RSS Mesoscale Discussions from Storm Prediction Center
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0148 PM CST Sat Dec 13 2025
Valid 132000Z - 141200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected today or tonight.
...20z Update...
The previous forecast remains on track with only minor adjustments
may to the thunder line along the southern TX Gulf Coast where a
cold pool associated with offshore convection is spreading onshore.
Thunderstorm coverage is still expected to increase later this
afternoon/evening across southeast TX and southern LA, but the
potential for severe thunderstorms remains limited.
..Moore.. 12/13/2025
.PREV DISCUSSION... /ISSUED 1004 AM CST Sat Dec 13 2025/
...Southeast TX/Southwest LA...
Morning satellite loops confirm northward transport of low-level
moisture into parts of the southern Plains and lower MS Valley.
This trend will continue this afternoon and evening as a shallow
surface cold front sags southward through the region. Model
guidance suggests that weak but sufficient instability will develop
after dark from southeast TX into southwest LA to result in a few
pre-frontal thunderstorms. Shear is weak, and limited CAPE will
preclude organized severe storms. However, small hail is possible
in the strongest cores tonight.
...FL...
A low-latitude disturbance crossing the Gulf and a northward
moisture flux ahead of it will contribute to thunderstorm potential
across the Florida Keys/Florida Straits today, and also across the
southern Florida Peninsula tonight. Severe thunderstorms are
unlikely with these scenarios.
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0119 PM CST Sat Dec 13 2025
Valid 151200Z - 161200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Thunderstorms are not expected on Monday.
...Synopsis...
Upper ridging will build over much of the central and eastern CONUS
as a mid-level trough de-amplifies over the Pacific Northwest on
Monday. Surface high pressure will sweep across much of the southern
and eastern CONUS with a statically stable airmass, while a cold
and/or dry surface airmass encompasses much of the Plains into the
Interior West. As a result, thunderstorm development should be
negligible over most of the CONUS. The one exception may be over
portions of the Pacific Northwest Coastline. Here, the de-amplifying
ridge will aid in the advection of colder temperatures atop a marine
boundary layer. Given at least modest forcing for ascent and scant
buoyancy, a few lightning flashes may occur.
..Squitieri.. 12/13/2025
Read more
