RSS Mesoscale Discussions from Storm Prediction Center
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0117 AM CST Sat Dec 13 2025
Valid 151200Z - 161200Z
...NO THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Thunderstorms are not expected on Monday.
...Discussion...
Strong high pressure will dominate much of the eastern 2/3rds of the
CONUS on Monday with strong offshore flow into the Atlantic and the
Gulf, pushing rich moisture well offshore. Therefore, thunderstorm
activity is not expected across much of the CONUS. The only
exception may be across the Pacific Northwest coast where some weak
instability may develop. However, even within this area, lightning
activity should remain limited due to relatively warm air aloft.
..Bentley.. 12/13/2025
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0246 AM CST Sat Dec 13 2025
Valid 161200Z - 211200Z
...DISCUSSION...
Moisture return will begin on Tuesday/D4 across Texas with some weak
instability and thunderstorm potential arriving by Wednesday/D5.
Significant differences in the upper-level pattern begin on
Thursday/D6 and beyond which will significantly impact thunderstorm
and severe weather potential.
The ECMWF and AIFS have a sharper mid-level trough farther south on
Thursday/D6. This will result in a stronger cold front and farther
north moisture return ahead of the front. In addition, some weak
instability may develop beneath the stronger mid-level jet. This may
create an environment favorable for a few stronger storms from the
Lower Ohio Valley to the Mid-Mississippi Valley. This stronger
scenario would likely push a strong cold front deep into the Gulf on
Friday and limit thunderstorm potential into the weekend.
A less amplified solution (as shown by the GFS and AIGFS) would not
support much of any strong storm threat on Thursday/D6. However, it
would keep low to mid 60s dewpoints across Texas and the Lower MS
Valley on Friday and into the weekend. This may result in weak to
potentially moderate instability across portions of the southern
Plains and possibly into the Mid-Mississippi Valley through the
weekend. Despite this lingering instability, a mostly zonal
mid-level pattern would not support a significant severe weather
threat.
Overall, severe weather potential remains somewhat low for much of
the period. Some low-end severe weather threat may exist from
Thursday/D6 and beyond as low-level moisture increases, but
significant uncertainties in the evolution of the upper-level
pattern make any forecast for time or location of any potential
low-end threat difficult.
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