SPC AC 270556

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1256 AM CDT Sat Mar 27 2021

   Valid 281200Z - 291200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE MID ATLANTIC...CAROLINAS AND SOUTHERN TO CENTRAL APPALACHIANS...

   ...SUMMARY...
   Strong to severe storms are possible from the Carolinas into the Mid
   Atlantic Sunday afternoon. A few strong to severe storms will also
   be possible from the central and southern Appalachians into parts of
   the Southeast.

   ...Carolinas/Mid-Atlantic/Southern and Central Appalachians...
   An upper-level trough will move eastward from the mid to upper
   Mississippi Valley into the Great Lakes and Ohio Valley on Sunday.
   At the surface, a cold front will advance quickly eastward across
   the central and southern Appalachians as a surface low deepens in
   southwest Ontario. By midday, the warm sector will be located across
   all of the Carolinas and Mid-Atlantic where surface dewpoints are
   forecast to be in the lower to mid 60s F. Convection is expected to
   develop along much of the front in the Ohio and Tennessee Valleys
   during the morning. Thunderstorm development will likely take place
   as the storms move eastward into the central and southern
   Appalachians. An isolated wind damage threat will be possible with
   the stronger line segments as the storms move into the higher
   elevations during the late morning into early afternoon.

   Further to the east, moisture advection will take place across the
   Mid Atlantic as a 50 to 60 kt low-level jet strengthens during the
   day. Warming surface temperatures will result in a corridor of
   instability from the eastern Carolinas northward into eastern
   Virginia, where MLCAPE is expected to reach the 500 to 1000 J/kg
   range. The storms in the central and southern Appalachian Mountains
   should move quickly eastward across the Appalachian Foothills during
   the mid afternoon, reaching the lower elevations near peak heating. 

   Forecast soundings along the instability axis from northern North
   Carolina into eastern Virginia at 21Z on Sunday have nearly
   unidirectional winds in the low to mid-levels with effective shear
   in the 60 to 70 knot range. In addition, 0-3 km lapse rates are
   forecast to peak near 7.5 C/km. This combined with about 40 kt of
   flow at 1 kilometer above ground should be favorable for damaging
   wind gusts. The fast moving nature of the storms could result in
   wind gusts above 65 knots along the leading edge of the stronger
   line segments. For this reason, a hatched significant wind contour
   has been maintained from parts of central and northern North
   Carolina northward into Virginia, Maryland and Delaware. In
   addition, the stronger cells in the line could rotate and have an
   isolated tornado threat. The line of storms is forecast to move
   offshore during the mid to late evening.

   ...Southeast...
   An upper-level trough will move eastward into the lower to mid
   Mississippi Valley today as a cold front advances southeastward into
   the Southeast. Ahead of the front, surface dewpoints will be in the
   mid to upper 60s F from parts of southern and central Mississippi
   northeastward across much of Alabama and Georgia. As surface heating
   warms, a narrow corridor of moderate instability may develop ahead
   of the front. Thunderstorms are expected to form along the front
   around midday as low-level convergence increases. Steep low-level
   lapse rates and strong deep-layer shear may be enough for a marginal
   wind damage and hail threat during the early to mid afternoon.

   ..Broyles.. 03/27/2021

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z