RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0712 AM CDT Fri Mar 13 2026
Valid 131300Z - 141200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Organized severe thunderstorms are not expected.
...NY/PA...
a fast-moving and well-defined shortwave trough is indicated over
WI. This feature will track across the Great Lakes and affect parts
of PA/NY later this afternoon and evening. Strong low-level warm
advection and lift will aid in the development of showers and
isolated thunderstorms over southern Ontario and parts of
central/western NY/PA. While lightning activity will likely be
sparse, strong low-level winds and steepening mid-level lapse rates
could result in gusty showers and thunderstorms with isolated severe
winds possible.
...FL...
A few afternoon thunderstorms are expected today over central/south
FL, along and ahead of a surface cold front. Weak winds aloft
should preclude severe storms.
..Hart/Weinman.. 03/13/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0226 AM CDT Fri Mar 13 2026
Valid 151200Z - 161200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
ARKANSAS INTO INDIANA...
...SUMMARY...
Potential for a widespread damaging wind event along with a few
tornadoes exists from Sunday afternoon through Sunday night from
northeast Texas to southwest Lower Michigan. The greatest threat
appears to be from northeast Arkansas into Indiana during the
evening and overnight hours.
...Discussion...
On Sunday, a powerful upper trough will move across the Plains
during the day, with a strong midlevel speed max nosing into MO by
00Z. Shortly thereafter and over the next 12 hours, the trough will
rapidly deepen, with an intense mid and high level jet developing
across AR, MO, IL and IN.
At the surface, low pressure is forecast to move across northern MO
and into IL, with a prominent cold front extending southwestward
across MO western AR, and northeast TX. Low-level moisture quality
will gradually improve throughout the period, with mid 50s F into
southern MO by 00Z and as far north as IN and OH by 12Z Monday
morning.
Initial activity will occur along the cold front during the late
afternoon where instability will be strongest, perhaps as high as
1000 J/kg from AR into TX. It should be noted that substantial
variability exists among models regarding instability and capping,
though strong ascent near the front should mitigate these factors.
Hail and damaging gusts may occur with the late afternoon activity.
Of greatest concern is potential for a severe squall line capable of
widespread wind damage, along with a few tornadoes, developing
during the evening across northeast AR, southeast MO, much of
southern IL, central and southern IN, western KY and TN. The shear
environment will be rapidly increasing during this time, and while
forecast soundings show low levels of instability, it will be more
than sufficient to sustain a strongly forced QLCS, producing
corridors of significant wind damage and a few embedded tornadoes.
Southerly winds at 850 mb along the front may exceed 70 kt, with a
very strong frontal surge out of the west.
The envelope of greatest threat will likely shift in later outlooks
as the event nears and predictability increases.
..Jewell.. 03/13/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Fri Mar 13 2026
Valid 161200Z - 211200Z
...DISCUSSION...
Significant severe winds and the potential for a few tornadoes will
develop on Monday over parts of the Carolinas and Mid Atlantic.
Models are in good agreement with the large scale pattern on
Monday/D4, depicting a deep upper trough moving out of the
Mississippi Valley and ejecting in negative-tilt fashion across the
Mid Atlantic and into to the Northeast.
Given the antecedent upper ridging on the previous day, low-level
southerly winds will help to moisten the air mass well ahead of an
approaching cold front. By 12Z Monday, 60s F dewpoints will already
extend from northern GA across the Piedmont and into southeast VA,
and this plume of moisture will rapidly spread north with near 60 F
dewpoints into southeast PA by 00Z.
There appears to be two regimes for severe potential on Monday.
First, up to 1000 J/kg MUCAPE may develop well ahead of the
approaching cold front, and there is some indication that scattered
convection may occur across the warm sector from mid to late
afternoon. If this occurs, supercells would be most likely, with
potential for a few tornadoes from the Carolinas into eastern VA.
Models also indicate an elongated pressure fall/rise couplet, which
when combined with 50-70 kt 850 mb winds and extreme low-level
shear, could easily result in a QLCS along the cold front with
corridors of significant damaging winds and embedded tornado risk.
Beyond Monday/D4, stable air behind this system will likely preclude
any severe threat through Friday/D8.
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