SPC AC 161240

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0740 AM CDT Sun Mar 16 2025

   Valid 161300Z - 171200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR WESTERN
   INTO CENTRAL PENNSYLVANIA...

   ...SUMMARY...
   Sporadic damaging wind swaths and a few tornadoes will be the
   primary threats this morning through dusk across a broad portion of
   the East.

   ...OH Valley/northern Middle Atlantic...
   Water-vapor imagery this morning shows an upper trough over the MS
   Valley with an embedded mid-level vorticity maximum rotating
   northeastward over the lower OH Valley.  This mid-level feature will
   be accompanied by an intense belt of flow (110+ kt at 500 mb)
   shifting eastward across the upper OH Valley/central Appalachians
   through the day.  In the low levels, a surface low over southeast
   Lower MI will develop northward reaching the Quebec/Ontario border
   by late afternoon.  A moist/weakly unstable warm sector to the
   southeast of the low will only slightly destabilize through peak
   heating.  Yet, short-term model guidance indicates 200-500 J/kg
   MLCAPE will develop later this morning across the central
   Appalachians into the eastern OH/western PA border region.  A
   strongly forced band of convection is forecast to gradually evolve
   over the upper OH Valley.  Largely unidirectional southerly flow and
   elongated hodographs will support a risk for scattered damaging
   gusts (55-70 mph) and perhaps a couple of brief tornadoes with this
   activity.  The area of greatest model agreement for a convective
   line posing a risk for severe appears most likely/concentrated
   across western into central parts of PA.  Farther south, gradual
   intensification of convection within a weakly unstable airmass will
   support a risk for damaging gusts and perhaps a tornado or two
   through early evening.  

   ...Southeast...
   The southern portion of a mid-level trough will continue east
   through the lower MS Valley into the Southeast today, as a low-level
   jet steadily shifts east across north FL through much of SC by
   mid-late afternoon while gradually weakening south of North
   Carolina.  An ongoing broken band of pre-frontal strong to severe
   thunderstorms will move east into a weakly unstable airmass
   (reference the 12 UTC Charleston, SC raob).  Prior to a gradual
   weakening of 850-mb flow by early to mid afternoon, adequately
   enlarged hodographs within a destabilizing airmass (1000-1500 J/kg
   MLCAPE across north-central FL with considerably weaker instability
   over the coastal Carolinas) will support organized storms, including
   line segments (mainly north) and some supercells (south).  Scattered
   damaging gusts (55-70 mph) and a couple of tornadoes are possible as
   the severe threat shifts east through the period.

   ..Smith/Thompson.. 03/16/2025

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