Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0240 PM CDT Sun Oct 18 2026

Valid 182000Z - 191200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not forecast through tonight.

...20z Updates...

No changes are necessary for the Day 1 update. See previous
discussion below.

..Leitman.. 10/18/2026

.PREV DISCUSSION... /ISSUED 1114 AM CDT Sun Oct 18 2026/

...Synopsis...
Tranquil conditions will exist across much of the contiguous United
States through tonight.  Extensive surface high pressure influencing
much of the central and eastern U.S. will favor offshore flow into
the northern Gulf of America and feature a seasonably dry/stable
airmass.  A few weak thunderstorms are possible over south FL and
the Keys to the north of a surface front undergoing frontolysis
across the southern Gulf and FL Straits.  Farther west, an upper
trough migrating northeast across the Four Corners will be
associated with isolated showers/thunderstorms across parts of the
Southwest.

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1158 AM CDT Sun Oct 18 2026

Valid 191200Z - 201200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not expected on Monday.

...Synopsis...
An upper low will linger off the East Coast while an upper trough
amplifies just off the West Coast. Meanwhile, a leading wave will
affect the area from Baja CA into the Four Corners states.

Instability will be minimal over most of the CONUS due to an area of
high pressure, with the surface ridge extending from the Great
Lakes/Upper Midwest to the Gulf Coast. The exceptions will be near
the FL Keys where moist easterly winds will persist, supporting
scattered showers and a few thunderstorms, and over AZ and NM, where
midlevel moisture will support weak instability. In either case,
severe weather is not anticipated due to weak instability.

..Jewell.. 10/18/2026

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0207 PM CDT Sun Oct 18 2026

Valid 201200Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
No severe thunderstorms are expected on Tuesday.

...Synopsis...
A large upper trough is forecast to amplify just off the CA coast,
with increasing south/southwest winds aloft, as well as cooling
aloft near the coast overnight. To the east, minor height rises will
occur over the Plains, while an upper low meanders off the Mid
Atlantic coast.

At the surface, high pressure over the Upper Great Lakes and Ontario
will shift eastward, though the surface ridge will remain entrenched
into the Southern Plains. This will maintain stable conditions over
the central and eastern states.

General thunderstorm chances will be limited to parts of the
southwestern states in relation to the upper trough. Veering winds
with height and moderate deep-layer shear will develop over AZ and
NM as the upper trough amplified. However, forecast soundings show a
subsidence inversion above 500 mb during the day, which will limit
storm intensity. Overnight, elevated instability may increase as
cooling aloft occurs, with isolated storms still possible. Potential
should generally increase into Wednesday/D4 as the upper trough
strengthens.

..Jewell.. 10/18/2026