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

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.