak mid/upper-level low centered over the eastern
Pacific and Baja Peninsula.

..Gleason/Kerr.. 10/17/2026


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SPC Oct 17, 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
1214 AM CDT Sat Oct 17 2026

Valid 171200Z - 181200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not expected today.

...Synopsis...
In the wake of a cold frontal passage, much of the CONUS will be too
dry and stable for thunderstorm development today. The front will
continue moving southward along the central/southern FL Peninsula,
where scattered storm development will be possible within a very
moist environment. Poor lapse rates and weak deep-layer shear should
limit organized severe potential, though localized strong gusts may
occur. Across the Southwest, sporadic lightning flashes may
accompany weak convection associated with a slow-moving mid/upper
low centered offshore of Baja California.

..Dean/Chalmers.. 10/17/2026


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