Storm Prediction Center Mesoscale Discussion 1707

   Mesoscale Discussion 1707
   NWS Storm Prediction Center Norman OK
   1205 PM CDT Fri Jul 18 2025

   Areas affected...2North Carolina into Virginia

   Concerning...Severe potential...Watch possible 

   Valid 181705Z - 181900Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Thunderstorms moving off the southern Appalachians will
   intensify as they move into North Carolina and Virginia and may
   produce several swaths of damaging wind. Watch issuance is expected
   in the coming hours to address this threat.

   DISCUSSION...Latest GOES imagery shows increasing depth and coverage
   of convective towers with occasional lightning flashes within a
   broad cumulus field within the southern Appalachians likely driven
   by a combination of increasing orographic ascent and weak lift ahead
   of a decaying MCV. Based on recent RAP mesoanalysis, modified
   forecast soundings, and areas of lingering low/mid-level stratus,
   some residual inhibition remains across the region, but this should
   quickly erode through 19 UTC as temperatures climb into the upper
   80s/low 90s. Thunderstorm development is expected around this time
   within/in proximity to the higher terrain as MLCIN is removed and
   glancing ascent ahead of a mid-level trough over the Great Lakes
   overspreads the region. 

   Moderate westerly mid-level flow will support storm propagation into
   VA/NC. The combination of warm surface temperatures and seasonably
   moist conditions downstream (dewpoints in the mid to upper 70s) will
   support MLCAPE values between 2000-3000 J/kg by peak heating.
   Consequently, thunderstorm should intensify as they move into this
   environment. GOES-derived wind estimates show 30-35 knot flow
   between 6-7 km AGL across northern VA, which appears to be slightly
   stronger than anticipated by recent forecast guidance and should be
   adequate for organized clusters, and perhaps a few organized
   discrete cells, given weak low-level winds. While a few instances of
   large hail are possible (mainly over central VA where mid-level flow
   is slightly stronger), the predominant threat should be
   damaging/severe winds given steepening near-surface lapse rates,
   high PWAT values, and 20-25 K theta-e deficits, which will all favor
   strong to severe downbursts. Damaging wind swaths should become more
   probable through mid/late afternoon as organized clusters begin to
   materialize. Watch issuance is expected in the coming hours to
   address this concern.

   ..Moore/Smith.. 07/18/2025

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...AKQ...LWX...RAH...RNK...GSP...MRX...

   LAT...LON   36378194 38437897 38587840 38577789 38437748 38157723
               37837699 37567687 37317681 36907684 36317719 35867766
               35707824 35607868 35587939 35648109 35728156 35898189
               36068204 36188208 36378194 

   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN